Mileage with 325/60/20's??

[Summitman]

I have a 2011 crew/long black on black, with black Rock Star's, & Goodyear Dura Trac 325/60/20's.

What are guys doing for mileage on yours. With my stock 18's I was at 19.5-20.5. I went to the 325's and it droped to about 15-15.5 average. I am running a Bully Dog tune. Wondering if I should pull my programer & see what my mileage does or if I should try a differant tuner, maybe h&s??

If I could figure out how to post a picture on here, I would.

Thanks

[SuperCrutyPS]

Question: Are you compensating for the tire size difference in your mileage calculations?

Here is a calculator. Punch in stock size and the new size. It will show you the difference in size and the percentage of difference. Use that difference in your mileage calculation.
http://www.miata.net/garage/tirecalc.html

[PUMPED 101]

I have hannkook dynapro's in that size my truck says 17.7 with winter fuel i'm deleted also. I would assume it would go up this summer.

[Summitman]

I reprogramed for the new tire size already. I use Tire size calculator for my tire size adjustments. My speedo if off 1.5 mph at 70 acording to my GPS.

I am not deleted as bully dog won't give me that option. Are you running the h&s? I've been looking in to those.

[PUMPED 101]

Yes H and S minimaxx

[Joey wash]

I have a 2012 ccsb with 35/12.5/20 and I can not get better then 11mpg. No tune.And with the stock baby fuel tank this sucks!!!!

[Joey wash]

http://i1241.photobucket.com/albums/...P/ed784b32.jpg

[95strokerpaul]

I'm with joey on this 1. I just made a 3000 mile trip with my 12. First 1500 was stock tire size doing 75 avg 17-17.5 hand calculated. Then I leveled it. With a set of 35-12.5-18 toyo mt's. The second 1500was i avg'd 13-13.5 hand calculated doing 75. I expected 1 maybe 2 mpg loss, but not 4. But from the sounds of you guys, im right in the ballpark. I expect to see a little difference when I get the computer set for these tires.