[Hammer]

I am in the process of setting the suspension up for the up comming track day. I have set the sag, and have set the front tubes up 5mm as Mike Fitzgerald suggested for my bike and the tires I will be running. But what I cannot get is how do you measure to figure out the correct angle of the bike/Frame. I have read that sometimes you have to shim the rear to get the suspension dialed in correctly. Is this something I should do, or don't worry with? Tell me if these settings sound right for a baseline.

2005 GSXR 600
Stock Forks w/ T-man work
Metzler Racetec 180/120
Stock Rear shock
rider 204lbs w/gear


Settings on the forks & shock now

FRONT
No weight 124mm
Bike wt only 95mm
Rider weight 86mm

Total 38mm


REAR
No weight 118mm
Bike only 118mm
Rider weight 94mm
Total 24mm

[luvtolean]

I'd add a bit of preload and get that front sag up to 35mm, unless you were told specifically to run 38 by a reputable source.

Despite what all the bullshitters say, chassis set up as far as rear ride height is really a rider preference thing. Some people like a quick handling twitchy bike, some like it real solid and can deal with a bit slower turning bike. Both can be made fast. My suggestion is just to experiment with it some.

Over stock, you probably will want to add some rear ride height. Say a 5mm spacer/washer stack to start. "Most" people like their bikes to turn as quickly as possible, so they raise the rear to the point headshake happens in a rough spot or two every lap. This happens to be how I like it.

The Computrack "Sweet Numbers" made my 929 an evil mother****er, very unstable.

[Hammer]

I am going to have to try the settings that I have for now, Mike F. put a .95 spring in the front and I more than likely need a 1.0 in there for my weight. In other words, it is all the way down.

[luvtolean]

Ah gotcha.

Yeah, a fork with maxed out preload is less than ideal from a mechanical standpoint anyway. When you can, get those springs swapped out. I'd go to 1.0's in both legs.

BTW, that little bit of sag will make the bike turn more quickly. It's not exactly the same, but that would be the effect of at least a 1mm spacer in the rear (the linkage ratio on a sportbike is normally around 3, the shock moves 1mm for every 3mm of wheel movement) and maybe more.

[abtech]

Originally Posted by luvtolean

Ah gotcha.

Yeah, a fork with maxed out preload is less than ideal from a mechanical standpoint anyway. When you can, get those springs swapped out. I'd go to 1.0's in both legs.

BTW, that little bit of sag will make the bike turn more quickly. It's not exactly the same, but that would be the effect of at least a 1mm spacer in the rear (the linkage ratio on a sportbike is normally around 3, the shock moves 1mm for every 3mm of wheel movement) and maybe more.

24 mm of rear sag is a bit low. I would set it between 30 and 33 mm unless your bike has shorter than normal rear travel. This is based on Lance Holst's recommendations for the 600 GSXR when I did the Schwantz school.

[Hammer]

Originally Posted by abtech

24 mm of rear sag is a bit low. I would set it between 30 and 33 mm unless your bike has shorter than normal rear travel. This is based on Lance Holst's recommendations for the 600 GSXR when I did the Schwantz school.

Will do the 30 to 33mm




Here is a pic of the front end. Looks weird to me.

[abtech]

Originally Posted by Hammer

Will do the 30 to 33mm

Here is a pic of the front end. Looks weird to me.

Your preload spacers could be too long. Based on your earlier comments about possibly going to heavier springs, the pic shows quite the opposite. If the springs were too soft, you would need to dial the preload all the way in just to get close to 35 mm. The springs could be close (Although the extended measurement minus the unloaded sag measurement would indicate otherwise). Your bike without rider has 31 mm of sag and this usually means the springs are too soft for the bike. I usually look for between 14 and 20 mm of sag between fully extended and just the bike's weight.

If this were spot on (correct spring and spacer length), you would see something like this:

FRONT
No weight 124mm (fully extended)
Bike wt only 106mm
Rider weight 89mm

Total 35mm