Ford 10 speed with regear anyone done it yet

[Skinhyfish]

Found a killer deal on a ford F350 7.3 gas. It has the 3.73 rear end. Wanted the 4.30. Price of pickup I can pay for regear. There is an option for 4.88 aftermarket. Going to 37in tires with fulltime camper. Did 4.88 on a 6 speed. Curious about the 10 if anyone has experience

 

[TexasSixSeven]

As someone with a 7.3 and 4.30s with full time camper I wouldn’t want 4.88s. I’m running a 305/70-18, which is roughly a 35.5x12. Low end torque is never an issue, but highway RPMs are as high as I’d like them to be. Id think they’re perfect with 37s.

 

[Skinhyfish]

As someone with a 7.3 and 4.30s with full time camper I wouldn’t want 4.88s. I’m running a 305/70-18, which is roughly a 35.5x12. Low end torque is never an issue, but highway RPMs are as high as I’d like them to be. Id think they’re perfect with 37s.

What’s RpmS at 70mph?

 

[SDDiver5]

Contact your local driveline or gear shop. They should be able to calculate what the RPM will be at a certain MPH with different gear/tire/trans.

I regeared to 4.56 and my guy sent me the RPM at 65 MPH with 4.10, 4.56 and 4.88

Different truck, of course, but my guy said he would not do anything higher than 4.10 with the 10 speed trans.

 

[carterd]

There are numerous websites that allow you to calculate rpm at various rear gear ratios, transmission gear ratios, and tire height. One example is here:

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

purperformance.com

The 10 speed transmission ratios are shown below.



And if you are in 4-wheel low the transfer case is ratio 2.64:1.

A few examples:
- 33" inch tire, 3.73 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 1,800 RPM
- 35" inch tire, 4.30 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 1,957 RPM
- 37" inch tire, 4.88 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 2,101 RPM

Keep in mind actual tire sizes are usually shorter than advertised.

 

[Skinhyfish]

There are numerous websites that allow you to calculate rpm at various rear gear ratios, transmission gear ratios, and tire height. One example is here:

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

purperformance.com

The 10 speed transmission ratios are shown below.

View attachment 840846

And if you are in 4-wheel low the transfer case is ratio 2.64:1.

A few examples:
- 33" inch tire, 3.73 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 1,800 RPM
- 35" inch tire, 4.30 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 1,957 RPM
- 37" inch tire, 4.88 rear gear ratio, 0.632 10th gear ratio, at 75 mph = 2,101 RPM

Keep in mind actual tire sizes are usually shorter than advertised.

37’s and 4.88 with fulltime flatbed and camper, RPMs doesn’t look to bad or far off from 4.30. Could help with climbing passes

 

[Jupiter58]

With the same tires you will have about a 31% increase in rpm’s going to 4.88.
You can make a guesstimate based on final rpm’s based on difference in the actual tires on the truck (as measured) and the tires you buy (as measured and under load).
I say as measured because there is huge differences in the stated size of tires by different manufacturers.

Fortunately lots of folks are measuring their tires as installed now a days so you can likely find the actual sizes with a little searching.