Off Road Suspension Thread

[Buddy L]

OK i titled this thread as such, so it dosn't get moved to the main suspension fourm.

I have a new bike and have done, close to 3 and a half hours on the beast.
And i want to make sure that the suspension is doing it's thing correctly for my weight and riding type/style.

Now i waiting for the 5 hour mark to come up first, so the suspenion has a chance to run in a bit more, before adjusting things, as advised.

My first question is.

The front forks:
For them to be effective, should they be using the full travel under hard Conditions?
example. i was out at ardmore on wednesday arvo, and tied some cable ties on the front fork sleaves just to see how much of the travel i was using.
(as they would slide down the tubes and stay at that point under hard landings and give me a idea how much travel i was using)
Used ardmore as a guide as im sure i won't be doing, much bigger jumps then that.

now i had some rather hard landings and the clable ties moved down to only about 30mm left on the travel which is a long motion from top to bottom.
So i gathered that the shocks were in fact rather closely sprung to my weight.
not quite bottoming out, but in fact using the full motion.
would this be a good "evaluation"
or am i going about it the wrong way.

ill wait untill 5 hours are up then ill set up the rear sag for my weight.

[telliman]

thought you were going to park the beast under the tree at the end of the back straight there at one stage buddy!

[cheese]

Honnestly, take it to Danger. he will put much better compentry in and does a bloody good job.

[Buddy L]

thought you were going to park the beast under the tree at the end of the back straight there at one stage buddy!

yer i was having trouble with the gear leave have to move it up, one position on the spline. boot was getting caught under it on the up change. and need to get more balls on the front breaks, never had realy good ones.

[Danger]

Some say that unless you are using full travel every ride, you are wasting suspension travel. But sometimes your bike has to be so soft to bottom every ride that it feels like a baby buggy, which is not good for handling. 30mm from full travel is fine. If it was bottoming it would be fine, as long as it was not hard bottoming. Bottoming can depend on the shape of the bump rather than the size.

Spring rate is only one component, and the spring rate sets your dynamic ride height, even under braking. Springs store energy, which is released on rebound. Spring force is related to position. There is another spring that has an effect on your suspension, and thats the air spring which is related to your oil height or volume and has a greater effect the further into your suspension travel your forks move. The air spring is compressible. BTW, springs that are too soft can make your suspension harsh! A softer spring with more preload is less progressive than a stiffer spring with less preload.

Damping prevents your suspension from over shooting, and is speed or velocity related, and is not position related as the springs are. Oil is incompressible and is controlled via valving and clicker adjustment and to a lesser degree oil viscosity. Viscosity is a measurement of resistance to shear or flow and is a range ie it is not specific. As the oil is forced through pistons and shimstacks (damping) it turns energy into heat. Oil height has no effect on damping.

Friction is another component in suspension, and we want to minimise friction because it is bad! Every static movement has to overcome friction before dynamic movement can be achieved. At the top and the bottom of every suspension movement there is static friction to be overcome. Friction also turns energy into heat. Friction can be caused by binding, materials and normal force. But we want to minimise friction because it has no positive effects on our suspension.

So to have the perfect ride, which is really just a case of having the least amount of compromises, we need to match spring rate to the riders weight to set the dynamic ride height and improve the handling, and we need to control the compression and the rebound (suspension velocity) of the suspension with damping (pistons, shims, clicker adjustments) and minimise causes of friction, bad fork alignment, over torqued triple clamps, damaged or dirty bushings, sticky fork seals, bad finishes to components.

Components when searching for the perfect ride maybe:
Max traction-wheel on the ground
Supple-minimal harshness, no hammering
Chassis and pitch control
Balancing the progressive/digressive conflict
Bottoming resistance, jumps and ground outs
Stability in the midstroke
Firmness
Lack of deflection
Confidence
Turning and cornering
Minimize kicking, swapping
Control and safety
Consistancy, no fading
You may have more?

The trick is to weigh up the above components and have the least amount of compromises for the broadest range of conditions. A MX or Supa X suspension is not ideal for the off road world, and vice versa. Changes can be made to tailor any bikes suspension for the sort of riding that you do most of.

[Buddy L]

Very very good points Greg.
Reading meterial for bed time.
Thanks very much
Coppied an saved on computer. for latter use