Engine/Transmission (1998.5 - 2002) helpful tire sizes

[dodgeram1998.5]

what is the tallest tire to increase to help my gear ratio on a 4. 10 axle seem seem like a numerically lower # to 1 ?i have a dually that i heard u have to make sure so much clearance in between them. the truck sees 2500 rpm @70 mph and I hope to lower the rpms without a gear change . .

 

[SRadke]

what is the tallest tire to increase to help my gear ratio on a 4. 10 axle seem seem like a numerically lower # to 1 ?

You lost me on that last part. What size tire do you have now? 245/75/16's are approx 31 inches tall. 235/85/16's are approx 32 inches tall. 255/85/16's are approx 33 inches tall. I would opt for the 255's but you'll have to ask your tire shop too be sure there will not be clearance issues on your dually. They will be about 3/4-1 inch wider.



-Scott

 

[John - K5AWO]

My dually has 235 85 16s on it and 70 is about 2250. That should be good enough for you. Any faster than that and the wind resistance is going to suck a lot of fuel.

 

[Hohn]

A 255/85 tire is a pretty good option for duallies that don't want to run spacers or other bandaids to get larger tires on. Many trucks can run them with no mods.



The 255/85 is close to a 285/75 in terms of revs/mile (625 for the 255 vs 628, so the 255 is actually a hair taller). This is a 33. 3" diameter tire.



IMHO, the 255/85 is the best size for a 33" tire on duallies while keeping a little mpg because of the narrower profile.



It's kind of a rare size, though, and hard to find sometimes in hwy tread patters. I know BFG M/Ts are available in this size, but can't think of other tires that are.



Justin

 

[SRadke]

It's kind of a rare size, though, and hard to find sometimes in hwy tread patters. I know BFG M/Ts are available in this size, but can't think of other tires that are.



Justin

If you're in the Northwest Les Schwab carries 255's in all of their LT tire styles. If you want a better tire and are willing to spend a little money Toyo makes them in the M-55 which is a great tire IMO. A friend of mine got 45k out of a set on his SRW with a lot of heavy towing.

 

[Tcolesanti]

What about switching to 19. 5's? They would bring your gearing down a lot.