Rebound & Preload????

[oilcan]

Not wishing to appear thick - but would someone mind explaining to me in laymans terms what rebound and preload are and how they work on the bike, and how different settings, front and rear effect the bike?

This has always been a bit of a grey area for me and would appreciate someone taking the time to explain it in a way even I can understand.

I understand that the GS with its telelever front end has very little dive under braking so how can you tell how to adjust the front shock?

 

[Canuck]

Think of rebound in terms of a basketball... it is comparable to how high the ball bounces back up once it has been dropped.

Okay now pretend I have a meter of suspension travel. With no preload (a neutral setting) I have 0.5 meters to the 'top' and 0.5 meters to the 'bottom' of available travel. Without preload I get +0.5 (like when your tire hits a bump and your fork tubes slide into one another) and -0.5 (like when you crest a hill going quickly and your front end feels like it is rising) meters travel. So I can push the fork down by half a meter and also if I held onto my bars and someone pulled my tire down I could extend the distance by half a meter. If I increase the preload what I am doing is effectively moving the Neutral, so that I could have +0.3 and -0.7 meters travel.

The other factor which you didn't ask about is compression... this will alter the ease at which your fork boings! With more compression I may get a slower response... but it a bit more complicated as there are many factors which can come into play (oil vs. gas / springs / etc). All of these three things can affect each other but for ease of argument I think the above should suffice.

How to adjust your front suspension... look in your manual it says in the first few pages. You should have a took in your tool kit to do this. There are three setting and you use the tool to 'turn the sucker around'.

Real world example:

On my GSA i turn the black knob of my rear shock to adjust to the high or low setting. If it is set at the High setting then my +/- would be perhaps +8/-2 ... meaning I would (after both myself and wife sitting on the bike, have the bike at the neutral position as our weight would compress the shock down to the 0.5 level... thus giving us a half meter of compression and a half meter of rebound... though it I compress the shock 0.2 meter I'll then have 0.7 meters of rebound available until I 'top out'.

By increasing the shock absorber adjuster our your bike (the screwdriver one at the base of the spring) you are basically decreasing (towards the H) or increasing (towards the S) the boinginess... or how quick the basketball bounces back up!

 

[oilcan]

Hey thanks Canuck - that makes sense and has gone a long way to explain this to me.