Anyone out there in Email land able to give me suggestions for the correct static sag - without & with rider for trials bike forks & rear suspension.

Its about time i sorted out the suspension on one of my bikes & since I aint got a clue about setting up trials forks (Motocross or road - yes) I am looking for some help.

Its fair enough saying look at the handbook BUT the forks & bike are not std - it would take too long to explain! What I am looking for are some guideline figures.

Check Stoodley's article on suspension setup on the GG website.

He's the man.

You got a link for me?

http://www.gasgas.com/Pages/Technical/tria...nsion-tips.html

I don't own a GasGas any more but I've still got that page bookmarked because it's an excellent all-round trials suspension primer that helped me immensely when setting up my Beta.

thanks

Hopefully just what the doctor ordered!

Suspension AGAIN

I have a reasonable feel on the front suspension on my bike - but I have one problem which I would like to be able to cure.

Spring rate/sag & compression damping are fine but the bike seems to have far too much rebound damping in that there is too much delay in the forks returning over a series of bumps.

I have no options for adjusting damping except via oil weight & level/volume (also the addition of air pressure)

Any suggestions

My thoughts were :-

too high an oil weight (I only have 5wt in at the moment)

Too high oil level or volume (this has been checked and is very close to the recommended for the forks)

Too much preload making springs too far compressed - the forks are from a lighter bike - I dont know whether the damping orrifices are std ( i needed to add 10 - 15mm preload from std - the springs are within tolerance)

Yours confused

G, too high an oil level will only effect the last 1/3- 1/4 of the travel, effectively adding some bottoming resistance. By adjusting the oil height, what you are effectively doing is adjusting the volume of the air pocket. This air pocket acts as a spring once it is compressed. The more you compress it, the greater it's resistance to compression, so the stiffer it gets. However, because of the relatively large volume of air this effect is not noticable until the later part of the travel.

Preloading the springs too much, or having a spring rate too stiff, will actually make the fork rebound faster. Generally speaking, the dampers are setup for the stock spring rate. As you preload the spring, or increase it's rate with a heavier one, the energy stored in the spring will be greater than stock and therefore generally rebound faster.

You might try a really light oil, like 2.5wt. Aside from revalving the actual damper, this is really your only resort at this stage.

Joe

Thanks for the prompt reply - Going to 2.5wt oil appears to be my best bet as you say, i am glad you agree with my interpretation (which I did not put down to see the response i got!) . It may be the 5wt oil I had was miss-labeled? I have some 2.5wt oil I used for an experiment on an MX bike in the past - its more like water than oil!

First of all I am going to try increasing the 'air pressure' - this will increase the spring rate a little to see if this has a noticable effect - but this is NOT the route I wish to go down more pressure = more chance of seal failure & I prefer to run with zero air pressure. The other thing I will check is alignment in that there is the risk of 'stiction if the forks are not aligned properly.

Some day I will my trials bike to handle the way I want it - then again I won't have any excuses if this is the case?!******

Gordon