Sag is independent from damper settings.
Damper settings are always in a certain range only, no damper is really "open" or "closed" (or should be).

So you have to think about what you want to achieve - a lower spring rate needs more compression damping, true. And more progression (tokens). And vice versa.

You have to try it out, and go out riding to find out. Most people dont know and put all knobs in a middle setting and stay there.

I always try first to get maximum travel, on a decent drop to flat. This leaves not too many options. Then go riding on a bumpy trail, as fast as possible, and find out about LSC and HSC.

 

Here is some setup tips from fox themselves.
Start around minute 5:

Classically, you open your damper(compression and rebound open) and use pressure to set your air spring/sag. Then once you are satisfied with sag, you start dialing in your damper settings.

 

I'm familiar with the general concept of bracketing. I think part of the issue I'm running into with the 38 is the fork is very sensitive to pressure changes. If I drop 2 psi (112) the fork has tons of traction but feels too mushy, if I add 2 psi (116) it feels supportive but a significant traction loss. So I compromised at 114 psi but maybe 112 psi would be best with a lot more compression or maybe 115 psi would be better with less compression. On my old 36, a couple psi didn't change the characteristics that much and I didn't have this issue. It basically just felt a bit more or less firm when I changed a few psi. On the 38 I'm getting big changes in traction and ability to lift the front. It seems like it would make setting it up even easier but it hasn't. I guess I'm trying to avoid having to set the pressure at every psi from 112-116 then go through bracketing with the damper at each pressure.

 

OK. Originally you were talking about the influence of the dampers. I linked that video to illustrate that the damper is somewhat independent of sag settings and your air spring, and not so much the bracketing.
Other things to consider ... how much do you trust the gauge on your shock pump? Most have (easily) an uncertainty of +/-5 PSI, being generous. It's cold in a lot of places in North America. Are you in one of those places? Because that will have an impact on suspension settings if you set up in a warm home then ride outside where it's much colder.

 

Right I found the 'best pressure' based on a certain damper setting. Had my dampers been set differently I might find a different 'best pressure'.

I set pressures at the trailhead and my pump seems consistent. I live in TN (warm).

 

What if you try setting your pressure for the traction you like and then increasing your low speed compression damping to make up for the lack of support? (I assume by lack of support you meant it was compressing too much due to brake dive and when you shift your weight). Or did you already try that?

 

I did briefly but may have not added enough compression. I'll try to take it further next time. I also thought about trying more pressure and less compression... but that's the issue I'm trying to figure out. The 'what if' options are endless and when you start down one rabbit hole it's easy to get lost.

 

I feel ya! Not that this will make it any less of a rabbit hole, but I liked this article, and it touches on support, traction, and lsc damping:

https://www.shockcraft.co.nz/technical-support/suspension-setup/tuning-low-speed-compression-damping

 

If your base tune is too firm, then going too soft with the spring is a usual result.
Only when you have the right amount of damping will the right spring-rates feel perfect. If you are overdamped they will feel harsh even with the correct spring rate. If you are under-damped then it will wallow and lack support even with the correct spring-rate.

 

First things first, have you dropped the lowers and pulled your air spring out? Fox is notorious for over greasing their air springs and basically reducing the volume of the negative air spring with huge globs of grease which can cause harshness and have you chasing your tail trying to tune it.

 

No, I don't have a shaft clamp to pull the spring from the sleeve.

 

You often need to roll through each adjustment then retest as you refine each one. You don't always get each thing "perfect" before moving on to the next.

So bracket one adjustment quickly as good as you can, then move on to the next. Once you've gone through them all do it again and see if you get a different result

 

The 38 uses an air sleeve.

 

For me, the 38 has been the most particular fork I've ever owned that's sensitive to spring rate

What I mean is there is about a 1-3psi window where you have the small bump & relative support of the spring, any variance outside that window just creates harshness IMO.

Find that magic sweet spot for spring rate, then sprinkle on some damper for the finishing touches. I found running HSR a lot more open that recommended helped for me.

It's a great fork, but definately takes some time to get setup well.

 

Thanks . I'll try opening up the HSR even more. I also still haven't bracketed to within 1 psi difference.

 

On the F36 the mid-valve is restrictive and closing LSR makes it worse. That's why GRIP2 owners get better results from running HSR more closed and LSR more open.

 

I'll try both so far I've stuck with the ratios Fox recommends (typically LSR 1 click faster than HSR).

 

Yeah in my experience the recommended hsr is pretty good so you only need to tune with lsr. Lsr affects the hsr a lot too so you can do the bulk of the fine tuning with just that