RE: [CR]Running new drivetrains on 120 mm or 126 mm bikes

(Example: Framebuilders:Rene Herse)

From: <"">
Subject: RE: [CR]Running new drivetrains on 120 mm or 126 mm bikes
Date: Wed, 25 Jun 2003 17:58:47 -0400


As far as trying to fit a modern 9/10 speed (130mm) setup into a 120mm frameset:

I'd suggest that you try finding a freewheel type hub, and find an index-friendly narrow freewheel. Then you (probably) could use a modern Ergo setup with fewer gears.

You will likely have to modify a modern Ergo lever to change out the right lever's indexed shift cog to correlate to the slightly wider spacing on a Compact 6 or Compact 7 freewheel.

Branford Bike (in Connecticut) has a good website for Campy interchangibility. But your task does require some expert experience, and I recommend that you consult a local expert.

As far as dropping a 9/10 speed 130 mm setup into a 120mm frameset: Forget About It! Because:

I doubt very much that you can run a Campy 130 mm 9/10 speed hub in a narrow 120mm frame. You would have to remove 1cm of axle length from the left side of the rear hub. I'm 99.99 percent certain that there isn't enough margin to remove the original left side locknut and substitute a thinner one.You could only try to do this on the older 8/9 speed hubs (1998? or earlier, with a steel axle).

The modern alloy axle hubs (I believe) have no margin or spare parts available for this modification

In any case, this modification will make the dish of the rear wheel significantly worse, with the drive side spokes (probably) vertical.

You might be able to do a modification to a Campy 7 cassette hub (if you can find one) to fit 126 into 120, but the same risks exist, only to a lesser degree. I recall that Campy 7 cassette splines are different than 8 or 9 speed (also not interchangeable) so you will have difficulty also finding a 7 speed Campy cassette.

Your best bet is to stick to a freewheel setup, if you try this at all.

Have you checked your brake caliper size requirements? Your task is feasible here only if you originally used short reach, allen bolt calipers.


Andrew Gillis (Long Beach, CA)

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