I currently run 35X12:50's but my 411 axles need a bit more tire for fuel economy I would like to go to 37X13:50 tires on 17" wheels. The room is there with other mods but I need to find some wheels to use with these tires.

I need 17X9" wheels with properbackspace which I would estimate at 5.25 or something in that area. My truck is a 2004 with stock wheels now. They don't rub anything with these tires and the 4" lift. They do however ever so slightly rub the dust off the arms that run from the frame to the axle It's so light that the paint is not even rubbed off in 20K miles. with 13:50 tires and 9" wheels I'll have about another inch and a half to move out from under the body. I think the current stock wheels are 6.5" offset.

Anyone with the right offset on their truck knowing it works and everything fits good would be great info for me. Also what wheels are available in this configuration?

 

You and I are in the same boat...I am going to have a set of custom steel wheels made. 17x9 with 5.5 bs should do it. I have 17x9 with 4.5 bs now and a 37 would barely rub the back of the front wheel well at full lock and upward compression. I think one more in of BS will fix it.

 

quote: I currently run 35X12:50's but my 411 axles need a bit more tire for fuel economy I would like to go to 37X13:50 tires on 17" wheels.


Your mileage will be reduced by going to a tire that much bigger. It's not engine RPM (within reason), it's work done that matters with mileage and the bigger tires have a lot more rolling and wind resistance. The change from 265's to 315's cost me 1.5 MPG

Wetspirit

 

I think it is more complicated than that...many factors.

Type of driving (stop and go will be worse for big tires....highway better for big tires)

Speed

Gearing

My switch from stock to 35's with 4:11 was no net change...worse in city...better on highway. I drive too fast on the highway for 265's and 4.11's.

 

This is not my first experience doing this and I'm not inexperienced with the physics of this. That Big cummins will rotate 37" tires just fine and will certainly improve mileage on the highway. As stated stop and go is another story with the energy to get that rotational inertia going. However once it's rolling it's not a serious issue other then gearing. Certainly there are other things that matter but they small by comparison.

As an example with the 411 axles and stock tires I was getting 14.5-16 MPG Switching to 35" tires I instantly jumped to 17.5-18MPG I fully expect an additional 1.5-2" of tire height to put my final drive back to the stock ratio and my mileage will be someplace about 19-19.5

There are factors which will not allow my truck to achieve the great 20+ MPG that a completley stock truck will get because of the much greater wind resistance due to the height of my truck. AS an example I pick up 1.5-2 MPG when I have the canopy on the back of my truck compared to the empty bed. The airflow over that canopy is much better.

I drive long stretches on desert highway and can accurately predict my mileage based on the wind and the amount of mountain driving. Wind and steep inclines have a very decisive effect on the milage. That is for me the greatest deterrent to good MPG.

 

19 mpg with 37" tires....unless you drive 65 downhill with a tail wind, here is your sign.