3.73 ratio or higher.

[LWDUPPONG]

I was wondering if anyone is running a higher gear ratio than 3. 73? I run on the highway 1200-1500 miles a week usually with a load but not that heavy. I am running about 2400 rpm's at 79 mph. I am switching to 285 tires in the next month but am looking for more input.



Thanks,

Lowell

 

[SRadke]

I'm running 285/19. 5's for a high load rated, narrow, tall, tire. 10% lower cruise rpm and much better life. Not sure I'd like them for a 1000 miles a week though...



-Scott

 

[cksh8me]

I have no way to back this up and I could be wrong as wrong could be.



I would only go to 33" tall skinny tire. Taller than that and fatter I think will hurt more than help.



I say this after running different tires on my 97.

 

[MAllen1]

I have a 99 w/3. 55 and 285/75/16 and like the way it runs. The only thing with that combo is that I shy away from pulling anything over 10000, and, keep it out of overdrive with anything over 5k (mainly due to having a manual w/the infamous 5th gear nut problem). When I ran stock tires I ran 2500 rpm at 80. With the taller rubber, I run 10% lower (2200 at 80). If you hit dirt, I would say hit a 285/70/17, but if you run mainly road, I would try to find a 255/80/17. The 255/80 and 285/70 are just as tall, but, the 255 is about 1. 25 inches thinner.

 

[LWDUPPONG]

Thanks for the input. I'll take it into consideration.

 

[JDiepstra]

I am running BFG AT's, size 315/70/17. At 70 mph I am at 1950 RPM's. I have the 4. 10's.



I am not sure what input you are looking for though. Anything else you wanna know?

 

[SRadke]

The automatic transmissions have a higher overdrive ratio.

 

[magothy1]

That 1950 rpm at 70 mph sounds pretty good, I'll have to check mine, I'm stock, with a 4. 10, same size Michelins as original. Sure seems like it would be better miles per gallon.

 

[RMarkey]

I run 37" with my 4. 10's, about 2k around 75mph. The wider you go, the lower you mpg pretty much, I agree with MAllen1, find the narrowest tire for the best mpg.

 

[JDiepstra]

That 1950 rpm at 70 mph sounds pretty good, I'll have to check mine, I'm stock, with a 4. 10, same size Michelins as original. Sure seems like it would be better miles per gallon.

The big tires will help on the highway, but not around town. Just keep that in mind before you make the switch!

 

[Red Rocket]

Another option

I have the 4. 10s and I swapped to a set of Toyo Open Country A/T. Rated at 4,000 lbs apiece, they don't squat at all under the front end, so you can even run them at lower pressure. I like that. Plus I got them in 285-75-17 load range E. I think they are 34. 5 inches tall. And REALLY! heavy. Looks nice, and dropped my rpm by around 8 percent. I'm pretty sure they improved my mileage even in town, and around 1 mpg on highway. I'm pretty sure they roll easier with the extra rating. Great traction too, so there's that.



Nick

 

[ronman]

I put a Gear Vendor's OD on my truck and never looked back. Driving that many highway miles in a week, I'd highly recommend it! Rev's drop. fuel economy goes up (I get 2-3 more MPG) but best of all, the truck is quieter and less high-strung.

 

[LWDUPPONG]

Thanks a ton guys. I got some great information from all of you. I am getting about 21-22 mpg at 70 mph. On the interstate at 80 I get about 17. 5 mpg. I have been recording the mileage and will see how much teh larger tires help. Thanks for the gear vendor info Ron. I could stand for it to be quieter on the long run home. 2-3 hours listening to it sing at 2400 rpms is a bit much after driving for 8 hours prior.

 

[SBeretz]

I second the Toyo 285/75R17's. They are a great tire with excellent traction, and they hold weight really well. I would buy another set in a heartbeat. Plus they are about 33. 5" tall, so they have some good height for the trucks. Had a GV on the last truck, and liked it, but it seems like too much trouble if you have an exhaust brake. Scotty