Thread: tire diameter
View Single Post
Old 09-19-2008, 11:29 PM   #10 (permalink)
EcoModding Lurker
Join Date: Apr 2008
Location: Kampsville
Posts: 77

stinky - '97 geo metro lsi
90 day: 44.71 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
Can anybody see me pulling my hair. DO NOT CARE. Let me try an exteme to pound this into u guys head. I take a 5 inch diameter tire. YES 5 inch. put it on the car. Change the gearing in the car to where it turns 3000 rpm at 55 mph. find out the mpgs. then i put a 100 inch tire on, yes 100 inch, change the gearing to where rpm is 3000 at 55 mph. find out the mpg,s compare the results.

now for the people who are going so say a 5 inch tire wont work cause of ground clearence, do not care. I know that lower rpms are better, thats not the question so, do not care. tires can get smaller as rim gets bigger, do not care. NORMAL tires get wider as the diameter get bigger, so special (code name, expensive) tires that get narrower as the diameter goes up, do not care. What i am trying to compare is something (but not limited to) 155/80/13 tires to 145/82/12 geared to make the rpms and speed equal. I hope that i am getting specific enough.
  Reply With Quote