Engine RPM

[Jerky]

I have a 2002 truck, 6 speed, with the 4. 10's. When running 60 mph I turn right at 2000 rpm. Was wondering what the same setup for the 03's is running in rpm's since they have 17 " wheels. My understanding is that since Dodge went to 17" wheels they had to lower the gear ratio some to allow for the 17" wheels and keep the the same speed when running running a constant rpm. To my way of thinking it should have effectively raised the overall gear ratio a touch using the 4. 10, due to 17" wheels, axle. Maybe lowered the rpm by 50 or 75 rpm's say at 60 mph. Any Comments or comparison's. Thanks - Dean

 

[Spooled-up]

I have an '03 with the 4:10's and a six speed. The 17 " wheels aren't really a factor in determining a final drive ratio since they use the same size tires only with a bigger wheel to clear the larger calipers.



I run right at 2000 rpm at 60 mph with my stock 265 tires. I'm glad I got the lower gear ratio as I will be switching to 35" tires in the future and it will give me a lower rpm when cruising at 70-75mph.



Compared to my '99 that had an auto and the 3:54 ratio, I feel like I'm running pretty high in the rpm's with this truck. I'm confident that this won't hurt anything though because I read on another post about someone who asked someone at Cummins and they commented that they run them at 3000 all day in marine applications. Also, they use them in gensets at rated rpm all day.

 

[Jerky]

Thanks Spooled-up, appreciate the info.

 

[Briman]

I have been setting the cruise at 1800 rpm with this last tank of fuel to see what kind of mileage I could get so I know it is showing right at 62 mph on the speedo (slower than I normally go). I have not verified speed with a GPS. I have a 3. 73 axle.