question for gearhaeds

[aquitted]

I have a question about gear ratio on rearends for a epediter trucks. I notice that the single axle straight trucks have around a 5.29 double axle straight trucks have around a 4.33 and a semi has around a 3.36 i thought the lower the number the better the fuel mileage on the hwy i would like your view on what rearend to use in a two rear axle straight truck.

 

[Moot]

While axle ratio is important, one must also consider engine and transmission in conjunction with axle ratio. The numbers you posted aren't really relative to the number of axles or straight vs. tractor. A truck can be spec'd with any gear ratio within reason. I'm guessing you are looking at used trucks. A higher gear ratio like a 3.36 would yield better fuel economy provided the engine and transmission were compatible. Do an on-line search for a driveline calculator or an axle ratio calculator. If you find a used truck from a dealer they should be able to enter the engine hp, transmission and axle ratio to determine the sweet spot.

 

[leezaback]

what Moot said. have to have the right gear ratio

 

[paullud]

You will also want to consider the terrain you will be operating in. A truck setup to operate in TX and OK won't be a good choice if you will be running in a place with mountains and hills.

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