Am considering my options for some new (secondhand!) forks.

I currently run Marzocchi freerides with normal qr axle. Having managed to blow my seals shortly after fitting new ones I want to avoid this happening again any time soon.

I ride jumps and drops (sometimes badly!) and can appreciate how 20mm axles might be the way to go but also want to avoid having to have a new hub.

If the consensus is that seals might survive longer with a 20mm fork due to reduced twist then I will probably be swayed from 9mm qr forks.

What do you think?

Thanks! :o)

Having managed to blow my seals shortly after fitting new ones I want to avoid this happening again any time soon.

fit them properly?

erm… yep I believe I did fit them properly!

it’s kinda difficult to fit fork seals incorrectly but if you did it would become apparent very quickly. when fitting them are you sure you refilled the fork with the correct oil weight/height/volume? and have them set up with the correct spring rate too?
Sorry, I have no knowledge of your particular forks internals but you probably want to work out what caused your seals to “blow” before seeking a solution.

What is your definition of a blown seal BTW?

a nice stiff 20mm axle fork “should” twist less so I suppose bushing wear “should” be less and torsional forces on the seals less also but seals being elastic should be able to deal with this fairly well.
Removing your front brake would make a bigger difference to longevity of your bushings than the difference between QR and thru axle would IMO.

Forks now permanently leak oil… 🙁

Oil weight and volume correct as far as I know.

I didn’t enjoy the process (or cost) of fitting seals so want to avaoid having to do this again any time soon!!

Am thinking that the twist of a qr fork can’t help with seals maintaining their seal but your suggestion of seals being flexible is noted thanks.

If there is a link it’s probably so insignificant that it will not make a big difference. The bigger cost than a new hub is probably new lowers or forks that have a 20mm axle

I’d never even had considered this as a factor in how long my fork seals last.

If there is a difference it would be tiny.

Buy 20mm forks if you like – they are an improvement over QRs in terms of stiffness but don’t buy them for fork seal longevity as I would not expect any difference

Are you sure the oil seals (i.e. the lower set of seals) are in the right way up?

First time I did mine I got it wrong, all the oil came out over the course of about 4 rides. They were even plusher than usual with all that lube on the dust seals, though!

Thanks for the replies!

Pretty sure seals are in right way up.

Yes I appreciate that 20mm forks are better for stiffness.

I think it may be my scrappy jumping technique making them blow!

Further thoughts welcomed! :o)

In short no, my three ride old Marazochi 55rs 20mm through axles blew the seal and were peeing oil even stood upright because of the little air left in the preload.
New seals fitted by LBS but they’re my spare forks and I haven’t ridden them yet………lovely smooth coil travel and super rigid with the 20mm axle, no rubbing brake disc noises caused by flex in the legs…..I’m 17 odd stone by the way so really can tell the difference between QR set ups and 20mm axles.