# Tire size



## OneBadDodge06 (Sep 22, 2004)

Lookin to get tires for my 02 2500hd....will 285's fit w/o rubbing and no lift required? How bad does the fuel mileage go down? Do they make 285's with 10 ply?


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## RMHSR (Mar 17, 2006)

285's will fit on the truck but you are definetely going to want to raise the front torsion bars if you haven't already. The rear should be fine without a lift. A friend of mine runs 285 on his 02 and the only time he rubs is in a turn and hitting a bump which causes suspension movement. Usually what rubs is the front of the tire on the plastic of the front bumper. As anything the bigger the tire the worse the gas mileage. He gets about 2 mpg different from my truck with 265's. The other issue will be the speedometer will be off. According to the dealership, 265's don't require reprogramming the speedometer but 285 will.


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## royallawn (Dec 1, 2005)

RMHSR;493945 said:


> 285's will fit on the truck but you are definetely going to want to raise the front torsion bars if you haven't already. The rear should be fine without a lift. A friend of mine runs 285 on his 02 and the only time he rubs is in a turn and hitting a bump which causes suspension movement. Usually what rubs is the front of the tire on the plastic of the front bumper. As anything the bigger the tire the worse the gas mileage. He gets about 2 mpg different from my truck with 265's. The other issue will be the speedometer will be off. According to the dealership, 265's don't require reprogramming the speedometer but 285 will.


2 mpg is huge. why would you put 285's on when 265's or 245's is what the truck probably takes. 2 mpg will add up fast.


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## OneBadDodge06 (Sep 22, 2004)

I doubt I'll go with 285's then.

That is a huge loss. As far as 245's go, they don't look right and I think 265's are a happy medium. Better look but not as bad on the mpg.


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## RMHSR (Mar 17, 2006)

I eliminated the 285 idea the same. I haven't noticed any fuel difference with the 265. I still only get 17mpg from my diesel. I tightened the torsion bars and lifted the front end an inch which made it look better too.


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## 04red2500 (Dec 21, 2007)

I have 285's on my 04 HD and havent noticed any difference in my mileage but i also have a 4:10 rear end so not much changes the mileage


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## Ctll (Jan 2, 2008)

*285/75/16e*

I've got 285/75/16E on my 05 cc Duramax w a truespeed spedo recal on it and it gets better mileage with these than with the stock tires. pulling trailer varies on load between 13 and 16 mpg, and without a trailer bed unloaded, it gets somewhere between 19 and 22 depending on my right foot and if I am in a hurry or not.


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## JD Dave (Mar 20, 2007)

285's are good summer tires but are terrible in the snow. 245's are the best for the winter but 265's will give you a happy medium. JMO


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## sparky8370 (Nov 26, 2007)

RMHSR;494066 said:


> I eliminated the 285 idea the same. I haven't noticed any fuel difference with the 265. I still only get 17mpg from my diesel. I tightened the torsion bars and lifted the front end an inch which made it look better too.


Have you either corrected the speedo or do the correction when you hand calculate the mileage? You can either multiply the miles by 1.03 or wait until the end and multiply the result by 1.03 
I also went from stock to 265's. For my tire size change (245/75/16-265/75/16) the difference is 3% If you are getting 17 even, you're really getting 17.51
If you were getting 17 before, then you'd get 16.49 un-corrected (17 times .97-the reciprocal of 1.03) and it would actually be the same mileage.


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## RMHSR (Mar 17, 2006)

I never did any calculations on speed difference. I never compared actual speed before changing tires. I used a couple of different methods that go along with my simple mind. First was perception. The speed when compared to traffic around me didn't seem any different. Second, the dealership said that the computer was able to compensate for the 265 with no changes but the 285 would change the settings. As for fuel mileage calculation, that was pretty simple minded too. I filled the truck and reset the trip. When it was time to get fuel again, it filled the truck and divided the miles traveled by the gallons pumped. 

What I want to know is what are guys doing that they are getting 20+mpg out of the Duramax? Computer programmer, Exhaust, Intake?


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## Vinster01 (Jan 23, 2008)

I run Kelly MSR (with studs) in the winter: 235-85-16 10 plys. I love em. There about the same height as a 265 & really doesn't do anything to mileage or speedo calibration. Plus it's a pretty common size so there are lots of tread pattern options.


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## Ctll (Jan 2, 2008)

*20+mpg*

What I want to know is what are guys doing that they are getting 20+mpg out of the Duramax? Computer programmer, Exhaust, Intake?[/QUOTE]

check out signature, all of the above


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## Rangerman (Mar 27, 2006)

Heres an '06 with 265's and they don't rub and they make it look bad to the bone. ?? on the gas mileage we don't pay much attention probably 6-8 with a trailer or plow 10-12 solo. This has about 20 bags of salt in it. Oh and i almost forgot the truxx torsion bar liftpayup.


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## 02DURAMAX (Dec 27, 2006)

JD Dave;496288 said:


> 285's are good summer tires but are terrible in the snow. 245's are the best for the winter but 265's will give you a happy medium. JMO


why does everyone say that about 245's?...i run 285's and they seem better than the 245's


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## bowtie_guy (Jan 1, 2004)

Being a 3500 SRW my truck came with 265's. This year I needed new rubber so ordered some BFG's in a load range E. 285's. I recalibrated the speedo with my efi life. With the truck MT it havn't affected mileage. 

Alot of people install larger tires and then calculate mileage without ever thinking about how the speedo is off. Over a long run it can affect the outcome.


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## bike5200 (Sep 4, 2007)

If you run a bigger/taller tire you are basically changing the gear ratio in the rear end, which would be a small ratio, which should help gas millage. The computer on the truck would need to be recalibrate for the taller tire. When calculating the MPG on you truck, this will depend on how much fuel you put in the tank . Gas pumps at one station might trip off sooner than pumps at another gas station which will affect how much fuel is put in the tank which will affect MPG. An other question is, are gas brands different from different suppliers. Shell or Exxon or Marathon or Mom and Pop Stations etc. 

Steve


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## lodogg89 (Jul 8, 2006)

i run a 305 on my half ton, i get the worst milage you have ever seen, i am lucky to get 13 on the highway. i should be pushing 20mpg with 245's, and this is hand calculated


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## PR Fect (Oct 22, 2003)

Ctll;496249 said:


> I've got 285/75/16E on my 05 cc Duramax w a truespeed spedo recal on it and it gets better mileage with these than with the stock tires. pulling trailer varies on load between 13 and 16 mpg, and without a trailer bed unloaded, it gets somewhere between 19 and 22 depending on my right foot and if I am in a hurry or not.


As you should. The taller the tire, the higher the gas mileage should be. Highway seeds. In town or plowing you may not see much difference. The mileage should only go down when you start getting into way over size tires like swamper's. It takes more fuel to rotate them, being wider, softer, and heavier.


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## AWLCO (Nov 25, 2007)

Winter 235/85/16 Nokian Hakkapeliitta LT 31.8" X 9.3"
Summer 275/70/18 Nitto Terra Grappler 33" X 11"

12MPG around town all year. 6.0L w/ 4.10 gears


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## Puller504 (Aug 15, 2005)

Vinster01;496768 said:


> I run Kelly MSR (with studs) in the winter: 235-85-16 10 plys. I love em. There about the same height as a 265 & really doesn't do anything to mileage or speedo calibration. Plus it's a pretty common size so there are lots of tread pattern options.


What truck are you running the 235/85/16's on? Ford? Chevy? Dodge? I'm trying to find out if this size tires will fit my 1998 Chevy K3500 4x4 without rubbing on the front axle. I'm also using a Meyer C8 snowplow but the front end only drops about one inch when the plow is lifted so I don't think that'll make any difference. Don


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