Changing Tire Size

[ldmc]

I'm in the need to replace my current tires and I'm looking to go up one size to help fill in the wheel well a little.

I currently have 265 75/r16 BFG Rugged Trails with 65k on them.

Looking to go to 285 75/r16 BFG Rugged Terrain (the next gen of the Rugged Trail)

Has anybody done this and noticed major mpg drop or towing/handling issues? They are only 4 lbs each more and around 2 mph difference at 70 according to the Web site.

I have a Diesel Excursion with 3:73 gears.

Any feed back is appreciated.

[ldmc]

I had Discount Tire put on th 285's they looked nice and fill the wheel wells. But they rubbed the inside of my mud flaps and less than a finger between the tire and inside wheel well when fully turned. Also when you go to a larger tire it changes your axle ratio, thus loosing some torque. I tried pulling with them and they didn't feel right. I even adjusted the air presssure to make it compariable to the smaller tire load range. Better but still didn't feel right, may have to be the taller side wall, not sure. Going back to the stock tire and live with the look. I would rather have a comfortable and stable towing vehicle than one with just looks. Really sad by this as they did look good on it.:(

[cutty72]

I did the exact tire size change you are considering on my F250 w/7.3l diesel and 3.73 rear end, results:
Slightly better mileage - hand calculated about 1-2 mpg
Much better look, tires fill the wheel wells.
Slightly more "wander" on roads with excessive depressions in the tire tracks, due to the wider tires.

I won't go back down to stock.

[dodge_guy]

No. no change in handling. yes the diesel will probably not see any mileage issues, I missed that part. no I didn`t touch my hitch as the 285`s are about an inch taller which only gives it a half inch rise. not enough to make a difference. I`ve had it down to Disney, the Smoky`s, Mackinac MI. Northern WI. and just recently Niagara Falls.

[ldmc]

Good to hear from another X onwer. So your handling didn't change with the larger tires? Did you have to change your hitch setup because of the taller tires?

I do have the 6.0, so I shouldn't see much difference in MPG, I hope.

More concerned about any change in handling. With the current tires and set up my wife is very comfortable driving also.

[transamz9]

dodge guy wrote:
I`m running 285 BFG A/T T/A`s on my X with no issues. you may actually get worse mileage (minimal approx. .1-.2 mpg) because they are slightly larger it raises the gear ratio slightly, 3.73 to approx. 3.68. either way they fill the wheel well and it looks much better. when my tires are done I will be going back to the 265 BFG Rugged Trails.

It depends on where his engine likes to run whether his mileage drops or not. Your V10 would probably do better with smaller tires because your motor likes to rev. His 7.3 will like the lower rpm.

[dodge_guy]

I`m running 285 BFG A/T T/A`s on my X with no issues. you may actually get worse mileage (minimal approx. .1-.2 mpg) because they are slightly larger it raises the gear ratio slightly, 3.73 to approx. 3.68. either way they fill the wheel well and it looks much better. when my tires are done I will be going back to the 265 BFG Rugged Trails.

[Passin_Thru]

You can get a tuner such as Edge and it will reprogram your speedometer according to tire size, neat huh? You can also add up to 60 HP to your engine for towing. Worked for me. You can track and compare injectors and watch 4 engine functions at once, like Trans Temp, Coolant Temp, EGT and Vacuum.

[ldmc]

Interesting chart. It does appear I should get better mileage. I was looking at an F250 with the same size tire on it and it appeared the side wall was bulging a little do to the larger tire size. Wonder if that will impact handling..

[elkhorn98]

Seems like you could actually increase your mileage according to the charts.

http://i45.photobucket.com/albums/f98/LPG_PWRD/interco.jpg

[transamz9]

ldmc wrote:
transamz9,

Nice truck and that does make it look better.

What gears are you running? Any mods?

I'm really leaning towards going with the 285.


Please keep the replies coming.

The truck has 3.73:1 and yes a few mods. Suspension,engine, and as you can tell, body.

I like running my truck level and not jacked up in the rear. After the tire size change I added a 2" level kit and some street Bushwackers. Before I added the level kit I had to run my rear low to be level. Here's a shot of it down the side after I added the flares and level kit.




I don't have any good pictures of it from the side with the level kit and flares yet.

[ldmc]

transamz9,

Nice truck and that does make it look better.

What gears are you running? Any mods?

I'm really leaning towards going with the 285.


Please keep the replies coming.

[transamz9]

This is what mine looked like with the factory 265's







This is what it looks like now with 285's





My mileage did not change but my rpm did. My truck runs 74 mph @ 2000 rpm now and with the factory tire it run 70 @ 2000 rpm. My truck loves to tow at 1800-2000 rpms so it did hurt the power while towing because I run at about 1800 out on the interstate. When I come up on a big hill I now have to run it on up to 2000 or so and let it back down going up the hill if I don't want it to gear down. Before, I could run it up around 2000-2050 and put my foot down and it would hold it's speed on a 5-6% without gearing down as long as I didn't come up on a gas truck screaming along at 50 mph. LOL!

[Eurocamper]

I went from 245/70r17 to 285/70r17 on my 2011 RAM. This was with a 3.77 axle ratio. This was a substantial change in diameter so I had the dealer reprogram the speedometer. I must say the tires look much better on the truck than the old ones.

There was a noticeably reduction in rpm when cruising and it seems like I gained some mpg - I get about 19 MPG on long freeway drives. Around town mileage is about as bad as it was before. I seldom use all the power available from the engine anyway, so acceleration still feels very good. The weight I tow is well below the maximum for my truck so I can't say I've noticed any difference there.

[Bionic_Man]

My last truck came from the factory with 265's. When they wore out (around 40k) I switched to 285's. Personally, I think they look much better. I did not notice any difference in handling, MPG, etc. I did have the dealer re-set my speedo.