OK, I've tried searching as I know this has been covered but "tires" and "MPG" are too common to search for! So here it is AGAIN.

Its time for new tires, I've came accross a fair deal on a set of factory H2's. I am running the stock tires as of now, (265/70/17 BFG's on my 05 with a g56). I have no problems in re-calc. the computer. I just wonder what these tires are going to do to my current mpg? I tow VERY often, 10k and under for the most part. I usually run 70 or less on the highway and get 14-17 mpg while towing. 17--empty trailer, 14 loaded all the way. Can anyone with a G56 and 3.73:1 gears chime in with any real world numbers? I am happy with the numbers I am currently getting but hey, more is always better!

Thanks in advance,

Jason

 

I have the same set up, minus the 6spd. My mileage went down about 1-2mpg. I just got the computer recalibrated to match the 35" tire rpm. I am waiting to see how it goes now. I do all my mpg calcs. by hand so we will see if it helps.

As for towing, not sure, I don't tow. I suspect your mpg will go down.

Bob

 

I think the big difference for us will be the tranny. My OD sucks bad, yours was closer before the tires!

Jason

 

I just put 315/70/17 BFG All Terrain TA KO's on and am very happy with them. I haven't calculated the mileage yet but my tach dropped 10% so the wear and tear is down in my opinion.

I cruise at 110kph (70mph) and run 1850 rpm with the 6 sp. Towing a horse trailer of about 6500# I notice a bit of power loss but not enough to worry about. I still kick my buddy's 02 GMC's butt .

The truck looks 100% better and I think my empty mileage is a bit better. Towing doesn't seem to be much off either but like I mentioned I haven't actually calculated it.

Cya

 

Thanks for the info. Those are exactly the tires I'm looking at. I'm not very concerned with the power loss, I have more at my fingertips than I need anyhow. I'm really more concerned with a drastic loss in mileage. I like the idea of running the engine a touch lower but just not sure if it will cause it to work so much harder that it will not be worth it.. Thanks again!

Jason

 

I don't think it's working harder, but the RPM drop is great. My hunting trips are about 4 hours return with 4 horses and still use 1/2 to 5/8ths of a tank, 265's and the 315's. No noticable difference.

Cya

 

1-2 MPG decrease here, speedo reads 4-5 MPH lower than actual speed. But they look better, handle and ride better and they certainly perform way better offroad than the stockers.

 

I have not seen any real difference in mileage since putting the BFG 315 AT's on my truck. I also cannot say that there is a power loss, power is still there, or at least the last time I looked under the hood it was. It is nice to have lowered the rpm's, less wear. First gear is still just as good starting out uphill with a 12K trailer, and 6th is now a better overdrive gear. As I see it - best of all worlds from performance to appearance.

CD

 

I have an auto & 315/75/17 MT's decreased my MPG by 2 mpg. That is adjusted for the size increase. I can feel the difference in the take off a little ,but not bad.

 

This is kinda what I expected. Lots of auto tranny guys losing mpg and some power while the manual guys with out crappy OD ratio not really changing much. I think I'm going to get the tires and just see how it does, if its terrible I can always sell the rims and tires and not loose too much. Thanks to everyone for their input. I will post back on how this works out!

Jason

 

with the h2s and 315s, speedo recalibrated and with the smarty on sw #5- my mpgs were around 18/19 highway. with the xzt, im looking at 15/17. the lowest ive seen is 14.

 

I did alot of highway miles and the 315's gained me 1-2 mpgs. Lower rpms while cruising. I am getting 18-19 mpg.

 

Thanks again! I've made an offer on these tires, we'll see how it goes. I hear these things are almost a dime a dozen due to the "south florida" 20" wheel craze. Is this true?
Jason

 

I have bought H2s and BFG's from a dealer in Vegas for $200.00 each and I got my first set for $800 for 5. Out here they seem to be hard to find.

 

Ahh, ok maybe its just a southeast thing. I definately would NOT pay that for them, but I'm not that excited about the wheels anyhow. If I can't buy them for 600 then I'll just buy new tires and get roadhazard ins. on them!

Jason