255/85 R16 Owners Experience

The diameter adjustment is primarily to compare to previous tires and is significant. To claim it doesn't matter in the real word is incorrect. There are many things that do affect your gas mileage like tire tread pattern and tire weight. Tire diameter will obviously affect things like weight and the moment on inertia of a tire, but it wont directly affect your gas mileage. That is why it is important to take the size difference into consideration.

So, according to tiresize.com the difference in circumference between 245/75 r16 and 255/85 r16 is 8.5%. That means that you are going 8.5% faster and further per revolution. This means that your odometer is also 8.5% behind. Which means that if you are doing MPG calcs you are 8.5% off from your real value. So lets do the math:

for 255/85r16 you calculate 19mpg from your odometer. 19+(19*.085)=20.6 Congratulations. You are still getting above 20 MPG with 255's.

This means you lost ~2.5 mpg to tread, weight, rolling resistance...etc. instead of losing 4 mpg. Of course your speedo/od may be off in the real world. But the difference is still gonna be the same-ish. (instead of 23/20.6 it would be 22/~19.6)


TL/DR: GPS is the best way to calculate your gas mileage. But adjusting for tire size is significant and should be accounted for assuming your OD is mostly correct.

 

I agree with all you said with no doubt, my point was to confirm everything with the gps but of course weight and size has to be taken in consideration.

I am now trying to figure out how to correct my odo since when my needle is at 100km/h (sorry for metric) my real speed is 96ish, and on a 100km trip, my odo is off by 0.550ish meters (gps is not accurate enough until I check it on the computer). Going 96 instead of 100 is 4% difference 0.500m on 100km is really far from that. Maybe you have a clue to help me out with this?

 

Unfortunately, I am at a loss there too. I think the easiest way is to just figure out how much you are off by and adjust your brain

 

Will try lol saw with the tire calculator that my speedo would work pretty good if I was on 235/75/15, but don't know yet what to do with this lol

 

lol just get the tires you want and don't worry too much about how fast you are going. As long as you know your speedo is slow you are good to go....or just feign ignorance.

 

Hahaha going fast is not my cup of tea lol just don't want to sip gas like a V8 lol but it will happen because I want them

 

I think Hypertech makes an inline speedometer calibrator that I assume would also fix the odometer.

 

lol yea, My Maxxis tires i get maybe 15k and i am happy lol.

 

Well I want too put 255/85 /16 tires on my stock 2006 rim's with a 2.5 inch lift,my last truck was a 1994 Ford F-350 with a 460 (10 miles too the gallon),so I could care less about losing a few miles in gas millage on my Taco,lol

 

YOu run bighorns?

 

yep, they get LOUD when warn too lol

 

Would you buy them again? For the price, I wonder if they might be worth it.

 

I know @fatfurious2 got rid of them because they were so loud. But if you run two sets of wheels, and only use them for the trail, it might be worth it.

 

I was barely getting 200 miles to a tank with them. I also tore 2 sidewalls on a stock friendly trail. They are a good mud tire, but not good for DD. I think the cheapest I found was $160 shipped, each.

 

yep, in a hartbeat. for the new truck i will go 35s though lol.

 

Looking to upgrade from stock 265/70/16 to 255/85s. Stock gears. My concern is I tow a 4k lb boat (no trailer brakes) to the lake and back at least once a week may through september. 12 miles each way, no highway. Am I going to feel a big difference with the 255/85s? If so I may just go to 265/75/16s.

 

Quick question for all of you guys running 255 cooper st maxx tires.

What tire pressure is everyone running for everyday driving?

 

35psi

 

40

 

34