Could I fit a 126mm wheel in a 130mm dropout?

[Ross 1964]

The reason I ask is this.

My late 80s 531 frame has 126mm rear dropout, with Shimano 600 hubs suitable for a 126mm spacing.

I plan to get the bike resprayed at Jacksons and at the same time have the rear end re-spaced to 130mm, so that in future I can fit modern wheels with a modern 8 speed cassette (this will probably be my only road bike for the next 25 years or so!) but for financial reasons I want to run with my old (126mm) 600/Mavic MA40 wheelset until they get so tatty I need to replace them.

I'm thinking that there is no reason why I can't just fit shims (ie stainless washers?) at each end of my 600 hubs to make up the 4mm difference, is that right? Not ideal, I realise, but not unsafe, assuming the quick release clamps are nice and tight?

Thanks,
Ross.

 

[paininthe]

I wouldn't bother getting it respaced, spend the money on some lining instead. Then when you go 130mm just ease the wheel in, you will barely notice 2mm per side.

 

[Ross 1964]

I had pondered exactly that question but had figured I can't afford the lug lining - maybe if I don't bother with cold setting I can afford the lining after all...

 

[Ross 1964]

After a load more research on this question, there appear to be two schools of thought:

1. Squeeze the 130mm wheel in (provided the frame is not made of aluminium or 753) and don't worry about it, cold-setting is a refinement not a necessity. Many people have done this quite successfully, with no problems encountered, it would seem.

2. The frame must be cold-set from 126 to 130 and it should be done professionally. The reason for this is that it must include resetting the angle of the dropouts so that they are back into a parallel position relative to one another. If you don't do this, the QR clamps cannot hold the wheel properly and the force of pedalling will twist the wheel out of the non-parallel dropouts. Also having the dropouts non-parallel means that the rear derailleur is not alined with the sprockets, leading to potential gear changing problems.

So it seems there is not one "definitive answer", but two!

ANYHOO......

My original question (which assumes that I get the rear end cold set) was "Can I fit a 126 wheel in a 130 dropout?"

 

[paininthe]

Sheldon

Ideally, the frame spacing should exactly match the hub spacing. This makes for easiest wheel replacement. In practice, however, there's a fair amount of latitude in fit. In fact, when the first 130 mm 8-speed hubs were introduced, they had locknuts with beveled sides, so that you could "spring" apart the rear triangle of a frame made for the then-standard 126 mm spacing.

In general, you can safely go up one size in spacing this way, just springing the frame apart. I can't give you an absolute guarantee that this won't cause damage, but the odds are very much in your favor.

 

[paininthe]

"Can I fit a 126 wheel in a 130 dropout?"

The QR will pull this in, I've rode many miles with a road wheelset in a MTB frame. But washer if you wish but this reduces the axle in the frame (not that matters).

 

[foz]

The short answer to your original question is yes, you can.

You can either just squeeze the 130mm frame in to 126mm, or it's easy enough to add 2mm of spacers to either side of the axle and make the hub 130mm. There won't be as much axle actually in the dropout, but that's not a problem. You could always just buy the correct length (140mm?) axle for a 130mm hub and swap all the cones and spacers over if you really wanted to have the proper amount of axle, but it's not necessary.

You can also just add 1mm to each side, and make the hub 128mm, which only requires squeezing the frame by 1mm each side. Sort of a half-way compromise.

If adding spacers, usually the same amount each side is the best way to go. But check the chainline: moving the sprockets further inward may affect it. In that case, add all the spacers to the NDS and redish. This should also reduce the dish slightly, which if done properly should make the wheel a little bit stronger (more equal tension between both sides)