Gearing

[peterod]

Can someone help with advice on rear end gear ratios what ratios can be used for hauling a dump trailer and i also want to be kinda quick

[Taglio]

Quick, as in fast, or quick as in get up and go?

[bob h]

Can someone help with advice on rear end gear ratios what ratios can be used for hauling a dump trailer and i also want to be kinda quick

tall gears will make power and quick acceleration, around here I see a lot of gravel trucks running 444s and 456s, ...not sure about a combo though...

[peterod]

Both thanks

[jimjim]

Lot's of things to consider. What Trany? How big are your tires? You can switch to a taller tire and gain speed, but you lose taking off. Lower the dia. of the tire, take off is good, but lousy on the top end. Changes in mpg also. High rpm, low mpg! and vise-versa. It's all in what you want.

Just remember, high number, 450-500 great take-off, high rpm, high fuel costs, low number, 399-449 lousy take off, low rpm, low fuel costs, many, many more speeding tickets in high gear!

Good luck!

[bcbasher]

around here 24.5 lo pro tire with 4:11 gears are running wild.gravel trains and dumpers (me) will pay good money for a set of 4:11 gears. good power and still have plenty of top end

[bob h]

around here 24.5 lo pro tire with 4:11 gears are running wild.gravel trains and dumpers (me) will pay good money for a set of 4:11 gears. good power and still have plenty of top end

the big lo-pros are about the same revs per mile as the 22.5s.

[Kranky]

Lots of variables here.
Depends on the lowest transmission ratio for startability off road.
Depends on the transmission hi gear ratio for top speed on road.
Depends on tire size.

If you do a lot of off road work & have to get a loaded truck moving in soft ground, my experience has been that trans low ratio multiplied times rear diff. ratio must equal at least 60 for acceptable startability

For example: One of my trucks was equipped with a Mack T2130 trans with a low gear ratio of 13.91:1, and Mack rears with a ratio of 4.42:1.
13.91 multiplied times 4.42 equals 61.4822. This overall reduction is satisfactory for a truck on 11R22.5 rubber, if using larger size tires then the total reduction must be a correspondingly higher number.

This particular transmission has a .71 overdrive in the highest gear, and the truck will run72 MPH @ 1900 RPM.

[peterod]

Thanks for the replies guys also would an Eaton 3:36 ratio be good for me with my setup? Reason i ask is i see a pete with the 3:36 ratio and 24.5 tires and Detroit 60 s rated at 430hp which im planning to buy

[Kranky]

Thanks for the replies guys also would an Eaton 3:36 ratio be good for me with my setup? Reason i ask is i see a pete with the 3:36 ratio and 24.5 tires and Detroit 60 s rated at 430hp which im planning to buy

Again, unless you tell us what transmission is in the truck, it's not possible to figure anything out.

[peterod]

Forgot its a 13 speed

[Kranky]

Thanks for the replies guys also would an Eaton 3:36 ratio be good for me with my setup? Reason i ask is i see a pete with the 3:36 ratio and 24.5 tires and Detroit 60 s rated at 430hp which im planning to buy

Forgot its a 13 speed

In my opinion that's geared way too high for dump trailer use.

Overall reduction (trans lo gear ratio 12.31 times rear axle ratio 3.36) = 41.3616, a far cry from the target number of 60.

In high gear with the 13 speed's overdrive of .73 with the 3.36 rears on 11R24.5 tires that truck will do 97 MPH @ 1900 RPM, and at 2100 it will do 108 MPH.

It'll go like hell out on the highway, but if you're planning on going off road on construction sites etc., you'll be screwed when you try to start off with a full load on, unless you slip the clutch to get it moving, and then the clutch will be shot very quickly.

[peterod]

Thanks Splitshifter u know your stuff