I know that there are a lot of threads concerning gas mileage on the forum.

I am just curious as to what change in mileage I should expect by going from 265's to 285's on the I-5.

I have only had the hummer a couple of weeks so I really don't know what mileage I get on the stock 265's.

Thanks alot.

twofish

 

i went from 265 to 305 mts. mpg went down a little but nothing too bad

 

From what I've seen here and on other forums, your gas mileage has more to do with how heavy your foot is than anything else. I think adding a bunch of weight with brush guards or a roof rack hurt affect mileage more than the tires do. I went to 285's and I plan on going to 305's at some point and since I'm not easy on the pedal I expect to get 15-17 mpg. I added an airdoc intake, catback exhaust and pcm tune to hopefully offset my bad driving habits a little.

 

Thanks for your reply.

I have searched this some and there are alot of broad discussions regarding all that you mentioned.

I would love to here more from others on effect of going from 265's to 285's. It is more of a curiosity thing than anything else.

Thanks again for your reply.

twofish

 

I think you will love the looks of 285's and gas milage isnt bad either. On my 09 with the ADV. pkg with 285's , i do a lot better than the 14-18 mpg as advertised!

 

I saw little difference in the MPG switching from 265's to 285's. When you get your 285's run a bit higher tire pressure. I am running 38lbs. in my new tires and I gained 1mpg over running them at 35lbs. with little to no difference in the ride quality.

 

I just put a new set of Pro-Comp X-treme A/T 285/75/16 on my 3.5 H3. we went to the beach over Labor Day. @85= 14mpg & @65-70=17mpg. i feel that is tolerable, considering in is a built like a block. Lynn

 

I have gotten almost 19 mpg highway and 17 running around town with 265's. I am planning on putting on a set of BF Goodrich All Terrain T/A.

 

I put 285/16 with intak and kn filter tires at 35 psi and get 19 to 20 mpg

 

Are you all adjusting for the difference in tire size when figuring your MPG's??