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  1. #1
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    Cool-blue Rhythm How to tune the Lenz suspension......Or other bike for that matter....

    As winter now has taken it`s toll.....even here in the desert southwest..... It`s time to tinker with the bike again. Sitting up in Glenwood Springs,CO over new year, I thought about posting another how to ....in my case on my Lenz Boxhemoth.....The principles you see here can be applied to all bikes.......but I will show you how you can make a great bike even greater. Before any of you gets in defensive mode of the Lenz..... This write up is not meant in any way to pick on....bash....anything Devin makes. I have the out most respect for Devin.....and i am a firm believer in him and his awesome bikes. With that out of the way.....Hopefully my fellow Lenz riders will now share a shot of espresso, and laugh as we go along. The line of Devin`s bikes are a handcrafted piece of goodness, but as with everything in life.... there are always room for a little tweaking..... The findings here are purely my own opinion....never the less as there might be other factors.... This is the conclusion I have come to.
    So the things I will point out here, are properly known to most....and in such case I will show how to apply it here. Here we go......
    There are a few issues that I would like to address.... One of them... The dreading lower swing arm bottom bolts squeaking/working them self out. There are two main issues here.
    1.... The bolt used to torque the lower swing arm is threaded in to the frame, by design, enhancing the movement of said bolt. It is always better to have a fully floating bolt....like the Lenz have around the RP23 shock.
    2.......... The bolts used are "shank less" bolts......Where as if they had a shank the fit would be better.....minimizing wear, and wobble......as well as rear swing arm movement.

    Stay with me.... It will all be explained...... ...... Here is the difference between the two bolt styles....."shanked bolt" on the right......

    Item one above.....will be addressed at a later point, since it requires drilling of the frame....thus encompassing more work....... So let`s tackle the easy steps first....
    Number two it is..... Picture the stress the pivots of any suspension bike endures......Then take a look on the hardened sleeve/inner race of the bearings..... As the suspension is being pounded.....They will slowly hammer....bang.....push...etc....on the threads on the bolts used here......And over time slowly will massage the overall diameter to a ....should we say ...lesser diameter.....Take a look at the following two bolts.....on the left you have a new lower swingarm bolt.....On the right..... a one year of bashing by a 200 pound danish viking.... bolt...... ..Pay close attention to the first 8mm of thread....See how it`s slightly flattened????.....


    And these are not the bolt`s that the bike comes with....These are stainless 304 bolts... The stock are steel alloy`s.....which are even softer.....and the results of those....will be more dramatic. Here is what that boils down to mathematically....... Fresh bolt OD measures 7.84mm......


    Used bolt.......7.78mm.......


    To some that is not much......But it`s enough....and will now allow the lower swing arm to move ever so slight....causing a squeak.....and possible over time working out the bolt.....thus the need for red loctite....lots of it.....
    Here is another way to illustrate this......Take a look at the following two vid`s......First one with a new Stainless "shanked bolt" Very little wobble......and little wear to be expected.......

    http://s180.photobucket.com/albums/x...t=MVI_0934.mp4

    Then a video of same bearing with the 1 year old viking bashed bolt.......

    http://s180.photobucket.com/albums/x...t=MVI_0933.mp4

    By now I`d like to think you see my point....... More to follow......

    Erling
    Last edited by ebrabaek; 01-07-2011 at 10:16 AM.

  2. #2
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    Now that I`ve determined this.... The fix is easy...... Get new bolts.......Well if it was only this easy..... . This is perhaps why Devin have not gone this route...... Pure speculating here. I speak with him on a regular base....but we have not talked about this...... To have this work one needs to find bolts with the shanks matching the exact length....and the threaded part just sticking out enough to hold a nut in place.... And their in lies the problem..... They don`t exist....in ready made quantity.... and need to be made custom. That cost a lot of money, and would add to the cost of the bike....... That is off course my opinion.... But I do believe that is at least part of the reason. So with a few tools....one can by a few ready make bolts....and tune them to Lenz spec`s....he-he... . I have done this with bolts from ace hard ware. I just bought a handful of M8`s with 35mm shanks....then just threaded those deeper in the shank to suit each mount.....then cut the bolt to length. It worked great....and so ordered same bolts from an online retailer.....in 18-8 stainless.....which will undergo same treatment upon their arrival. I will document each step so you can see what is involved....and determine if this is something you want to try..... As explained earlier...... The threads gets bashed..... But what happens when the same scenario is presented.......but where the outer race is of the softer material........??? Well ...... instead of the bolt`s threads being hacked..... The softer outer race does........ Take a look at the RP23 shock in this case.......



    Most of you will nod ....and say...well it`s wear item.... True....but why have it....if you can avoid it........ More to come......

    Erling

  3. #3
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    While the bolt`s are in transit...... I might as well clean the area up a little.......When you take a set of suspension apart.... you might find areas that need a little attention. Ehhhh.... like this....... Note the frame rub marks....and the marks on the ano black swing arm...or as Devin calls them " control levers".......


    You might or might not see these on your bike. Mine is a behemoth modded with a non 135 hub rear lunchbox...new levers.....to satisfy 6 inches of travel.... In short a lunchbox.....less the 135mm rear hub spacing...... So this could have materialized from the modding..... Never the less.... when you see these....they need to be addressed.... since you now have contact...... In this case....I just filed it a little......


    Other side.......



    After the filing.....


    Some might think this is being anal.... Perhaps you are right.... But I like to tune things....wheather it`s coffee grinders...or bikes...... But most important..... I wan`t the best.......and the bolt makeover will just run you $25.......and after doing this with the steel alloy "test bolts".... I felt the change. This will be stage one........ If the rear end begins to work itself out and squeak again...... We go to stage two......
    So enjoy....and fire away.....while I wait for the bolts to arrive.



    Erling

  4. #4
    jrm
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    U replied to your own post 2x and your post count

    didnt go up.
    Wreck the malls with cows on Harleys

  5. #5
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    Quote Originally Posted by jrm
    didnt go up.
    Gremlings...????



    Erling

  6. #6
    ballbuster
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    Problem with Stainless Steel is that it galls. Sometimes the threads curl up on themselves inside of whatever you are threading it into, and it jams and ruins both parts. It has to do with the way Stainless Steel behaves.

    I would be reluctant to use Stainless bolts on anything that has any real pounding loads on it... like say suspension pivot points. I don't know if anti-seize compound will help. Maybe somebody who knows more about metals and machining can chime in.

    Also, it's a major PITA to cut stainless steel bolts. You have to use cutting oil, and go very slowly with a hand saw sharp blade. If you try to saw too quickly, the metal anneals and gets super hard and brittle, probably harder than the blade you are cutting with.

    I would say use a good hardened steel, but not stainless steel.

  7. #7
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    Quote Originally Posted by ebrabaek
    As winter now has taken it`s toll.....even here in the desert southwest..... It`s time to tinker with the bike again. Sitting up in Glenwood Springs,CO over new year, I thought about posting another how to ....in my case on my Lenz Boxhemoth.....The principles you see here can be applied to all bikes.......but I will show you how you can make a great bike even greater. Before any of you gets in defensive mode of the Lenz..... This write up is not meant in any way to pick on....bash....anything Devin makes. I have the out most respect for Devin.....and i am a firm believer in him and his awesome bikes. With that out of the way.....Hopefully my fellow Lenz riders will now share a shot of espresso, and laugh as we go along. The line of Devin`s bikes are a handcrafted piece of goodness, but as with everything in life.... there are always room for a little tweaking..... The findings here are purely my own opinion....never the less as there might be other factors.... This is the conclusion I have come to.
    So the things I will point out here, are properly known to most....and in such case I will show how to apply it here. Here we go......
    There are a few issues that I would like to address.... One of them... The dreading lower swing arm bottom bolts squeaking/working them self out. There are two main issues here.
    1.... The bolt used to torque the lower swing arm is threaded in to the frame, by design, enhancing the movement of said bolt. It is always better to have a fully floating bolt....like the Lenz have around the RP23 shock.
    2.......... The bolts used are "shank less" bolts......Where as if they had a shank the fit would be better.....minimizing wear, and wobble......as well as rear swing arm movement.

    Stay with me.... It will all be explained...... ...... Here is the difference between the two bolt styles....."shanked bolt" on the right......

    Item one above.....will be addressed at a later point, since it requires drilling of the frame....thus encompassing more work....... So let`s tackle the easy steps first....
    Number two it is..... Picture the stress the pivots of any suspension bike endures......Then take a look on the hardened sleeve/inner race of the bearings..... As the suspension is being pounded.....They will slowly hammer....bang.....push...etc....on the threads on the bolts used here......And over time slowly will massage the overall diameter to a ....should we say ...lesser diameter.....Take a look at the following two bolts.....on the left you have a new lower swingarm bolt.....On the right..... a one year of bashing by a 200 pound danish viking.... bolt...... ..Pay close attention to the first 8mm of thread....See how it`s slightly flattened????.....


    And these are not the bolt`s that the bike comes with....These are stainless 304 bolts... The stock are steel alloy`s.....which are even softer.....and the results of those....will be more dramatic. Here is what that boils down to mathematically....... Fresh bolt OD measures 7.84mm......


    Used bolt.......7.78mm.......


    To some that is not much......But it`s enough....and will now allow the lower swing arm to move ever so slight....causing a squeak.....and possible over time working out the bolt.....thus the need for red loctite....lots of it.....
    Here is another way to illustrate this......Take a look at the following two vid`s......First one with a new Stainless "shanked bolt" Very little wobble......and little wear to be expected.......

    http://s180.photobucket.com/albums/x...t=MVI_0934.mp4

    Then a video of same bearing with the 1 year old viking bashed bolt.......

    http://s180.photobucket.com/albums/x...t=MVI_0933.mp4

    By now I`d like to think you see my point....... More to follow......

    Erling
    Both of those bolts you measured are still in spec. The difference between 7.84 and 7.78mm is not even 0.002". Not saying it doesn't matter, but there is a chance that you could buy a brand new bolt at 7.78mm.

    And I agree with pimpbot - grade 8 bolts are stronger and cheaper than stainless - even if they rust after awhile. They are cheap enough to buy a whole box and replace them when they're rusty.

    -F

  8. #8
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    Quote Originally Posted by pimpbot
    Problem with Stainless Steel is that it galls. Sometimes the threads curl up on themselves inside of whatever you are threading it into, and it jams and ruins both parts. It has to do with the way Stainless Steel behaves.
    True......But in this application I just have to deal with a nut.... I see that more when threading in very deep

    I would be reluctant to use Stainless bolts on anything that has any real pounding loads on it... like say suspension pivot points. I don't know if anti-seize compound will help. Maybe somebody who knows more about metals and machining can chime in.
    Interesting.... I have never had any issues on bikes...

    Also, it's a major PITA to cut stainless steel bolts. You have to use cutting oil, and go very slowly with a hand saw sharp blade. If you try to saw too quickly, the metal anneals and gets super hard and brittle, probably harder than the blade you are cutting with.
    Cutting it is not a too big of a deal for me..... Good blade....use oil..... and go easy.....Threading it is another matter....patience.....oil...back and forth......

    I would say use a good hardened steel, but not stainless steel.
    You can choose any metals for this..... I prefer SS and it`s corrosion resistance..... But what ever metals you`d like will be fine......

    Erling

  9. #9
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    Quote Originally Posted by Fleas
    Both of those bolts you measured are still in spec. The difference between 7.84 and 7.78mm is not even 0.002". Not saying it doesn't matter, but there is a chance that you could buy a brand new bolt at 7.78mm.

    And I agree with pimpbot - grade 8 bolts are stronger and cheaper than stainless - even if they rust after awhile. They are cheap enough to buy a whole box and replace them when they're rusty.

    -F

    I don`t particularly like the threading/cutting......but after not being able to find the bolt with the correct shank and thread length dimensions....I just decided to make mu own...... But please..... If you know where to get them in a finished state..... Please post the link. As far as spec`s go.... Perhaps...... along with the manufacture.....but as the vid`s indicator....that`s too much wiggle for my taste....

    Erling

  10. #10
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    Quote Originally Posted by ebrabaek
    I don`t particularly like the threading/cutting......but after not being able to find the bolt with the correct shank and thread length dimensions....I just decided to make mu own...... But please..... If you know where to get them in a finished state..... Please post the link. As far as spec`s go.... Perhaps...... along with the manufacture.....but as the vid`s indicator....that`s too much wiggle for my taste....

    Erling
    If I get your drift, one thing you might try to "manufacture" your desired bolt shank is to get some epoxy putty, lightly lube the inside of the mating bearing, squeeze some epoxy into the threads of the bolt where you don't want threads (making a sort of integrated bushing), and stuff the whole mess into the bearing race to size it properly. Trim off the excess epoxy while it's still workable, then let it cure (...like 15 minutes).
    The finished bolt should have an integrated bushing only where the bearing bears upon it, with usable threads for the remainder of the length.

    -F

  11. #11
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    Thanks for taking the time to photo document this :-)
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  12. #12
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    Quote Originally Posted by Fleas
    If I get your drift, one thing you might try to "manufacture" your desired bolt shank is to get some epoxy putty, lightly lube the inside of the mating bearing, squeeze some epoxy into the threads of the bolt where you don't want threads (making a sort of integrated bushing), and stuff the whole mess into the bearing race to size it properly. Trim off the excess epoxy while it's still workable, then let it cure (...like 15 minutes).
    The finished bolt should have an integrated bushing only where the bearing bears upon it, with usable threads for the remainder of the length.

    -F
    Yep.... But over time the epoxy will simply get mashed...... The fit is good with shanked bolts..... ......

    Erling

  13. #13
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    I know this sounds silly to some...... And perhaps to most people....it would feel/make no difference...... But after working with suspension on bikes....with and without pedals..... This is an area of concern....in striving for perfection. So as not to get drawn into metallurgy..... The take here is If you don`t have shanked bolts..... perhaps you can gain a little control, by merely installing them. If nothing else....they should prevent the squeaks.....and prevent movements. I felt the difference after 45 days with said tuning.......and steel alloy bolts. Most might not agree..... But for a few of you that have nothing else to do over this winter...... This is a great fix....while sipping a good shot of espresso.....

    Erling

  14. #14
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    Quote Originally Posted by CactusJackSlade
    Thanks for taking the time to photo document this :-)
    Yeppers.......

    Erling

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    Sooo... I thought I`d do a little house cleaning...... I`m sure that most of you do this on a regular basis........ But while the shock was off.... I`d clean and recharge the fluid. Any time I work on a fork/shock....I prefer to discharge the air chamber first......Then you remove the collar. I use a vice.....and hands........ It was good timing.... very little fluids left....


    Then wipe it all down with a clean rag...... get the float fluid elixir out, and ready.......


    Squeeze the fluids in the outer chamber....reinstall the collar....your done..... That`s all you can do....but you wan`t to make sure that shaft is well lubed.......

    Erling

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    I thought I`d post a picture of the test steel alloy lower swing arm bolt`s I tested this with......
    Note the old bolt on the top..... New on the bottom......


    Now....just waiting for the new bolts to get here...... Until then.....


    Erling

  17. #17
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    Cool-blue Rhythm Bolts are in.....

    I finally got home...and the bolt`s were here....... So if you are just joining in...... I`m simply replacing the regular bolt`s with shanked bolts.....to minimize any wobble in the suspension.... Not picking on any bike....but this is a simple fix you can do for a few $$$$....While you sip a shot of espresso.....
    Got an assortment....for future use.....


    The original bolt was all threads...... and perhaps a good way to illustrate the change....is this picture....where you can now see the shank is now running full length of the bushings....






    I have added washers on the outside of the anodized levers..... there were none prior......
    So it feels great...... Can`t ride it tomorrow....But hopefully Friday.... Until then...

    Erling

  18. #18
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    Instead of reducing the length of the shank by cutting more thread you could just space out the bolt with case hardened washers.

    Also, I think I'd prefer to use a nyloc nut rather than the domed one you have there.

  19. #19
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    Quote Originally Posted by Larryscustomcycles
    Instead of reducing the length of the shank by cutting more thread you could just space out the bolt with case hardened washers.
    Absolutely.....That would be fine as well...

    Also, I think I'd prefer to use a nyloc nut rather than the domed one you have there.
    That picture was just for illustrative purposes...... I did use nyloc`s......




    Erling

  20. #20
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    Cool, see the bottom bolt on the shock, it looks like you have 2 washers in there? Can you pull one out so the nyloc gets full purchase on the bolt?

  21. #21
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    Quote Originally Posted by Larryscustomcycles
    Cool, see the bottom bolt on the shock, it looks like you have 2 washers in there? Can you pull one out so the nyloc gets full purchase on the bolt?
    Yeppers...... I threaded a little short....and rather than threading more.....SS is a pain to thread.... I just fed it another washer..... It actually is fully seated in the nyloc.... The picture is just a bit blurred......

    Erling

  22. #22
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    I would suggest getting on the phone with EnduroForkSeals and trying to find a needle bearing kit that would work for the upper swingarm/shock pivot.

    I added one to my TNT sultan, with similar interface and it made a noticable improvement in smoothness.

  23. #23
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    I'm probably just paranoid about it.

    Quote Originally Posted by ebrabaek
    You can choose any metals for this..... I prefer SS and it`s corrosion resistance..... But what ever metals you`d like will be fine......

    Erling
    I once had to disassemble a siren horn stack in the field that had 5/16" bolts all over it. About 12 out of 16 of them were galled. It took me hours with a nut cracker and dremel to get it apart. The bonehead who assembled it probably used an impact gun.

    Stainless Steel chains also have this issue. When the lube runs dry, they start curling up on themselves and jam.

    Quote Originally Posted by sennaster
    I would suggest getting on the phone with EnduroForkSeals and trying to find a needle bearing kit that would work for the upper swingarm/shock pivot.

    I added one to my TNT sultan, with similar interface and it made a noticable improvement in smoothness.

    I have a bud who got that roller bearing kit. He says it makes a nice noticeable difference as well. Maybe I should spring for one.

    Then again, I almost never ride my suspension bike.

    OT....

    Huh... so you're in El Paso, right? I was out there last spring doing a job. I rented a bike and rode some of the trails out there, and had a blast. I'm not used to riding around cactus, tho. I'm used to brushing the bushes and grass just a tad. When I got back from my ride, I had tons of cactus needles stuck in my calves.

    Last edited by pimpbot; 01-20-2011 at 11:01 AM.

  24. #24
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    Quote Originally Posted by sennaster
    I would suggest getting on the phone with EnduroForkSeals and trying to find a needle bearing kit that would work for the upper swingarm/shock pivot.

    I added one to my TNT sultan, with similar interface and it made a noticable improvement in smoothness.
    Nice..... ... The alu bushings in the rp23 are Teflon coated and rotate very well in my app..... But in striving for better....perhaps that`s something worth looking into..... Thanks



    Erling

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    Quote Originally Posted by pimpbot
    I once had to disassemble a siren horn stack in the field that had 5/16" bolts all over it. About 12 out of 16 of them were galled. It took me hours with a nut cracker and dremel to get it apart. The bonehead who assembled it probably used an impact gun.

    Stainless Steel chains also have this issue. When the lube runs dry, they start curling up on themselves and jam.

    OT....

    Huh... so you're in El Paso, right? I was out there last spring doing a job. I rented a bike and rode some of the trails out there, and had a blast. I'm not used to riding around cactus, tho. I'm used to brushing the bushes and grass just a tad. When I got back from my ride, I had tons of cactus needles stuck in my calves.

    Very true..... Stainless can be a pain to unscrew....if dirt ar metal filings have accumulated in the threads......or if the threads are overstressed...... I usually just clean very well....and lube`em prior to assy..... That has worked great for me.....But again.... one can use any bolts of your choice...... I just chose SS......

    Erling

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