Wheel diameter
I thought this would already be a topic on this forum, but my search netted “0”. Specking out a new truck to tow a fifth wheel. Standard wheels are 18 inch. Wondering about going to 20 inch, any adv...
Forum Discussion
Durb wrote:
Doing ther math, 285/75R18 has a diameter of 34.83". The 285/60R20 has a diameter of 33.46". The difference is 4%. Theoretically, the 20" tires should accelerate better and stop better. The 18" tires might allow for better fuel economy. Your truck should sit 5/8" lower with the 20s, if all other things are equal. I trust Grit Dog that these are the sizes offered.
RAMs I believe still uses LT275/70R18E that are the same diameter as the LT285/60R20E ones they use.
Michelin list the LT275/70R18E Defender at 33.1" and the LT285/60R20 as 33.0". 627 revolutions per mile for the 18s and 630 for the 20s.
I went with 18", as the Laramie 18" wheels are the best looking of the lot. Chris
