Cycling UK Forum

This is a funny question but it just occurred to me the other day that there might be some incompatibility between a nutted axle wheel in a fork previously (and originally) used for QR wheels. And of course vice-versa.

I haven't even tried it yet but I think I picked up a passing reference somewhere so thought I would run it past the forum. I can't see a problem but I might be missing the obvious.

Thank you.

Hi,
Old style nutted axel could be 3/8", which is 9.52mm.
Shimano stuff tends to be 10mm nutted, which is also what your QR axel will be. There will be exceptions.
The threaded part of axel which will go in the dropouts will be a shade down off the stated size.
Horrible idea locating off threads, pretty unique to bicycles, not what you would do in engineering anywhere else.

I am not sure that old 3/8" nutted dropouts will be too small to accept 10 mm, a file will ease that.
Common for paint to make axels stiff into dropouts, burrs from nuts clamping in dropouts too.

As for fitting 3/8" axel into a 10mm fork dropout, its not far off and probably wont bother anyone.

If you have brake alignment problems after replacing wheels, disc or rim, once you have it set up correctly mark the top flat of locknuts on axel with tipex / white marker and always line up when replacing wheels.
Always weight bike before clamping axels.

Thanks very much for that NA. I hadn't even considered the axle diameter itself.

maybe try and source some nutted skewers? i think some usehex keys to undo, I think I was told that real nutted axles are not as strong as skewered axles as the first is stretched where as the second are compressed?

Hi,

mercalia wrote:maybe try and source some nutted skewers? i think some usehex keys to undo, I think I was told that real nutted axles are not as strong as skewered axles as the first is stretched where as the second are compressed?

Yes, normally a QR axel will be more reliable for the reasons you said, Brucey will also say that good quality solid nutted axels will be fine.
Citing that a hollow QR axel is almost unbreakable, unless the axel is poorly fitted.
Some shimano freehub cassette hubs were also nutted but I am not so sure that when the freehub first appeared it was nutted, I think that both versons were used, whether the nutted version were only intended for MTB or a cheaper line freehub I don't know, the actual release date of the freehub is a bit vague.
I attempted a swap for a 3/8 nutted axel to a 10 mm qr axel, unfortunately 1000 miles and the cups were worn.
Freewheel cheap Chinese cups and shimano 10 mm QR cones were not a good mix, it could be said that the two would not mix, BUT in my experience Freewheel axel bearings have a very limited life-
Be careful mixing 3/8" and 10 mm QR cups, some nutted axels are also 10 mm.
Six months and the cones were worn through the hardcase in the seventies, Freewheels of the day were suspect quality.
Then enter shimano freewheels and the Freehub
1000 miles on the turbo (Chinese freewheel) recently.
And my case above on mixing parts.
No doubt that say sturmey archer axel bearings are of better quality.

Imperial nutted axles are 5/16" front 3/8" rear. Metric ones tend to be 9mm and 10mm. As an oddity; I have a pair of Suntour hubs, 9mm and 10mm, but the nuts all take the same 15mm spanner instead of the front being smaller as might be expected.

Hi,

tatanab wrote:Imperial nutted axles are 5/16" front 3/8" rear. Metric ones tend to be 9mm and 10mm. As an oddity; I have a pair of Suntour hubs, 9mm and 10mm, but the nuts all take the same 15mm spanner instead of the front being smaller as might be expected.

Honestly I have never given it a second thought, that the front was different from the rear
Probably because there is never anything to do with front axels, its always rear stuff that needs work, and I have never tried mounting a front axel in the rear or vice versa.
I have some nutted front 3/8" generally used for mtb wheels.
The metric QR fronts tend to be 9mm.
Dawes 20" folder is 3/8" front nutted.
A cheap brand 20" folder has 5/16" front as you said with 15 mm nuts.
And a nutted freehub cassette which as you would expect metric 10mm.
Some disc front hubs can have spigoted ends at 9mm with adjuster nuts a larger thread, but why the front drop outs can be 10mm dead (9mm axel) where the rears are just a shade over 10mm (10mm axeI) have no idea.

Just looked at an abundance of front dropouts-
Many are 10 mm dead
Some are 10.15mm
A few are 10.6mm
And one is just 9mm dead. This is a old MTB frame, suspect that the front axel would be 5/16" (7.93mm)
I have a front suspension QR disc fork which seems to have massive clearance, and I have thought why, not measured just looked slack.
My 20" cheap folder still has the wheel in so not checked that.
Front dropouts can tolerate some slack but rears with vertical drop outs need to have a close clearance, otherwise the wheel will pull over with force from chain drive.
You learn something new everyday.

Well I tried them out (nutted on QR forks) and they fitted really snugly, no problems. However i noticed that the wheel wasn't true so I decided not to use it after all.

Thank you all for the replies - I've learnt a lot even if it's for next time!

Sorry to drag this one up from the past but I've come across a 9mm QR in a 10 mm fork drop out. This will be swapped out ASAP. I take it that this is the right thing to do.

But the other question is: would a new 10 mm axle (nutted/QR) fit on another bike with a 9 mm QR drop out? Or would it be a case of filing the fork drop outs? Or just trying it out (I don't have a 10 mm axle to hand).

font dropouts of 9mm and a 10mm for rears has been the de facto standard for the last 50 years or so. Older hubs used 5/16" nutted front axles and 3/8" rears. I would not modify a fork to anything over 9mm because it just isn't necessary. The reason for this is that every front hub you might want to fit can be adjusted to fit in 9mm dropouts. Both 3/8" and 10mm threaded axles can be very swiftly modified if necessary, using an angle grinder. This cannot weaken the axle in any way, since only the top parts of unused threads are ever removed.

BITD SA had a 3/8" threaded front axle in their dynohub design. They made it fit in smaller dropouts (often 5/16" at the time) by putting flats on the axle.

Brucey wrote: ↑3 Feb 2024, 7:21pm font dropouts of 9mm and a 10mm for rears has been the de facto standard for the last 50 years or so.

I've been looking through my pile of old 26" front wheels and took a couple off other bikes. All were 9mm. And yet the bike I'm interested in, an old Dawes Die Hard circa 1992, has 10mm drop outs. How rare is that?

I want to be able to interchange a new wheel between two bikes, one with 9mm drop-outs and this one with 10mm drop-outs. The wheel can have either a 9 or 10 mm axle. As things stand, AIUI I have to choose between one or the other!

BTW, I started this thread originally because of the possible differences between nutted and QR axles but what I see now is that the real issue was axle diameter.

I know exactly what I'd do in similar circumstances; I'd modify the oddball 10mm fork/wheel to meet with other 9mm expectations. Correct use of welding set and grinder required; not too difficult.

Brucey wrote: ↑3 Feb 2024, 8:30pm not too difficult.

For some!

Other people suggest using the 9 mm QR willy-nilly in the 10mm drop-outs. I'm also wondering whether they could be padded out with some sort of tape just to get a snug fit.

Having said that, I'm not greatly happy with either idea.

horizon wrote: ↑3 Feb 2024, 8:38pm

Brucey wrote: ↑3 Feb 2024, 8:30pm not too difficult.

For some!

Other people suggest using the 9 mm QR willy-nilly in the 10mm drop-outs. I'm also wondering whether they could be padded out with some sort of tape just to get a snug fit.

Having said that, I'm not greatly happy with either idea.

Removed

I think that provided the front QR/track nuts are tight enough, you won't have a real problem using a 9mm axle in dropouts designed for 10mm axles. i think this is more or less automatically the case with rear wheels because they are more highly loaded, more of the time. Any lack of tightness soon makes itself apparent. But it is possible to ride a bike, little knowing that the front wheel isn't really tight enough.