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  1. #1
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    HDR Fork question

    So I placed an order last month for an HD-140, IBIS changed it to an HDR after announcing the new model which Im pretty stoked about and it should be arriving as soon as next week..

    Anyway I have a new in the box 26 fox fork, but now Im Bi-Curious and wondering if maybe I should try to be more flexible in allowing a future upgrade to 650b.

    Wondering if it would be prudent to sell the new fork while I can still get a pretty good resale value and get a 650b fork. Can I expect any negative characteristics in running a 650b fork with 26 wheels?

    Thanks for any input on the matter.
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  2. #2
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    The A2C will be the biggest drawback. Depending on what 26 fork you bought it may fit a 275 wheel.

  3. #3
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    I think the answer should be no... For example the XFusion Sweep & Rockshox Pike both have A-C of around 542mm (27.5"@150mm travel), which is very close to the Fox 36, Marz 55, Lyrik (545mm for 26" @ 160mm travel). So theoretically any of these forks should give you the same geo & ride characteristics, assuming you're not bothered by 15/20mm axle and 34/36mm stanchion differences. The thing I can't wrap my head around is what the HD140/HDR130 would be like in 650B mode with one of those 150mm forks. I think you'd end up almost a degree slacker than in 160mm mode, which might not be so ideal (at least for me). I'm hesitating pulling the trigger on the Sweep/Pike b/c of this very issue. Fortunately the Sweep isn't out yet, so I can play geo nerd...

    HDR 130/27.5" mode: 67.1* HA w/140mm fork (presumably 27.5 ~ 532mm A-C?) --> approx. 66.6* HA w/542mm fork?
    HDR 160/26" mode: 67.5* HA w/160mm fork (presumably 26 ~545mm AC?)
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  4. #4
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    Thanks for the responses, the new fork I have for this bike is a Talas 140, from what I've researched there is a chance I'll get some buz with bottoming out the fork depending on the tire being run.

    Maybe I'll temporally throw a 140 fork from another bike for a bit and see if if I can borrow a 650b fork for a day to try out if I can find one before selling the new fork and getting a 650b.

    Looking at the IBIS website it seems
    HDR 130 Rear, 140 front 26 wheels = 68.1 head angle and a 13" BB
    HDR 130 Rear, 140 front 27.5 wheels = 67.1 head angle and a 13.53" BB

    So I guess 26 wheels with a 140 650b fork is going to fall somewhere in between the two which could be a good thing.
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  5. #5
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    HDR Fork question

    I believe Ibis refers to the dropped travel mode as 130mm to result in a 68.1* head angle. Looking at some geometry on the computer (shh, I'm at work), I'm getting 67.1* HA and 13" BB with the Fox 34 650b fork @ 140mm. It makes sense that the HA would stay the same and only BB would drop if reducing wheel diameter.HDR Fork question-imageuploadedbytapatalk1372355645.199649.jpg

    My numbers are assuming a medium frame and 676mm overall tire diameter (Schwalbe RR 2.25).

  6. #6
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    HDR Fork question

    Running the HDR in 130 mode rear with a 650b fork @ 150-160mm and 26" wheels could actually turn out to be pretty reasonable, at least if you are talking short term until building up some 27.5 wheels. The angles and trail numbers look good but the BB would be a tad low for my terrain. YMMV of course.

    Here are some numbers on three of the main contenders, all 650b:
    Fox 34 @ 160 (13.3 BB, 101 Trail)
    HDR Fork question-imageuploadedbytapatalk1372356330.077117.jpg
    Rock Shox Pike @ 160 (13.3 BB, 103 Trail)
    HDR Fork question-imageuploadedbytapatalk1372356539.083448.jpg
    X-Fusion Sweep @ 160 (13.2 BB, 98 Trail)
    HDR Fork question-imageuploadedbytapatalk1372356563.400880.jpg

  7. #7
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    What about fork off set guys true 650b fork and trail for HDR in 650b?

    conekilr is the only one talking about this, are all threads on what fork I have and can use for 650b assuming A2Cs are on 650b forks or std 26" forks Im confused.

    Seatpost Diameter 31.6mm
    Front Derailleur 34.9mm
    Headset Mixed Tapered (Mixed Tapered (1.5" EC49 lower, 1.125" ZS44 upper)
    Bottom Bracket 68mm (BSA) English Thread
    Chainline 50mm
    Trail 100mm
    Axle to Crown geometry is based on 534.4mm

    Trail or fork offset to me will be more important than A2C, first step if you want to maximise wheel size advantages? why compromise on such a frame, I just don't get that, people always trying to put round pegs in square holes even if they fit.

    Also got to see the new Pike have a wee play in shop, very impressed, looks fantastic and felt even better, both shop guys always ride Fox, usually the same guys end up on a new RS and Fox over the season for customers, but both are running the new Pike, never seen them do that before, wont repeat what was said about the Fox forks.

    But both were absolutely loving the new Pikes, these guys are top local riders in our area in XC and DH, both on Solo air versions and man are these light and just look stunning, new maxle design is also looking great.

  8. #8
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    Trail and BB height will be your deciding factor if 26" wheels work for you with the 650B fork. The HA is unchanged swapping between the wheels but your BB Height will be ~ 0.5" lower (12.5mm) depending on tire heights between the two wheelsets. So with a Fox 34 650B @140 you will have a 67.1 HA, 13.5" BB and 100 Trail with 650B wheels and 67.1 HA, 13" BB and 95 Trail with 26" wheels which means it will feel like a 67.8 HA with a 32 Float handling wise. The Trail and BB height means you essentially have a TRc type bike in 26" mode which may or may not be what you want. There is alot of difference in 650B offset between Fox, RS and Xfusion forks. I assumed taller 2.1" high tires (VEE Trail Taker/Hans Dampf for my Trail calculations).

    I personally like the RS Pike in 150mm as the compromise if you can live with the BB height.

    650B mode: 66.76 HA, 13.6" BB, 104 Trail
    26 mode: 66.76 HA, 13.1" BB, 99 Trail

    I'd keep the fork and use a 160 mode shock to raise BB height in my Pike example above if not.

    Here is a Trail calculator. Fox offset is 44, RS 42 and Xfusion 46 offset in 650B mode. I use 53.34mm (2.1") for tire height because I like bigger rubber

    Bicycle Trail Calculator | yojimg.net

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  9. #9
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    Thanks everyone! lots to think about.
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  10. #10
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    New PIKE tested by Pinkbike, is that a new Ibis 650b frame I spy or a modified Mojo?

  11. #11
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    HDR Fork question

    Levy mentions somewhere in the article that the test bike is a mojo HDR. They must have a review in the works.

    It is by no means a full indication of the Pike's performance, but its so good to hear that its everything it should be, right out of the box. That's how things should be for this level of suspension components. I guess we will see how longevity plays out.

    Getting more and more excited for my HDR/Pike combo!

  12. #12
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    conekilr- can you run some numbers for me please?

    I contacted Ibis and they advised against running a 650B front fork at 160mm with 26 rear tire and shock at 160mm. They said it wouldn't ride well. So I thought since people have been running Fox 26 forks for a few years in conversions, that perhaps I would get a 26er Talas 160/130 with a 27.5 wheel in it.

    The idea is to save some money and cost. I can run 130/130 in full 27.5 or when I hit some lift assisted trails I could just swap a shock and rear wheel and run 160/160 with 27.5 front and 26 rear.
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  13. #13
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    Quote Originally Posted by conekilr View Post
    Levy mentions somewhere in the article that the test bike is a mojo HDR. They must have a review in the works.

    It is by no means a full indication of the Pike's performance, but its so good to hear that its everything it should be, right out of the box. That's how things should be for this level of suspension components. I guess we will see how longevity plays out.

    Getting more and more excited for my HDR/Pike combo!
    Well spotted, missed that, was focusing more on the fork review from the headtube picture the frame looked different in reverse VP for me compared to the online stuff which is a good thing!

    Personally I have no issue with reliability of Rockshox and they're easy to work on plus the new charger damper is service able which is why Im a fan of it over Fox as much as anything. I'm still waiting on my Veng, so am torn but too many people here are changing they're Foxs for Pikes so I don't want to be a sheep and be like everyone else, so will stick with it and also go back to 20mm if they had a 20mm option, might have swayed me over actually so sick in person and feels so nice ahh dam you ugi!


    It is clear that RockShox has been listening over the last few years. The Pike's Charger damper offers a supportive feel that doesn't translate to harshness when the rider isn't charging hard, somehow striking a great balance for those times when you are really on it, but also for days when you are dialled back a bit. This aligns with our earlier impressions of the Pike when we first rode it in Sedona, Arizona, with it continuing to impress us on our home terrain in southwestern B.C.. Low-speed compression moments - rolling down a steep rockface, landing on a nice transition, and heavy braking - all showed that the fork remained very composed and stable, leaving both more travel available for when it was needed and also preserving the geometry of our Ibis HDR test bike. We found that it was possible to dial in a bit too much low-speed compression via the dial atop the right fork leg, though, and that six clicks out of twelve was more than enough for our liking. Even with it backed completely off, there was still a considerable amount of control.

  14. #14
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    HDR Fork question

    I dont see why. Was their concern BB height? When I quickly looked at your numbers you would have ~ 66 HA (ok its 2.5mm taller so 1/8 of a degree slacker) and a 107 trail which is in line to running a 180mm Fox fork which seemed fine to me. It will be tall but no worse than a 27.5/26 with a 170mm Lyrik. I ride a 170 Lyrik and don't think a 27.5 in front would be bad on big days.

    A Fox 26 fork is going to be really low in 130mm mode and the 34 has a lot less tire clearance which would be a nonstarter for me. Seems less than ideal unless you want a low A2C and BB height in that mode.

    If you want one fork what about a Sweep (lighter) or Vengeance (heavier). With the Sweep you have to use their internal pin ladder but you can set it up any where between 130 and 160 in 10mm increments and the 46 offset will be nice with 27.5 tires in both modes. Think 140/130 and 160/160 would be cool.

    Not sure how big the trails are in your resort, but you may want something stiffer than a 34 stanchion fork.

    If so the Vengeance gives you a bigger, stiffer fork for resort days and then drop it down with their pin ladder to 130mm in low mode days. Good clearance. Bit tall. Less offset. Heavier weight.

    Derby rode a 27.5/26 at the park in his write ups to try it. Would PM him for his thoughts. He played a lot with fork height also. His hack on his Vengeance to add the RS travel adjust to it would be perfect but the pin ladder adjust isn't that bad if you are not doing it every day.
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  15. #15
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    HDR Fork question

    Zoned for a min. On the new Talas you can change it from 160/130 down to 150/120 and then shorten the 30mm travel to 25 or 20. To me a Talas 275 150/130 is perfect for a one fork option if you can live with the 34 stiffness
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  16. #16
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    Quote Originally Posted by seleniak View Post
    I dont see why. Was their concern BB height? When I quickly looked at your numbers you would have ~ 66 HA (ok its 2.5mm taller so 1/8 of a degree slacker) and a 107 trail which is in line to running a 180mm Fox fork which seemed fine to me. It will be tall but no worse than a 27.5/26 with a 170mm Lyrik. I ride a 170 Lyrik and don't think a 27.5 in front would be bad on big days.

    A Fox 26 fork is going to be really low in 130mm mode and the 34 has a lot less tire clearance which would be a nonstarter for me. Seems less than ideal unless you want a low A2C and BB height in that mode.

    If you want one fork what about a Sweep (lighter) or Vengeance (heavier). With the Sweep you have to use their internal pin ladder but you can set it up any where between 130 and 160 in 10mm increments and the 46 offset will be nice with 27.5 tires in both modes. Think 140/130 and 160/160 would be cool.

    Not sure how big the trails are in your resort, but you may want something stiffer than a 34 stanchion fork.

    If so the Vengeance gives you a bigger, stiffer fork for resort days and then drop it down with their pin ladder to 130mm in low mode days. Good clearance. Bit tall. Less offset. Heavier weight.

    Derby rode a 27.5/26 at the park in his write ups to try it. Would PM him for his thoughts. He played a lot with fork height also. His hack on his Vengeance to add the RS travel adjust to it would be perfect but the pin ladder adjust isn't that bad if you are not doing it every day.
    Ibis said the head angle would be about .7 degrees slacker and the front end higher- good for step DH riding but corner would suffer.

    So this is my dilemma, I actually want the higher BB since I'm riding east coast trails with rocks, log over etc.. I'm really torn on which way to go, the lift riding would only be a few times a year so the bike will be 130/130 27.5 most of the time so that is the most important to get right.
    I'm in MD so there are number of places around to go lift riding, I think the 34 will be enough. I was also considering a Pike dual air 160/130, but having trouble finding the AC measurements for them.
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  17. #17
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    HDR Fork question

    I think the Pike is going to be nice. A2c is 552mm for the 650b 160 and a 42mm offset
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  18. #18
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    HDR Fork question

    I think a 26/26 in 160 mode and 130/130 in 650B would be perfect then with the Pike. 66.5 HA in 160 with a 101 Trail. It essentially would be the same HA and BB as my Lyrik with a shorter WB.
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  19. #19
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    HDR Fork question

    Worse case you try a 27.5 up front in the 160 for really big days and if you prefer the 26 you stay there
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  20. #20
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    Quote Originally Posted by seleniak View Post
    I think a 26/26 in 160 mode and 130/130 in 650B would be perfect then with the Pike. 66.5 HA in 160 with a 101 Trail. It essentially would be the same HA and BB as my Lyrik with a shorter WB.
    Quote Originally Posted by seleniak View Post
    Worse case you try a 27.5 up front in the 160 for really big days and if you prefer the 26 you stay there
    I think you're missing what I'm trying to do, I don't want a 26 front wheel at all. I'd like to have it 130/130 27.5 for most of my riding and to save money only sway out the rear wheel to a 26er to get 160/160.
    So it would be 27.5 front 26 rear, I'm just trying to wrap my head around all the numbers and how it will effect the bike.

    The 180mm Fox 36 has an AC of 562.3 with a HA of 66 degrees with a 26 inch wheel.
    The 160mm Fox 34 650B has an AC of 554.4 plus the height of the taller wheel, so I'm guessing a HA around 65, that just seems really slack.

    I do agree I don't think I what to go with a 26er fork because I lose the BB height, so I just may have to abandon the idea and run it 130/130 and just rent when I go somewhere.
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  21. #21
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    HDR Fork question

    I understand what you're trying to do. Conceptually though you are looking at a fork that is the same A2C as a 170mm 26 fork and then are adding 12.5mm more to the front end with a 27.5 front tire. It will be tall but not much different than a Totem or Vengeance which are 565mm. I used Geometry Calc with a 568mm equivalent front fork (too lazy to do the trig so just used 13mm) to get a 66 HA.

    My point was that if you find the 27.5 too tall you could always buy a 26 front and the numbers would be the same as running a Lyrik.

    I'll post a link to Geometry Calc if you want to play with the geo yourself. I have a link a few posts back to a good Trail Calc also. Hopefully both help
    Last edited by seleniak; 07-04-2013 at 09:40 PM.
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  22. #22
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    HDR Fork question

    Geometry Calc link http://bikegeo.muha.cc/
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  23. #23
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    Quote Originally Posted by seleniak View Post
    Geometry Calc link geometryCalc
    Thanks
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