Do they make...
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Give me an RPM, tire size and I assume you have an automatic tranny, so I need to know what gear you are in with the rest of the info.
Just assuming for a bit, if you have 4.10 gears with an E4OD transmission, in overdrive 1850 RPM would be 70 MPH.
That is great for MPG's, but very bad for towing.
Lock out overdrive and the RPM goes up to 2550 at 70 MPH with the same tires and gear, and the truck will tow much better.
Tall tires an towing are not a good combination.
Very hard on the driveshaft and u joints.
If you have 4.10 gears, top speed in overdrive at 3300 RPM works out to 126 MPH.
33 in first
58.5 in second
90 in third
If by some chance you have 3.55 gears, 146 MPH in overdrive.
38.5 in first
67.3 in second
103.7 in third
Another thing, unless the speedo has be recalibrated, the speedo is off by about 20%.
So an indicated 40 MPH would actually be about 49 MPH.
An indicated 70 MPH would be 84 MPH.
5.13 gears would get you back close to what it was stock with 31" tires, but the .71 overdrive would still make it run over 100 in overdrive.
5.38 gears would be a better choice for towing and having some off the line power.
Running tires that tall would be like putting 2.76 gears in ther drag car.
Top end would be great, when you got it wound out 3 miles down the road, but the quarter mile times are going to be terrible.
Just assuming for a bit, if you have 4.10 gears with an E4OD transmission, in overdrive 1850 RPM would be 70 MPH.
That is great for MPG's, but very bad for towing.
Lock out overdrive and the RPM goes up to 2550 at 70 MPH with the same tires and gear, and the truck will tow much better.
Tall tires an towing are not a good combination.
Very hard on the driveshaft and u joints.
If you have 4.10 gears, top speed in overdrive at 3300 RPM works out to 126 MPH.
33 in first
58.5 in second
90 in third
If by some chance you have 3.55 gears, 146 MPH in overdrive.
38.5 in first
67.3 in second
103.7 in third
Another thing, unless the speedo has be recalibrated, the speedo is off by about 20%.
So an indicated 40 MPH would actually be about 49 MPH.
An indicated 70 MPH would be 84 MPH.
5.13 gears would get you back close to what it was stock with 31" tires, but the .71 overdrive would still make it run over 100 in overdrive.
5.38 gears would be a better choice for towing and having some off the line power.
Running tires that tall would be like putting 2.76 gears in ther drag car.
Top end would be great, when you got it wound out 3 miles down the road, but the quarter mile times are going to be terrible.
