Suspension setup

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Arctic Donkey

Active Member
With the help of a friend or two you can do a lot by yourself. The "right" spring weight is dependant on what you think the "right" amount of sag is. Opinions vary, but if you are on any modern sportbike I would start with 35mm of sag in the front and 30mm in the rear as a begining point. If you can get those numbers without having a crazy amount of preload (>15mm of preload on shock = too much). This info is for the track, I have no idea what needs to be done on a streetbike. What bike are you wanting to setup?

Steve
 
racer51

racer51

Active Member
Bottom out pre-load adjusters

Is it true that if you bottom out the tension adjusters on your fork spring pre-load, they become non-functional?
 
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Arctic Donkey

Active Member
Rick, are you talking about the preload adjuster on the top of your forks? If yes, they don't become non-functional, they just only go in so far. If they are in all the way and you need more preload you need to open up the forks and add longer spacers. To start with you could measure the length of the external preload adjuster (from all in to all out) and then cut a spacer that is that much longer than the current spacer that is in the forks.

If you having to add a lot of preload to get the sag you want it could be a sign that you need heavier springs. If you don't have much sag with only the weight of the bike but the correct rider sag (rider on bike)then the springs are too soft. If you have excessive bike sag and the correct rider sag the springs are too stiff.
 
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Arctic Donkey

Active Member
Well that clearly is a track only bike and a bit of a different animal. Forget about what I said on the sag numbers. I don't really know what the best starting point would be on a RS125 but on a lightweight bike with that amount of power you would run less sag than on say a 600. I'll have to look around a bit and get back to you.
 
A

Arctic Donkey

Active Member
OK, from what I could find a good starting point for the front is ~20mm of bike sag and 30-35mm of sag with rider. The rear is a little different than on most bikes because you don't want it to squat very much at all. So basically zero bike sag and 20-25mm of sag with rider. Hopefully some of the other racers that are actually on 125s will chime in and correct me :)
 
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