I just have a few questions. I changed from LT235/85 R16, the oe tire, to LT 265/75 R16.

Am I correct to read the code this way: The LT235/85 is thinner and taller, the distance from rim to tread being 85% of distance from sidewall to sidewall?

If that is so, my new tires would throw off my speedo slightly, would it not? wheels spinning the same speed but covering less ground, right?

My mpg seems to have dropped a bit. Would I notice a change?

 

The 265 is actually a bit taller than a 235 . That is the height aspect . 85 to 65 is the width aspect . And yes , it may throw off your spedo a bit . So , your mileage accounts will not be accurate .

 

The new tire size is about 1-1.5" wider (+/-) in both section and tread width.

But it's only about a tenth of an inch taller, your speedo won't even notice that slight fraction of a difference.

 

.25% to be exact :-)