Ditto, take a look at the wear pattern on the tire. I have a rated D level tire requiring 65 psi (max), I run at 40 now and I'm still bleeding it down. I'm testing the streetability, traction (mostly rain now), turning, sliding, skidding, etc at these different pressures.
Get a better set of aggressive tires on it and see. Swap your wheels from the 91 to the 01 and go for a ride.