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Old 02-01-2020, 08:01 AM   #6
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Re: Effect On Handling of Tires With Different Speed AND Load Ratings on SAME Axle?

Originally Posted by RidingOnRailz View Post
Ok. And do higher load ratings, and for that matter, higher speed ratings, mean stiffer tire sidewalls?
First, THEE most contributor to sidewall stiffness is inflation pressure. You get a much harsher ride when you add inflation pressure than you get between load ratings of the same make/model tire.

Plus. load ratings and speed ratings aren't necessarily tied to sidewall stiffness - BUT - higher speed ratings TEND towards stiffer sidewalls in order to get better handling (quicker response.), but not always, and there are so many exceptions, it's almost wrong to say what I just said.

Load ratings are a bit more difficult to explain. If we are talking about passenger car tires, sidewall stiffness (that is ride harshness) varies more between makes and models, than between Standard Load (SL) and Extra Load (XL) - and as I explained above, the difference of a single digit load index in the same size is not really a difference.

But in LT tires (ones that use Load Range), within a given make and model, a higher load range will have a stiffer sidewall - BUT - that stiffness will be over shadowed by the inflation pressure.

Put another way, if I operate a Load Range C tire at 50 psi, it will ride harsher than the same make and model tire in a Load Range E at 40 psi.
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