Many variables to consider when comparing tyre for tyre and bike for bike. I purchase the ST in 2008 with Bridgestone 021's. My riding is 99% 2 up with panniers and topbox full, in other words all up weight at maximum. All OK for the first 5,000klms, then one day in December +34 degress, went over Mt Glorious and tore the sides out of the rear. The whiskers were outstanding. The tyre mechanic said that it was symptomatic of high temps, high weight but he said more importantly marginal low tyre pressure. Changed for a 023 and was disappointed in the general tyre wear in particular the flat spot in the centre.
After reading and listenting, changed the F & R to Michie PR2's as the PR3 was not available at the time. At the same time I fitted TPMS. Doing this made me starting thinking about the theory of tyre which could a subject of a separate discussion. In short, the cold tyre pressure should be measured at 20 degress C. Before the Mt Glorious ride, I checked the tyre the previous afternoon when it would have been 32+ degress outside however the bike resides in a metal shed, who knows what the temp of the tyre was when measured. The rear was set to 42 as per manual. I now check the tyre pressures at 20 deg if possible. There are plenty of articles on the web concerning tyre pressures, in particular articles by the 4 wheel racing fraternity.
Since being disciplined in setting the correct pressures, the PR2's have been excellent except for the road noise from the front tyre. All quiet on asphalt, big roar on stone bitumen. After some 6,000klms no flat spot in the centre and as I am not exactly gentle in the corners particular powering out of the corner, side wear in very good, only now showing signs of cupping. Handling good, wet weather good. BTW now run at 44 lbs at 20 degrees. Of interest, on a 32+ day rear at 100kph tyre pressure is 60lbs front 49 both due to temperature of the tyre/wheel assy.
