Oil and alternatives for Rockshox Charger Damper

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coarselanguagw

Likes Dirt
I need to replace the oil in a charger damper in a Rockshox fork.
I am a 95kg rider riding aggressively on black trails.

I am looking for advice on what oil to use.
Rockshox recommend a 3wt oil.
So should I just use this Rockshox oil?
I have also been told I can just use Maxima 3wt oil as well.

Someone in a shop said that they use a 10wt fork oil when servicing dampers as they think the 3wt stuff "is a bit thin".

Just wondering what everyone here recommends.
 
D

Daniel Hale

She fid, he fid, I fidn't
the maxima is slightly thicker, but yep a 5wt or above will b fine for your weight, as slow as i go i use the 3wt RS dropper fluid, very thin
 
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SummitFever

Eats Squid
Oil weight can make less of a difference in damping than you think. It's only when your bleed ports are fairly closed and on the hits are not big enough to open the shim stacks that the fluid weight will have a noticeable difference. Once you're talking fork velocities that have the shims open then the difference between 3wt, 5wt and even 10wt is pretty minimal.
 
The Duckmeister

The Duckmeister

Has a juicy midrange
Yeah, you can tune the fork with different oil weight; going heavier will slow the oil flow through the damper, thus increasing the damping effect, both in compression and rebound, which isn't a bad thing as rider weight increases.
 
link1896

link1896

Mr Greenfield
Depends how hard you’re pushing things summit, xc bike not using all its travel on a warm day, sure. Full endurobro pushing a 150mm bike to the limits, you’ll feel it.

While it’s outdated slightly, Peter Verdone published an amazing summary of suspension oils for fork and shock usage here: https://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid


My advice is pick a synthetic oil with very high viscosity, blend two or more to get a blend that works if you want something inbetween. (And write it down for next time)

Look at fully synthetic oils with viscosity indexes in the high 300’s or better. These oils don’t make the suspension feel rock hard in cold winter temperatures, a pet hate of mine.

Shift the oil viscosity a little and you’ll just have to move compression and rebound one or two clicks, or maybe you’ll just like the extra damping and leave them where is. Get it wildly different and you need to reshim.
 
rockmoose

rockmoose

his flabber is totally gastered
Sounds like we all need Summer forks and Winter forks. May as well have seasonal wheel setups hanging in the shed too.

There is another way...........

New bike time.

Sent from my SM-A205YN using Tapatalk
 
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SummitFever

Eats Squid
The Duckmeister said:
Yeah, you can tune the fork with different oil weight; going heavier will slow the oil flow through the damper, thus increasing the damping effect, both in compression and rebound, which isn't a bad thing as rider weight increases.
Click to expand...
This is basically correct but harkens back to a time when dampers were simple port-orifice systems. Viscosity makes a difference when squeezing oil through an un-changing restriction. eg. a bleed hole in your damper controlled by a rebound needle, the low speed bypass on your compression adjuster etc. Viscosity makes only a minor difference when the oil is flowing through a shim stack. The shims simply bend more to accommodate the thicker oil and things pretty much remain similar provided the port size on the piston is not the restricting factor (and if you take a look at any modern damper - Charger, FIT4, GRIP2 or even Moco RCT3, port size is NOT the restriction to oil flow).

Yes, as @link1896 says you may need to tweak your adjusters (if the adjuster in question actually controls an orifice size) but otherwise for a "95kg rider riding aggressively on black trails" you will be relying on your shimstack 99.9% of the time and so whatever weight high quality oil you put in the fork is not going to make much of a difference. Note: if you are at the limit of any of your adjusters, then a change in oil weight might be helpful to shift the adjustment point back to somewhere that makes sense.
 
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