Tires: wheel/tire size limits, winter tires, tire failure

Question
A tire dealer just told me that the 285/50r/20 tires on my '04 Ram 1500 4x4 QC would cause wear in my drive train.Is this true, or do all the computerized shift points etc. adjust accordingly? I'm not very concerned with a speedometer error, but i would be about any mechanical wear implications. I know that the maximum optional size offered was 275/60/20. So is there a difference between these which affects the hardware?...or the gas mileage? Also, are there concerns when i switch to my winter tires : 265/75/17 ?

Answer
Manfred,

I think what the tire dealer was trying to say was that he had some concerns about using a tire with lower load carrying capacity.  The P275/60R20's have a load index of 114 and the P285/50R20's have a load index of 111.  This difference increases the risk of an overloaded tire failure, which can sometimes have tragic results - and the tire dealer didn't want to take that risk - especially considering the legal liability he would have put himself in.

FYI, the 17" tires that also came of the truck have a load index of 113.  I suspect you got the size wrong on your winter tires and you really have the same size as the originals.

So while the tire dealer didn't get the true message across to you, he was right to raise the concern.