Preload Confusion

[slayermd]

Ok, just to double check that I am doing this right, here is what I did to get my preload on my FZR with Race Tech springs and emulators.

1. With fork leg off the bike and compressed (with oil, spring and washers) I took the measurement from the spring to the top of the inner fork tube.
2. I took that measurement and subtracted the length of the cap from the bottom to the lip (at this point there is zero preload).
3. I then added 16mm to the measurement I got in step 2 to get my preload spec.

This seem right? After I had the forks back on it seemed to raise my front end a bit.

[MattTLS]

Almost. The fork needs to be extended, not compressed. And put the emulator in place, too. Basically, all of the parts that go into the fork should be in place before taking the measurement from the top of the spring/washer to the top of the fork tube. One other thing, oil need not be in the fork to measure for the spacer length.

[slayermd]

I had the emulators in when I was measuring, just forgot to mention that.

So its done with the legs extended huh? That makes sense as to why the front end was raised. Ill try doing that now.

Thanks.

[MattTLS]

According to Race Tech, both the FZR 400 & 600 used a .464kg/mm fork spring rate. When replaced with a stiffer spring and set up to a proper range of sag, you may very well have a front end that rides a little higher than it did with stock springs. How much difference is there now as compared to before?

[slayermd]

Well, I just got done doing the measurements with the fork legs extended and while the front end does seemed raised it is not as bad when I did it with the legs compressed. I read over the Race Tech instructions and it seemed that I passed up the sentence saying to extended to fork leg while getting the measurement.

I set it to 20mm preload, I figured if I need less I can just swap out to the 18mm and 16mm spacers that I made to get it right.

[BigE]

And you know that preload only affects the first inch of travel, right????

[rybo]

And you know that preload only affects the first inch of travel, right????

More importantly it also affects ride height...

[slayermd]

And you know that preload only affects the first inch of travel, right????

I do know that, thanks.


More importantly it also affects ride height...

Yup, know that too. All I did wrong was take my measurements with the fork legs compressed instead of extended (like the RT instructions said :banghead:). Everything seems ok now, all I have to do is take it for a spin and see how it feels.

[rybo]

:up:

There are two ways of changing front ride height, one is to adjust the position of the forks in the triple clamps, the other is to use preload. To measure ride height you SHOULD be doing it with the forks at their "static sag" point (loaded) If you are just trying to get the forks back where they belong in the triples and you want to use ride height to measure it, then that should be done with the forks fully extended.

Your next step will be to set static sag front and rear. From there you'll make the other adjustments (compression and rebound damping)

good luck!