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  1. #1
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    New question here. XX1 gearing for 650b

    I'm getting a new Turner Burner with XX1, and am trying to match the gearing I currently have on my BlurLT w/26" wheels (32/22 front, 11-32 rear - running 2x9). My best guess is that I'd need a 28T chainring to pair up with the 10-42 cog, but I'm not 100% sure since getting accurate info on the actual wheel diameter differences between 26" and 650b seems difficult. The Sheldon Brown gear calculator seems to have a bug in it for the 650b option - when I compare its results to those of a 26 x 2.35 (60-559) for the exact same gearing, the 26" wheels show *more* gear inches. Should I be using the "27 inch (nominal)" option instead?

    -Sean

  2. #2
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    Sean, I'm running XX1 with the 32 ring. I also have a 26er with a similar setup as your 2x9 & yes the 28 ring will match it well. I don't know your riding level but for most people the 28 ring may be to small, youll be suprised at the range of gears the XX1 will give you. I tried using the gear calcs online too but you just have to ride it! I did a gravel road race 2 weeks ago with a lot of climbing. I never needed to get even close to the granny gear. I could have used a little more gear on some of the long descents. So if anything I may go up to a 34 or 36, especially later in the season as fitness improves. Good Luck!

  3. #3
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    SB's gear calculator has a spot where you can input the wheel circumference, at least it used too. Yes I bet that a 26'r with a 2.35 tire has as large or larger circumference that a 650b in a 1.9. Fat tire 26'rs have about as much circumference as a 29'r. Out on the trail I bet you will not even notice the difference between a 32 or a 28 ring front. So what if you are in a different gear? Have fun and ride, don't over think it!

  4. #4
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    I just ordered an XX1 kit with a 30 for 650. I'm occasionally the fastest guy on a ride. Spinning a lower gear to go faster is just a good idea. I have found that I run into problems when I try to mash a bigger gear for longer periods of time. I do a local 100-miler every year and the smartest thing I ever did was drop down to a 26-39 2x10 instead of a 42 3x. Singlespeeding helps me work on the spin and gearing down a bit helps on longer rides.

    Odd coincidence that I'm wearing my 'Gear Down' shirt from Family Bike Shop right now...

    mk
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  5. #5
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    Thanks folks. Sounds like my 28T choice will match my current 26" setup pretty closely, which is perfect. (I looked and I don't see where you can manually input the wheel circumference in the Sheldon Brown tool - maybe they've changed it.) I know my gearing looks low, but I wanted to try to match my current setup since I've been riding it for years and found I do use the lowest gear every once in a while. Not often, but when I need it it's really, really nice to have it, and I rarely miss having the top end. I live in Colorado and most of my rides involve some pretty gnarly/long climbs, and rarely have wide open fire road-style descents or pavement sections where a tall gear is useful.

    -Sean

  6. #6
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    XX1 gearing for 650b

    I'm running the 28t on my Carbine 27.5. My last bike was a stumpjumper fsr evo 2x10. The 28t - 42 feels very close, if not exact, to my 24-36 on the stumpy. My carbine is a few lbs lighter than the stumpy so that plays into it a little. I live in the northeast and have used the 42 a whole lot more than the 10.

  7. #7
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    My math (rounded up to the nearest even number) has:

    To match lows:
    28T X 42T on 650B ~ 22T X 32T on 26"
    40T X 42T on 650B ~ 32T X 32T on 26"

    To match highs:
    20T X 10T on 650B ~ 22T X 11T on 26"
    28T X 10T on 650B ~ 32T X 11T on 26"


    My low is equivalent to 32T X 32T on 26"; this is for AZ, NM riding. Like trailbildr says, riding a bigger gear for a longer ride is tougher. I'm good for a couple hours, even on tough tech climbs, but them I'm dunzo. I wouldn't mind dropping a couple teeth on the chainring.
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  8. #8
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    I'm anticipating a large gear-swapping market as people get settled on front rings on XX1. Is this the beginning?

    Damn you and your Carbine 275! I'm waiting to hear back about a Tracer 275... I'd rather fsr it (spec'd, norco) but ain't nobody got bikes right now.

    That Enduro looks amazing but I just can get over flexy 29r wheels for my adult-sized body...

    And I think the Sheldon Brown 650 calculator is set up for 650c road or 650b slick wheels/tires/bikes. I know that 650b was popular on some mtn-style touring bikes in Europe over the past decades. I rode one all over northern Ireland back in 2002.

    mk
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  9. #9
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    For what it's worth, I was running a 22-34 2x9 on my 26 inch bike with an 11-32 cassette.

    I recently built up a Tracer 275 with a XX1 28t crankset and a Canfield 9-36 Rear hub/microdrive setup with 10 speed X0 rear.

    I feel that the new setup is superior to the 2x9 and has same lower end with more range at the higher end of things.

    Just an option that is viable in case you didn't want to drop all that cash on the complete XX1 drive train.

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