badme

Has anyone gone from the 225/75-16's to 235/85-16's and if so did your fuel mileage improve on the highway? If not, did it go down? and do they clear ok?
Thanks
Eric

Big Blue24

235/85/16 will improve mileage, all else being the same. Less aggressive tread will always get the best mileage. No problems clearing 235's either. I can't believe that your running 225's that must look funny!

volly818

You can clear up to 305/70r16 with no rubbing. Now it depends on what gears you are running if your fuel milage goes up or down. If you got 3.55 then you fuel milage will go down or up with 4.10. If you are only looking to go to the 235 then you should have no worrys about fuel milage. I dont think it will be enough to even notice.

HOHN

Gearing won't really determine if your mileage goes up or down with tire choice. That's largely because the diesels have variable air/fuel ratios, so when the engine is loaded harder (taller gears) it burns more fuel, and at lighter loads (shorter gears) it burns less (runs leaner).

For mileage, you want a tall, thin, hard tire. A 235/85 is pretty much the champion of MPG for tire sizes, assuming you are comparing the same load ratings and tread patterns.

A tire that puts more tread on the road has higher rolling resistance, and thus lower MPG on the hwy. A larger tire also weighs more, and therefore takes more energy to get rolling (which is then wasted as heat when you hit the brakes).

Ph4tty

255/85 is taller than a 235/85. I'm trying to decide if I should make the switch for a little more gear.

badme

I don't know about funny, but I think it would also look better with the 235's

badme

I am thinking that running empty with 3.55 gears @ 75mph it will drop the rpms a bit and the fuel mileage may improve a bit. If not it will look better with the bigger tires. Being in the northeast I am going with Goodyear Workhorse tires. I have them on my plow truck and it is almost impossible to get stuck with them, yet they are not all that agressive looking.

GFB

I would imagine you'd have trouble keeping those 235s planted to the road with that juice! You must have a lot of self control driving with those 225s now. Those things are pizza cutters.

badme

That is what brought this about. I put my truck on its side on new years eve.
It had snowed here and all that power with those 225's just did not work out. When it finally gets back from the bodyshop I am going with the 235's.

GFB

10mm wider isn't really that much more contact area. You probably won't notice much difference unless you get something with a significantly softer compound.

HOHN

I'd recommend the Toyo M55s in a 255/85 size. They will fit on the factory 16x6.5, 16x7.5, and 16x8 wheels and will clear without a lift.

They will give you taller overall gearing (the same as a 285/75), wear like iron, and have good snow traction.

I'm considering them myself. Either this size or the 285 (since I have factory alloys that can handle a 285).

Justin

johnh

my truck came with 235/85/r16 new, i used them until t converted to 04 17's..i got 80000 miles on with the 16's

Ph4tty

Only thing I don't like about them is the speed rating.

Big Blue24

Hohn, you have factory alloys so you can run 285's! Heck, I ran 315's before these 285's that I'm running now and all on the stock steel 7" wide rims.

HOHN

I agree but I don't drive that fast

BB24-- If you look at the recommended rim widths, most manufacturers say 8" wide is the minimum for a 315, and that 7" wide is the maximum width for a 235/85.

Thus, those who have the 01-02 alloys like me should not be running a 235/85 tire.

Neither should you be running a 315 on a 7" wide wheel, mister