2014 Ultimate 1 Ton Challenge results

4x4ord wrote:
If they had raced a 3.73 Ram against a 4.10 Ram, the 4.10 would not necessarily do any better in any one particular test but could possibly have done better or worse in some of the hill climbs. Look at it this way: the Cummins is capable of delivering a certain maximum amount of horsepower to the rear wheels. Let's say that number is 300 ponies. Now some of that power will be used to overcome rolling resistance and drag so let's guess that at 50 mph there is 220 HP available to pull a loaded trailer up a hill. By definition 220 horsepower is enough power to lift 121000 lbs 1 foot in 1 second. Now consider a particular hill: say one with a 7% grade: at 50 mph the truck and trailer are gaining elevation at the rate of 5 ft per second. If my assumptions of available rear wheel power are right the Cummins could pull a 24,200 lb truck and trailer combination up a 7% grade at 50 mph (121,000 lbs divded by 5 equals 24,200 lbs). In order to achieve that maximum speed of 50 mph the transmission and rear end need to have a ratio that will allow the engine to run at the rpm it makes maximum power while spinning the rear 50 mph. If the rear end is geared too low the truck will upshift and the rpm will drop to where the engine makes fewer ponies and the truck will slow down. Now choose a different hill or different weight and the perfect gear ratio is something different. This why the Ford was able to leave the Ram and Chevy in the dust on the Davis hill but was very close on the Eisenhower. It got stuck between gears where it couldn't make its 440 HP.

Agree.

I think the Davis test would have been closer if they didn't start the clock from a stop, but from a moving speed like most hills are approached at.

The 4.10 Ram would have gotten up to speed easier/quicker, but once at speed probably would have done about the same just in a different gear.

Each trans/gear combo has speeds where it excels based on the final drive ratio and tire size. The more gears the more speeds a truck can utilize uphill.

Cummins12V98 wrote:


I have the 3:42's and tow a combined near 29K. I assume the big reason for the 3 different rear axles is how much weight each can get rolling on a steep grade. 4:10's would make a difference for me.

As far as fuel economy driving solo with 3:42's I don't think it makes a bit of difference over 4:10's, I get 14.7 or so hand calc freeway. I also don't think the tall gears hurt me either towing as some think. I average 9.5 hand calc West Coast towing averaged over many tanks.

Yes starting power is a big difference, but still gear for gear 4.10's can put 20% more torque to the wheel.

As you have noted in other posts and threads you gear down and get the same effect, or even more. 3.42's in 3rd is slightly lower than 4.10's in 4th and 3.42's in 4th is within .06:1 of 4.10's in 5th. So the torque available to the wheels is close enough to not notice a difference at higher speeds.