micknmeld wrote:
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Mr Blue wrote:
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Rear race sag is usually around 1/3 of total travel
That gem doesn’t help with my front end issue though. :laugh:
Sorry Mick, inexcusable of me front is usually a tad over 1/4 of total travel
here’s a good quik read I borrowed from an expert
RACE SAG
Make sure your forks are at the standard height in the triple clamps before starting any adjustments. 3mm down from the fork cap to the top of the triple clamp. Most run it 5mm for better steering.
Increasing the preload on your rear spring will decrease the Race sag. Most run 100mm of race sag on the rear. I run 85mm~90mm this is about 3.75″. This will raise the rear of your bike putting more weight on the front wheel and reduce the front-end rake and be more like an MX bike. This will always make the bike turn sharper. If you tighten the spring too far it will make the bike unstable and make the bike prone to headshake.
Less preload on the rear spring will increase the Race sag at the forks. This will cause the front end to float and be light with hard acceleration. The back end will squat, putting less weight on the front wheel and causing it to ride like a “chopper”. This will reduce head shake, making the bike go straighter and be more secure at high speed. The bad side of not enough shock pre-load is the bike will become hard to turn.
To fine tune the spring preload (Race Sag), start out with 4″. The bike will pull the front end up sooner. Much easier to pull a wheelie. Try tightening the rear spring adjusting nut 1/2″ turn down and mentally note how much easier the front end will dive into a turn and hold the inside line. Continue this spring tightening until the bike becomes twitchy and unstable, or it feels like you’re always pulling up on the handlebars to get the front up in the whoops. Measure and record your Race Sag.
Then try loosening the rear preload 1/2 inch turn at a time and mentally note how the rear end “Squats” down and traction increases as you exit each turn. When you reach the point of excessive front-end lift (wheelies) and loss of steering, or you begin to have trouble holding a tight turn, the spring is too loose and you have too much Race Sag. Measure and compare these two extremes, then reach a compromise between them that balances “stability” and “tight turning”.
Tune the front-end ride height to match the rear end!
If the Race Sag compromise you determined above is close to the typical (4″~3.75″) measurements listed above, your fork height adjustment in the triple clamps is probably about right.
Raising the forks in the triple clamps will lower the front end making the bike turn sharper but will reduce high-speed stability. (Similar to increasing the rear preload.)
Lowering the forks in the triple clamps will raise the front end making the bike harder to turn, but will increase high-speed stability. (Similar to lowering the rear preload.)
