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  1. #1
    official eMpTyBRain
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    650B wheels on a 29er frame/fork set?

    I assume this topic has been covered? Other than a very slight drop in BB height, is there any real issue here?

  2. #2
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    Quote Originally Posted by ambassadorhawg View Post
    I assume this topic has been covered? Other than a very slight drop in BB height, is there any real issue here?
    I don't understand the point. What would be the gain?

    It will still have long chainstays, and a long wheel base, with a lower BB, and smaller wheels. It's like taking away the good things about 29er, but keeping the bad.

  3. #3
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    I'm not really sure??? My 29er frame has "short" chain stays. I was thinking less rotational mass, slightly faster response riding techy terrain, and slightly tighter turning.

  4. #4
    usually cranky
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    its a pretty decent bb drop. probably in the area of 20mm. most 29ers already have low bbs as it is. id be careful if you ride rocky trails.

  5. #5
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    Give it a try - I did - worked just as you described.
    Lower BB - bike handled like a dream, but not ideal for technical terrain.

  6. #6
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    Do it in the back, which you don't need anyway. And shorten your cranks to take care of the BB thing. Speaking from a 5'5" Rider.

  7. #7
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    Quote Originally Posted by LukeSPOOK View Post
    Give it a try - I did - worked just as you described.
    Lower BB - bike handled like a dream, but not ideal for technical terrain.
    What frame/fork and what travel do they have?

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    B9er(b out back) felt good on my bros ride.
    '10 Marin MountVision 650b conversion

  9. #9
    orthonormal
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    Quote Originally Posted by ambassadorhawg View Post
    I'm not really sure??? My 29er frame has "short" chain stays. I was thinking less rotational mass, slightly faster response riding techy terrain, and slightly tighter turning.
    Since you'll still have the same wheelbase, it won't be much help in terms of tighter turning.
    The glass is twice as large as it needs to be

  10. #10
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by ambassadorhawg View Post
    I assume this topic has been covered? Other than a very slight drop in BB height, is there any real issue here?
    I do not consider 19mm (3/4") to be a very small drop in BB ht. For me it would take most frames into the not-suitable-for-trail-riding range.
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  11. #11
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    I made the change to my 2012 Trek Superfly from 29er to 650B with Stan's flow ex with Schwalbe RaRa 650B x 2.25" and tube setup. BB is about 11.75". Yes, it is lower but feels much more easier to pedale. Don't have much time to ride though.
    Attached Thumbnails Attached Thumbnails 650B wheels on a 29er frame/fork set?-rsz_1img_3518.jpg  

    Last edited by ckspeed; 10-24-2012 at 06:07 PM.
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  12. #12
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    Quote Originally Posted by ckspeed View Post
    I made the change to my 2012 Trek Superfly from 29er to 650B with Stan's flow ex with Schwalbe RaRa 650B x 2.25" and tube setup. BB is about 11.75". Yes, it is lower but feels much more easier to paddle. Don't have much time to ride though.
    Weight? And please, tell me how to paddle on a bike!!

  13. #13
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    Quote Originally Posted by donkeykong0 View Post
    Weight? And please, tell me how to paddle on a bike!!
    That is because the pedals are always hitting the ground
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  14. #14
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    Quote Originally Posted by shiggy View Post
    That is because the pedals are always hitting the ground
    So, you're saying my idea is dumb?

  15. #15
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    Quote Originally Posted by ambassadorhawg View Post
    What frame/fork and what travel do they have?
    I had a 2012 Scott Spark 29er with 100mm travel - had a chip attached to the shock linkage that can change the BB height by about .3" (or 7mm).
    I was hoping to change the travel on my Reba from 100mm to 110 or 120mm, to give some more height but was unable to.
    Had a 650b wheelset and a 29er bike, so had nothing to lose
    Found good acceleration, less gyro effect with 650b wheels and less weight.

  16. #16
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    I think converting a 26er may be a better id'er. The Santa Cruz TRc is a popular retrofit. Or hook up
    on a real one like a Jamis 650b. I really like my 650b conversions. And its not from any Kool-Aid talk either because I don't walk around recommending it to anyone, I just like the extra umph you get from climbing opposed to a 26 or 29 and the cornering on ST is less tedious on a than on a 29er...Good luck. And come over a ride one of mine

  17. #17
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    I'll try to be nice as people seem to think my replies are "Cruel" a lot

    I gave it a try, put a 650B on the rear of my Prime with it in the steep geo setting where the BB is about 13.4" (un-sagged) with 29" wheels, the pedal strikes alone annoyed the crap out of me, but I could work with that height, as d365 said, you loose all the benefits of the 29er platform and gain no benefit - I had tyres to test and both had more tread than my worn out old Ignitor I was beating on and on the same climb I cleaned previous on those Ignitors I lost traction with the 650B.

    I did it just to see if it would spin up easier, make getting up steep climbs easier since in theory it would accelerate easier, the wheel stayed on the bike for 2 rides because I had 2 650B tyres to test, that's it, case closed. Only time I'm putting a 650B anywhere it'll be on the front of a 26" wheeled bike, where you can gain some benefits.
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  18. #18
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    Yes

    The reason to use 650b wheels is to get some extra rollover/traction/etc without having to make some of the geometry sacrifices of going to 29" wheels (ie chainstay length, potential toe overlap, reduced suspension travel, standover, etc). There is pretty much zero benefit to converting a 29er unless you *really* hate how high the bb is and want to drastically lower it, and are otherwise ok with the geometry.

    One last quibble - while a 650b *wheel* is definitely easier to accelerate than a 29" one, a 650b or 29" *bike and rider* have so much more mass than the wheels (not to mention that when accelerating you also have spend a lot of energy to overcome various forms of friction, especially air and rolling resistance, that are unaffected by the size of the wheels) that you'd never be able to tell a difference while riding.

    -Walt


    Quote Originally Posted by LyNx View Post
    I'll try to be nice as people seem to think my replies are "Cruel" a lot

    I gave it a try, put a 650B on the rear of my Prime with it in the steep geo setting where the BB is about 13.4" (un-sagged) with 29" wheels, the pedal strikes alone annoyed the crap out of me, but I could work with that height, as d365 said, you loose all the benefits of the 29er platform and gain no benefit - I had tyres to test and both had more tread than my worn out old Ignitor I was beating on and on the same climb I cleaned previous on those Ignitors I lost traction with the 650B.

    I did it just to see if it would spin up easier, make getting up steep climbs easier since in theory it would accelerate easier, the wheel stayed on the bike for 2 rides because I had 2 650B tyres to test, that's it, case closed. Only time I'm putting a 650B anywhere it'll be on the front of a 26" wheeled bike, where you can gain some benefits.
    Last edited by Walt; 10-24-2012 at 08:58 AM.
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  19. #19
    just some guy
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    Quote Originally Posted by Walt View Post
    One last quibble - while a 650b *wheel* is definitely harder to accelerate than a 29" one, a 650b or 29" *bike and rider* have so much more mass than the wheels (not to mention that when accelerating you also have spend a lot of energy to overcome various forms of friction, especially air and rolling resistance, that are unaffected by the size of the wheels) that you'd never be able to tell a difference while riding.

    -Walt
    Do you mean that a 650b wheel is easier to accelerate, or am I just confused?

  20. #20
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    Fixed, thanks.

    My brain is apparently not working very well this morning.

    Quote Originally Posted by talabardio View Post
    Do you mean that a 650b wheel is easier to accelerate, or am I just confused?
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  21. #21
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    Quote Originally Posted by ambassadorhawg View Post
    So, you're saying my idea is dumb?
    Not if you like dragging your pedals on the ground
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  22. #22
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    Quote Originally Posted by Walt View Post
    The reason to use 650b wheels is to get some extra rollover/traction/etc without having to make some of the geometry sacrifices of going to 29" wheels (ie chainstay length, potential toe overlap, reduced suspension travel, standover, etc). There is pretty much zero benefit to converting a 29er unless you *really* hate how high the bb is and want to drastically lower it, and are otherwise ok with the geometry.

    One last quibble - while a 650b *wheel* is definitely easier to accelerate than a 29" one, a 650b or 29" *bike and rider* have so much more mass than the wheels (not to mention that when accelerating you also have spend a lot of energy to overcome various forms of friction, especially air and rolling resistance, that are unaffected by the size of the wheels) that you'd never be able to tell a difference while riding.

    -Walt
    A wheel that accelerates quickly also decelerates more easily.

    I have a road bike with 20x1-1/8" wheels. Very light wheels. Terrible climber. Feels like you are walking up stairs as the forward momentum almost stops at the bottom of each pedal stroke, and surge forward on the power stroke. Rollover ability is not even a factor here.

    My best off road climber is my fat bike, even for longer steep smooth trails, and my complete rear wheel alone weighs 10+ pounds.
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  23. #23
    The White Jeff W
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    I ran 650B on my Yelli Screamy for awhile. It has a 140mm fork so no issues with ground clearance. I really liked how it rode but eventually put the wheels back on the the bike they came from so I could ride it again.
    Attached Thumbnails Attached Thumbnails 650B wheels on a 29er frame/fork set?-yelli-650b.jpg  

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  24. #24
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    Ambassadorhawg---shoot me an email and come over and borrow this bike for a couple weeks.
    Its a pig though but its a 650b. Ride it up around our hillsides and see if the B is for you.
    Attached Thumbnails Attached Thumbnails 650B wheels on a 29er frame/fork set?-p4pb8632301.jpg  


  25. #25
    MTB B'dos
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    Jeff, care to give more in depth thoughts on what you liked or why you liked the 650B on your Yelli, quite interested to hear?

    Quote Originally Posted by jeffw-13 View Post
    I ran 650B on my Yelli Screamy for awhile. It has a 140mm fork so no issues with ground clearance. I really liked how it rode but eventually put the wheels back on the the bike they came from so I could ride it again.
    Not what the OP was asking about, but not a bad idea to see if in general he likes the 650B platform. Suspecting though that there's something about his Pivot that he just doesn't like, thinking it's the steep HA and its handling characteristics and that bike will handle totally different for sure.
    Quote Originally Posted by fatcat View Post
    Ambassadorhawg---shoot me an email and come over and borrow this bike for a couple weeks.
    Its a pig though but its a 650b. Ride it up around our hillsides and see if the B is for you.
    One day your life will flash before your eyes, will it be worth watching??
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