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100mm hub into a 90mm front fork

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100mm hub into a 90mm front fork

Old 10-13-21, 07:46 PM
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100mm hub into a 90mm front fork

Hi everyone, new member, first post.

Went down the vintage rabbit hole and now paying the price I bought a vintage Swedish Crescent road bike. Not sure the age, but it's a 10 speed with Huret components. Interestingly I thought the front fork was the standard 100mm spacing, but turns out it is 90mm. Does this make it an older bike or is it a French spec - despite being a Swedish bike?

Anyway, I bought a NOS 27" wheelset because the front and rear wheels were mismatched. Turns out the front was a 700C. So I thought I was doing the right thing buying a 27" wheelset but as the title of this thread says, the hub is 100mm but the fork spacing is 90mm. So what are my options?

Do I leave the new wheelset alone and find a vintage wheel with a 90mm hub?

Do I coldset the fork and try to gain 10mm spacing?

Or, and this is what I am leaning towards - do I grind down the lock nuts and to a degree the cones? The lock nuts are pretty beefy and I could easily find a couple of mm there, the cones could also be ground down a bit a still leave room for a thin hub wrench.

I feel more comfortable grinding down a fastener than I do pulling my forks apart. 10mm is not a lot, but also not insignificant. Maybe I can win enough by just grinding down the lock nuts and muscling the fork apart to mount the wheel.

Thanks for any suggestions!
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Old 10-13-21, 07:50 PM
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Spread the fork.
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Old 10-13-21, 07:52 PM
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I think you're right. Might mangle a pretty nice wheel by grinding things down.

Last edited by Stickers66; 10-13-21 at 08:12 PM.
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Old 10-13-21, 08:07 PM
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...the older French standards for front hub OLD were more like 92 and 96mm (that I have seen.)
The last time I offered an opinion on Crescent bikes, some guy was all over me like white on rice.

He lives there, and apparently has encyclopedic knowledge of Crescent bikes. So I'm not gonna venture an opinion other than to say I would just reset the fork by cold bending.

And this is a good chance to repost the Crescent Girl, who must be something like 90 years old now.

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Old 10-13-21, 08:14 PM
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Lol, you won't offend me, and this is hardly a restoration project. Basically I'm trying to recuse as much as I can, but new wheels, flat bar, new grips. The shifters, Mafac brakes, cranks, etc. are all in pretty decent shape. I'll starting reading up on cold setting the forks.

One other thing, The axle is slightly wider than the fork dropout - by I'm guessing 1mm. How did I find out? My threaded rod is 3/8" and I had to file down the thread. So once I'm done with the spreading and all is well, do I file the fork, or file down the axle (just in one spot of course).

Last edited by Stickers66; 10-14-21 at 11:39 PM.
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Old 10-17-21, 11:56 AM
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Front axles are often 9mm, and 3/8" is bigger than that. Put away the files until you've done more reading.
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Old 10-17-21, 07:23 PM
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I had the same problem with an old Schwinn once. I solved it by finding some very thin lock nuts for the cones. Shimano makes some very thin ones.
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Old 10-17-21, 08:38 PM
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I would take a third path, try to reuse the original hubs. I don't like the idea of reducing the thickness of the cones and locknuts, because they will be weaker than they were originally. Taking off several mm on each side seems like a lot. I once had a Campagnolo Record front hub locknut split, and I had not made any modifications. In old parts like we are talking about, no matter how plebian in the first place, it can be hard to find replacement small parts. So I would not take that path.

I also would not modify the fork dropout spacing if you don't need to. It can involve a lot of effort, and I'm discovering this now. It can also expose flaws in the original construction, like poor brazing or tubes that do not have the strength you think they do. These are problems which are invisible until you expose them, talk about rabbit holes!

What I would do first is to rebuild the bearings of the original wheels and make sure the cups and cones can be servicable. I.e, they are not excessively pitted, wheels spin free and smooth. But If the bearings can be adjusted, are smooth and free and the flanges will hold spoke heads, the hubs are basically sound. Then if there is need or desire to replace the rims I would do so without opening up unnecessary rabbit holes.
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