Topic: Wheel Torque with Low range Gears?

[Toybrota]

I have been rather curious lately at the wheel torque of a built Toyota with Low gears,
I have done equations for this kinda stuff and it doesn't calculate up right. My Question is, Given:

85' 22R with 129 Ft.-Lbs or torque,
G52 Transmission with a 1st gear ratio of 3.928:1
Low Range with 4.70:1
Crawl box with 2.28:1
Diff Ratio of 5.29:1
33 inch tires

Does anyone know how to calculate the wheel torque given these numbers? If I am right,
wouldn't these gears give you torque greater than that of a 350 Chevy to the wheels?

[emsvitil]

129 * 3.928 * 4.70 * 2.28 * 5.29 * .98^4 (That's 98% efficiency for each gear) = (you can do the math)

[H8PVMNT]

If you could get the traction and hold the truck still you could spin the earth backwards and turn back time like superman.

[blackdiamond]

I have been rather curious lately at the wheel torque of a built Toyota with Low gears,
I have done equations for this kinda stuff and it doesn't calculate up right. My Question is, Given:

85' 22R with 129 Ft.-Lbs or torque,
G52 Transmission with a 1st gear ratio of 3.928:1
Low Range with 4.70:1
Crawl box with 2.28:1
Diff Ratio of 5.29:1
33 inch tires

Does anyone know how to calculate the wheel torque given these numbers? If I am right,
wouldn't these gears give you torque greater than that of a 350 Chevy to the wheels?

The simple answer is yes, with the dual ultimate gearing you're more than capable of putting more torque to the rear tires than a 350 Chevy.

If you assume 129 ft-lbs of torque @ 2,800 rpm

The theoretical torque to the rear wheels in low low 1st, ignoring losses, would be the following:

129 ft-lbs x 3.928 (1st gear in transmission) x 2.28 (low crawl box) x 4.70 (low t-case) x 5.29 (ring & pinion) = 28,724.3 ft-lbs

BigMike has done a write up on this in the past. The question is why don't things break and the answer seems to be that the torque is potential torque that is never realized.  We know this because our axles have been proven to break at a much lower torque.  Something always breaks long before the engine puts out that much torque.  Also, the fact that we're geared so low pretty much eliminates impact loading from the drivetrain when the torque potential is that high.  I'm fairly certain that if you had beadlocks and could lock your tires in place you could torque your front tires off the ground at idle if nothing in the drivetrain where to break.

I attached an old picture from Longfield that showed his axles and D60 35-spline axles breaking at under 8,000 ft-lbs of torque.  If you don't break one then you have not exceeded this torque in your drivetrain.

[blackdiamond]

As a side note, you'll notice that the chart specifically references the 300M race.

RCV maintains the 300M race in their design: This axle set upgrades the weak 27 splines at the CV to a 300M 30 spline race eliminating the need to neck down the shaft.

http://www.rcvperformance.com/product-details.aspx?sku=CVJ2851-PU

The TG version uses chromoly: The internals of our Longfield™ birfields are made out of 4340 chromoly steel and heat-treated for superior strength.

https://www.trail-gear.com/TG/Longfield_Birfield__30_Spline_Chromoly/i_0_0_4948/_303397-1-KIT.aspx#.V1HRczZf3xg

I would love to see this test run again comparing RCV and TG.  Really, the chart shows the result for RCV (original Longfield design), we just don't know how the new TG version compares.

[H8PVMNT]

I would say the loss is in traction on the ground.  Your traction sheers long before you can bind up that much torque.  It would be interesting to sacrifice some parts with the axles mounted firmly to flanges sunk in concrete and see what gives first.

[blackdiamond]

I would say the loss is in traction on the ground.  Your traction sheers long before you can bind up that much torque.  It would be interesting to sacrifice some parts with the axles mounted firmly to flanges sunk in concrete and see what gives first.

Parts do break so between the applied torque and impact loading there must be enough traction at least at times. Crawling almost eliminates impact loading so a loss of traction is likely what saves us in many cases.

[Rockcrawlintoy]

I would say the loss is in traction on the ground.  Your traction sheers long before you can bind up that much torque.  It would be interesting to sacrifice some parts with the axles mounted firmly to flanges sunk in concrete and see what gives first.

usually the stock output.

[Toybrota [OP]]

I wanna apologize for ignoring all the responses to this, to much wheelin.
Thanks for all the info and replies to all of you.
Sorry again!