Forum menu
+ve/-ve air - how d...
 

[Closed] +ve/-ve air - how does it alter spring rates in my forks?

Posts: 1193
Free Member
Topic starter
 

I understand that a little more -ve air than +ve in my dual air forks makes them more supple initially, but reviews of forks suggest that i can alter the springs curve by playing with the pressures.

My forks are spot on at the pressures i am running, but ramp up a bit more than i would like towards the end of the travel, meaning that I only get about 2/3rds of my 130mm from them.

Does less -ve give a more linear spring?


 
Posted : 19/08/2010 11:21 am
Posts: 11843
Full Member
 

I don't think it alters the 'curve' as such, once the fork is near the end of the stroke I think its all just to do with the +ve pressure.

However, by lowering your positive pressure you can make the end of the stroke more linear, as it ramps up less. This would make the fork a lot softer initially, so it would sag more and bob more, but you could decrease the -ve pressure to counteract this.

This sort of setup would probably mess with the spring rate in the middle of the stroke, but I don't pretend I'm good enough to notice 8)

I've done pretty much exactly that with my Rebas, and they ride brilliantly now, nice and firm in the corners and under sprinting, but lots of travel when I hit things a bit harder.


 
Posted : 19/08/2010 11:35 am
Posts: 1193
Free Member
Topic starter
 

sounds like what i am trying. Will keep playing about with them. Perhaps I am just not hitting stuff fast enough ๐Ÿ™‚


 
Posted : 19/08/2010 11:40 am
Posts: 19914
Free Member
 

Keep +ve and -ve pressures about the same. A bit more (10psi) gives a more supple initial stroke, a bit less makes them a bit more progressive. If you use too much -ve all that happens is you drag the fork down a bit and the pressures equalize. So that's a waste of time.
If you're not getting full travel, reduce the +ve pressure a bit. But you won't get the last 5-10mm unless you hit something REALLY hard anyway, as that's bump stop territory. It will go though, seals all the way to the crown if needed. I think I did that to my Rebas twice in 4 years, but that was hitting stuff by mistake, silly hard. Emergency use, basically! ๐Ÿ™‚


 
Posted : 19/08/2010 11:40 am