How much preload is too much preload - SM

My SM seemed to be very soft in the rear, so I got out the measuring tape and went to work. From Eddie's recommendation, I was after 25 mm static sag, and 75mm with me on the bike. I cranked down the rear pre-load so that I got 25mm of static, but when I sit on the bike (with gear on), it settles to 60-65mm of total race sag. Is that too much pre-load, or is it ok. I'd prefer it to be a little on the firm/tall side. Thanks for the info, I just don't know much about the suspension set up on these bikes (newb).

Follow Eddies lead but also watch you dont compress the spring tighter than recommended by the manual or your rear suspension wont work right despite the sag being set correctly.

something is strange with your measurements.usually if you have to really crank the pre load to get 75mm or race sag the spring is too soft and will have no static sag or almost none.

Hmmm, bike is a stock 2005 SM, white spring, I weigh about 180. The spring adjusters are about 2/3rds to 3/4th down the threads on the shock. As I mentioned, static looks like about 25mm, and race is about 65mm. I'm just not sure if I need to back it up a bit to get back above 75mm of race, or if it's good as is. ??

looks about or actually measured?

Actually measured. The static was pretty much dead on 25mm. The race measurement varied by about 5-10 mm based on how far forward or back I was sitting.

Edit: I just went out and re-measured. From the swing arm (at the top of the axle adjuster block) to the bottom edge of the front of the helmet lock bracket (where the open hole is) was 590 mm at full droop. With the bike on the ground, it was 565 mm. So static sag is 25 mm. With me on the bike, the measurement was 500 mm. So 65 mm of race sag. It seems like the ratio of static to race is close to the recommendation I've seen for an SM (25/75), but I guess I'm just concerned that a race sag of less than 75mm may be too much.

id back it off to 75mm race sag my self.

After I re-read my own measurements, and re-read the instructions on how to set up sag, I realized I was doing the math wrong. Duh. I was subtracting my race measurement from my static measurement (565-500) to get 65mm of race sag. If I understand correctly, what I should have done was subrtact the race measurement from the full droop measurement (590-500) to get 90 mm of race sag. So it looks like what I have right now is actually 25mm if static sag with 90 mm of race sag. That sounds a little more normal.

I dont know metric measurements, but I run just over 3 inches of total sag, thats from the bike stretched out to where it sits with me on it....

Feels a bit stiff to me but I ride motocross so maybe I just need to suck it up?

2 completely different measurements.no math needed.

race sag is with you on the bike in normal riding position.

static sag is the bike under it own weight.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now