Tire diameter vs. MPG...??...

[Emmettology 101]

I am buying new tires for my DD Tahoe. Was thinking about going up a size or two, but how much will changing tire size affect my MPG? Seeing how a am driving a gas sucking pig already, I dont want to kill my MPG much more than I have too. currently I get anywhere from 12-13mpg on average.

Any idea how it could be figured out from one tires size to the next as far as how my MPG would be effected?

Current I have some Kelly Safari MSR tires that are 265/75/16's. Kellys specs are 31.9 tall x 10.7 wide. I got a set of 17's cheap so I will be getting new tires for these. Was looking at Goodyear Silent Armor tires in either 265/70/17, 275/70/17 or 285/70/17. The specs on these are:

265/70/17 = 31.7 x 10.7 revs = 650 and the weight is 48#
275/70/17 = 32.2 x 11.0 revs = 645 and the weight is 53#
285/70/17 = 32.8 x 11.7 revs = 633 and the weight is aroudn 58#


Would there be a huge difference in MPG performance between the (3)? Or not much at all? The sizes are very far apart, but the weights change a decent amount from the 265 to the 285.......


Anyone?

 

[gmcman7202]

narrow taller tires will get better milage than wider ones, less rolling resistance. that is what you need to compair, to determine the milage factor.

 

[Emmettology 101]

Well, smallest I'd go would be the stock 265/70/17. Wanted to upsize to one of the other sizes. BUt I may just stay stock since goign up would also get wider.

 

[NEK5]

sorry to hijack but right now i`m runnin 14.5 wide and theres alot of mud around here....would you recommend goin to a 12.5 or sticking with the ones i got?

 

[Emmettology 101]

sorry to hijack but right now i`m runnin 14.5 wide and theres alot of mud around here....would you recommend goin to a 12.5 or sticking with the ones i got?

No prob. You'd probably get more responses if you started your own thread.. But I always like wider tires in the mud. I used to run 15.50s.

 

[gmcman7202]

Well, smallest I'd go would be the stock 265/70/17. Wanted to upsize to one of the other sizes. BUt I may just stay stock since goign up would also get wider.

not true, do you know how the tire numbers break down? a 245/85r16 is 32.4" and a 265/75r16 is 31.6" with most likely less weight since there is less weight on the sidewalls than the belt, thus less belt and more sidewall = less weight. you might want to look to see if you can find some tires that are maybe 265/80 or 75/ r15???

 

[gmcman7202]

sorry to hijack but right now i`m runnin 14.5 wide and theres alot of mud around here....would you recommend goin to a 12.5 or sticking with the ones i got?

do you need the high floatation of the wider tires? the narrower the tire, the less it needs to displace when going through snow and mud, but it all depends on what exactly you are doing and trying to get through. personally, i rather take the narrower ones if its just like feild driving, but if its hard core mud pits, i would want the wider ones for the more traction surface.

 

[Emmettology 101]

not true, do you know how the tire numbers break down? a 245/85r16 is 32.4" and a 265/75r16 is 31.6" with most likely less weight since there is less weight on the sidewalls than the belt, thus less belt and more sidewall = less weight. you might want to look to see if you can find some tires that are maybe 265/80 or 75/ r15???

Yes I know how he tire numbrs breakdown. I lised the measurements for some above. I meant I didn't want to go with a smaller tire height OR width wise than the 265/70/17..