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  1. #1
    Drops small screws noteon's Avatar
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    Crank arms in general, Xootr Swift in specific

    I know this must already have been covered someplace, and I did try the search feature before posting, I swear.

    I have a Sram Dual Drive and 11/32 cassette on my new Xootr Swift. The pedaling feels small, so I think what I want is longer crank arms.

    Never having done this much customization on a bike before (and being new to learning about drive trains in this much detail), I have two questions:

    1. Does my conclusion (that I need longer crank arms) make sense?
    2. What else don't I know enough to ask?

    Thanks much in advance. If you're interested, my Swift customization thread is here, and bike specs are here.
    Last edited by noteon; 07-10-08 at 07:22 AM.
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  2. #2
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    How long are the crank arms now? If they are too long will they hit the ground when you corner? Change the chain gear?

  3. #3
    bac
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    Quote Originally Posted by noteon View Post
    I know this must already have been covered someplace, and I did try the search feature before posting, I swear.

    I have a Sram Dual Drive and 11/32 cassette on my new Xootr Swift. The pedaling feels small, so I think what I want is longer crank arms.

    Never having done this much customization on a bike before (and being new to learning about drive trains in this much detail), I have two questions:

    1. Does my conclusion (that I need longer crank arms) make sense?
    2. What else don't I know enough to ask?

    Thanks much in advance. If you're interested, my Swift customization thread is here, and bike specs are here.
    Crank arm length is a personal decision. However, in terms of geometry, those with longer femers (and feet) are the best candidates for a longer than normal (172.5 in general for a road bike) crank arm. You'll have to actually ride a bike with longer crank arms to find out if it works for you.

    ... Brad

  4. #4
    Drops small screws noteon's Avatar
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    Much appreciated.

    They're currently 170mm. The crank arms on my road bike are 175mm, and I'm fine with them. Does that mean I've identified the wrong culprit for this sensation of pedaling "small?"

    I don't know how to calculate how long I can go before I wander into pedal strike territory, but I can't imagine another few tens of mm would put me over the line... would it?
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

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  6. #6
    Air
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    Quote Originally Posted by noteon View Post
    Much appreciated.

    They're currently 170mm. The crank arms on my road bike are 175mm, and I'm fine with them. Does that mean I've identified the wrong culprit for this sensation of pedaling "small?"
    One large camp of riders will swear that you'll feel a huge difference going up to 175s. I changed mine to 180s and felt the differences immediately. Another camp will say it's only 5 mm and it's all a marketing thing.

    If it feels 'small' and you have 175s on your road bike I'd say you'll feel the difference upgrading to 175s. Your lbs may have a used pair in the parts bin in back which would only set you back $25 or so. They're easy to install (if they're standard) so it could be a cheap experiment.

    I don't know how to calculate how long I can go before I wander into pedal strike territory, but I can't imagine another few tens of mm would put me over the line... would it?
    Naw - it may mean on some turns you'll want to really remember to have your near pedal up instead of down to avoid it.

    I have noticed a lot more pedal strikes when I put my kneesavers on - really have to be on top of that.

  7. #7
    Drops small screws noteon's Avatar
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    Quote Originally Posted by Air View Post
    it may mean on some turns you'll want to really remember to have your near pedal up instead of down to avoid it.
    You mean that pointless anal-retentive habit is actually going to come in handy? Cool...
    RIDE: Short fiction about bicycles • RUSA #5538
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  8. #8
    Senior Member Bill Kapaun's Avatar
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    IF you are comfortable with 175's, go for it.
    I've had the opposite problems with 175 being too long for my bad knees. Going to 170 upped my (very low) cadence by 20+%. It was a very different pedaling "dynamic".
    I would take a bit different approach with your style before switching though. Try a consciously faster cadence with a lower gear for a few days. I found I was a bit faster with a lot more stamina.

  9. #9
    Drops small screws noteon's Avatar
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    Interesting, thanks.

    I've been wanting to do a little less spinning and a little more pushing so I can get better on hills, but I think I have New Bicycle Syndrome, where everything just feels different. I think I'll give it a little while to settle before I change anything else.
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

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