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  1. #1
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    15 mm axle on 650b specific forks, WTF? Why are fork companies going backwards?

    The new Fox 34 is only offered with a 15 mm axle, which will not be as stiff as my 20 mm and the spokes are longer on 650b adding to the problem.

    My only guess is they are doing it to sells forks now and next will release the 20 mm so they can sell more forks. So what gives?

  2. #2
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    solution: fox 36. and for the record, of the dozen 650b wheels i've built, all spokes were around the 270mm range....again, so what problem is there to solve?

  3. #3
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    Yeah, 272-274 spokes over here. I have 20mm and 15mm axle forks and I can't tell a difference in stiffness. Can you?

    Could you estimate some sort of percentage? 10% stiffer? 70% stiffer?

    I look more at chassis than axle so if I want stiff, I go with 35mm product or above. I think the 20mm standard is bleeding down from DH where the 15mm axle points more towards xc, trail and enduro for whatever reason.

    mk
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  4. #4
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    15mm is more than stiff enough for anything you want to do, dude, and the tiny increase in spoke length is going to be just fine as well. Go ride.

    -Walt
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  5. #5
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    I went from a Fox 36 with 20mm TA to a Fox 34 with 15mm TA and can't tell a difference. My last bike had a 9mm QR rear and now on 12x142 TA and can tell a big difference in stiffness. I think frame and rear wheel is much more important and noticeable than fork axle IMO.

  6. #6
    No Clue Crew
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    I'm over 200 in gear and have both 15 and 20 forks. Can't tell a difference. Relax and go ride your bike.

  7. #7
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    Not all 650b specific forks come with a 15mm TA.


  8. #8
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    What do spokes have to do with axles? I'm confused. Does a stiffer fork make your wheel stiffer?
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  9. #9
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    Quote Originally Posted by 1rider View Post
    The new Fox 34 is only offered with a 15 mm axle, which will not be as stiff as my 20 mm a

    My only guess is they are doing it to sells forks now and next will release the 20 mm so they can sell more forks. So what gives?
    I like 20mm axle as well, even more I prefer not to convert my 20mm hubs.. and that fox34 is too flexy if you prefer the 36

  10. #10
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    Thanks for the replies however I still don't see an answer to my question, why fork companies have gone to 15 mm in this wheel size? I run a fox 36 w/20mm axle and love it, plain and simple.
    Glad to hear some don't feel a difference.

  11. #11
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    Quote Originally Posted by StiHacka View Post
    Not all 650b specific forks come with a 15mm TA.

    Wow, an inverted XFusion? I didn't know they made such a beast. What model is this? Looks killer.

    I agree with the whole 15mm axle thing. I think it was just another marketing scheme by Fox simply to make their products sell. We should have just stayed with 20mm. There's barely a weight diff and more stiff, though most couldn't feel it. It was yet another new size that meant changing hubs and wheels for most.
    We Ride In God's Country!

  12. #12
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    You guys must be bombing some serious hills to be complaining that a 15mm and 34mm stanchion is "too flexy".

    My weight varies between 225-235# and riding flow EX's on a 32mm stanchion 130mm fork with 15mm axle had no discernible flex in XC/trail riding. Any flex that occurred I couldn't detect so it obviously didn't effect my riding and I wouldn't want the extra pound of weight off the front of the bike when running a 36mm fork with a 20mm axle.
    Hardrock 29er, Niner EMD9, Cannondale F29, Camber Expert, 650b Nickel all gone.
    2014 Giant Anthem 27.5 here.

  13. #13
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    Quote Originally Posted by myitch View Post
    Wow, an inverted XFusion? I didn't know they made such a beast. What model is this? Looks killer.
    XFusion Revel HLR. It is not available in stores yet but shall be coming soon. Most likely way out of my budget though.

    X-Fusion Revel HLR Fork - First Look - Pinkbike

  14. #14
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    Quote Originally Posted by StiHacka View Post
    XFusion Revel HLR. It is not available in stores yet but shall be coming soon. Most likely way out of my budget though.

    X-Fusion Revel HLR Fork - First Look - Pinkbike
    It looks sweet. However, I know inverted forks of the past were flexy but it sounds like they're trying to stiffen it up. Even motocross forks used to be inverted but not many now. I remember, I think it was Manitou, made an inverted fork with a hexagonal axle to try reducing the flex, but it still didn't work that great. If XFusion can pull this off, it should be a sweet fork and with their pricing, maybe still come in less than the bucko bucks RS Pike.

    The concept is great though. Greatly reduced unsprung weight not having to rebound up the weight of the lower legs-arch unit. Probably takes off at least a pound of weight right there. But definitely lose the rigidity of that rectangular lower legs-arch-axle structure. Also, on inverted forks, the stanchions have to hold the structure with a smaller OD than the lower legs on the standard forks. That's a lot to demand of the fork. We'll see...
    We Ride In God's Country!

  15. #15
    650b me
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    Quote Originally Posted by 1rider View Post
    Thanks for the replies however I still don't see an answer to my question, why fork companies have gone to 15 mm in this wheel size? I run a fox 36 w/20mm axle and love it, plain and simple.
    Glad to hear some don't feel a difference.
    I don't really understand where you're coming from. Other than DH, 15mm is and has been the standard for several years now.

  16. #16
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    Quote Originally Posted by 1rider View Post
    Thanks for the replies however I still don't see an answer to my question, why fork companies have gone to 15 mm in this wheel size? I run a fox 36 w/20mm axle and love it, plain and simple.
    Glad to hear some don't feel a difference.
    Short answer. The xc crowd was never going to adopt the 20mm axle, but they did need something better than dropouts. Contrary to the opinions on pinkbike, the xc/trail segment is still the biggest segment of mtb.

    Once created, fork companies needed to decide which standard to adopt for long travel trail bikes. Axle is only one component of overall fork stiffness and 20mm is not noticeably stiffer based on axle alone. 15mm is winning out on these markets because it reaches the widest audience, even if 20mm complain.

  17. #17
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    Quote Originally Posted by madsedan View Post
    You guys must be bombing some serious hills to be complaining that a 15mm and 34mm stanchion is "too flexy".

    My weight varies between 225-235# and riding flow EX's on a 32mm stanchion 130mm fork with 15mm axle had no discernible flex in XC/trail riding. Any flex that occurred I couldn't detect so it obviously didn't effect my riding and I wouldn't want the extra pound of weight off the front of the bike when running a 36mm fork with a 20mm axle.
    This brings up another point. Most of the 36mm stanchion forks are 20mm, whereas the 34mm and 32mm are 15mm axles.

    Still, I just think 15mm was unnecessary when it came out and I still think 15mm is silly. Everything should've just stayed 20mm.
    We Ride In God's Country!

  18. #18
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    Quote Originally Posted by myitch View Post
    Still, I just think 15mm was unnecessary when it came out and I still think 15mm is silly. Everything should've just stayed 20mm.
    It pretty much has... What forks were available with 20mm before that are only 15mm now? It's a few Rock Shox XC forks like the Reba IIRC had a rare 20mm option but for the most part 15mm comes on forks and bikes that didn't even have through axles before like hardtails and race bikes.

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