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700c 26inches

ThanksByeThanksBye Posts: 884
edited December 2008 in The workshop
Would it be possible to run 26'' wheels on a 700c frame?
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  • redddraggonredddraggon Posts: 10,862
    If you are using disc brakes - Yes.
    I like bikes...

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  • wgwarburtonwgwarburton Posts: 1,863
    Hi,
    700c rims are (622/2) mm from the axle, 26" rims are (559/2) mm, so the fundamental difference is this 31.5mm change: If you have rim brakes they won't reach.

    The secondary issue is that your bike is now closer to the ground- it'll be easier to put a foot down but you're more likely to ground the BB over a bump or suffer a pedal strike when cornering. This will probably be mitigated by bigger tyres, but watch out for lateral clearance- frames made for 700c wheels are often built for narrower tyres, so a fat 26" tyre may not fit. A 29er frame would have clearance, I guess?

    There are some tertiary issues with chainline, mudguards, maybe shift-indexing? etc that might trip you up but probably won't matter enough to be a showstopper.

    Cheers,
    W.
  • Buns has got the right drift, but the figures he gives are for the diameter of the wheel, not the radius. So the frame will be ~16mm lower, and the rims will be 16mm lower than they used to be (relative to the brake pads).

    I can see mudguards to be a possible issue, but I wouldn't have though that chainline and indexing would be affected at all.
  • wgwarburtonwgwarburton Posts: 1,863
    ansbaradigeidfran writes:

    > Buns has got the right drift, but the figures he gives are for the diameter of the wheel, not the radius...

    Those would be the figures I'm dividing by 2, would they?

    622-559 is 63mm, by my calculations. Curiously, that's twice 31.5....

    Chainline & indexing arn't affected by the change in wheel diameter, but by the likely substitution of an "ATB" wheel, dished and spaced for a chainline of around 47mm for a "road" wheel, set up for something like 43mm. Probably not enough difference to be a showstopper but the sprockets are likely to be in different places and the drivetrain may not quite work quite as well as it should.

    Cheers,
    W.
  • whyamiherewhyamihere Posts: 7,336
    Chainline & indexing arn't affected by the change in wheel diameter, but by the likely substitution of an "ATB" wheel, dished and spaced for a chainline of around 47mm for a "road" wheel, set up for something like 43mm. Probably not enough difference to be a showstopper but the sprockets are likely to be in different places and the drivetrain may not quite work quite as well as it should.
    Nope, not an issue. You're forgetting the difference in OLD between a road hub and an MTB hub. MTB hubs are 135mm, roadie ones are 130mm. The extra width of an MTB frame compensates for (and is the reason for) the greater chainline measurement. Basically, put in a hub that fits and it will index perfectly.
  • ansbaradigeidfran writes:

    > Buns has got the right drift, but the figures he gives are for the diameter of the wheel, not the radius...

    Those would be the figures I'm dividing by 2, would they?

    622-559 is 63mm, by my calculations. Curiously, that's twice 31.5....
    :oops: Sorry. I completely blanked out the "/2" bits somehow.
  • nicklousenicklouse Posts: 81,520 Lives Here
    Would it be possible to run 26'' wheels on a 700c frame?
    has the frame got disc mounts? or drop outs suitable to take a disc adaptor?

    New fork needed.

    then there is finding a suitable hub if you are going discs...

    Putting 700c onto an MTB is easy...

    But saying that there are many hybrid 700c frames out there with disc mounts and 135mm OLD spacing so it does really depend on where you are starting from.. but if it os not disc ready i would not bother.


    Unless it is a fixie :wink:
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
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