ASMike

At the moment, I've been trying to move all my bike parts onto a second hand Cannondale T700 frame, as my old one broke in half from an accident. Pretty much all my parts on the old bike can be used, beside the Caliper brakes (the frame uses Cantilever/V brake). The only problem I'm encountering at the moment is my rear wheel. It's 126mm while the frame is 135mm.


I've been searching around the internet with regards to respacing frames, and the general consensus is to not respace/cold set aluminium frames. But a lot of the examples I've seen is with regards to widening the frame. So I was wondering if the same is true for clamping down a frame, or would the quick release be able hold onto the clamp and not burst open in the middle of a ride.


If that's a no go, is there a way to extend the axle from 126 to a 135?

Bill Kapaun

Just get a longer axle.
Add 9mm spacing on the NDS.
Redish the wheel by slowly & evenly tightening the NDS spokes.
You now have a stronger, more symmetric wheel.

ASMike

Oh, didn't realise I can take the axle out. Is there anything I should look out for in an axle, like depending on the wheel, or are they somewhat standardised?

Bill Kapaun

If it's a Quick Release axle, you'll want a 146mm replacement. Nutted you need "long enough".
QR axles are typically 11mm longer than DO spacing.

andrewclaus

If you didn't know you can take an axle out, I assume you've never rebuilt a hub. Removing an axle involves removing all the bearing parts and reassembling carefully in a fairly exact procedure. Fine adjustment is very important. You would need a couple of inexpensive special cone wrenches.

And wheel dishing and truing similarly requires careful and exact work, and some knowledge of spoke tension limits. And more special tools--a truing stand and dishing tool would make it much easier. But those are expensive.

If there's a bike coop in your area, there's staff there to help out and access to the tools.

ASMike

Yeah I went to my local bike co-op/recycling place to see if they can help, they said it might ruin the hub and just swapped the back wheel for another one that fits *shrug*. Ah well then.

Thanks for the help anyway

Bill Kapaun

That's absurd.

Dave Mayer

I volunteer at a high-volume, big city bike Co-op. In the best case scenario, modifying a 126mm OLD wheel to 135mm will take about 30 minutes of dedicated attention from someone who has done the operation several times. This is assuming a plain-vanilla Shimano hub, and no unexpected difficulties, such as the hub nuts corroded tight onto the old axle, or the cones needing replacement. Or what used to be ball bearings have turned into iron oxide filings. Or we find that the freehub is locked-up and needs a replacement.


Since this will require re-dishing the wheel, this best case also assumes no missing spokes, spoke nipples not corroded tight onto the spokes, a rim with no flat spots, etc.


I sympathize with the assessment of the Co-op in question. They are probably overrun this time of year; we are.


Working as a mechanic at our Co-op, although immensely rewarding, is more challenging than working at a regular shop, as we cannot just take a bike from a client, give them a ticket, and ask them to come back in 2 weeks with a Gold Card. We have to diagnose and solve complex challenges on bikes with mostly low-end, obsolete components. This has to be done quickly, in real time, with the client right next to us. We draw upon an inventory of donated parts, of which at least half are damaged/unrepairable, sometimes subtly so. So we have to become experts on all the things that can go wrong with bikes and components, and then try and anticipate what is seriously wrong with a donated derailleur or brakeset.


Finally, all of this has to be done at almost no cost, and to high safety standards. To many of our clients, $5 is a Big Deal.

Bill Kapaun

I understand WHY they don't want to undertake the task. A lot of time with little "obvious" reward. Just redishing the wheel can be problematic if the nipples are corroded tight.

However, The OP should get an ACCURATE explanation instead of an INCORRECT excuse.
They may have taken in a Free Hub wheel and left with a Free Wheel hub. Definitely a down grade.

ThermionicScott 

Adding 8-9mm to the left side of a 126mm hub would give one a really strong wheel in the end, but if I had a 135mm bike in my hands, I'd take that as a pretty clear sign to upgrade to 8-10 speed. Building out a 130mm hub to 135mm yields a pretty strong wheel, too.