Suburban more efficient than Prius

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Dec 9, 2010 | 6:38 AM

#11

vrso2

CF Active Member

Joined: Apr 2010

Posts: 232

Likes: 1

From: toms river, NJ

also, u can increase fuel efficiency when u drive with closed windows. I know that for sure !!!

Dec 11, 2010 | 2:44 PM

#12

73shark

Administrator

Joined: Apr 2006

Posts: 11,337

Likes: 194

From: KC, MO area

Quote:

Originally Posted by RacerX

if you were driving 60mph and had 15" tires, your engine would be at 2400 rpm in 4th. But using an 18" wheel has increased your rolling radius by 3 inches your rpm should decrease by 20%.

Actually it only increases the rolling radius by 1.5" (9" - 7.5" = 1.5") and that's if you put the same profile tires on as the 15s had which if you did would probably cause tire rub somewhere.

Larger tires that increase the diameter are the same as a higher axle ratio (numerically lower) which might actually lower mpg as the tire/wheel combo will weigh more and may put the engine in a less efficient operating region.