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  1. #1
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    Changing 29er fork to 650b with more travel to get slacker head angle?

    I have a dated 29er with 80-100mm travel, if I could fit 650B wheels and tires, but get a new 650B fork with more travel, would that give me a more slacker angle, and raise the bottom bracket close to it's original location ?

  2. #2
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    depends on how much more travel the fork has. I would be conservative with this. if the frame was designed for a 80-100 fork, it was designed to be strong enough to handle for forces put on it with a fork that long. if you go considerably longer, it might compromise the strength of the frame.
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  3. #3
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    You would need to check the A2C (axle to crown) measurement of the forks you're looking at. As Turtle said, your frame will have been designed around a specific A2C length, so you could safely go to a similar length 650B fork which would give you roughly 30mm more travel without worry and mostly 20-30mm more A2C should be OK for frame integrity.

    Yes you will then slacken out the HT and ST angles and raise the BB back up a bit with the longer fork, but not sure if it'll be higher than it was setup as a 29er as comparing like size 2.3" tyres, a 29er is about 1.5" taller overall, which translates to about a 3/4" taller BB, but then you have the 3/4 lower BB from the 650B tyres/wheels.
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  4. #4
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    You're going to go 650b on the front and stay 29 on the back? Putting 650b front and back will likely drop the BB enough that lengthening the front probably won't compensate unless you go really long.

  5. #5
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    Quote Originally Posted by MSU Alum View Post
    You're going to go 650b on the front and stay 29 on the back? Putting 650b front and back will likely drop the BB enough that lengthening the front probably won't compensate unless you go really long.
    That wasn't the plan, it was 650b on both, so I could get more volume, but you did give me the idea of just going 650b in the back

  6. #6
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    Quote Originally Posted by madpanda View Post
    That wasn't the plan, it was 650b on both, so I could get more volume, but you did give me the idea of just going 650b in the back
    You really didn't mention any details, what bike, if you want to go plus, if you just want to slacken head angle...we're mostly just guessing.

  7. #7
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    Quote Originally Posted by MSU Alum View Post
    You really didn't mention any details, what bike, if you want to go plus, if you just want to slacken head angle...we're mostly just guessing.
    You are absolutely right, honestly none of it would make sense since I really don't know what I am talking about, so I can't really convey it correctly. my bad.
    Ultimately I was trying to figure out a way to have more volume so I can roll harder on ruts and tree roots. I was also hoping to make my head tube more slack so I could take the down parts with more confidence. All this without having to buy a new bike. Thanks for your help, but if there was a way to do what I want easily, it would probably be common knowledge. I now have to come to terms with putting my steed down, and going with the new trend. Or buck up and become a better rider with my current tool set.

  8. #8
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    Go with bigger tires?

  9. #9
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    I'd go with a better/more fun/more appropriate-to-your-style bike.....then become a better rider.

  10. #10
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    You can put wider rims with high volume rounder profile tires on your bike. You can go to 2.6 on a non Boost Rockshox or Fox 100mm fork with a 40mm inner rim width. 35mm rim on the back with a 2.35 possible. Bontrager XR2 Teams are tires designed like that. Frank Stacy design. 30mm if the 2.2 is all you can fit on the rear. You'll have sidewall support so you can lower your tire pressure way down for a bigger footprint. It'll up your confidence because you'll now slowly slide out when you begin to lose traction. You get time to correct and change your line. Way more fun. XR4 for loamy soil.

  11. #11
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    Roughly, if you replace a 100mm 29er with a 140mm 27.5 wheel and fork, it'll be the same height and head tube angle.

    If you want slacker, get an angleset, longer fork, or both. Changing to a smaller front wheel is the opposite of what you want.

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