You can run the 315/75R16's on a stock truck with no issues. No new rims, no spacers, no lift. They are close to a 35" tire, so that's no more than 2" at the most that your truck will grow.

 

Even on a dually (as in the sig)?

 

thank you

 

No!

Dually rims are only 6" wide. The widest tire you can mount safely on a stock dually rim is LT255/85R16. Even the LT265/75R16 requires a rim at least 7" wide - per the engineers at the tire makers and their Tire&Rim Association (TRA).

Of course, lots of folks ignore the experts and do what they want to do. Good luck if you try that.

Running 315s or 35s on a dually is do-able, but only with custom wheels with custom width and offset to safely work on a dually. Stay away from spacers between the rims. Order the right wheels with the right offset and backspace to do it right. Then you won't need spacers. However, expect to wear out the wheel bearings much sooner than with stock-width rims. The bearings are not designed to handle the increased leverage of wide tires hanging out in the air past the hubs.

The "right wheels" are available but not cheap. One popular source is Stockton Wheel Service - Custom Wheels . Notice they make custom wheels to meet any spec you can dream up. Or tell them the tire size and the truck you want to mount them on, and Stockton will figure out what is required for specs of dually rims.

 

oh good catch. I totally missed the fact that it's a dually. I hope I didn't mess up too many people.

 

255 85 16 will make your dually with the 4:10 R&P run close the the 3:73 found in most single wheels. Speedo will be off so rember your going more miles, I figured about 10% off??

 

255 85 16 will make your dually with the 4:10 R&P run close the the 3:73 found in most single wheels.

Ummmmmmmmmmm. No.

4.10 to 3.73 is a nine percent change. LT235/85R16 to 255/85R16 is a 4.6 percent change in the speedo/odo/tripmeter. So if you have a 4.10 gear ratio now with 235/85R16 tires, it will be equivalent to a 3.91 with 255/85R16 tires.

 

4.10 to 3.73 is a nine percent change. LT235/85R16 to 255/85R16 is a 4.6 percent change in the speedo/odo/tripmeter. So if you have a 4.10 gear ratio now with 235/85R16 tires, it will be equivalent to a 3.91 with 255/85R16 tires.

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which would drop the rpms how much???

 

which would drop the rpms how much???

4.6 percent.

Assuming you have a calibrated speedo both before and after the tire size change, then 70 MPH with stock size tires and 4.10 gear ratio is 2,200 RPM. 2,200 minus 4.6 percent = 2,099, or about 101 lower RPM at 70 MPH.