Suspension Guru required!

[yorkie_chris]

Falkner make some pleasantly cheap rear springs.

Rear sag should be set static with 8mm minimum through to 16mm if your running a race spec TTX Ohlins. Not enough sag will cause the shock to top out and create a "judder" type feeling on the brakes from the rear.

Hi Had 3cm static and 7.5 rider on the day so actually about twice what it should have been.

Maybe It's my thing about braking points? I keep a list of where the top boys in whatever class of racing brake for particular corners then try and get as close to that as possible. If they can brake from there and still get around the corner... etc.



C

Woh! 30mm static sag on the rear?. How did you measure it?. Thats way too much.

I would suggest a teensy bit more compression on the front coupled with what the other guys have said on the rear. Is the rear wheel coming up when you brake? Make sure your body positioning is right as well, you want to be up against the back of the seat.

Originally Posted by SV650Racer

Woh! 30mm static sag on the rear?. How did you measure it?. Thats way too much.

Its about right with someone sat on it... With rider its supposed to be between 30-40mm.

Static sag measured after three bounces at a marked point on the tain unit. Unloaded sag measured with rear tyre just starting to compress with bike on side stand at same point

Rider sag measured with feet up after three bounces at same point.

From a susopension forum, it looks like the ohlins preload unit is full of air and needs bleeding. You have to take the shock off, spring off the shock and then increase the preload manually if this happens so its a big job and it'll be done over the winter.

C

Rider sag is pretty much useless. We never ever use that to set the rear up. Static sag measured from a fixed point with the bike sat under its own weight compared to the measurement to the same fixed point with the rear shock fully unloaded - ie with the bike pulling the rear wheel off the floor - to measure the about of free movement at the top of the shock.

If the preload canister has air in it then it needs bleeding and re-gassing.

Originally Posted by SV650Racer

Rider sag is pretty much useless. We never ever use that to set the rear up. Static sag measured from a fixed point with the bike sat under its own weight compared to the measurement to the same fixed point with the rear shock fully unloaded - ie with the bike pulling the rear wheel off the floor - to measure the about of free movement at the top of the shock.

That sounds a little silly to me... Not trying to say you are wrong, from the way you talk it sounds like you know a thing or two, but here is how I see what you put;

The way you set it must mean that spring rate simply doesn't matter, (or that it is already known to be right, which lets face it isnt common). You'd effectively use your method set it up the same for me and Berlin (or any other rider using the same bike)... I can tell you that me and Berlin certainly would not want the same preload!

Also its rare id say that someone has the right spring rate and so using your method would have something that would handle less than perfect.

Rider sag takes all that problem out as you set sag to suit the whole weight of the unit (rider and bike).

Cheers

Of course spring rate matters. BUT you cant postively tell correct spring rate from just measuring rider sag. Ok it gives you a ball park but you dont ride the bike sitting stationary on it. This particulary applies to race applications.

If you set my supersport bike using just rider sag it would show me i require a .8kg spring whereas my perfect setup in terms of my pace, riding style and general bike chassis setup requires a .9kg spring.

Ohlins work with their non ttx shock on a 8-12mm static sag range whereas the TTX works to a greater 10-18mm range.

Im not the techy geek here, this is only what ive learnt watching Steve work for the past six years. So excuse my lack of technical terms!..