245s vs 285s

Trprowen · 02-24-2009, 11:37 AM

Ok So when i got my truck it came with 285s on it pretty aggressive tread... i mean who doesnt like a bad ass looking Duramax, BUT id rather get better MPG and towing MPG thats what im after so ....

i know you guys been doing this alot longer than me , will it make a difference to go back to factory 245s or stay with what i have ? remember i want better mpg here

thanks

duramax07tmd · 02-24-2009, 11:44 AM

I have heard that the 245's get better mgp around town, but the 285's would do better on the highway. That is just what someone told me. I have the stock 245's on mine now but im getting ready to switch to 285's I dont think it will make THAT much difference.

duramax07tmd · 02-24-2009, 11:45 AM

oh, just be sure whenever you switch that recalculate your speedo!

**TYREBOYZ_DEMAXIN** · 02-24-2009, 12:25 PM

yes the 245s will get better fuel economy local and over the road for the most part now you can do the 265's without suffering more then 1MPG over the 245's but still have a tire that looks decent on your truck..thats what i run over the road and it gets better then the 285's or the 245's.

**timespentsearching** · 02-24-2009, 12:41 PM

if you want relaly good mileage 235/85R16 is the best tire to get. its the best all around town and highway tire, great for towing as well. if your looking straight highway a 255/85r16 is going to be the best. they are .5 taller then the 285's and are narrower. im getting another set of rims for some 285's this summer and when my 235/85's wear out im getting some 255/85's for the stock rims for winter.

**n0useforaname** · 02-24-2009, 12:43 PM

Here is what I can tell you from experience....and these are hand calculations.

Bone stock..LBZ...I ran a steady 17.5 city mileage...never dropped below 17. On the highway...it was 20-21MPG...even with the AC on.

After 265's....my mileage is around 15-16 city...mostly 16...and my highway numbers are at 18-19.

My 285's get put on HOPEFULLY in a week or so...just waiting for the garage to call. But most get 13-14 with 285's city....and 17-18 highway...and some claim better. They say at a steady fast cruising speed..a bigger tire has less rotation which equals lower RPM's...and at a slower speed higher RPMs.

04LB7DmaX · 02-24-2009, 12:56 PM

Im sure you will be safe with at least 265s and itll look better on your truck.

**TYREBOYZ_DEMAXIN** · 02-24-2009, 12:59 PM

the best i ever got with the 285's on our CC SB LBZ was like 21-22MPG doing a whole 68MPH.

N2BRK · 02-24-2009, 02:41 PM

Quote:

Originally Posted by n0useforaname

Here is what I can tell you from experience....and these are hand calculations.

Bone stock..LBZ...I ran a steady 17.5 city mileage...never dropped below 17. On the highway...it was 20-21MPG...even with the AC on.

After 265's....my mileage is around 15-16 city...mostly 16...and my highway numbers are at 18-19.

Did you account for the difference in distance traveled with the larger tires, or had your odometer adjusted for the new tires size each time?

Thanks!
Wally

Trprowen · 02-24-2009, 02:47 PM

wow i have to be doing something wrong or have a major issue , cause i can only get 15 mpg right now ! Thanks everyone for the help too! So so far it looks like it is a toss up on sizes hmmm guess more ressearch is needed !