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I have a Trek 620 (Reynolds 531 lugged steel frame) from the mid-80s the rear dropouts are spaced at 126 mm. I'd like to be able to run an 8- or 9-speed cassette and I was wondering about the issues involved with running a modern road hub with 130 mm spacing without adjusting the frame spacing.

It seems to me that the rear triangle would have the ability to flex 4 mm without needing to be cold set – at the expense of a small misalignment of the dropouts.

Are there problems with doing this? Other than the slight hassle when installing the rear wheel?

Would it impact the value of the frame – the bike is a rider, probably not a candidate for a restoration (frame could use repainting and I'm not sure the components are original, the wheels definitely are not)?

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    No problem on a steel frame, with some doubts on an aluminium frame and an absolute no-go on carbon.
    – Carel
    Commented Oct 11, 2015 at 18:48
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    When 130 mm first came out, they had specially designed locknuts which made it easier to slip into a 126 mm frames. It's mostly an annoyance thing if you don't cold set it, given you're only going one size up. If you're going 2 sizes up (e.g. to 135 mm), you really should cold set it.
    – Batman
    Commented Oct 11, 2015 at 20:15
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    youtube.com/watch?v=QwxEPRk3LFg - nice technique to spread the dropouts. I haven't tried it but it looks easier than Sheldon Brown's method. Only works with steel frames.
    – obelia
    Commented Oct 18, 2015 at 0:02

4 Answers 4

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No need to cold-set.

I have a BSO with the same problem. The rear dropouts are about 6mm too close for the hub. I can just flex them apart and let the hub in.

The misalignment of the dropouts would be virtually nonexistent at 4mm flex.

If you remove your wheels often, and putting the wheel on is a pain, it might be worth cold-setting your frame. Other than that, don't bother.

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I've done this by putting an 8 speed free-hub wheel with a 7 speed cassette into a bike that had a 5 speed freewheel wheel.

The only issue is wheel fitting/removal - a bit of leverage to separate the dropouts and the wheel tucks in nicely. If you needed to do this on the road Murphy's Law may ambush you and make it fiddly.

Mounting the wheel square is awkward - I use a clamp on the brake lever to close the rim brakes, one hand where the tyre passes the chainstay, and the other hand to close the quick-release.

Functionally it works fine for me, I'm riding that bike in a 12 hour relay this weekend.

(Post-race edit) My 12 hour relay is over, and I noticed that the rear quick release was not great at holding the wheel. Every second lap (2x 13 km) I had to realign the wheel because it had started to rub on the left chainstay. Off road riding exaggerates the effect of distance - I could probably do 500-1000 km on the road to get the same loosening effect.

Collectively I think the not-quite-parallel dropouts plus the dropouts were never intended for QR so have no lips or roughenings, and the intense workout of carrying my fat arse down undulating singletrack made the rear quick release slacken off a bit quicker than normal.

Depending on your monthly mileage and the road conditions, it may never be an issue for you. For me checking that QR is now part of the maintenance check. If it gets really bad I will return to a solid axle with normal nuts.

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There's only 2mm on each of the rear triangles has to move. Sheldon Brown has an elaborate system using strings to make sure that the motion is symmetrical but I think this is rather overkill for anything but the most expensive/vintage bikes.

I cold set my 1975 Peugeot UO-18 to use a 9-speed cassette with no issue.

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Do not flex, otherwise wheel is probably not aligned with the frontwheel. Axle could be broken, because the dropouts are not longer parallel. If microfusione made they could crack. Better you have exactly the cogs you need, having different cassettes will help, if you are one day in the mountains, the next in the plaines.

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  • Gidday and welcome to SE Bicycles. Can you edit your answer - I'm not sure what you mean by "microfusione" are you trying to say "small weld" ?
    – Criggie ♦
    Commented Oct 18, 2015 at 1:10
  • It is a special kind of casting.
    – Joe
    Commented Oct 18, 2015 at 13:40

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