Tire upsize?

[Iraqvet05]

The OEM 275/65/18 Continental tires on my F250 are well worn at 33k miles. I have been debating up going with a taller and/or wider tire to fill the wheel wells a bit more. Much of the info I find on the truck forums involve guys trying to stuff 37" tires on a factor truck but I don't want to go that extreme. I understand a taller tire will throw off the speedometer a bit but will a 275/70/18 (or similar 34-35") tire effect towing my 7000 lb trailer? I have the 3.73 gears.

[macjom]

My F250 has 20-inch rockstar wheels with 295/60 tires. Have an aftermarket rear stabilizer bar. The ride quality is good and no wobbling.

[ksss]

I went from 265/7018 OEM to 285/70/18 on a 2018 3500 Duramax. I am going back down to 275. The truck looks great but it I lost a couple mpg in the process. When I pull real heavy it is even worse.

[Super_Dave]

My 06 Dodge came with 16" wheels and the gap between the rear tires and the wheel wells is gigantic. I'd love to fill that space with rubber but don't want to hurt my performance.

[Hannibal]

I also went to 265s from 245s on our F250 to correct a fast reading speedometer. It corrected the speedo, looks better and I can't tell any difference in towing power.

[Sandia_Man]

We went from stock 245s to 265s, they are just over an inch taller and less than an inch wider, did not see much of a difference in towing prowess with our 4.10 gearing.

All we noticed at first was they were a bit squirrely being that the new tires had a more aggressive tread design, and were constructed with stiffer sidewalls and harder rubber compounds for their extended mileage rating.

About a mile difference on the speedometer in town and 2mph at highway speeds. Since we tend to do most of our RVing off the beaten track we really appreciate these tires as opposed to the stock LT highway tires.

[ScottG]

Deleted

[Iraqvet05]

285/70r18s are a 33.7" tire but that size seems to be an odd one. I found a few but they are aggressive treaded ATs in the $300-400 price range.

I may stick with a 275/70r18 for a price break and availability. This size is optional on the 2017 F-250s that I assume come on 4.11 geared trucks. This tire is only 33.2" and only 1" larger than my current tires.

[Garry_Gayle]

I went with a 255/80R/17 Toyo Open Country AT on my 15F350 DRW and my gears are 3:73 and I'm towing a 13 38" Mobile Suites 19K loaded with no issues, I can barely tell the gear change. Improved my handling over the stock tires.

[Grit_dog]

ScottG wrote:
I went from a 265 to a 285 both series 75 and it was a terrible mistake - even with extra power. Then I went to a 285/70 and it works well. (our TT was 7300#)
If you tow, don't go much bigger in dia or it will suck.

Ya because you have a better geared trans than the early G56 in ours!
With 3.73s and 34-35" tires, the old Dodge could still use a 7th gear. Anything over 80 mph is really screaming!

[Lynnmor]

old guy wrote:
I went from 265 to 285's and I pull mine just fine. I have a 35 ft TT and it weights in at 8500 lbs.

But what size are the tires? :h Incomplete information.

[old_guy]

I went from 265 to 285's and I pull mine just fine. I have a 35 ft TT and it weights in at 8500 lbs.

[ScottG]

I went from a 265 to a 285 both series 75 and it was a terrible mistake - even with extra power. Then I went to a 285/70 and it works well. (our TT was 7300#)
If you tow, don't go much bigger in dia or it will suck.

[APT]

Larger tires will change the effective gearing by an amount proportional to percentage of the diameter. That may be a small amount. However, larger tires weigh more. Your OEM tires might weigh 50 pounds each while the proposed 34" tire weighs 65 mounds. You will likely feel that in terms of more fuel used, increased brake wear, and slower acceleration.

I experienced exactly this with my prior tow vehicle. It sure looked sweet, but going back down to stock size really woke the truck up.

[blt2ski]

You are talking maybe a half inch over all Siam difference. Your 3.73 might now be a 3.6-3.65.....3.55 at tallest. A 2" inch taller tire would put you at a 3.42 effective ratio.
Your rim will not matter, as both tire sizes are 275mms wide. Only difference is that sidewall height.
Marty