revelation rlt air pressures - how low can you go?

xixang

just taken delivery of brand new set of 2011 rev rlt's (140mm) to replace my rebas

So, I fit them, remove all air from +ve and -ve chambers then reinflate both (+ then -) to 100psi.

roll o-ring to bottom of stanchion, sit on bike kitted up and measure movment - 15mm movement (sag?) from unweighted bike to weighted bike

I then reset and try 85 psi in both - sit. measure again. 25mm sag

As i should be aiming for around 35mm sag (25% of 140) I'll need to go lower, maybe 70-75psi. How low can you go on the pressures??

Surely this can't be right. RS say significantly more for my riding weight of around 165lb. Are they so far off with their recommendations??

BTW I've tried 2 pumps and same with both, so not a faulty reading (unless both screwed the same)

Also, went for a ride at 85psi, max travel was to within 40mm of stanchion top, again indicating too much pressure limiting travel as I'd expect around 30mm more (so to 10mm from top)

I'll try 70-75 but it just seems wrong

Briggo

I'd ignore the recommended, my fox forks have about 50psi in them but for my weight it says 70 which is quite a difference.

Just set the psi to your correct sag then work on the rebound.

xixang

thanks, thats what i'd figured on doing but it just seemed wrong to go so low compared to RS levels. Can't believe they are so far off.

so, how do people set up dual air? I've seen two methods..

inflate +ve only until sag is as desired then match -ve; OR

inflate both +ve and -ve to same, play with pressures, keeping them matched until sag as desired

in both cases, once sag set then play with -ve pressure to increase/decrease frok sensitivity

Or doesn't it matter??

97th choice

Do it the basic way, go ride it, then fiddle/fettle as necessary.

Hugely depends on the riding you do as well.

bonezy

Ignore the recommended. I'm a light rider with a light riding style, doing mainly XC stuff. I've got about 70 PSI of pressure in the fork. You'd think that at lower pressures, the fork would be under less stress too...

vanamees

xixang wrote:

just taken delivery of brand new set of 2011 rev rlt's (140mm) to replace my rebas

So, I fit them, remove all air from +ve and -ve chambers then reinflate both (+ then -) to 100psi.

roll o-ring to bottom of stanchion, sit on bike kitted up and measure movment - 15mm movement (sag?) from unweighted bike to weighted bike

I then reset and try 85 psi in both - sit. measure again. 25mm sag

As i should be aiming for around 35mm sag (25% of 140) I'll need to go lower, maybe 70-75psi. How low can you go on the pressures??

Surely this can't be right. RS say significantly more for my riding weight of around 165lb. Are they so far off with their recommendations??

BTW I've tried 2 pumps and same with both, so not a faulty reading (unless both screwed the same)

Also, went for a ride at 85psi, max travel was to within 40mm of stanchion top, again indicating too much pressure limiting travel as I'd expect around 30mm more (so to 10mm from top)

I'll try 70-75 but it just seems wrong

Revelation is a DA fork -no sense to set it up as SA fork.

xixang

vanamees wrote:

xixang wrote:

just taken delivery of brand new set of 2011 rev rlt's (140mm) to replace my rebas

So, I fit them, remove all air from +ve and -ve chambers then reinflate both (+ then -) to 100psi.

roll o-ring to bottom of stanchion, sit on bike kitted up and measure movment - 15mm movement (sag?) from unweighted bike to weighted bike

I then reset and try 85 psi in both - sit. measure again. 25mm sag

As i should be aiming for around 35mm sag (25% of 140) I'll need to go lower, maybe 70-75psi. How low can you go on the pressures??

Surely this can't be right. RS say significantly more for my riding weight of around 165lb. Are they so far off with their recommendations??

BTW I've tried 2 pumps and same with both, so not a faulty reading (unless both screwed the same)

Also, went for a ride at 85psi, max travel was to within 40mm of stanchion top, again indicating too much pressure limiting travel as I'd expect around 30mm more (so to 10mm from top)

I'll try 70-75 but it just seems wrong

Revelation is a DA fork -no sense to set it up as SA fork.

you've lost me...

how am I setting up as single air by running low pressures?

vanamees

xixang wrote:

vanamees wrote:

xixang wrote:

just taken delivery of brand new set of 2011 rev rlt's (140mm) to replace my rebas

So, I fit them, remove all air from +ve and -ve chambers then reinflate both (+ then -) to 100psi.

roll o-ring to bottom of stanchion, sit on bike kitted up and measure movment - 15mm movement (sag?) from unweighted bike to weighted bike

I then reset and try 85 psi in both - sit. measure again. 25mm sag

As i should be aiming for around 35mm sag (25% of 140) I'll need to go lower, maybe 70-75psi. How low can you go on the pressures??

Surely this can't be right. RS say significantly more for my riding weight of around 165lb. Are they so far off with their recommendations??

BTW I've tried 2 pumps and same with both, so not a faulty reading (unless both screwed the same)

Also, went for a ride at 85psi, max travel was to within 40mm of stanchion top, again indicating too much pressure limiting travel as I'd expect around 30mm more (so to 10mm from top)

I'll try 70-75 but it just seems wrong

Revelation is a DA fork -no sense to set it up as SA fork.

you've lost me...

how am I setting up as single air by running low pressures?

SA have equal pressure in both chambers.DA forks - more pressure in negative side - fork is softer, more sag. Lower pressure - fork is stiffer, less sag.

xixang

gotcha, thanks

the plan for tomorrow is to try 70 each side to start and refine -ve after, maybe try around 70+ and 80- and take it from there

vanamees

xixang wrote:

gotcha, thanks

the plan for tomorrow is to try 70 each side to start and refine -ve after, maybe try around 70+ and 80- and take it from there

You have to rise both pressures if fork bottoming out too easily or lower pressures if fork dont use most of travel. It takes time to find best set up.

Greggors

Remember to stand on the pedals not sit on the saddle when setting sag as you should be doing most of your riding in this position and puts more weight on the front so will effect your sag measurements.

sanchez89

just asked pretty much exactly the same question in my bike thread and was directed here. wish i had searched here first.

i have to agree with the OP, the rockshox settings given on the fork are miles too high.

if others have been running them much lower then i think ill be ok to do so.

mine were at 100psi and were a bit too firm for my weight (85kg) so ill defo have to reduce and try more pressure in negative chamber for softer start to travel.

rowlers

Try here:
http://www.bikeradar.com/mtb/forums/vie ... t=12629675
Explains all...
sag is set via the +ve spring. The -ve spring allows you to tune the feel to your preference