Fox 40 & DHX 5.0 Tuning?

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Fox 40 & DHX 5.0 Tuning?
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Posted: Sep 18, 2008 at 7:32 Quote
So my bike is finally all built up and ready to rip, now to tune the fork and shock...

The bike is a new Intense Socom with a 2009 Fox 40 and a Fox DHX 5.0 out back. I'm basically an ex-BMXer (Trail/Street) and will be using this rig as my all-around FR/DH ripper. I'll be hitting some pretty decently sized stuff/lines while being pretty smooth at the same time, most of my riding will be at Mountain Creek and Platekill here in the NY area. I'm about 175 in just shorts and no equipment on.

Can anyone recommend any initial setting?
Psi, Preload, sag, high & low speed compression, propedal...
Could someone please clarify the high & low speed compression, ie what I should look for, how they differ, how they change the way the fork reacts, etc.

Any and all recommendations as far as suspension tuning are greatly appreciated

Posted: Sep 18, 2008 at 8:59 Quote
cobrakillerta wrote:
So my bike is finally all built up and ready to rip, now to tune the fork and shock...

The bike is a new Intense Socom with a 2009 Fox 40 and a Fox DHX 5.0 out back. I'm basically an ex-BMXer (Trail/Street) and will be using this rig as my all-around FR/DH ripper. I'll be hitting some pretty decently sized stuff/lines while being pretty smooth at the same time, most of my riding will be at Mountain Creek and Platekill here in the NY area. I'm about 175 in just shorts and no equipment on.

Can anyone recommend any initial setting?
Psi, Preload, sag, high & low speed compression, propedal...
Could someone please clarify the high & low speed compression, ie what I should look for, how they differ, how they change the way the fork reacts, etc.

Any and all recommendations as far as suspension tuning are greatly appreciated

I'll try and help out where I can.

I don't know much about the fork at all, but I have the same shock on my bike. I do know that the low speed compression deals with the small bumps and brake diving, and the high speed compression deals with the big hits (large rocks, drops, jumps, and such).

Anyway, I would put about 150 psi in the shock to start off with. I weigh much less than you and I run around 130 psi in mine. I have mine with ProPedal fully off (really increases the small bump sensitiviy a lot, and my bike pedals just fine as it is - plus if I really have to go on some uphill then I just crank the ProPedal up which only takes a few seconds).

There should be about 30% sag on the fork and shock. That means about 60mm on the fork. The rear depends on what size shock you have.

Posted: Sep 19, 2008 at 17:15 Quote
about the rear shock:

sag is how far the shock compresses when you're in an "attack" position (how you would be when you're riding down the trail). set the sag in the rear shock by twisting the ring above the spring down so it compresses the spring more. this is called "preloading" the spring. if you do more than 2 full turns of the ring to compress the spring and you're still sagging too much, then you need to order a heavier spring. you need a lighter spring if you have 0 preload and you're not getting enough sag. putting air in the "boost valve" will make the shock more progressive. this manages how quickly/easily the shock will go through it's travel during hits. you want, for small bump sensitivity, for the shock to go quickly though the initial part of the stroke, then get harder to deal with larger hits. i think you need something between 75 and 200 psi in that chamber (maybe not 75, it might be 125--im getting my forks/shocks confused--maybe you can download the manual from the fox site if you dont have one). increase the "bottom out" nob to make the very end of the travel more progressive. this will help if you're bottoming out (fully compressing the shock) too often or off things you consider too small (occasionally bottoming out is ok only b/c the goal to setting up your shock is to get the most out of your travel). if the nob is too hard to turn by hand, stick a 4mm (i think that's the size) allen key in one of the holes to get some more leverage. the rebound controls how fast the shock springs back out after being compressed. the little red rebound nob should be low enough not to buck you off the bike after a hit, but high enough to not let the shock slowly sink further and further into it's travel over time as you're riding down repetitive bumps.

for the fork:

i dont ride a fox 40 (but i do ride a 36). most of the "theory" behind the above stuff about the shock can be applied to the fork, but i just dont know the specifics, sorry. but i hope i was helpful! have fun!

Posted: Sep 26, 2008 at 23:40 Quote
with setting the sag in the fork its the same idea as setting sag in the shock except you use the preload knob on the top of the fork tube (its blue)
if you have to turn it all the way out (counterclockwise) and can't get enough sag you need a softer spring and if you turn it all the way in and still it sags too much you need a stiffer spring rate.
as for setting the rebound and high/low speed compression its personal preference/experience. back all 3 adjustments off and ride it. if it rebounds too fast
(buckin u up after bumps or kickin you front end high on jumps turn it in a couple clicks, keep goin till the wheel tracks well on chattering bumps. whick means its always in contact with the ground on the rough, if you turn it in too much it'll pack (sink into the travel farther and farther without rebounding to full out. as for high speed compression it works in situations like fast ROUGH/ trails where you don't want it to sink into the travel too far in that stuff and hard landings where you moreso drop instead softer landings. the high speed compression is for fast hits. the low speed compression is for situations like hard front braking, floater jumps and slower stuff in general. you might have to add to the oil level in combinatioin with a stiffer spring if it dives too much

anybody correct me if I'm wrong

Posted: Oct 17, 2009 at 12:30 Quote
so what does the high/low speed compression do? im still a little confused

Posted: Oct 17, 2009 at 12:33 Quote
mooseman414 wrote:
so what does the high/low speed compression do? im still a little confused

high speed controls big impacts,low speed controls low to moderate impacts.

Posted: Oct 17, 2009 at 12:39 Quote
You can also contact Joey Alva at Fox and he'll send you manual (hardcopy or disk)
javila@foxracingshox.com

Posted: Oct 17, 2009 at 12:40 Quote
but how does it effect the way the shock performs on the trail?

Posted: Oct 17, 2009 at 12:42 Quote
mooseman414 wrote:
but how does it effect the way the shock performs on the trail?

twiddle your knobs and see how it feels differently.

Posted: Mar 24, 2010 at 17:59 Quote
easiest way to remember is that low compression and rebound control the first 20-25% of your travel. Thats why its mostly small bumps and brake diving.

High SPeed compression anda rebound is the last 75-80% of your travel and thats why its for larger hits and stuff.

Bottom Out Cntrol is for the last 20% of your travel and will gradually increase the force required to push the shock until you bottom out or your rebound kicks in

remember: its oklay to bottom out2-3 times a run

Posted: Apr 7, 2010 at 16:56 Quote
my 2009 fox 40 that comes stock on the 2009 glory is making a clicking noise when it gets about half way into the travel. what the hell??

Posted: Apr 7, 2010 at 17:01 Quote
it might be the coil knocking off the inside of the lowers, the shrink wrap might have moved

Posted: Apr 7, 2010 at 17:16 Quote
ok thanks ill check. can i just put regular shring wrap on it if thats what the problem is?

Posted: Apr 8, 2010 at 18:17 Quote
regular shrink wrap prolly wont do it. take off the top cap(youll need a large wrench or socket. then the spacers and then check the wrap on the spring,

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