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  1. #1001
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    Quote Originally Posted by bdundee View Post
    Positive we are not talking about limiting but extending. Now if someone has 20mm of spacers limiting the travel by the bottom out bumpers on a 140 fork giving you only 120mm of travel but the same a2c of of 140 than yes removing said spacers would give you back all 140 and keeping the A2C the same. That being said they are not configured that way (as stated above) and have absolutely no idea why one would set up a fork like this that way. Now a lefty that's another story.
    Gotcha thanks, I just saw the a2c table above.

  2. #1002
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    My wife keeps bugging me that I swap parts between bike to make a rideable one lol....(only have 1 lefty)....

    Problem solved.
    Worldwide cyclery with 20% of coupon, along with 6% back from gear obsession. Couldn't pass it up.

    Now I need a new front wheel lol.

  3. #1003
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    Just experienced the second Mastodon. Sold the previous with my Mutz. The new mastodon is a STD set at 150. Want to say it that it is just up there with the best forks. So smooth so plush. I use it with the IRT kit set at 120-140psi and the shock at 72psi.

  4. #1004
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    Add my name to the long list of people praising the Mastodon!

    I have a 120mm EXT Pro. Mounted up on my medium BlackBorrow with no clearance issues. It did raise the front quite a bit, but I expected that. I also had to buy yet another Hope brake mount adapter, as this is the first fork I have had with a 180mm post mount.

    I never really had any beef with my Bluto, but it was getting tired,and I wanted a bit more travel. The Mastodon is much smoother than the Bluto, and so much beefier. Its exactly 1lb heavier than the Bluto, at 4.98 lbs.

    I'm a 250lb rider, and am still playing with the suspension settings. I have run just over 100 pounds of pressure and use all the travel on jumps and small drops to flat (2' or so). I am going to play around with the volume spaces to see if I can make it a bit more progressive.

    Manitou Mastodon?-20180116_170333.jpgManitou Mastodon?-20180110_222857.jpg

  5. #1005
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    Quote Originally Posted by 9GUY9 View Post
    I'm a 250lb rider, and am still playing with the suspension settings. I have run just over 100 pounds of pressure and use all the travel on jumps and small drops to flat (2' or so). I am going to play around with the volume spaces to see if I can make it a bit more progressive.
    I'm 255 and I run all 4 IVA tokens above the piston/seal. I then run 95 psi (on my Fox pump) and that seems to be a really good balance between bottoming resistance on jumps and plushness in the chatter. I run high speed all the way out and compression 2 clicks in. You might start around there..
    With the way the fork was stock (1 token above) it would blow through the whole stroke and I could feel it bottom out. With the 4 tokens above I never "feel" it bottom out but the o-ring says I'm using everything...

  6. #1006
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    Just a thought about the STD vs EXT fork option:

    Itís not generally necessary to buy the EXT version of the Mastodon because nearly all the existing fat and tall tires clear the STD crown and bridge.

    Even in those cases where the clearance is ďcloseĒ, the addition of a single 10mm spacer will provide a margin of safety without having an increase of 20mm in A to C.

  7. #1007
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    ive seen the "extended "version also advertised as 27.5,as opposed to 26-is this the case or have I misinterpreted it?Also anyone think the silver stanchioned versions of the mastodon would be a lesser preformer than the black stanchions? My bluto is black stanchioned and has stiction like a fat kid on a slippery dip.They are on sale here in Australia for 650 ($520) US free postage and are advertised as 27.5 or 26,hence my previous question.Thoughts please folks,cheers

  8. #1008
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    Quote Originally Posted by bikemad1 View Post
    ive seen the "extended "version also advertised as 27.5,as opposed to 26-is this the case or have I misinterpreted it?Also anyone think the silver stanchioned versions of the mastodon would be a lesser preformer than the black stanchions? My bluto is black stanchioned and has stiction like a fat kid on a slippery dip.They are on sale here in Australia for 650 ($520) US free postage and are advertised as 27.5 or 26,hence my previous question.Thoughts please folks,cheers
    The silver versions were OEM I believe....

  9. #1009
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    Not sure if this was asked before, is Mattoc IRT upgrade compatible with Mastodon pro forks?

  10. #1010
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    Yeah, I think that's how they are listed in some places.

    I have no idea about those silver stanchion'd Mastodon's, but in my experience there's a reason they are a different color and it probably ain't for looks; think price break.

    Nothing wrong with the Comp, I put one on my son's bike, but it is heavier and it is not going to be as well dampened as the Pro.

    Quote Originally Posted by bikemad1 View Post
    ive seen the "extended "version also advertised as 27.5,as opposed to 26-is this the case or have I misinterpreted it?Also anyone think the silver stanchioned versions of the mastodon would be a lesser preformer than the black stanchions? My bluto is black stanchioned and has stiction like a fat kid on a slippery dip.They are on sale here in Australia for 650 ($520) US free postage and are advertised as 27.5 or 26,hence my previous question.Thoughts please folks,cheers

  11. #1011
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    So do you think the silver stanchions would be worse from a preformace point of view?My X-fusion sweep on the front of my Trek Slash was super smooth with silver stanchions,better than a Yari I rode with the black anodised ones

  12. #1012
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    Quote Originally Posted by bikemad1 View Post
    So do you think the silver stanchions would be worse from a preformace point of view?My X-fusion sweep on the front of my Trek Slash was super smooth with silver stanchions,better than a Yari I rode with the black anodised ones
    The smoothness or lack of stiction has more to do with seals and internal design than the color of the stanchions.

  13. #1013
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    Headset keeps coming loose on every ride. LBS cannot diagnose.

    Manitou Mastodon Std Pro 120mm installed on Kona Wozo with Chris King headset. Previous fork installed was Fox 34 140 27.5 Plus Boost which worked great with this bike/headset and did not loosen.

    LBS has checked all parts of the headset, crown race, etc. They say the star nut keeps pulling loose. Tried a CK star nut. Tried a star nut that was 1"-1.125", tried one that was 1.125". Tried a compression plug and tightened it so hard it broke the bolt.

    Conjecture is that it has something to do with the inner diameter of the steer tube. They say maybe it's a warranty issue. Anyone know what the hell is going on?

  14. #1014
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    Quote Originally Posted by PCT View Post
    Headset keeps coming loose on every ride. LBS cannot diagnose.

    Manitou Mastodon Std Pro 120mm installed on Kona Wozo with Chris King headset. Previous fork installed was Fox 34 140 27.5 Plus Boost which worked great with this bike/headset and did not loosen.

    LBS has checked all parts of the headset, crown race, etc. They say the star nut keeps pulling loose. Tried a CK star nut. Tried a star nut that was 1"-1.125", tried one that was 1.125". Tried a compression plug and tightened it so hard it broke the bolt.

    Conjecture is that it has something to do with the inner diameter of the steer tube. They say maybe it's a warranty issue. Anyone know what the hell is going on?
    Star nut isn't what holds your headset together. It's for setting preload.

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  15. #1015
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    Quote Originally Posted by compengr View Post
    Star nut isn't what holds your headset together. It's for setting preload.

    Sent from my Pixel XL using Tapatalk
    Yeah I hear that once the preload and stem bolts are tightened, you can actually take off the cap. Maybe something is up with the stem or stem/steerer interface?

  16. #1016
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    Quote Originally Posted by PCT View Post
    Yeah I hear that once the preload and stem bolts are tightened, you can actually take off the cap. Maybe something is up with the stem or stem/steerer interface?
    Most likely.

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  17. #1017
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    Quote Originally Posted by PCT View Post
    Yeah I hear that once the preload and stem bolts are tightened, you can actually take off the cap. Maybe something is up with the stem or stem/steerer interface?
    Yes, this is a stem/headset problem. Check and clean all the clamping surfaces. Also check the headset has been assembled correctly.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
    www.dougal.co.nz Suspension setup & tuning.
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  18. #1018
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    Quote Originally Posted by Dougal View Post
    Yes, this is a stem/headset problem. Check and clean all the clamping surfaces. Also check the headset has been assembled correctly.
    LBS said they checked all the headset components.

    Will clean all clamping surfaces and try a different stem to see if that solves it...

  19. #1019
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    Take this for what it's worth.
    My headset kept getting loose on my first Mastodon upper. I noticed (but didn't measure to verify) that the steer tube looked like it was more inset (from the bottom). I ended up getting a new upper from Manitou and haven't had any problems since.

  20. #1020
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    Quote Originally Posted by KTMNealio View Post
    I ended up getting a new upper from Manitou and haven't had any problems since.
    This is super interesting. In 34 years mtbing, working as a professional wrench and obviously on my own stuff - the Mastodon is the only fork this happened to where I did the install myself. Interesting that there's three of us on the thread that it happened to too.

    My star nut keeps pulling out - micro by micro but sure enough. The stem is tight but after riding some (I do A LOT of long wheelies which I though was culprit) I get some subtle play.

    My next steps were to disassemble, reset the star nut and maybe rough up the steerer tube where the stem clamps. Now I wonder.

    Edit: you can actually see my post here on 12-7 talking about finding my HS loose; I later discovered that the starnut was indeed moving. just been tightening as matter of course and not taking the time to diagnose - but now I'm curious.

  21. #1021
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    Is the top of the steerer lower than the bottom of the cap? There typically needs to be 2-3mm of a gap there to allow for preload to be set properly. Only other thing that comes to mind...

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  22. #1022
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    Star nuts are for preload only, if your stem is not properly clamped on your steerer, the headset will loosen and the Star nut will get pulled out. Over torquing a star nut will also pull it out.

    There is nothing wrong with the fork.

    Quote Originally Posted by Carl Mega View Post
    This is super interesting. In 34 years mtbing, working as a professional wrench and obviously on my own stuff - the Mastodon is the only fork this happened to where I did the install myself. Interesting that there's three of us on the thread that it happened to too.

    My star nut keeps pulling out - micro by micro but sure enough. The stem is tight but after riding some (I do A LOT of long wheelies which I though was culprit) I get some subtle play.

    My next steps were to disassemble, reset the star nut and maybe rough up the steerer tube where the stem clamps. Now I wonder.

    Edit: you can actually see my post here on 12-7 talking about finding my HS loose; I later discovered that the starnut was indeed moving. just been tightening as matter of course and not taking the time to diagnose - but now I'm curious.

  23. #1023
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    Your LBS thinks the star nut keeps the headset tight? No mention of your stem, trying a different stem, etc...

    I think you should go to s different shop.

    Quote Originally Posted by PCT View Post
    Headset keeps coming loose on every ride. LBS cannot diagnose.

    Manitou Mastodon Std Pro 120mm installed on Kona Wozo with Chris King headset. Previous fork installed was Fox 34 140 27.5 Plus Boost which worked great with this bike/headset and did not loosen.

    LBS has checked all parts of the headset, crown race, etc. They say the star nut keeps pulling loose. Tried a CK star nut. Tried a star nut that was 1"-1.125", tried one that was 1.125". Tried a compression plug and tightened it so hard it broke the bolt.

    Conjecture is that it has something to do with the inner diameter of the steer tube. They say maybe it's a warranty issue. Anyone know what the hell is going on?

  24. #1024
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    Quote Originally Posted by compengr View Post
    Is the top of the steerer lower than the bottom of the cap? There typically needs to be 2-3mm of a gap there to allow for preload to be set properly. Only other thing that comes to mind...

    Sent from my Pixel XL using Tapatalk
    I've seen this on a few friends bikes, always the same thing, the steer tube was slightly too long. It might look like you have 1/8" when assembling, but then you preload, and depending how many spacers etc you have along with the stem, you can lose that gap and the bottom of the cap touches the top of the steer tube.
    Ride or two later, loose.

  25. #1025
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    Quote Originally Posted by Nurse Ben View Post
    Star nuts are for preload only, if your stem is not properly clamped on your steerer, the headset will loosen and the Star nut will get pulled out. Over torquing a star nut will also pull it out.

    There is nothing wrong with the fork.
    Preload is the difference between "loose" and "properly adjusted." Preload is not, as your post suggests, the process of getting the headset ready for the stem to be tightened. The bearing preload, aka, the force that keeps the headset properly adjusted, is applied and held there by the headset bolt/star nut. If the star nut is "pulling out," it is not properly installed or tight enough in the steerer tube.

    The stem has nothing to do with headset preload and does not have a fastener in any plane that would assist with maintaining bearing preload.

    If the star nut backs out of the steerer, the headset will not maintain proper preload regardless of if the stem is properly torqued or not.

    And a star nut is not "torqued" in any sense of the word. The bolt that tightens into the star nut is adjusted and tightened to create the proper preload. The bolt's torque is that which is necessary to create proper bearing preload, like a wheel bearing, not a particular torque setting.

    I suspect, as some above have suggested, that the steerer tube is too long and doesn't have enough spacers to actually achieve preload. Try a small additional spacer or replacing a small one with a slightly larger one and see if it solves your problem. If the headset cap is bottoming out on the steerer before it can pull the assembly together, you will have no preload and your headset will be too loose.

  26. #1026
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    Quote Originally Posted by Nurse Ben View Post
    Star nuts are for preload only, if your stem is not properly clamped on your steerer, the headset will loosen and the Star nut will get pulled out. Over torquing a star nut will also pull it out.

    There is nothing wrong with the fork.
    Yeah, I hear ya. But I've been through all the obvious stuff. Headset is dandy. The stem is clamped just fine torque-wise. The cap is seats as it should - with a gap; I even upsized an under spacer just to check - same.

    So I think you're missing the point. I need more of a look but my theory is the moving startnut is the symptom: the stem / steerer interface is not proper: eg: too slick, micro discrepancy undersized. Pull up on stem via handlebars - stem moves (cause the steerer is, say, too small) ever so slightly and exerts pressure on the top cap - over a couple of thousand times the nut wiggles loose - evah so slightly. My whole movement has only been a few mms but it's continually happened since I got the bike. Loosen the stem bolts and give 1/ 4turn (not over torqued) on the top cap bolt and all is right again - until it isn't.

    We'll see tho. As I said, this is odd.

  27. #1027
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    Quote Originally Posted by twodownzero View Post
    The stem has nothing to do with headset preload and does not have a fastener in any plane that would assist with maintaining bearing preload.
    You set the preload with the cap bolt and hold it by tightening the stem.

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  28. #1028
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    Quote Originally Posted by twodownzero View Post
    Preload is the difference between "loose" and "properly adjusted." Preload is not, as your post suggests, the process of getting the headset ready for the stem to be tightened. The bearing preload, aka, the force that keeps the headset properly adjusted, is applied and held there by the headset bolt/star nut. If the star nut is "pulling out," it is not properly installed or tight enough in the steerer tube.
    I like your post. This is will be an fun one to find out the real cause. I do think it is really, really interesting that 3 people have the same issue in one thread and one guy's magically went away with a new upper. It's a relatively obscure issue too - don't hear too much chatter about starnuts pulling loose. I'm not angling for a warranty or anything like that - just the mystery. I can't claim to be a perfect mechanic, so yeah, I could have made a mistake - everyone has - I do feel I went through pretty much the same and usual checks that your better than average bike shop would; I stopped short of getting out the calipers. I hope to eat crow and laugh at myself at some simple shit I missed.

  29. #1029
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    After you have snugged / preloaded the top cap and tightened the stem, have you ever removed the top cap to see how much space is under there, down to the steerer?

    Are there any marks on the bottom of your top cap?

    Have you tried a different stem? Is the metal between the pinch bolts bottoming out when the stem is tightened?

  30. #1030
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    Quote Originally Posted by Carl Mega View Post
    Yeah, I hear ya. But I've been through all the obvious stuff. Headset is dandy. The stem is clamped just fine torque-wise. The cap is seats as it should - with a gap; I even upsized an under spacer just to check - same.

    So I think you're missing the point. I need more of a look but my theory is the moving startnut is the symptom: the stem / steerer interface is not proper: eg: too slick, micro discrepancy undersized. Pull up on stem via handlebars - stem moves (cause the steerer is, say, too small) ever so slightly and exerts pressure on the top cap - over a couple of thousand times the nut wiggles loose - evah so slightly. My whole movement has only been a few mms but it's continually happened since I got the bike. Loosen the stem bolts and give 1/ 4turn (not over torqued) on the top cap bolt and all is right again - until it isn't.

    We'll see tho. As I said, this is odd.
    I would start examining the interface at this point. See if anything jumps out. Is the stem bore uniform? Can you measure the diameter of the steerer tube? I can measure mine if needed. Compare numbers.

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  31. #1031
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    Quote Originally Posted by compengr View Post
    I would start examining the interface at this point. See if anything jumps out. Is the stem bore uniform? Can you measure the diameter of the steerer tube? I can measure mine if needed. Compare numbers.

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    Ah - cool - thanks that'd be fun. Now that I'm curious, I'll take an ID/OD and re-check tomorrow. Appreciate it.

    B4 anyone asks again - I tried with two different top caps and under stem'd an extra few MMs spacers to be absolutely sure there is no way the top cap could touch the top of the steerer - miles away.

    Anyway - before I read of other ppl maybe having the same issue, I was leaning towards that perhaps I bungled the star nut install by maybe grabbing the wrong one off the work bench OR that I may have gotten heavy handed on the bolt when doing it on the trail - happened several times since tho and been very deliberate about treating that bolt nice

  32. #1032
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    When we your forks made and where did you buy them from, curious?
    I have one sitting on my kitchen table new in box. I can measure the steer tube as well.

  33. #1033
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    Brrrrrr. Braved the cold garage and did my recon. Ha. Good timing as I'm due for a run thru on this bike - by my counts since I built it in Nov: 75 mountain bike rides plus 45 days commuting. Yippee.

    Anyway - I think I'm ready to rule out the outer diameter as it was 28.7mm. The inner diameter is 25.45.

    When I got at it - I remembered why I really chose to swap top caps (and add spacers) - the Spank Spike one has a lot of depth (I put on a shallower depth CaneCreek one):

    Manitou Mastodon?-036.jpg

    Here you can see how much my starnut moved:

    Manitou Mastodon?-035.jpg

    The HS was fine. The stem was properly torqued. The finish on the steerer seems pretty consistent with any other. So was this just me over torquing the topcap bolt when I was on the trail thinking I just had a loose HS? Maybe but I certainly didn't go nuts on a mad wrench turning rage and it's gone a bit loose since I've been delicate with it. [Edit: I should add - likely I am at fault here but with things that are perplexing, there's usually two factors that are not immediately apparent & related - eg: I suspect I had a crappy stem/top cap install at first but may be also true that this steerer isn't as secure w/ it's starnut grasp so what would normally be a tolerable amount of preload (but high) results in it moving some]

    So at this point, I'm just going to:

    • Cut the steerer to my final length
    • Reset the star nut
    • Clean steerer & stem clamping surfaces
    • re-assemble keeping eye on torque, etc
    • Ride the hell out of it and report back


    Cheers.

    Edit: Got the fork from WorldWide Cyclerly - everything built up beginning of Nov. It's a Std Comp.

  34. #1034
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    Quote Originally Posted by Carl Mega View Post
    Brrrrrr. Braved the cold garage and did my recon. Ha. Good timing as I'm due for a run thru on this bike - by my counts since I built it in Nov: 75 mountain bike rides plus 45 days commuting. Yippee.

    Anyway - I think I'm ready to rule out the outer diameter as it was 28.7mm. The inner diameter is 25.45.

    When I got at it - I remembered why I really chose to swap top caps (and add spacers) - the Spank Spike one has a lot of depth (I put on a shallower depth CaneCreek one):

    Click image for larger version. 

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    Here you can see how much my starnut moved:

    Click image for larger version. 

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ID:	1179306

    The HS was fine. The stem was properly torqued. The finish on the steerer seems pretty consistent with any other. So was this just me over torquing the topcap bolt when I was on the trail thinking I just had a loose HS? Maybe but I certainly didn't go nuts on a mad wrench turning rage and it's gone a bit loose since I've been delicate with it. [Edit: I should add - likely I am at fault here but with things that are perplexing, there's usually two factors that are not immediately apparent & related - eg: I suspect I had a crappy stem/top cap install at first but may be also true that this steerer isn't as secure w/ it's starnut grasp so what would normally be a tolerable amount of preload (but high) results in it moving some]

    So at this point, I'm just going to:

    • Cut the steerer to my final length
    • Reset the star nut
    • Clean steerer & stem clamping surfaces
    • re-assemble keeping eye on torque, etc
    • Ride the hell out of it and report back


    Cheers.

    Edit: Got the fork from WorldWide Cyclerly - everything built up beginning of Nov. It's a Std Comp.
    Very interesting stuff. Staying tuned for details.

    I am running out of time before Crested Butte and planning to run my Fox 34 for the weekend. Fits a 4.6 Flowbeist on Marge Lite. Handing the Mastodon back over to LBS and hopefully they can figure something out. Maybe warranty the upper, who knows. Purchased from Worldwide also. Would be interesting to get calipers on steer tube inner/outer diameters. Disappointed but surely there is a reasonable solution.

  35. #1035
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    Plenty of people have this problem because they misunderstand the purpose of the star nut.

    The star nut could never contribute to headset retention because it simply isn't designed for that purpose;, ie it will pull out of the steerer when enough tension is applied.

    Star nuts are only used for preload. Once you have established preload, the stem cinch bolts are tightened and thus preload is maintained.

    If you're headset loosens, there are a few different causes:

    1) the bearings/headset is installed incorrectly.
    2) the preload was insufficient
    3) the stem clamping force is inadequate

    Things to rule out:

    1) are the headset cups installed flush and square in the frame
    2) are the bearings straight and setting properly in the cups
    3) do you have enough spacer height above the steerer to preven the top cap from bottoming against the steerer
    4) is your stem wore out, clamping surface overly polished, etc...

    Once again, there is no way that a star nut can have anything to do with a headset loosening.

  36. #1036
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    This is below statment is untrue.

    The purpose of a star nut is to establish preload. The stemp clamping force maintains preload.

    Once the stem is clamped, you could remove the top cap and preload would be maintained.

    If the stem loosens, the star nut will pull out because it is not sufficiently strong to retain the preload.

    The key to a headset that loosens while riding is inadequte stem clamping force.

    Quote Originally Posted by twodownzero View Post
    Preload is the difference between "loose" and "properly adjusted." Preload is not, as your post suggests, the process of getting the headset ready for the stem to be tightened. The bearing preload, aka, the force that keeps the headset properly adjusted, is applied and held there by the headset bolt/star nut. If the star nut is "pulling out," it is not properly installed or tight enough in the steerer tube.

    The stem has nothing to do with headset preload and does not have a fastener in any plane that would assist with maintaining bearing preload.

    If the star nut backs out of the steerer, the headset will not maintain proper preload regardless of if the stem is properly torqued or not.

    And a star nut is not "torqued" in any sense of the word. The bolt that tightens into the star nut is adjusted and tightened to create the proper preload. The bolt's torque is that which is necessary to create proper bearing preload, like a wheel bearing, not a particular torque setting.

    I suspect, as some above have suggested, that the steerer tube is too long and doesn't have enough spacers to actually achieve preload. Try a small additional spacer or replacing a small one with a slightly larger one and see if it solves your problem. If the headset cap is bottoming out on the steerer before it can pull the assembly together, you will have no preload and your headset will be too loose.

  37. #1037
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    Quote Originally Posted by Nurse Ben View Post
    If you're headset loosens, there are a few different causes:

    1) the bearings/headset is installed incorrectly.
    2) the preload was insufficient
    3) the stem clamping force is inadequate

    Things to rule out:

    1) are the headset cups installed flush and square in the frame
    2) are the bearings straight and setting properly in the cups
    3) do you have enough spacer height above the steerer to preven the top cap from bottoming against the steerer
    4) is your stem wore out, clamping surface overly polished, etc...

    Once again, there is no way that a star nut can have anything to do with a headset loosening.
    1 Check - perfect
    2 Check
    3 Check - unless there's a defect in stem or steerer tolerances, 100% no doubt fine

    &

    1 again perfect
    2 again perfect
    3 as detailed, plenty of room
    4 new stem bought when did the build but nothing obviously wrong - it could be a finicky fit here tho - steerer slightly slick, stem interface slick or out of spec or poor clamping force be it design or mfging

    Quote Originally Posted by Nurse Ben View Post
    Once again, there is no way that a star nut can have anything to do with a headset loosening.
    I'll speak for myself here - but I don't think that's exactly what's being alleged by anyone. This is a clue, a symptom of something out of spec/tolerance. spit balling - steerers that are undersized, whose surface has crappy tolerances for clamping, out of round, wrong inner diameter, deforms excessively under load, material too soft or too hard for press fitting of a star nut... or maybe the stem(s) the culprit for roughly the same reasons or just enough of an issue when the two are paired together...Or just a coincidence and off day (2 months?) of wrenching.

    Hubris is my blindspot here - I sort of cringe that I overlooked something in the assembly. I've set 100s of starnuts, no doubt built over 1000 bikes. Diagnosed a mountain's worth of headset issues working at shops. Never happened on one of mine before. Figured out I had an issue - made a point to ensure top-cap seated as it should and that the stem was torqued - yadda yadda yadda. Yet, with this bike it still happened again and again and lo and behold there are 3 other ppl too - as I said - interesting. I'd like to think that if it were a normal thing, I'd see it. Maybe not - I'm getting old and could be grasping.

    Edit: Since I'm being all caffeinated & long winded, this "loose" headset is not like one where you can feel it rock back and forth or grab the HS bearing covers and feel it move. It's very, very subtle and it actually feels more like there's crappy bushing overlap/tolerance in the fork itself. If you are sensitive enough, you'll feel it on the trail when you unweight for rock gardens or put the front wheel down. It takes a deft hand to even feel it rocking the bike with the front brake applied - however, you can 100% tell when you make it go away by micro adjustment and riding again. It's right at the edge.

  38. #1038
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    Quote Originally Posted by compengr View Post
    You set the preload with the cap bolt and hold it by tightening the stem.

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    No. The stem might create some friction with the steerer, but it is the cap bolt that holds the preload, not the stem. Even if the stem is so loose as to be sloppy, a properly tightened cap bolt will hold the preload right where it's supposed to be.

  39. #1039
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    Quote Originally Posted by twodownzero View Post
    No. The stem might create some friction with the steerer, but it is the cap bolt that holds the preload, not the stem. Even if the stem is so loose as to be sloppy, a properly tightened cap bolt will hold the preload right where it's supposed to be.
    Sorry, have to disagree. I'm 99.99% sure

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  40. #1040
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    Quote Originally Posted by Nurse Ben View Post
    This is below statment is untrue.

    The purpose of a star nut is to establish preload. The stemp clamping force maintains preload.

    Once the stem is clamped, you could remove the top cap and preload would be maintained.

    If the stem loosens, the star nut will pull out because it is not sufficiently strong to retain the preload.

    The key to a headset that loosens while riding is inadequte stem clamping force.
    You are misinformed about the nature of the relationship between the stem and bearing preload. The stem does not maintain the bearing preload. You won't find any assembly where a fastener in another plane holds a bearing's preload.

    I've got news for you--the nut on your front wheel bearing holds the bearing preload. Not the tire you bolt on afterward, not the cotter pin that prevents vibration loosening, and not the hub cap that prevents dirt from entering. It's the nut--the one you tighten to adjust the bearing preload--that holds the bearings in the correct place while they work.

    I understand what you're trying to say and while you believe that, but you're still wrong. The cap bolt has plenty of strength to hold the assembly together. In fact, a properly installed star nut should either swell the steerer tube or break the bolt or both before it pulls the star nut out.

    The clamping force of the fasteners certainly creates friction between the stem and the steerer, but even if the stem is loose, preload is maintained by the cap bolt.

  41. #1041
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    This may not be the exact situation, but I have had something similar happen. I have 2 Jamis XCT3 Carbon 26ers from 2011. It was my main ride at the time and is now my sons and the other now my gravel bike. On the one that saw more use I had a constant problem with the headset loosening up and racked my brains like the OP. I could put fingernail in-between the gap of the headset top bearing cover and the frame (IS headset) and I had no rubbing on the cap, but the loosening persisted. I read in a prior post on MTBR that although I thought there was enough gap between the bearing cap and the bearing/frame interface there was not. I bought FSA micro-spacers and 2 .25mm on just under the bearing cap. The problem has been gone for over 2 years with no other changes. If you exhaust all other resources, that may work. Here is a link to them:

    FSA Headset Microspacers | Jenson USA

  42. #1042
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    No dude, I am not misinformed, the star nut is a simple mechanism, it is not rocket science. Ask any trained professional bike mechanic and they will explain it to you.

    https://www.parktool.com/blog/repair...icle-section-7

    "NOTE: The cap and bolt at the top of the stem do not secure the stem onto the steering column. The bolt or bolts on the side of the stem keep the stem from moving once the adjustment is made. The cap is used for bearing adjustment only."

    Your wheel bearing comparison is fraught with misunderstanding as well, but no need to go into that too.

    Feel free to disagree and good luck using a star nut to keep your headset tight.

    Quote Originally Posted by twodownzero View Post
    You are misinformed about the nature of the relationship between the stem and bearing preload. The stem does not maintain the bearing preload. You won't find any assembly where a fastener in another plane holds a bearing's preload.

    I've got news for you--the nut on your front wheel bearing holds the bearing preload. Not the tire you bolt on afterward, not the cotter pin that prevents vibration loosening, and not the hub cap that prevents dirt from entering. It's the nut--the one you tighten to adjust the bearing preload--that holds the bearings in the correct place while they work.

    I understand what you're trying to say and while you believe that, but you're still wrong. The cap bolt has plenty of strength to hold the assembly together. In fact, a properly installed star nut should either swell the steerer tube or break the bolt or both before it pulls the star nut out.

    The clamping force of the fasteners certainly creates friction between the stem and the steerer, but even if the stem is loose, preload is maintained by the cap bolt.

  43. #1043
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    Quote Originally Posted by twodownzero View Post
    You are misinformed about the nature of the relationship between the stem and bearing preload. The stem does not maintain the bearing preload. You won't find any assembly where a fastener in another plane holds a bearing's preload.
    I'm not an ME but Shimano Hollowtech cranks seem to fit the bill. Plastic preload nut, then the crank arm is clamped down (much the same way a stem is) to hold the arm's position on the spindle plane.

    In both cases the preload force is applied in the correct plane, only the clamping mechanism that maintains the force (in the preload plane) is in a separate plane. Remove the step cap after clamping down the stem and the same preload force remains.

  44. #1044
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    Thanks David, but all the engineers in the group already know the answer. I only have a couple years of engineering under my belt, but I know how things work.

    Honestly, I'm kind of suprised that so much misinformation exists on such a simple mechanism. No wonder people have a hard time with tubeless.

    On a bright note, it keeps the LBS in business

    Quote Originally Posted by david.p View Post
    I'm not an ME but Shimano Hollowtech cranks seem to fit the bill. Plastic preload nut, then the crank arm is clamped down (much the same way a stem is) to hold the arm's position on the spindle plane.

    In both cases the preload force is applied in the correct plane, only the clamping mechanism that maintains the force (in the preload plane) is in a separate plane. Remove the step cap after clamping down the stem and the same preload force remains.

  45. #1045
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    Quote Originally Posted by Nurse Ben View Post
    On a bright note, it keeps the LBS in business
    Best thing I've read here.

    What's up Carl?

  46. #1046
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    Quote Originally Posted by BIke N Gear View Post
    Best thing I've read here.

    What's up Carl?
    Ben does get it right with that one.

    I'm doing great Gary and so happy to hear from you; you've been in my thoughts more than a few times - shoot me a PM will ya?!

  47. #1047
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    Quote Originally Posted by david.p View Post
    I'm not an ME but Shimano Hollowtech cranks seem to fit the bill. Plastic preload nut, then the crank arm is clamped down (much the same way a stem is) to hold the arm's position on the spindle plane.

    In both cases the preload force is applied in the correct plane, only the clamping mechanism that maintains the force (in the preload plane) is in a separate plane. Remove the step cap after clamping down the stem and the same preload force remains.
    Those are splined. The bolt as clamp creates an interference fit by tightening the splined connection. It isn't the same.

    Removing the spacers or cap after tightening the stem would result in only the friction between the smooth stem and steerer holding the assembly together.

    The other way to think about it is what the star nut replaced. The star nut replaced the nut on a threaded steerer--a nut that unquestionably held the bearing preload just like a wheel bearing nut does.

    Your quote from Park is no more instructive. What it says is that the headset spacers and cap bolt do not hold the stem in place. I never argued that was the case, and in fact, that is also wrong for the same reason that the cap bolt does hold the bearing preloaded. The stem bolts create clamping force in a horizontal plane. That clamping force holds the stem in position laterally. The stack of spacers and cap bolt hold the bearings in their races vertically.

    The stem could be entirely missing from the bike and replaced with a stack of headset spacers and headset preload could still be proper. There would be no handlebar to turn the fork and the bike would be basically useless in that condition, but headset preload would be correct.

    As I said earlier, it seems you've created a complex explanation regarding how preload is maintained that is simply not correct. Bearing preload comes from the cap bolt. The friction between the stem and the steerer keeps the front wheel and handlebar perpendicular to each other (aka, alignment). While in theory that same friction assists in preventing the steerer from moving in the vertical plane, that is not how preload is maintained.

    If you don't believe me, there is a simple way to experiment with this. Properly tighten the headset cap with the stem loose. Then align and tighten the stem. Once that is completed, remove the headset cap and go for a ride. It won't take long before your headset will be loose. Without the cap bolt and spacer stack to maintain the bearing preload, the stem/steerer interface will slip vertically and you will have headset slop. There just isn't enough clamping force from the stem to maintain the vertical preloading of the bearings with only the friction between stem and the steerer. If your theory were correct, the stem could maintain headset bearing preload indefinitely even without the headset cap. In reality, one good bounce and the steerer will slip enough to create bearing slop.

    My wheel bearing nut analogy is absolutely no different. In the days of threaded steerers, the nut held the bearing preload just like a wheel bearing nut does. Nothing changed with the introduction of a star nut other than that threadless steerers became possible.

  48. #1048
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    Why don't we help out with the headset loosening issue first. Once we get that out of the way, we can go back to arguing why the stem is what (and it does) holds the preload in place.

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  49. #1049
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    Luckily the Turbine stem had cutouts which made it easy to measure the steerer diameter (28.70mm). Mine is a Mastodon Pro Std, also purchased from Worldwide a little over a month ago. Cane Creek 40 headset (IS) in a Salsa Mukluk. I'm using a compression nut in place of a star nut.

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  50. #1050
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    Wait a minute. One poster stringing along multiple posters by arguing against established and empirically proven facts in long drawn out posts based on nonsensical logic... Troll of the year? Gah.

    Back on topic - I experienced some headset loosening within the first few rides with my Mastodon. I believe that adding a larger spacer on top of the stem took care of it, but I may go back and check for the minute play Carl mentioned.

  51. #1051
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    I'm hoping for a brilliant troll but have some doubts. Either way its very entertaining.

  52. #1052
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    Quote Originally Posted by twodownzero View Post
    No. The stem might create some friction with the steerer, but it is the cap bolt that holds the preload, not the stem. Even if the stem is so loose as to be sloppy, a properly tightened cap bolt will hold the preload right where it's supposed to be.
    OK, you go ride with a loose stem, see how long your top cap keeps everything together lol.

    I have ridden without a top cap before, and with missing spacers above the stem (after the preload was set correctly). The stem holds everything together.

    Sorry but you are wrong or not understanding...

  53. #1053
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    twodownzero isn't wrong. I got a RS1 from a guy who parted his Camber and it came with a SWAT plug thingee. I didn't want to pay the $30 or so to get the cap and tool, so thought to borrow a cap and bolt from another Spec bike (to tighten mine, and return the bolt and cap). Went for a ride and headset came loose mid-ride. Didn't want to pay for a new headset either, so I aborted the ride. Stem slipped vertically, but was still aligned with the front wheel.
    We're all on the same ship, and it's sinking.

  54. #1054
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    Since we can't seem to stop beating this dead horse, I wonder how the seatpost stays in place. It's clamped much the same way as a steerer tube. Is it magic?

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  55. #1055
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    Seeing as reality appears to be skewed on this thread, I vote for magic.

    Quote Originally Posted by compengr View Post
    Since we can't seem to stop beating this dead horse, I wonder how the seatpost stays in place. It's clamped much the same way as a steerer tube. Is it magic?

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  56. #1056
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    Yep magic trolls darnit.

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    Quote Originally Posted by compengr View Post
    Since we can't seem to stop beating this dead horse, I wonder how the seatpost stays in place. It's clamped much the same way as a steerer tube. Is it magic?

    Sent from my Pixel XL using Tapatalk
    What part of your seat tube involves properly preloading bearings in the vertical plane? Does your seat tube magically spin about the seat post on these bearings, and does their adjustment somehow change your enjoyment of the bike? Or is it trolling to point out that there are no bearings or races involved in that assembly?

    The experiment to confirm my theory is simple:

    1. The poster complaining that his headset is coming loose can install a taller spacer and observe that once the assembly is put together correctly (which I certainly agree involves loosening the stem, tightening headset cap, aligning stem/bars, and torquing stem), the headset stops coming loose.

    and

    2. Those of you who doubt me can remove or loosen your headset cap and go for a ride and wait for your headset to come loose. It shouldn't take more than a turn or two to observe this. I can't predict how long it'll take the stem to slip on the smooth steerer, but I would bet that it will.

    While you all are doing that, I'll continue to try to think of a set of bearings loaded similarly to a headset that do not use a fastener or some kind of interference fit in the same plane as preload is required. None come to mind at the moment.

    Note also that I'm not denying that the friction fit between the stem and steerer provides some resistance from the steerer tube slipping downward and thus the preload loosening, just that it's insufficient to accomplish the task in the absence of the cap bolt. The headset cap bolt is capable of doing so because so long as the star nut is properly installed, the stretching of the cap bolt physically holds the dimension between the headset cap and the fork within the range of dimensions that we regard as "proper" preload, and it can do so with or without a stem installed.

    In my experience, I've never observed a star nut that moved upward in the tube after being properly installed. The ones I've worked with were capable of putting far more preload than necessary on the headset bearings. In fact, I'm quite confident I could go out to my garage right now and either break those bolts or damage the headset bearings/races or both by overtightening them--they have that much power over the headset bearing preload. I could probably accomplish that same damage without loosening the stem as well, but I guess it'd depend on how strong the bolt is in tension, how good a "bite" the star nut actually has, and how much friction a properly torqued stem creates--all facts that I admittedly don't have at my fingertips. I bet I could tighten it enough to make it difficult to turn the handlebar even without breaking anything, which is itself a demonstration of my point. The stem alone simply cannot hold the whole assembly tight indefinitely.

  58. #1058
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    Quote Originally Posted by Carl Mega View Post
    1 Check - perfect
    2 Check
    3 Check - unless there's a defect in stem or steerer tolerances, 100% no doubt fine

    &

    1 again perfect
    2 again perfect
    3 as detailed, plenty of room
    4 new stem bought when did the build but nothing obviously wrong - it could be a finicky fit here tho - steerer slightly slick, stem interface slick or out of spec or poor clamping force be it design or mfging



    I'll speak for myself here - but I don't think that's exactly what's being alleged by anyone. This is a clue, a symptom of something out of spec/tolerance. spit balling - steerers that are undersized, whose surface has crappy tolerances for clamping, out of round, wrong inner diameter, deforms excessively under load, material too soft or too hard for press fitting of a star nut... or maybe the stem(s) the culprit for roughly the same reasons or just enough of an issue when the two are paired together...Or just a coincidence and off day (2 months?) of wrenching.

    Hubris is my blindspot here - I sort of cringe that I overlooked something in the assembly. I've set 100s of starnuts, no doubt built over 1000 bikes. Diagnosed a mountain's worth of headset issues working at shops. Never happened on one of mine before. Figured out I had an issue - made a point to ensure top-cap seated as it should and that the stem was torqued - yadda yadda yadda. Yet, with this bike it still happened again and again and lo and behold there are 3 other ppl too - as I said - interesting. I'd like to think that if it were a normal thing, I'd see it. Maybe not - I'm getting old and could be grasping.

    Edit: Since I'm being all caffeinated & long winded, this "loose" headset is not like one where you can feel it rock back and forth or grab the HS bearing covers and feel it move. It's very, very subtle and it actually feels more like there's crappy bushing overlap/tolerance in the fork itself. If you are sensitive enough, you'll feel it on the trail when you unweight for rock gardens or put the front wheel down. It takes a deft hand to even feel it rocking the bike with the front brake applied - however, you can 100% tell when you make it go away by micro adjustment and riding again. It's right at the edge.
    That description would fit my Bluto well- I couldnít articulate it but your description is exactly what I would say my Bluto does- hence the reason I want to get a Mastodon

  59. #1059
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    So I contacted Manitou in regards to the silver stanchioned Mastodon. They confirmed it was their product and it was an OE product, not aftermarket. Iím assuming that they were made for a particular fatbike company, but as far as I can tell they are the same fork so I think I will take a punt on them

  60. #1060
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    The problem can be in the steerer tube of the mastodon.

    If the fork is ridden with top cap and preload bolt removed after proper headset/stem setup, the starnut will not move upward, because there is no leverage of the top cap bolt to bring it up.

    If the starnut is moving upward, so is stem too. So stem is slipping in steerer tube.

    Outside diameter of the steerer tube is too small or/and stem clamping diameter is too large or/and steerer tube inner diameter is too large.

  61. #1061
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    Quote Originally Posted by twodownzero View Post
    What part of your seat tube involves properly preloading bearings in the vertical plane? Does your seat tube magically spin about the seat post on these bearings, and does their adjustment somehow change your enjoyment of the bike? Or is it trolling to point out that there are no bearings or races involved in that assembly?
    If you can't see the similarity between how the seatpost and steerer tube are held in place...then I'm not sure I can help you. (Hint: they are both clamped horizontally but see vertical forces)

    Also, look at the construction of the top cap/star nut assembly. Now, look at the surface area of the stem-steerer tube interface. Which one do you think was designed to carry loads? Which one will have a higher loading capacity?

    Let's look at the expanding wedge nut design, like Hope Head Doctor. It works on the same principle as the stem; clamping onto the steerer tube from the inside to set the bearing preload. What do you think will be able to stand up to greater loads, the stem, which clamps onto a larger diameter and has a significantly greater surface area on the steerer tube, or the wedge on the Hope device?

    Oh, while looking at the OneUp EDC tool, I saw this video . Go to 2:50.

  62. #1062
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    Quote Originally Posted by forward View Post
    The problem can be in the steerer tube of the mastodon.

    If the fork is ridden with top cap and preload bolt removed after proper headset/stem setup, the starnut will not move upward, because there is no leverage of the top cap bolt to bring it up.

    If the starnut is moving upward, so is stem too. So stem is slipping in steerer tube.

    Outside diameter of the steerer tube is too small or/and stem clamping diameter is too large or/and steerer tube inner diameter is too large.
    ^This is my guess too. Planning to put some calipers on the steerer tube inner/outer diameters, and also swap in a different stem to see if that helps. May be possible that certain steerer tubes were out of spec, that would explain why replacing the upper has solved certain instances of the problem. What a pain.

  63. #1063
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    Quote Originally Posted by forward View Post
    The problem can be in the steerer tube of the mastodon.

    If the fork is ridden with top cap and preload bolt removed after proper headset/stem setup, the starnut will not move upward, because there is no leverage of the top cap bolt to bring it up.

    If the starnut is moving upward, so is stem too. So stem is slipping in steerer tube.

    Outside diameter of the steerer tube is too small or/and stem clamping diameter is too large or/and steerer tube inner diameter is too large.
    If you're right and the stem is the right size, then the stem is potentially not tight enough. Generally I use a torque wrench for this because I'm anal.

  64. #1064
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    Without digging through the whole thread, does anyone have calipered/measured width of the Mastodon at the crown/top of the legs?

    Curious if I can pull off a Mastodon on my fatty, if I decide to move to wider than my Magnum Pro will handle.
    "I ride to clear my head, my head is clearer when I'm riding SS. Therefore, I choose to ride SS."~ Fullrange Drew

  65. #1065
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    Quote Originally Posted by nitrousjunky View Post
    Without digging through the whole thread, does anyone have calipered/measured width of the Mastodon at the crown/top of the legs?

    Curious if I can pull off a Mastodon on my fatty, if I decide to move to wider than my Magnum Pro will handle.
    The compression adjustment knob seems to be biggest issue.


    I measured about 114mm from center of fork to the edge of the dial (pic didn't turn out) and 14mm from top of crown.


    Hope that helps.

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  66. #1066
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    Quote Originally Posted by compengr View Post
    I measured about 114mm from center of fork to the edge of the dial (pic didn't turn out) and 14mm from top of crown.
    Hope that helps.

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    That definitely helps, much appreciated!
    "I ride to clear my head, my head is clearer when I'm riding SS. Therefore, I choose to ride SS."~ Fullrange Drew

  67. #1067
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    Quote Originally Posted by compengr View Post
    Luckily the Turbine stem had cutouts which made it easy to measure the steerer diameter (28.70mm). Mine is a Mastodon Pro Std, also purchased from Worldwide a little over a month ago. Cane Creek 40 headset (IS) in a Salsa Mukluk. I'm using a compression nut in place of a star nut.

    Sent from my Pixel XL using Tapatalk
    Adding info here from mine (brand new not installed) also from worldwide cyclery, std pro.

    Outside steer 28.4mm
    Inside steer 25.25mm

  68. #1068
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  69. #1069
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    Quote Originally Posted by Nurse Ben View Post
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    Ha - if AKRider knew it'd only take posting some measurements, he'd have measured every part of his bike and probably a few extra for good measure in the "Tubeless overrated" thread.

  70. #1070
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    I have a little info to add to the whole steer tube issue.
    What you donít see in that EDC cap video is they have a go/no go gauge that is supplied with the cap and installation kit. If the no go end drops into the steer tube, you can NOT install the EDC cap on the fork. Simply because the inner diameter of the steer tube is too large and there isnít enough material to get full threads.
    I purchased a EDC cap kit for my 2017 Magnum Pro 27.5+ fork, however the inner diameter was too large (no go end went in the steer tube). Therefore I returned the EDC cap.
    "I ride to clear my head, my head is clearer when I'm riding SS. Therefore, I choose to ride SS."~ Fullrange Drew

  71. #1071
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    Will a King Cage top cap work with the Mastodon? What if I use the Wolftooth B-Rad with it? Will my headset come loose? Asking for a friend.
    Manitou Mastodon?-king.jpg
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  72. #1072
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    Quote Originally Posted by Co-opski View Post
    Will a King Cage top cap work with the Mastodon? What if I use the Wolftooth B-Rad with it?
    Heh - Mastodon level thirst!

    3 mtn rides & 3 commutes in; things are peachy so far for those who care. Starnut not replaced just reset lower as I cut off some excess steerer off. Cleaned all surfaces with alcohol. Otherwise, everything was installed the same as before: hs, steerer bolt & stem bolts at the same and proper torque/adjustment.

    Btw - I'm pretty happy to stand on the shoulders of all those early adopter Fat bikers who dealt w/ lesser forks cause their experiences led to the Mastodon which is a pretty solid product.

  73. #1073
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    Just ordered a Pro 120 standard for my Canyon Dude. Currently running JJ 4.0s but like that I would have space for 4.8s in the future.


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    2018 Canyon Dude fatty with Mastodon

  74. #1074
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    I just pulled my fork off my fatboy.
    It's up for sale $600 or $800 with wheel (hope hub,spec rim)

  75. #1075
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    Quote Originally Posted by nitrousjunky View Post
    I purchased a EDC cap kit for my 2017 Magnum Pro 27.5+ fork, however the inner diameter was too large (no go end went in the steer tube).
    And it's the same with the Mastodon. I don't have my measurement on hand but it was quite a bit larger than the maximum 24.80 mm specified for the EDC cap.

  76. #1076
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    Quote Originally Posted by bikemad1 View Post
    ive seen the "extended "version also advertised as 27.5,as opposed to 26-is this the case or have I misinterpreted it?Also anyone think the silver stanchioned versions of the mastodon would be a lesser preformer than the black stanchions? My bluto is black stanchioned and has stiction like a fat kid on a slippery dip.They are on sale here in Australia for 650 ($520) US free postage and are advertised as 27.5 or 26,hence my previous question.Thoughts please folks,cheers
    Correct:

    26" = STD
    27.5" = EXT

    I took the risk and ordered a Pro 26" STD version with the silver/gold-ish stanchions and it arrived this and is indeed not black. I just pulled it apart and moved the travel from 120 to 140mm and it looks identical to my black stanchtioned Pro.

  77. #1077
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    Surly Ice Cream Truck owners, what length are you running?

  78. #1078
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    Duplicate

  79. #1079
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    Quote Originally Posted by compengr View Post
    The compression adjustment knob seems to be biggest issue.


    I measured about 114mm from center of fork to the edge of the dial (pic didn't turn out) and 14mm from top of crown.


    Hope that helps.

    Sent from my Pixel XL using Tapatalk
    I have that same Mukluk, does the knob clear or not? It's hard to tell from the photo. What size is the frame? Just out of curiosity which version did you get? It seems like only the 100 MM standard will fit Salsa's specs.

  80. #1080
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    Quote Originally Posted by akt42 View Post
    I have that same Mukluk, does the knob clear or not? It's hard to tell from the photo. What size is the frame? Just out of curiosity which version did you get. It seems like only the 100 MM standard will fit Salsa's specs.
    Using a Cane Creek 40 series headset (regular crown race), it clears with about 2mm to spare. Medium frame. I got the 120mm standard Mastodon.

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  81. #1081
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    Quote Originally Posted by compengr View Post
    Using a Cane Creek 40 series headset (regular crown race), it clears with about 2mm to spare. Medium frame. I got the 120mm standard Mastodon.

    Sent from my Pixel XL using Tapatalk
    Awesome, thanks for the quick reply. I'm on a large with Cane Creek 110 so I can't see any reason it wouldn't clear. Now to decide on 29+ or 27.5+ for summer. I am looking at the 100mm standard to keep the geometry in tact but it's not rated for 5" tires (which I run) or 29+, gonna have to take Dougal's advice in this thread on how to get more clearance/less travel. Thanks again.

  82. #1082
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    Quote Originally Posted by akt42 View Post
    Awesome, thanks for the quick reply. I'm on a large with Cane Creek 110 so I can't see any reason it wouldn't clear. Now to decide on 29+ or 27.5+ for summer. I am looking at the 100mm standard to keep the geometry in tact but it's not rated for 5" tires (which I run) or 29+, gonna have to take Dougal's advice in this thread on how to get more clearance/less travel. Thanks again.
    Which 5" tire are you running?

    I have a 120mm STD with a Bud and it used to rub, just a bit, at full compression with the IVA set from the factory. I adjusted the IVA based on KTMNealio's suggestion and it's been good enough for me ever since. As in, almost never rubs and when it does the rub is so slight that I'm ok with it. In fact, I only moved two IVA spacers not all three and it's been great. Yes, I can still bottom it but only on really big stuff and not hard enough to worry my.

    I'm not suggesting you take the risk like I have chosen to with a Bud but if you have a slightly smaller tire like the FBF 4.8 then I don't think it'll actually rub.

    You could use the 120mm fork and limit the travel to 10mm either with internal spacers or with the air pressure trick. Then at least you have the option for more if you decide to go that way.

  83. #1083
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    Quote Originally Posted by Troy Carter View Post
    Which 5" tire are you running?

    I have a 120mm STD with a Bud and it used to rub, just a bit, at full compression with the IVA set from the factory. I adjusted the IVA based on KTMNealio's suggestion and it's been good enough for me ever since. As in, almost never rubs and when it does the rub is so slight that I'm ok with it. In fact, I only moved two IVA spacers not all three and it's been great. Yes, I can still bottom it but only on really big stuff and not hard enough to worry my.

    I'm not suggesting you take the risk like I have chosen to with a Bud but if you have a slightly smaller tire like the FBF 4.8 then I don't think it'll actually rub.

    You could use the 120mm fork and limit the travel to 10mm either with internal spacers or with the air pressure trick. Then at least you have the option for more if you decide to go that way.
    I am running Dillinger 5's for Winter and was thinking Jumbo Jim 4.8 for Summer which has the same Diameter as the Bud according to this chart. https://www.manitoumtb.com/wp-conten...-TIRE-SIZE.pdf

    I am running 100mm Whiskey carbon rims and don't want to use a skinnier tire and expose the rim to strikes but I also can't risk the tire not fitting. I ride in Western Colorado and Utah where a crash in certain areas can be life threatening. I haven't seen KTMNEalio's suggestion so I'm not exactly sure of the method. Did you move the tokens below the bottom out bumper? If so, does it affect the ramp up or change the characteristic of the fork beyond limiting the travel?
    I am sticking with the 100mm as I don't want to change the A to C compared to the factory fork. I also don't want to change the bikes intended geometry nor the ride characteristics that I am accustomed to.

  84. #1084
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    I just bit the Bullet and did the same,but got the ext comp version.How much fuss was pulling it apart to extend the travel to 140,as this is what I also intend to do>Cant get over what a massive fork it is!!Manitou Mastodon?-fatm.jpg

  85. #1085
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    Quote Originally Posted by bikemad1 View Post
    I just bit the Bullet and did the same,but got the ext comp version.How much fuss was pulling it apart to extend the travel to 140,as this is what I also intend to do>Cant get over what a massive fork it is!!Click image for larger version. 

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    Not much fuss at all with the tools and supplies on hand. I followed the manual and was done in 30 minutes or so the first time and would expect to be able to go much faster.

  86. #1086
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    Quote Originally Posted by PCT View Post
    Headset keeps coming loose on every ride. LBS cannot diagnose.

    Manitou Mastodon Std Pro 120mm installed on Kona Wozo with Chris King headset. Previous fork installed was Fox 34 140 27.5 Plus Boost which worked great with this bike/headset and did not loosen.

    LBS has checked all parts of the headset, crown race, etc. They say the star nut keeps pulling loose. Tried a CK star nut. Tried a star nut that was 1"-1.125", tried one that was 1.125". Tried a compression plug and tightened it so hard it broke the bolt.

    Conjecture is that it has something to do with the inner diameter of the steer tube. They say maybe it's a warranty issue. Anyone know what the hell is going on?
    Ignoring all of the craziness that followed your post...

    Have you figured this out yet?

    I ask because my fork is having the same issue. It came loose twice before your post which I thought was very odd but assumed I didn't get something right during install.
    I pulled off my stem cleaned things up and took a look but couldn't find anything wrong after the second occurrence. So, I swapped to a different stem, just to be sure, and gave it a couple more rides. And, it still comes loose.

    I happen to have a brand new Mastodon here as well so I started to look at the two of them and noticed that the steer tube is seated at a different position in the crown on the new fork compared to the month old used fork. The new fork steer tube looks to be nearly perfectly flush with the bottom of the crown. The used fork steerer is roughly .5mm into the crown.

    Maybe this is a production variance? Or maybe it's moving and causing the headset to come loose when it shifts?

    I'm going to tighten things back up and take a proper measurement of the amount the steer tube is set into the crown before I ride any more. When or if it loosens again I'll recheck that measurement to see if there is any movement between the steerer and crown.

    I'd kind of expect that if this were the issue then it may also rotate and I may see the fork/wheel off center some at times. I have not seen this rotation and I cannot guarantee I'm on the right track with this theory but I'm a bit confused as to what is going on and this seems like it may be an area of concern.

    Used fork.


    New fork.

  87. #1087
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    Iím getting ready to pull the trigger on one of these, but with all the problems with loose headsets, Iím having second thoughts!

    What are all you Farley owners using, I have a 9.6 medium frame, from my research it looks like the 120 pro standard will work, I plan on running the 27.5 x 4.5 Gnarwhalís with studs in the winter months , and the Barbís once things warm up. Looks like Iíll need to add one 10mm bottom out spacer for tire clearance, and maybe a 3mm crown race spacer under the headset for knob clearance.

  88. #1088
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    FYI, salsa has a comment on their website regarding the knob clearance, sounds like it is possible to swap compression knobs with one from the circus fork, must be slightly smaller?

  89. #1089
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    Nope, haven't figured it out. Gave it to the LBS and they have been sitting on it for (another) week. I will ask if they still have it and can see if the steer tube is slightly inset to the crown as in your photos. Hoping to get at least a replacement upper if not an entire new fork. At this rate, winter will be done before I get a fully functional Mastodon!

    I have several other fat fork options to play with in the meantime: Fox 34, Supermax, and rigid carbon.

  90. #1090
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    This is must definitely the era of misinformation.

    There is nothing wrong with any of these forks that would not be resolved with correct installation. Sorry to be so blunt, but not all home mechanics get it right.

    At install, make sure you allow enough space between the cut end of the steerer and the top of the spacer stack. If in doubt, give yourself a little more space. For best installation, donít use the stem above the top of the spacer stack.

    Great fork, had four so far, still riding three, no complaints, no issues, loving the Mastodon; the fork SRAM wishes theyíd built.

    Quote Originally Posted by tmbrown View Post
    Iím getting ready to pull the trigger on one of these, but with all the problems with loose headsets, Iím having second thoughts!

    What are all you Farley owners using, I have a 9.6 medium frame, from my research it looks like the 120 pro standard will work, I plan on running the 27.5 x 4.5 Gnarwhalís with studs in the winter months , and the Barbís once things warm up. Looks like Iíll need to add one 10mm bottom out spacer for tire clearance, and maybe a 3mm crown race spacer under the headset for knob clearance.

  91. #1091
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    Yes, if the steerer was loose in the crown, the headset would remain tight and the fork and wheel would move. I experienced this with a Wren. Itís exceedingly rare and itís not happening with you fork.

    You need a proper install on your fork.

    ďI'd kind of expect that if this were the issue then it may also rotate and I may see the fork/wheel off center some at times. I have not seen this rotation and I cannot guarantee I'm on the right track with this theory ... Ē

  92. #1092
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    Quote Originally Posted by Nurse Ben View Post
    At install, make sure you allow enough space between the cut end of the steerer and the top of the spacer stack. If in doubt, give yourself a little more space. For best installation, donít use the stem above the top of the spacer stack.
    This seemed to be the key to keeping the headset from loosening up for me. During the initial install I thought I had enough space above the end of the steerer but headset was loosening due to not being able to reach proper pre-load and eliminate play at the headset. Added a thicker spacer above the stem, and ensured the stem was properly torqued and haven't had problems since (a couple of months and 100+ miles later).

  93. #1093
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    Quote Originally Posted by Nurse Ben View Post
    Yes, if the steerer was loose in the crown, the headset would remain tight and the fork and wheel would move.
    This is not true. If the steerer is loose and moves so that the bottom of the steerer is more recessed into the crown then the distance from the top of the crown where the lower headset bearing races sits and the top of the steer tube would grow in length. I would expect it to rotate if loose as you experienced but I learn new ways that things can go wrong all the time so I'm looking at this as a possibility.

  94. #1094
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    very basic bike mechanic 101. the star nut has nothing to do with headset once its been properly installed. your stem is the part that should keep everything tight. once your stem is tight, you can ride without a top cap and starnut. star nut is just to preload your headset/headset bearings. if your star nut keep coming loose. your stem is not tight which is super unlikely because the handlebar would turn. or another possibility is the crown race is too short/ barely does not have enough stack for it to clear the top flat part of your fork crown and bottom of the headtube.

    ive owned and rode 2 mastodons. there is nothing wrong with these forks.
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  95. #1095
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    No problems with mine either. Why is this so difficult?

  96. #1096
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    People are quick to blame the product, sign of the times I suppose.

    Troy, dude, if the steerer was pulling out of the crown it would also rotate. They cold press the steerer into the crown, sometimes adding adhesive, but they are not keyed.

    Pullout would by very unusual; a sign of which is your crown race would also be loose, so no, your steerer is not loose.

    I recommend getting your fork back and having a different shop do the install, then youíd be able to ride your fork this season.

  97. #1097
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    Quote Originally Posted by Troy Carter View Post
    This is not true. If the steerer is loose and moves so that the bottom of the steerer is more recessed into the crown then the distance from the top of the crown where the lower headset bearing races sits and the top of the steer tube would grow in length. I would expect it to rotate if loose as you experienced but I learn new ways that things can go wrong all the time so I'm looking at this as a possibility.

    Steerer tubes are flanged. They can't pull up.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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    So maiden ride today, definitely alot heavier than the bluto it replaced, quite noticeably so.played around with the rebound it was set all the way to non.10 km into the ride it started feeling like it had terrible stiction.then I noticed it has the same issue as my Bluto, a few mm play with the fork uppers and lowers. I'm hoping this all improves after abit of time riding the thing, as I'll be well pissed if I've gone got a new fork that has the same issue as the ( not so)old bluto.

  99. #1099
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    The guys who are getting loose headsets probably didn't get the crown race fully set. Anyways, I'm digging my fork.
    Attached Thumbnails Attached Thumbnails Manitou Mastodon?-img_20180128_151210.jpg  


  100. #1100
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    That is what mine feels like, as if the headset is loose. But so did my Bluto, and we worked out it was the stanchions moving subtly in the fork legs, like just a few mom's, but enough to be very irritating.Im hoping a bit of slick honey on the stanchions and setting it up for my weight ( rode it straight out of the shop, no adjustments).I'm also keen to extend it to the 140mm travel, will see if any of these things make it preform better.at the moment it feels like one of those low end piece of shit fork you would find on a department store bike!!😠

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