"Let me explain the speed ratings, though. Remember HR, SR, TR, VR, and ZR? Respectively, the tire is good up to 110, 115, 125, 149, and 150+ for long sustained speeds. If there is just an "R" then 105 is the sustained limit for safety at that speed. The higher speed rating will also bring increased ride harshness, as the tires have to be built to withstand the speeds for which they are capable." - http://www.midsouthvw.com/TechTips/tech_tip_tires.htm
black side wall
Bridgestone
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standard radial
Speed Rating
155/80r13
SR - S = 112MPH speed rating, R = Radial
Front to back, no. Side to side, yes. If the tires are directional, no.
The 1991 Coca Cola 600.
what is the effect on digestive system of voveran SR 100
chock tires
http://en.wikipedia.org/wiki/SR-71_Blackbird