I have BST 17s fited, with Metzler racetec 190/55, bike understeers (brakesteers) in current set up, so may be to tall in rear ?
If you have not changed the rear height when you went to the 190/55 you should still be close to the factory set up with the OEM rim/tire.
To be clear- are you saying that you feel you need to trail brake for the bike to turn in crisply- or are you saying when you trail brake the bike wants to go wide?
I found that the bike does respond crisper when you trail brake into sharp turns but I have never had it stand up or run wide while on the brakes when leaned over. Off the brakes when picking the bike up with throttle the bike can be sensitive to rear ride height and not keep the line- but I do not think you are saying that.
At what speeds does this happen?
Did it feel this way with the stock tires?
Since I am not clear what you are describing I will give you my general thoughts.
I found that tires, speed, and riding position make a big difference in turn-in on this bike on the street and on the track. The stock set up felt very numb to especially at lower street speeds. I went through two different sets of 17" tires before I found what felt good on the street. On the track I only use Ntec slicks. I had to play with the set up on both bikes to get what I wanted.
I played with a number of geometry setups especially for the track. In the end I went back to the original stock swing arm adjusted height but with the taller Ntec so my rear height was higher then stock. Anything more radical in the rear or a drop in the front did not work for me- but it does for other track riders. Damping changes evolved as I rode faster and changed my riding style.
We all ride differently and my set-up may not work or feel good at all for you.
In the end the changes I made to my riding style made the biggest difference.
Also -----this bike handles much better on the track then at any speed on the street.
