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2.5 weight oil in Pike or Boxxer...?

Cant Climb

Turbo Monkey
May 9, 2004
2,683
10
RS reccomends 5wt but i was going to try so 2.5 wt. The trails here are seriously rocky and my Pike seems to spike quite a bit....so just thought i'd try it on this next oil change..

It was discussed in UDI's boxxer tuning thread of trying it (to reduce compression spike).....anyone ever do it....?..
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,917
1,211
Motion control doesn't spike hey, especially if you're not running any compression damping like the majority of people out there. If you're running loads of LSC then maybe, but even then the floodgate will sort things out. If the LSC is open, oil weight changes won't do anything, end if you're running some damping, IMO the setup works better with slightly thicker oil anyway.

I'd look at other things, like making sure the seals are well greased, and lowers/bushings well lubed. Run stanchions through bushings by hand to make sure they aren't tight.

Also the pike runs foam rings between seals/wiper (which are really cool, I run some in my boxxer) so you can use those to help with the grease packing.

My personal recommendation is -
Silkolene Pro RSF 5wt for damper, 10wt for lowers, 2.5wt for air spring (if you have one)
Grease between the wipers/seals with silicone grease, grease up the coil spring if it's a coil pike, and if it's an air pike, make sure you're running adequate negative air - the fork will get really harsh if you run too high a positive to negative ratio. Try all that and see how you go, if you're not happy, something is wrong with the fork.
 
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Cant Climb

Turbo Monkey
May 9, 2004
2,683
10
My personal recommendation is -
Silkolene Pro RSF 5wt for damper, 10wt for lowers, 2.5wt for air spring (if you have one) Grease between the wipers/seals with silicone grease, grease up the coil spring if it's a coil pike, and if it's an air pike, make sure you're running adequate negative air - the fork will get really harsh if you run too high a positive to negative ratio. Try all that and see how you go, if you're not happy, something is wrong with the fork.
Are you saying to use the 5wt, 10wt, 2.5 all in the same fork......?...or switch the 5wt for the 2.5 if it is air......?......also, would you reccommend the same oils for the Pike Vs. Boxxer WC.....

I have a Pike UTurn Dual Air.......It is great on medium rocky stuff but on trails where all you see is rock it seems harsh. I am comparing it to the ride of an old Z1. Less negative air seems to help a bit at high speed but of course it is a bit more rigid at low speed. Was just wondering if the lighter oil (2.5wt) would pass through better at higher speeds.....

FYI, i have never rebuilt the fork but looking to do it in the next couple days. So just trying to do it right the first time......just got the Boxxer (used) so haven't ridden enough yet to understand what it's doing or not doing....the Pike i have alot of time on.....
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,917
1,211
Nah read my post again, the fork has many different points of function that need different oil viscosities. I think you're missing the point though - a rebuild will probably do you good (re-read my post for specifics), running a lighter damping oil won't really do anything, especially if you are running little to no compression damping.
 

toodles

ridiculously corgi proportioned
Aug 24, 2004
5,646
4,970
Australia
When I tried 2.5wt in motion control I found it actually made the fork harsher as the lower viscosity tended to run through the LSC circuit rather than force the HSC circuit to open.