I’ve got a venerable Fox 36 set of forks (probably about 2015) and the thru axle has started to stick. I used yo use the 20mm axle but started using a 15mm axle about 2 years ago when I changed wheels. I’ve never had a problem with the axle but now it is binding so much, I’ve got to drift it out using a big Allen key and a rubber mallet.

Any ideas why the might have started to happen? I’ve ordered a new axle in the hope it solves the issue. Using a dt Swiss 350 hub if that makes any difference.

Have you tried cleaning everything and applying little grease?

The push in end caps on some hubs can distort quite easily during servicing, they don’t need to be much out of round to cause a problem as they’re such a precise fit. If finances or availability are a problem then try a bit of wet and dry on a dowel round the inside, carefully!

Is it bent?

Does it work easily enough without the wheel in? Get an idea if it’s the fork or the hub.

Yep, what Onza said. And also, if you find it’s definitely the fork, then if you still have the 20mm axle try that and see if it fits.

If they’re ’15s with the choice of 15mm and 20mm then they’ll have the pinchbolts in the fork legs and the wee inserty things so there’s a bit of room there for parts to misbehave

It is all cleaned and greased. I already tried the axle with the wheel out and it is definitely sticking in the hub. The hubs seem to have a couple of ring spacers inside the hub and I think it is binding on them. I’ve seen a woolftooth replacement axle that has a narrower bore for parts of the axle and I’m wondering whether that would work but it looks very different to the fox axle at all points along it, so I’m not sure it will fit.

So … a new standard Fox axle has fixed the issue. Still can’t see what is wrong with the existing axle as can’t see any corrosion or damage on it. Ah well.