I just bought a 2001 Dodge Ram 2500 5 speed manual. The current tires are looking kinda small and I was interested in beefing them up a bit in the future. Current tires are LT235/85R16E.

I have looked at tire information all over this forum, but I thought I'd ask my own question anyway. From the information I've seen, tire size has a hell of a lot to do with the way your truck runs, drives, consumes fuel, and reacts to wear and tear. It seems like most folks were just concerned with getting bigger tires for looks. I want that too, but I'm also concerned with the other factors I just mentioned.

I am interested in obtaining the largest possible tire with no modifications, no rubbing, keeping the stock rims (my door plate says stock rims are 16"x7.5"), no massive changes in fuel economy, and no abnormally adverse wear and tear on the transmission/transfer case/differential gears (I have the 3.55)

According to the Tire Rack sticky thread, the sizes I would be interested in would be either LT255/85R16D or LT295/75R16. Door plate says my stock tire is a LT245/75R16E.

I am guessing that stepping up to the larger sizes mentioned in the sticky thread would have little to no negative effect on my aforementioned concerns, but I thought I'd ask to be sure. What do you guys think? I think those sizes would fit in the spare tire rack as well, correct? This truck isn't going to do much heavy hauling, so I was thinking I could probably downgrade to D rating, rather than E?

Thanks for any replies!

 

LT235/85R16E = 31.7 inch diameter.
LT255/85R16D = 33.1 inch diameter.
LT295/75R16 = 33.4 inch diameter.

Going to the larger diameter tires WILL affect performance, gas mileage, and longevity of various parts. That said.... LOTS of folks run 33's with the 3.55 gears, and don't really have trouble with it. They DO notice decreased performance though.

How much will you lose? Alot of that depends on the condition of the engine currently. If everything is up to snuff, simply driving with O/D off when not expecting to see highway speeds will alter shift points, and kinda sorta offset things. (there is a diy to set up your truck so the default mode is O/D off.... see the faq section.) Installing a good aux trans cooler will also help your trans live with the change. (but, won't help performance)

Regearing for larger tires is the best way to handle it, but, it also happens to be the most expensive.

 

You've got a manual, so you don't have to worry about the transmission going out.

Your MPG WILL drop though, since you have more unsprung weight on all four corners of the truck and a wider tire will have more friction with the road. This can be offset by installing 4.10 gears, but you'll still lose some mileage compared to when you had the smaller tires.

 

i had 35s on my ram i still got 10mpg and i still drive it daily 24 miles to work and back... couldnt be happier

 

I'm definitely not interested regearing it. Not yet at least. I only drive about 10 miles round trip daily to work and back, and then just bum around on weekends.

The engine seems to run well. The truck only has 56K miles on it. I'm giving it a tune up this Saturday just because I'm not sure when it had one last. Copper plugs, plug wires, cap, rotor, maybe even a fuel filter. The bushings on the front end are looking rough so I may do them as well. And an oil change - planning on using conventional 10w-30.

The 33's seem like a good compromise. I don't see how they could kill me much more in MPG. I guess it won't matter much whether I go with load rating D or E. They should fit in the spare tire rack without issue too, right?

 

All original?

May not have even needed a "tune up" at 56k....

 

As far as I can tell it's all original. The plug wires are still the ones from the factory.

 

hell you have a 2500 like me. i wouldnt even worry about gears unless you went above a 35,

 

Just cause he has a 2500 doesnt make it any different than a 1500... If he has the 3.55's it will impact his performance just like it would a 1500...

 

I appreciate the info guys.

One more question while I have you here. I noticed a sticker inside the glove compartment with three letter codes on it. Transmission: DDP Transfer Case: DHG etc.

Is there an online resource I can visit to see what exactly these codes mean? It's got me curious.