Lightweight Axles

[Bill Edgeworth]

Listen to Wade.

Lightest AND smallest diameter.
Taking two rotating parts of the same weight lets say a solid axle verses a larger diameter gun drilled axle the larger diameter part of the same weight takes more energy to accelerate to the same speed. In fact a lighter part that is significantly larger in diameter can take more energy to accelerate.

Here is some casual reading on the subject;

http://en.wikipedia.org/wiki/Moment_of_inertia

Now when it comes to aluminum verses steel spools I think there is much more too it than rotational inertia. I think flex and friction may play a big role.

So just build your whole drive train out of titanium then we can start talking about $200,000 stockers LOL

[FED 387]

Most manufacturers specifically recommend NOT TO USE aluminum spools in cars that weigh over 2800-3000 pounds ---You MIGHT get away with an aluminum spool in a heavy (over 2800) car if it is a real LOW HP car---No hi torque hi HP applications for HEAVY CARS using aluminum spools- No trans brake/stick shift cars either--Rotating mass is where its all at---In stock/SS stock applications yer not looking for that last hundreth or thousandth like in a Comp/Pro Stock Application--that is the most likable application for aluminum spools/lightened ring gears/scalloped flange rifle drilled axles NOT stock or SS---Comp 387

[Cam]

Our car is 3200 pounds with a stick and a MW aluminum spool. We ran a best 60' this summer of 1.38. Sounds like the clock is ticking.

[mopar jeff]

Originally Posted by FED 387

In stock/SS stock applications yer not looking for that last hundreth or thousandth

I guess I have it all wrong then.

[Stick Racing]

Originally Posted by Bill Edgeworth

Listen to Wade.

Lightest AND smallest diameter.
Taking two rotating parts of the same weight lets say a solid axle verses a larger diameter gun drilled axle the larger diameter part of the same weight takes more energy to accelerate to the same speed. In fact a lighter part that is significantly larger in diameter can take more energy to accelerate.

Here is some casual reading on the subject;

http://en.wikipedia.org/wiki/Moment_of_inertia

Now when it comes to aluminum verses steel spools I think there is much more too it than rotational inertia. I think flex and friction may play a big role.

So just build your whole drive train out of titanium then we can start talking about $200,000 stockers LOL

LOL? I was in Orlando some years ago and walked by a SS Hemi car. They were changing the center section in the rear. The axles were sitting behind the car. They were a shiny grey, unlike any axles I have ever seen. I commented to a friend about it. He walked over and picked one up. It wasn't steel.

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Andy Stone 1102 A/S 1112 SS/C

[Wade_Owens]

Originally Posted by Bill Edgeworth

Now when it comes to aluminum verses steel spools I think there is much more too it than rotational inertia. I think flex and friction may play a big role.

Bill, you are exactly right. I have talked with a couple of Pros extensively on this topic. Its the flex that kills the Pro Stock cars. Trust me, if aluminum would live, even for just 2 passes, AND be faster, it would be in their car.

Ed, what Haas said to you is right, but, as is said here before, apples and oranges with what we do and a Pro Stock car, I'll never have to worry about the later!

As for longevity in one of our cars, when I finished my car in late '07, I put an aluminum Moser spool in. Tim Irwin told me at that time that they had previously had breakage problems, but, got it fixed. I have had the rearend apart at least 3 times a year since then. The axles are as tight as day one with no visual signs of problems. Without gears installed and dial indicator check, it still only has .001 runout. You be the judge........

Wade O

[Ed Wright]

Wade, what will live in a foot braked 283" stocker won't necessarily live in a trans braked SS car. When I pulled that spool out it had .004" run out. Jerry Hass was with that Hemi SS car because he built it. Not only Pro Stock cars.
I have talked to others that made only the light spool & ring gear change as I did, and nobody found any gain. I'm usually between 1.29 & 1.34 in 60' with the steel spool, exactly the same with the lightened ring gear and aluminum spool.

[Rich Aceves]

Ditto: Wade & Bill.

[FED 387]

Mopar Jeff---Most Comp cars weigh considerably less than a Stock/SS car ---pro cars all weigh 2350 min wt- MOST COMP cars weigh about 1180-1600 for a dragster and from about 2300-2900 for a door car although some are a little lighter or heavier depending on the combination/class---granted most pros have 1190-1300 hp but they are spinning the tires a bit at the hit with the power they have and they all have 40 spline set ups too--Most pros run the 9 1/2 inch Dewco gears along with the Dewco spool---Some run MW or Strange and a few use a Moser spool---The high HP Comp LIGHT WEIGHT cars all use 40 spline parts mostly Dewco some also use Strange/Moser/MW too- Those lightweight cars weigh anywhere from about 1100-2400 pounds weight wise--- no comparison to a 3500-4200 pound Stock /SS car they also use Carbon Fiber or aluminum drive shafts Again NOT recommended for HEAVY cars.--I'm not trying to convince ya on what to run just merely trying to enlighten ya on why certain types of cars utilize certain kinds of parts. If it works for YOU great but ya better be diving in that rear end every weekend or so to check for any signs that might predict failure--Those 10,00 RPM launches are brutal on drivelines--I honestly believe that the typical Stock or SS car RARELY pulls the rear or axles out to check them and if at all maybe one time a season whereas we take the driveline out after every other weekend to check !!! If alum works for ya or Titanium is legal and ya don't wanna run steel OK---If ya are happy with Steel stuff OK too----It's all in your combo what works for me may not work for you and vice versa-- Your still not looking for that coupla extra thousandths which can translate into hundreths tho like a comp or Pro car is--Comp 387

[FED 387]

Ed wright that 1.29-1.36 60 foot is .06 in ET which in a Comp car translates to about .12 in ET at the 1320----No Comp car is gonna give up a TENTH +++ to run a steel setup versus an aluminum/ liteweight axle set up--- never gonna happen---Comp 387