The increasing tire size hummer h3 performance and fuel consumption
 

hi i have hummer h3 3.5l and tires 265/75/16. I want to upgrade to 285/75/16 tires i will see differences in performance and fuel consumption? I want one of you who made this upgrade help me!!!

You are not talking a big difference in size here, but there will be a small loss.

I went to 315/75/16's and saw a big dip. By doing other mods like exhaust, intake, ported throttle body, new plugs, ignition coil spring deletes and a PCM tune, I was able to get some of that back. Any time you make changes to the factory set up you will see differences in performance and milage. The question is how much and in which direction will the changes go.

Well said . . .

zarogian keep in mind 285's came on some H3's from the factory so the performance/gas mileage should still fall within the factory parameters. I got hung up on the same thing in the past and regret putting the 265's on that are taking forever to wear out.
I was previously informed by someone that has run a couple different sizes that he didn't see reductions until getting to 305's which dropped it about 0.5 mpg's. He reported 315's dropped him 1.0-1.5 mpgs.

Anytime you go to a bigger size tire, performance will suffer. It simply takes more power to turn a taller and heavier tire. Braking performance suffers as well.
On my last Jeep I went from 31's to 32's to 33's. There was a noticable power loss with each jump, but nothing earth shattering. By the time I got to the 33's, the overdrive became a pain for in town driving. I usually ran with the OD off.

I find with the stock 265 size that came on my H3, I do not encounter any of the "underpowered" issues/complaints that seemed to pop up when I was researching this vehicle.

One other option you have in tires is to go with a 285/70 rather than a 285/75. You get the beefier looking tread width of the 285 with the smaller tire diameter of the more efficient 265. The drawback of the 285/70 is only a couple brands offer this size currently.
I believe you can find it in a Toyo MT and in the new Nitto Trail Grappler.
The Toyo is available in a "C" load rating which would offer a smoother pavement ride than the "E" rating that most 285/75's come in.

Thank you all for your help and quick answer, of course, expect and other holders h3 answers. I am thinking to buy bf km2 285/75/16. these tires come in Greece. course, other brands of tires are only ordering. The best I can do is buy 4 wheels and change them when I go for off-road adventure. In this case you buy and 35 '. I have the 265/75/16 on long trips and 285/75/16 or 305/75/16 for off-road.

Heck for OffRoad only get the 315/75R16s 34.5" tall (35s). You will appreciate the extra differential clearence, approach and departure angles plus they can be aired down and still have the same or more clearence as the 285/75R16s 32.7" tall (33s) all aired up to highway pressure.

Before you ask, NO LIFT or LEVELING KEY KIT is required to run 35. We have owned 5 H3/H3Ts and they have all had at least 35s on them with no lift or LEVELING keys.

all great responses in my opinion, anyway you look at it, it's a Hummer how fast is anyone planning to go