Is there a problem with my forks

andy_welch

Hi all,

I've had my 2012 Trance X2 for a few months now. In fact it's overdue its first service at the LBS, so I'll take it back there and get them to take a look at it soon, but just wanted to get the views of the forum fist.

I'm very happy with the bike, which does all I need and a whole lot more, but I've never been fully convinced that the forks (Fox evolution) are working as they should. I've set it up with 20-30% sag (a bit more on the front than the rear at the moment). But despite the fact that the O ring on the rear shock is usually off the bottom after a ride, the one on the front always has at least an inch left to go. Today I decided to let most of the air out and make sure that it could at least go all the way. When I did this I noticed a bit of green oil squirt out of the valve. But I could then fully compress it and it seemed to pump up OK.

Finally the rebound adjuster seems to have 12 or 13 clicks. Turning it all the way clockwise makes the return very slow, but after only a couple of clicks it seems to be almost undamped, with little noticeable change in the other 10 clicks (maybe a bit, but nothing like the change in the first couple).

So what do you think? Is this all normal or do they sound faulty to you?

Cheers

Andy

supersonic

All sounds perfectly normal to me, the rebound adjuster middle settings can be very subtle.

Try a little less air in the fork. Less air pressure also makes the rebound a little slower, so may have to compensate.

bennett_346

They will use that last few cm of travel when you make a mistake and ride into a tree stump doing an endo. You'll thank it when it does cos it'll save your arse.

andy_welch

Thanks Folks,

I dropped the pressure from 60psi to 50psi (and dialled in a bit less damping), which is well below the 70psi that Fox recommend for my weight, but I think it felt a bit better. Seemed to be a bit more pedal induced bobbing, although I think I was pushing a bigger gear on the climbs. I dd clear one climb that I've never managed before though. Probably more to do with getting a bit fitter/stronger and losing a few pounds than the change in pressure, but it clearly didn't hurt too much. No sign of a knocking noise that I was sometimes getting, which I think was the forks topping out. So I think it is sitting better in its travel now.

Funny thing was though, when I finished the ride the O ring was still an inch from the top. I guess I shouldn't rule out the possibility that the ring gets shaken down a bit as I ride. Still seems strange though.

I'll mention it when I get the bike serviced and again when the forks go for their annual service/tune. But it sounds as though they are working fine and I just need to learn how to set them up properly (and ride a bit harder) to get the full travel. No harm in having that bit in reserve for the day when I really need it either though.

Cheers

Andy

paul.skibum

My forks rarely ever bottom out - I have got them to so I know they can but generally speaking the rear goes through its travel at least once on a ride, the forks less so but as one of the other posters said if I ever mistime a jump and end a little nose heavy or mis a tranny they'll use that extra bit and save me from a faceplant.

YeehaaMcgee

andy_welch wrote:

Thanks Folks,

I dropped the pressure from 60psi to 50psi (and dialled in a bit less damping), which is well below the 70psi that Fox recommend for my weight,

The recommendations ultimately mean nothing. Just set the air pressure so that you're getting the correct sag range.
As for bottoming out, most, if not all forks have a bugger in them to prevent damage when bottoming out hard, this means that the last few percent of travel is only ever used in BIG impacts. Forks don't often have impacts anywhere near as heavy as the rear suspension, since they have less of your weight on them.

andy_welch

I can see the logic of using sag to set up suspension. It's a direct measurement of the "neutral" position when you are riding. But there doesn't seem to be any real agreement on exactly how to measure it (e.g. sitting vs attack position etc) and short of setting up some rig to lower you onto your bike and lift you off again it seems quite hard to get an accurate measurement.

For example, when I had the pressure at 60psi I thought my sag was 30%. When I dropped it to 50psi I also re-read the Fox manual and realised that they recommended pushing the O-ring back down once you were on the bike. By doing that and being really careful not to compress it further when getting off I was able to drop the pressure by 17% and keep the measured sag pretty much the same !

On the other hand, the bike manufacturer should know how the forks will behave on their bike, so I would have thought (with all their fancy labs) they could produce a curve of pressure vs sag for a range of weights that was more accurate than I can get in my shed.

Still, I guess it doesn't matter that much. It's just a starting point, right? You still need to adjust it and ride the same section of few times to really decide what works best for you.

Cheers,

Andy

nicklouse

YeehaaMcgee wrote:

As for bottoming out, most, if not all forks have a bugger in them to prevent damage when bottoming out hard,

so how did Sheeps get in there?

Nice typo.

Bumper.

YeehaaMcgee

andy_welch wrote:

I can see the logic of using sag to set up suspension. It's a direct measurement of the "neutral" position when you are riding. But there doesn't seem to be any real agreement on exactly how to measure it (e.g. sitting vs attack position etc)

Yes there is.
On bikes ridden mainly in the attack position, as in AM bikes, or freeride/dh bikes, you set the sag in the attack position.
On XC bikes, you set the sag in the seated position.
Ultimately, you set the sag for the position you're in most of the time when riding.

YeehaaMcgee

nicklouse wrote:

YeehaaMcgee wrote:

As for bottoming out, most, if not all forks have a bugger in them to prevent damage when bottoming out hard,

so how did Sheeps get in there?

Nice typo.

Bumper.

I didn't see that!

andy_welch

YeehaaMcgee wrote:

Yes there is.
On bikes ridden mainly in the attack position, as in AM bikes, or freeride/dh bikes, you set the sag in the attack position.
On XC bikes, you set the sag in the seated position.
Ultimately, you set the sag for the position you're in most of the time when riding.

That makes sense, but I still haven't worked out how to get off the bike without compressing the forks a bit. Maybe I need to work on my Frankie Dettori dismounts.

Cheers,

Andy

bails87

If you're really struggling then put the bike next to a wall or in a doorway so you don't fall over, put the saddle low, stand in the attack position to measure the sag then sit down on the saddle. Then, keeping the weight back, put a foot on the ground, then get off the bike. Easy.

cooldad

YeehaaMcgee wrote:

andy_welch wrote:

I can see the logic of using sag to set up suspension. It's a direct measurement of the "neutral" position when you are riding. But there doesn't seem to be any real agreement on exactly how to measure it (e.g. sitting vs attack position etc)

Yes there is.
On bikes ridden mainly in the attack position, as in AM bikes, or freeride/dh bikes, you set the sag in the attack position.
On XC bikes, you set the sag in the seated position.
Ultimately, you set the sag for the position you're in most of the time when riding.

Still depends. My bike is XC, but I still ride all the interesting stuff standing up ready to attack. So I set sag accordingly.

YeehaaMcgee

andy_welch wrote:

YeehaaMcgee wrote:

Yes there is.
On bikes ridden mainly in the attack position, as in AM bikes, or freeride/dh bikes, you set the sag in the attack position.
On XC bikes, you set the sag in the seated position.
Ultimately, you set the sag for the position you're in most of the time when riding.

That makes sense, but I still haven't worked out how to get off the bike without compressing the forks a bit. Maybe I need to work on my Frankie Dettori dismounts.

Cheers,

Andy

Get someone to help you. they can measure the sag whilst you're still on the bike.