What do you use to shim the rear 16 Gsxr 600 to raise it a little so it turns in a little better
Great Write up JCW, AND everyone else also!So everything said above is absolutely correct. And if you want a sweet handling bike you can haul ass on the track follow what was offered above. :wink
However, my advice to you wasn't necessarily incorrect given your stated goal. And in my humble opinion will get you what you want with the least drama.
The reason I believe this to be true is that a perfectly set up bike for the track is not necessarily what is needed for the streets. What do I mean by that? Well, on the track, you are potentially much harder on the brake and gas and you put the bike through the extremes of suspension travel. On the streets, you might use 1/3 or 1/2 or 2/3 of that travel depending how hard you ride and how much you risk.
Since the track season has ended up here I have dedicated time to try to understand the geometry questions about this bike, and I think I've finally wrapped my head around it. At least in a general sense...
The following is my understanding of why the changes are being made in one particular way.
Suzuki has set up this bike so that 1) it is stable mid corner and 2) has plenty of traction in the rear on exit. In doing so, once the pace picks up riders notice the slow turn in usually first. Then if they venture on the track and get on the gas sooner and harder, they find the bike running wide on exit.
For the trackday heroes and more importantly the racers, this running wide on exit is unacceptable. By using different riding techniques, turn in can be sped up by trail braking into the corner, but running wide can only be fixed by easing out of the throttle. That kills exit speed and lap times. So, the first thing they fix is the swingarm angle and rear squat. This is why everyone raises the rear. Not so much to speed up turn in but to cure the running wide on corner exit.
The next thing people do is what confused me for the longest time. Why would you go to the trouble of raising the rear then take away that improved turn in by raising the front as well... However, ALL the fast gsxr's on track are raised front and rear.
Was it that the rear height increase took too much trail away from the front making the bike too unstable? or was it a center of gravity thing? or was it a weight transfer thing? I couldn't believe that raising the rear ITSELF caused the front of the bike to lose that much trail that it became unstable when the bike turned in slowly to begin with. It just did not compute.
UNTIL! I realized what they were fixing by raising the front was instability caused at a particular point in time! that was on the brakes <HARD>. If you think about it, without raising the front, on the brakes hard will cause the front to compress. With the rear ride height increased but the front ride height the same, more and more weight is transferred to the front and the front dives harder and faster reaching the bottom of travel easier. Once you reach the bottom of travel, the rear wheel starts to lift and maximum braking is reached sooner. I have noticed that since raising the rear, it is more difficult holding the bike steady at maximum braking. Never did it occur to me this was a geometry thing. I thought it was simply me being chicken.
What raising the front through the forks does is limit how much the front dives on hard brakes (suspension bottom is raised) and keeps a little more weight toward the rear allowing more stable and harder braking. This is what I was missing. This is why raising the front produced a faster bike! It was a eureka! moment.
what does this have to do with a street bike? Are you on the gas hard enough coming out of a corner that you squat the rear causing you to run out of road? Are you braking hard enough that you compress the front to the point your rear wheel is becoming unstable? if not, I propose that fixing the swingarm angle with a rear ride height increase is unnecessary and to improve your turn in you could either drop the front through the forks a little or even better take some preload out of the front and run a little higher sag (this won't change the bottom of suspension travel like moving the forks will).
Hope some of this makes sense. But experiment and keep an open mind.
The faster you ride, the more you feel the perceived limitations of the bike set up then adjust accordingly.
So, yeah, braking and downshifting will loosen the rear end and make the bike want to come around. That is different though than just full brake application to the point of lifting the rear.YES, but I also attribute it to the fact of it happening when I downshift to the lower gears as I enter a corner, and let out the clutch a little quick when I'm already braking hard, and it will drift slightly outside as I turn in.
With my forks pushed up thru the triples barely enough to get my clip on on top ot the triple (I have a thread on that), this did get it to turn in nicely, and I've been liking the way it has been handling.
I'm still thinking of trying a few shims in the rear as well!
Also, if you could find a good suspension person to set the bike up per your weight it would help more than anything I think.That is not a bad plan.
If you don't know where the bike is set now, find out and write the settings down so you know what you changed and what effect it had. And it makes it easier to go back if you don't like it. I would be sure that the settings are somewhat near the factory recommended base settings. They are in your owners and service manual.
I should have mentioned earlier that tires can make a huge difference how the bike turns in and handles. If you have old, worn or squared off tires, you will be chasing your tail trying to make it handle well.