Spring rate vs. compression damping – fork comfort for sustained rocky descents

I notice some Manitou discussion, not got time to read it all. When I last used mine in the Alps I couldn’t find a setup I liked I serviced the Fork and found too much oil in the damper.

Came with gold, loved it (the damping) compared to my previous fork. Was keen to try one of the progressive valves (less LSC, more HSC) so got the blue, was way too harsh with all that high speed so it only stayed in for one ride. Now on violet (a softer gold) but haven’t spent time experimenting to make the most of it. The blue might go back in to try the soft spring more damping idea. If I buy one more valve I might as well have bought the whole box set for just a couple more pounds!

Oh I see there are way more options with the Selva.

The Mod is nice and simple to choose a CTS by comparison.

TBH I’ve sort of forgotten what you were after in the first place now, but if it was more comfort over rocks then I’d say stick with that softer CTS and fiddle with the settings. Or try the “maximum comfort” one.

I’m not an expert on this stuff but I think you can gain a lot from having the quickest rebound that you can handle – the faster the suspension can return towards the top of its stroke, the more time you spend in the regions where the spring rate is lowest and the more travel you have to work with when you hit a bump. I find I prefer shocks on the slower side so the back end doesn’t buck easily but I’ll run the fork quicker.

On my Lyriks I run the HSC close to open, just adding a bit if needed to stop the fork plunging through the travel on bigger landings, and the LSC about a third closed so the bike pumps and preloads in a balanced but not soggy way.

Bear in mind that with an air fork the spring curve will depend on the negative and positive spring pressures and volumes and how much travel you’re running will affect how that feels – like I remember my old Pikes felt better at 150mm than 130mm because of how the negative and positive chambers interacted.

There’s a lot of variables but I think but changing one parameter at a time and riding consciously before and after to assess it you can dial things in much better.

Also, on sustained rocky descents, a bike that lets you ride “hands light” will be less fatiguing than a bike that needs you more forwards. Stem/bar/spacers will affect that as much as suspension set-up, and also any flip-chips etc.

jamesoz Full Member

I notice some Manitou discussion, not got time to read it all. When I last used mine in the Alps I couldn’t find a setup I liked I serviced the Fork and found too much oil in the damper.

I thought there was a check valve (on the Pro Damper at least), like a little pressure release valve that pops open with excess pressure from too much oil?

I might have made that up  but I think that’s the little silver thing under the HsC knob?

I think it’s possible for the the damper to ingest the bath oil from the lowers so they added that valve to stop the thing exploding and/or bending delicate bits.

“ thought there was a check valve (on the Pro Damper at least), like a little pressure release valve that pops open with excess pressure from too much oil”

Dunno, my Mattoc Pros are pretty old now. It was also a while ago. I just remember drawing some excess oil out.
The fork was better after, however it could have just been the service.

I’ve tried the recommended pressures but ended up maybe 10 psi lower than suggested in the bottom chamber and 110 in the IRT (100kg).
3 clicks from open on rebound IIRC, the HSC I can’t remember, but enough so that there’s an actual noticeable difference on LSC adjustment and 1 click of HBO.

I did have a Pike bladder go pop once, maybe from sucking in excess oil.

I’d say your fork sounds set up about right, but ultimately if you want to use all of the travel on smaller terrain then your only option is reducing the pressure/spring rate, which will increase the sag regardless of compression settings.

Assume you have no tokens to remove, then adding in some low speed compression dampening will stop you moving further into the travel a bit, but I’d rather have a more active fork getting less travel than the opposite, if that makes sense?

Ultimately, I tend to set things up for my weight, not the terrain and my suspension moves as much as is needed – not more, or less. I inevitably end up at 30% or so sag.

Did some experimentation on a few recent rides, but nothing totally focused on suspension testing.

On a rough fastish trail centre red (e.g. Laggan), the Gold CTS is more comfortable than the Violet. Presumably the higher HSC keeps the fork up in its travel where it’s more sensitive. So more damping, less travel used, improved comfort. However the bike is unbalanced on drops etc. now as the rear has less compression damping and only minimal adjustment available.

On trails with steep steppy technical features to negotiate, the Violet CTS is pretty dodgy. Blows through the travel too easy, pitching you forward, steepening the head angle, and setting you up for a huge rebound energy release (as the Fox guy said). Almost bounced me half off the big staircase at the end of Laggan black. Maybe it’d be fine with a few clicks of compression damping added to add more HSC (which would also add LSC due to there being only a single adjuster).

I remembered this bike check from Pinkbike where for comfort on a long race they used a much lower spring rate but with high levels of compression damping to compensate.

This was specifically low LSC and high LSC. Turns out it’s called progressive damping, and apparently it’s a racer thing and has some issues. I don’t expect it’s much use for mere mortals to compensate for a softer more comfortable spring, you wouldn’t be riding hard enough for the suspension to create enough force you can push into.

DVO doesn’t think much of it, neither do a few posts in this thread.

The Selva CTS options make a lot more sense now.