PDA

View Full Version : Track bike setup questions



mattology
04-23-2014, 03:38 PM
anybody tracking their bikes ? Garrett are you still on here ?

What kind of magic sag #'s can you give me ? :)

Have you run the sava slicks yet and tried them out ? tire pressures?

I am going to try and get to a EuroCycles track day and bring the 125 out, this time on full slicks...

XERO
04-23-2014, 07:02 PM
Best thing I can tell you is the same thing I was told long ago when I was setting-up my ZX ...
There is no "magic" suspension #'s ...
Meaning what works for someone might not be what you want or need.
Start with the basics:
Sag = L1 - (L2 + L3) / 2
Front Sag ...
Fork tube length at full extension (L1)
Fork tube length gently settled with Rider (L2)
Fork tube length gently pushed down, slowly rise up with Rider (L3)

Rear Sag is same but you will usually have to measure between solid point on body and swingarm ...

Starting point for Sag numbers is usually around 25mm - 35mm, 25 -30 race, 30-35 street.
This is typical starting point for both Front and Rear.

Another Sag number you should check is the "Free Sag", this is good for sorting out if your spring rate is in the correct range for your bike.
Free Sag measures same L1, but L2 & L3 without a Rider.
Here you want like 5 - 10mm.

Too much preload needed to get in this range of numbers and you need stiffer rate spring(s), opposite for too stiff spring(s).

That is the starting point for sag, addjustments here depend on tons of things like road conditions, speeds, tires, style, etc ...
Ideally Sag is ment to get your suspension's spring(s) into it's "working" range and keep you from "topping" or "bottoming" out ...
Valving does the real work ...