Crate gears

[Scamper]

What best/lightweight gears for crate?

[Matt49]

I have a theory about lightweight rear end gears and lightweight spools: Any perceived gains from lowering the rotating weight of these items (which happen to already have low mass moments of inertia) are lost by the holes drilled in them causing additional drag and windage issues in the heavy oils used in most rear ends.
Just a theory...
I'd be interested to know if anybody that has run these gears on a chassis dyno has an observation to share.

[Scamper]

Makes sense, I would like to hear more from someone who has done some testing maybe

[lindsey97]

I run the Coleman Prolite gears, there is a very noticable difference in the weight compared to standard gears. And they aren't drilled, just machined down thinner in the center between the teeth and the hub. When run with a 8"/ 411 ringgear option, saves considerable rotating weight.

[race09]

lightweight does not make more horse power. it will just accelerate and decelerate quicker

[race09]

and most dynos do not measure acceleration speed

[lindsey97]

I will have to agree with you Race09. My thoughts for lowering roataing weight is not making more hp but is being able to use more of the available horsepower that you have. If you can take two identical cars except one has 50 lbs less roating weight, the later one will be able to bring the car up to speed quicker. From my experience, i swapped to a new chassis, I took the time to put as much lightweight options on the car as possible ( flexplate, hubs, rotors rearend internals), now using the same motor, 602 crate, I had to change from 6.48 to a 6.00 to keep my top end rpms the same. So I believe I was able to come out of the corner quicker and gain more top end speed at the end of the straight with 6.00 gear. But keeping it in perspective i still get beat most every night, so I still haven't got to the magic of putting all the available hp to the ground.

[Matt49]

The moment of inertia of rotating parts defines how much torque is required to rotate them. What's left is the torque delivered to the tires/surface. If you can lower the rotating weight and it will spin faster given the same torque, then you'll have more torque left to deliver to the ground. Lowering rotating weight of any drivetrain component doesn't mean the engine itself makes more HP but it certainly does mean that it will deliver more HP at final output.
The only thing making any power in a motor is the combustion of fuel. Any thing that explosion has to move or rotate between the explosion and the rear wheels is robbing torque and horsepower from getting to the ground. From pistons to lug nuts this is true.
The notion that something can somehow accelerate faster without a change in torque output is physically impossible.

All that being said, I think that the gears with holes are lowering moment of inertia (robbing less horsepower) in exchange for creating more drag (robbing more horsepower) which could just end up providing a break even net result of sorts.

The Coleman Pro-Lite gears looks like a good deal and they aren't nearly as pricey as the drilled stuff. Might have to check that out.