fork oil weight ?

I'm completely new to modern suspension stuff, so please bear with me if this is completely obvious or has already been covered!

I want to reduce the travel on my new RS rebas to the minimum, so need to take them apart and install the extra spacers. My doubt is with the oil I need when putting them back together again. the RS manual indicates 5wt oil for the upper tube, and 15wt oil for the lower leg. This may be a daft question, but do I really need two different weights of oil, or can I get away with using the same weight in both places? Am I likely to run into problems, void the warranty, or anything else that wouldn't be good?

I assume I can just use motorbike oil, as it's a lot cheaper than the official bike stuff?

thanks, Andy

of course you can use whichever in each place but the forks will be crap. they spec that for a reason
it'll alter the damping properties so might be too quick/slow to compress or come back up.

needs to be fork oil afaik for rockshox. be it motorbike or mtb. they Don"t cost a lot and I buy the mtb as they seem to make the lighter weight and work for me.
get the same brand and you can usually mix them to make the in-between weight to tune the forks to your liking or for other forks.
for the sake of 5 quid for not buying the other weight it seems like a no brained to me.

That's what I thought the answer might be...

Thanks!

As a side, if you run retro forks or probably some others.
5wt (e.g. mag21's) and the mix of 5 and 15 i.e 7.5/8wt (e.g. judy and bombers) are commonly used weights.

Also check as your doing it yourself, see what tuning you can do, lightweights or heavy weights there might be a better oil setup suggestion rather than just stock.
Also get some fork grease, you normally need it for bits and bobs on them.


oh and of course, get some other people opinion, I'm not too 'up' on modern forks.

You may find you don't need to add any oil at alll, unless you're doing a mini service. I'm not sure about Rockshox but on both Magura and Fox adding the spacers is a quick "undo the bottom nuts, slide out the stanchions , fit spacers and put back together" job.

The 5wt oil will be for the damping circuit in the upper part of the damper leg (drive side if I remember rightly). You'll need to refer to the manual for the exact oil volume required.

The 15wt oil is simply there to lubricate the bushes and foam wiper ring just below the dust wipers. You only need a few cc's of the 15wt oil in each leg.
In practice you can get away with using 5wt in the lowers as well, but it's preferable to stick with 15wt.

As mentioned though, it may be possible to remove the spacers to alter travel without draining the oil.

No idea
Tastes not too bad though,a bit velvety

It weighs fork oil.