Sorry, I couldn't resist the pun.
I'll be looking at a new set of Michelin Pilot Road 3 in the spring and am considering getting the B-rated tire for the rear but I can't find any load rating information about the tire. I have the standard tire on the rear now but always run it at maximum pressure (42 psi) when riding two up and the bags loaded. The standard tire is rated at 805 max pounds at 42 psi. For rough calculations I took 1/2 of the bike's weight: (650/2) 325#, my weight with gear: 170#, my wife's weight with gear: 185 (just a guess because she won't tell me), and about 30# of crap in the saddlebags. All that comes to 710 lbs which is within 11-12% of of the max load rating of the standard tire and I want to have at least a 10% margin for safety (805x.10=724.5). So in my opinion I'm operating at the upper limit of the standard tire. The Michelin website does not provide the load rating for the B tire and the local shop had no information and no tire on hand for me to look at. Fwiw, the standard tire is $167 and the B-rated tire is $224, a significant premium, but probably worth the extra cost in peace-of-mind if nothing else.
Does anyone here have a PR3 B-rated tire in 180/55-17 and if so, would you do me a favor and provide me with the load rating stamped on the sidewall? Also curious if there is a rule of thumb for the number of pounds of load at which one should upgrade from the std to the B?
Thanks for your considered response!