Gas Mileage vs Tire Size
Gas Mileage vs Tire Size
I'm new member to the forum but have viewed threads on and off a few times. Obviously there have been plenty of threads on tire fitting but I haven't come across anything that talks about the impact of changing tire size on gas mileage. I'm still running my OE Wranglers as they wear forever regardless of how horrible of a tire they are. I'd like to move up to a 34" tire but wasn't sure if there would be a sacrifice in gas mileage if I do. Right now I get about 13.6 mpg daily driving. Any experiences and advice would be greatly appreciated.
Champion
Joined: Aug 2007
Posts: 4,702
Likes: 2
From: N. Florida
Larger tires seem to negatively affect mileage, probably due to increased unsprung weight, and perhaps because more air is allowed to get under the truck with the resulting increased turbulence and drag. Larger diameter also decreases engine rpm at any speed. Some say this reduced effective rear gear ratio hurts city mileage, but it certainly can help highway mileage.
As for 13.6 average mileage from a 5,400# 4x4... I suspect it isn't that good, unless you drive really slow on the interstate. How are you determining your mileage?
As for 13.6 average mileage from a 5,400# 4x4... I suspect it isn't that good, unless you drive really slow on the interstate. How are you determining your mileage?
Thanks for the info. That's mostly what I had heard. I was wondering if anyone that moved up to a 34" saw a 1/2, 1 or 2 mpg difference. My daily driving consists of a 10 minute mostly city street commute to work and seldom get any significant highway miles. 1 maybe 2 500 mile trips a year. I figure my mileage manually when I fill up. The in-truck display always shows at least 1mpg more than that. I call it my feel good calculator. Factory mpg are 14 and 18 which I have never seen. A tail wind both directs on a trip to Minn. with cruise at 70 yields 16 mpg if I'm lucky.
Side note: Living in Iowa, I do run a 10% ethanol 89 octane fuel. It's 15 to 20 cents cheaper a gallon than the non-ethanol grade which is 87 octane or 40 cents cheaper than the premium 91 octane. You can't make up those savings.
Side note: Living in Iowa, I do run a 10% ethanol 89 octane fuel. It's 15 to 20 cents cheaper a gallon than the non-ethanol grade which is 87 octane or 40 cents cheaper than the premium 91 octane. You can't make up those savings.
