Just my 2 bobs worth and my comments apply to the 1300, tyre pressures are important and critical to tyre wear. My tyre supplier finally convinced me to run higher pressures for Mich. PR4 F&R and as I run a tyre pressure monitoring system was able to confirm that what he suggestions were valid. At 42psi cold with 30 degrees ambient temp, the rear pressure would rise to 55-56 psi at 100KPH. At 47psi cold the pressure would rise to 54-55 under the same conditions, i.e. a lower running pressure. The result of this is less wear due to the lower temperature that the tyre is running at as pressure rise and temperature are directly related. The first PR4 (42 psi cold) lasted just over 8,000 K with most of the wear being the right side edge with lots of 'bearding'. The second PR4 (47psi cold) is at the 9000 K point with an estimated 30% life left. My riding habits have not changed, love that flat torque out of corners.
There are other factors that come into tyre wear, one of them being suspension setup. Rear suspension settings affect the performance/handling and front tyre wear. As well as checking tyre pressures on each ride and during the ride, I checked suspension setting, in particular, preload on the rear. Also use tyres that conform to the specs required for this bike, both in sizing and importantly load ratings. Remember that the weight on the tyres is not just the weight of the bike, rider, passenger, load and in some cases trailer ball weight. Those that undertake flying know that at a 60 degree bank, 2G is applied to the aircraft and it contents. When turning on a bike is no different and effectively starts to increase from 30 degrees upwards. This is taken by the tyres at an angle which produces tyre distortion, further increasing contact pressure/temperature.
I was iffy at first in increasing tyres pressures beyond the book value but tyre technologies have improved in the 18+ plus years since the design of the 1300 and 27+ years for the 1100 and monitoring has confirmed that the lower running pressures/temperatures=longer tyre life. BTW ride comfort has not changed significantly and ride handling is better if the suspension setup is correct. I know now if the setup is wrong as it does not feel right.
Trevor
