Can someone explain rear suspension preload to me?

[Cheesy Mike]

At the risk of sounding completely stupid (although I can do that without asking questions...)

Can someone explain the use of the preload to me? What does it actually do when you turn the knob?

What is the ideal setting for me riding solo?

What would the effect be of having it too high or too low and how would I notice?

Mike

 

[(RIP) Dennis]

Mike,
Preload will adjust the amount the bike "sags" for any given load, the heavier the load the greater the required preload. There is really no ideal initial setting, it's a question of trying different adjustments to see what works for you. It will depend on how heavy you are, whether you ride solo or two up, if you carry luggage and last but not least how hard you ride.

You will also find that if, like me, you are a bit of a short arse, reduceing the preload will lower the ride height.

 

[ralphy]

Mike,
You will also find that if, like me, you are a bit of a short arse, reducing the preload will lower the ride height.

He's not - but I am.
Thanks for the tip, Dennis!

 

[Sergeant Pluck]

don't feel stupid, you're not alone - i also get very confused when it comes to suspension. either that or we're both dumb ;-)

see my recent thread here for some useful info

http://www.ukgser.com/forums/showthread.php?s=&threadid=7587

and there's agood explanation here, also.

http://www.micapeak.com/bmw/gs/gs_tel2.html#suspension

pr0ne

 

[Malcolm]

Dennis

Surely increasing the preload (compressing the spring) reduces the ride height?

 

[Jimb]

Mike Belch

I'm glad you asked that, Iv'e always wondered as well, tried different settings but not really loaded it with luggage, will try it next trip.

It seem logical that turning the screw toward S, softer would let the seat come lower with the load and turning it toward H, hard would harden the shock so it would compress less.

 

[Howard Millichap]

Dennis

Surely increasing the preload (compressing the spring) reduces the ride height?

NO,NO,NO.
Pre load or pre compressing the spring will make it harder to move the spring because the spring will "think" it already has some weight on it and so pushes back harder (equal & opposite an' all that), so the bike will tend to sit higher.

As for the ideal setting. The bike should be set up with a certain "static sag". On proper bikes, this is given in the owners manual. Basically you need to adjust it to give a certain ride height. Once done, you then need to adjust the pre-load to account for any pillion & luggage weight so that the ride height is restored.