rear sag numbers

[MotoPsycho]

99 M750:

I've never set the rear sag up properly, what are the correct numbers for proper sag & stuff ?

Front end it Marzocci, so I'll have to deal with it.

[ducpainter]

99 M750:

I've never set the rear sag up properly, what are the correct numbers for proper sag & stuff ?

Front end it Marzocci, so I'll have to deal with it.

You can re-spring Marzocchis.

Loaded sag for the street should be about 1 1/8 - 1 1/4 "

Adding preload is not the best way to achieve it.

[mihama01]

Dude, proper SAG and stuff?

Well there is a manual for Model Year 2000 Monsters on ducati.com that give the correct damping setting for the 750 but nothing on default preload or rear ride height however.

http://www.ducati.com/en/bikes/service/manuals/2001.jhtml?family=manuals

Basically the only thing you can do is increase/decrease the preload on the rear spring and that should affect sag. If you can't get exactly what you want then you will need to change the spring rate i.e. change the spring

What sag should you use? Thats up to you, but the following link explains a ball park figure to aim for.

http://www.gostar-racing.com/club/motorcycle_suspension_set-up.htm

Having said that may be worth splashing out on a new rear shock/fork oil change since it is likely the damping is past its best after 9 years.

Additionally it is generally recognized that increasing the rear ride height may help speed up the steering, at the cost of some stability. It is something to do after you have got the suspension working properly. The ride height is not the same as SAG

Hope that is useful!

[mihama01]

Gotta love this board

ducpainter says

Adding preload is not the best way to achieve it.

and I say

Basically the only thing you can do is increase/decrease the preload on the rear spring

confused? I am 

Seriously, it all has to do with the anount the rear sinks under the weight of the rider and the bike. Getting the correct spring is the best policy, setting preload is the cheapest option but may not give the optimum result. i.e. you may not be able to get both rider and static sag to reasonable values without changing the spring.

Feel free to correct me if I am wrong....ducpainter
 

[ducpainter]

I was told by Bruce Meyers that the optimum pre-load for a spring is about 15mm.

If you have to add significantly more than that the spring is the wrong one for your weight.

You may achieve the correct loaded sag, but the spring won't perform as well as one that isn't over pre-loaded

Everything else Bruce ever told me was true, so I believe it.