QuestionQUESTION: The overall diamater on a truck 16in rim with tire is the same as on a 17in rim with the same size tire. That tells me the sidewall is an inch smaller.
Seems to me that the smaller sidewall would mean: 1 - the tire can carry less weight, 2 - the ride would be a bit harsher, 3 - the tire would be more subject to damage. Am I correct? Thanks for your help.
ANSWER: George,
There are a couple of quirks in tire sizing and without specifics on the tire size, I really can't answer your question.
So if you'll post back with the tire sizes, I'll try to explain.
---------- FOLLOW-UP ----------
QUESTION: oops, I made a mistake - it is 17 %26 18 in rims, not 17 %26 17.
According to the mfg: 17" P245/65 R17 105T and P245/60 R18 104T
I measured tire diameter on the truck and came up with the same measurement for both 17" %26 18"
AnswerGeorge,
As you have found out a P245/65R17 has the same diameter as a P245/60R18, but the load carrying capacity is slightly smaller.
But to address the question of ride quality...... well ........ it's bit more complex. Directionally the ride would be harsher - but the differences between tires (meaning make/model) has much more of an effect that the difference in size.
And impact damage? Yes, the 60 series would be slightly more prone to impact damage, but, again, the difference is fairly small.
