[ireland57]

I have a Trance X3 (09) model. It's my first duallie, is standard and has approx travel of 125-130mm (as advertised). It weighs about 12.2 - 12.5 kgs.

I weigh 66.5 kgs + pack (maybe 5) and water bottle/tools (maybe 2). So total 73.5 approx.

It has Mavic 117 rims, Kenda Nevegal tyres with standard tubes and tyre liners.


The fork is Fox F-Series R 32mm.

The bike shop set up the fork with (I think 130 psi, can't recall sag). It was way too hard.

The shock is Fox Float R. Lbs setup was 8mm sag and approx 150 psi. It was not too bad.

The hills I run here are steep, rocky and have a lot of steps, some tree roots, sharp cambered corners, etc. (Good tracks but rocky).
The front end was always bouncing off rocks putting me off line. The rear seemed ok.


I currently have the fork set at 85 psi, approx 25mm sag and on the fastest rebound speed setting.

The shock is at 140 psi, 12-15mm sag and fastest rebound setting.

Tyre pressure is 24-26 front and 26-28 rear.


The front end is now handling much better than it was, not so much bouncing now.
I'm considering letting more air from the forks (maybe down to 75psi) but am unsure whether it's a good way to go.


I'd been told by an experienced rider that the fork should be approximately 140 -150 psi.
The fork doesn't seem to have bottomed out yet.

Today I'm going to try 75 psi but would still be interested in opinions and advice from experienced (which I'm not) riders. I'm not fast yet either but am aiming to be given some time.

Which is the correct way to go here?

P.s. I'd like to lower the rear shock pressure too but it is almost using full travel I think. Should they bottom out at all or only by accident (bit hit on unseen obstacle)?

 

[tacubaya]

You should bottom out once or twice in a day of riding, but controlled bottom outs not harsh "clunk sounding" bottomouts.

Read your fork manual and see if the pressure you want to set up your fork is mentioned. Most of the time manufacturers state fork pressures much higher than they should be. Setup your forks and shocks by feel, not by a table or manual... but always taking care of the maximum/minimum pressures the shock/fork should have.

It seems that you should also increase your rebound damping (slow it down) to avoid the bouncing off rocks and stuff. Try to setup your rebound so it's fast enough so it doesn't pack up during repeated hits but slow enough that it feels controlled and doesn't wander all over the place and buck you off during drops and g-outs.

Cheers

 

[ireland57]

You should bottom out once or twice in a day of riding, but controlled bottom outs not harsh "clunk sounding" bottomouts.

Read your fork manual and see if the pressure you want to set up your fork is mentioned. Most of the time manufacturers state fork pressures much higher than they should be. Setup your forks and shocks by feel, not by a table or manual... but always taking care of the maximum/minimum pressures the shock/fork should have.

 The manual says fork pressure should be 75psi (surprise, surprise) for my weight but only mentions shock sag, not air pressure.

It seems that you should also increase your rebound damping (slow it down) to avoid the bouncing off rocks and stuff. Try to setup your rebound so it's fast enough so it doesn't pack up during repeated hits but slow enough that it feels controlled and doesn't wander all over the place and buck you off during drops and g-outs.

I'll try it this afternoon. I thought the idea of a good shock is to rebound as quick as possible to be ready for the next bump. Why does having on it's fastest rebound setting make it bounce off things. And it does bounce, believe me.

Cheers

With the rear shock should I keep letting air out until it feels right? Dvd says minimum of 50 psi so I got a lot of room to play.

 

[tacubaya]

Yeah, sag and air pressure is almost the same topic in air fork tuning. The air in the fork acts as either a complete spring system (negative and possitive chambers) or as a spring which just acts as preload aid. Setting the correct sag in an air fork will dictate how the fork will behave in the complete stroke most of the time. Of course this depends on the air system the fork uses or if it is being used only as preload. Pump some air into the fork so you archieve your target sag (25% for XC, 30-35% for DH is a good target) and see how it behaves.

As I said before, setup your shock by feel, not by manuals and tables, so yes, keep letting the air out until you like it.

Fastest rebound is not ideal, forks have a fastest rebound setting because heavy riders feel your fastest rebound setting as an average rebound setting so fork companies need to set a range that pleases almost everybody.

Rebound should be set slowly so it feels controlled and doesn't buckle you during landings but fast enough so it doesn't pack up and also it doesn't make your bike feel like it tucks under you during turns. Keep playing with the rebound!

 

[ireland57]

Many thanks.

I'll be back.

 

[ireland57]

Well, Geez.

Isn't that different?

Front fork at 75 psi and same tyre psi as previous is nicer than 85.

I came down some steps today easily at higher speed (yesterday, nearly over bars).

I let the rear shock down to 110 psi before the ride and I rode up our hills easier than I've ever done it. The rear sat on the ground where I was struggling yesterday; what a great feeling.

I didn't settle on rebound damping but have gained ground.

I didn't make it up some of my usual haunted spots but that's operator trouble. That'll come soon enough.

It's a different bike today. I loved how it felt. I was also able to ride much of it in a higher gear than previously. Is it because you're not working so hard because the rear wheel stays planted on the ground?

 

[tacubaya]

Yes, increase traction translates to a more efficient power transfer from wheels to terrain. Glad I was able to help you.

Cheers

 

[ireland57]

Yes, increase traction translates to a more efficient power transfer from wheels to terrain. Glad I was able to help you.

Cheers

Me too!

Many Thanks.