What's ideal sag for a 2003 cbr600rr front and rear for a track day rider. I'm currently pretty new to trying to figure out suspension tuning and I don't know if there's going to be anybody there tomorrow to help me out. Currently a little detail about the bike is I'm running a 15/47 sprocket setup. I'm also on a Penske double pass rear shock and I just built the 2003 front end with all race tech components. .95kg springs, The race tech big valve kit and the race tech rebound kit. If anyone can just give me an idea of what I'm shooting for I would greatly appreciate it. Currently, sag is front 20mm and rear 10mm. I've just started messing with it a little bit. Also my preload is all the way out in the forks and I'm assuming that's because they are now sprung for my weight? Like I said any help is greatly greatly appreciated I'm just trying to get an idea of what I should start from.
According to Race Tech’s Motorcycle Suspension Bible, pg 21: Front sag (bike plus fully-geared rider): 25-35 mm Rear sag (bike plus fully-geared rider) : 25-35 mm These are road race setup recommendations. 30-35 mm for street setup.
You are likely measuring the sag incorrectly if you are getting 20mm and 10mm. Remember, sag is from full-extension to rider-on-it. You have to lift the bike up to measure full extension. Measure again. When I raced that bike many many years ago, I ran 35mm front and 30mm rear. It worked good enough to win novice races. But don't stress too much about the sag. If you springs are within range for your weight and riding-style, it's not that important of a measurement. # of turns of preload is what you should be writing down in your notes. Zero preload is not good for most forks. Measure your sag again, set it to the numbers above, then report back with how much preload. Zero preload can be fine for aftermarket shocks, depending on how it was setup. 15/47 is not a good ratio for the CBR. I raced 15/43 most often, with a 112 chain IIRC. You really need that axle further back, especially if you are using larger race tires like the 180/60s.
Wow thank you both so much. I was trying to make up for how gutless this bike is with gearing. I had for some reason thought the suspension sag was bike specific. Idk why. I am planning on gearing it down in a week or so. I'll definitely give that 15/43 a shot. I am currently on stock tires as it's just a track bike. Thank you both do much
