What soap said. I think people are over complicating it.

Maybe there is something wrong with my forks, but as I understand it, when you compress the forks you compress the +ve air chamber (decreasing its volume) and expand the -ve air chamber (increasing its volume). If there is no air (or just atmospheric pressure) in the -ve chamber to start with and all the seals are intact then it’s going to be very resistant to expanding in volume. Certainly a lot more resistant than it will be with 100 psi in there.

So, if you measure the sag with (say) 100 psi in the +ve chamber and nothing in the -ve then pump up the -ve until it just moves (around the same pressure as the +ve) the sag increase by quite a bit. Making your original measurement incorrect.

Well that’s how mine seem to work, but happy to be proved wrong.

Stupid question: 454 dual air uturns here – should you set the travel first then air pressures or does it not matter? I run my forks at 120 pretty much all the time, should I wind them out to 140 when setting the air pressures?
Ta!

mulacs, i would set them up at 120, since you run them like that anyway.

75/70ish I am 71 kg

My thoughts on the matter. Seem to match up with real-world experince for me. YMMV

http://singletrackworld.com/forum/topic/dual-air-revs-my-thoughts

Long story short: Don’t overdo the neg pressure or you’ll lose travel. Even if it’s reading the same as the +ve you may have overdone it. Car park smoothness is not the same as good on the trail.

75/70ish I am 71 kg

i weighed myself today and i’m a shade over 71kg Was probably running way too high a pressure at 100 then!

It’s hard to set up forks when the trails are so damn muddy, what i need is some dry dusty Calafornian trails….one can dream.

Running them that soft will make them plush but if your riding involves steep drops onto fireroads etc you may find yourself flat on your face, spitting out teeth….
Only saying, like..

Right, i’ve had a chance to get out on them now and reckon i’ve got them set up pretty well, So i can now add my own setup to the list.

72kg/11.3 stone
85 +ve
65 -ve
rebound half way and then a couple of clicks towards the rabbit

I’ve set them up so they use all the travel and don’t dive too easily under braking, mainly by running 20psi less in the -ve chamber (they “equalised” as per Northwind’s post at 80+/ 70-) and messing with the compression.

They’re plush! I might put a bit more air in the positive chamber yet, maybe go to 90+/ 70- but i haven’t had any problems with fork dive or bottoming out so far. Very pleased.