Im ordering a new set of tires tomorrow. I have pretty much settled on Mastercraft Courser MXT. I just like the way they look and read some pretty good performance reviews and they seem to fit my needs. As well as my budget. Now I just need to decide on size. I'm currently running 265/70/17 cooper discoverer at3 tires and they are pretty much shot. I'm now deciding whether to get the 285 or 295 size tire. Will the extra size kill my mileage or transmission any faster? I have the 3.55 ls rearend. Will the extra size be worth it? Did any of you regret going with 285 when you could of gone with 295?

 

I had 285's and had no problems with them. What size tire does the sticker in the door jam say your truck should be on?

 

265/70/17

 

You shouldn't have any problems at all. My stock size is 235/75/16 or something like that.

As far as killing your MPG goes, it all depends on what tire you go for. If you go to a mud tire then it will have less mpg than a freeway tire.

 

285 70 17 will be fine on your truck man, that's what I've got.

 

Its not worth the extra height. I would go with 285's.

 

That's a nice looking truck.

 

Thanks man

 

You will be fine with 285. I noticed maybe 1 mpg difference switching even tho I got my best mpg yet the other day on a tank at 16 mpg and that was with 285. I'll probably be going to a 33/12.5/17 my next set

 

More more mpg or less? A 285 with the same profile, say - 70, wil be taller; more circumference. Your friction is a tiny bit more but your mpg should go up UNLESS you use more throttle, trying to maintain the same acceleration as you had before.
265/70 16" 30.6" tall 96.1" circum
285/70 16" 31.7" tall 99.6" circum +3.6%*
285/65 16" 30.6" tall 96.0" circum
*This makes a 3.55 feel like a 3.43.
300 miles on a tank could yield 11 more.
Depends on your foot. 😉
A 20 sec quarter might become 20.7 sec.
Nothing is 100% so simple and linear, but it's a way to generalize the effects you might see.
Under 3.55 there used to be a [discontinued] 3.37(?) I would like that. Others would go the other way. Different needs and goals.

I ordered my '76 Dodge Maxivan w a 360 and 2.71... made it like a 318, but the 360 was an actual truck engine. The calibrated computor said I got 16mpg w a 3 speed auto w/o lockup. 120 in 2nd. (In '77 you could get a 4spd stick. &#128534
BillSF9c