Lightweight Axles

[MLP]

I called MWs today as I was a little concerned about what was being said about aluminum spools. I told them I will weigh 3500lbs+ with a stick and was concerned their 40 spline aluminum spool I have in my Dana 60 wasn't going to be tough enough to take the punishment.

He assured me that the aluminum spool (8lbs) was every bit as strong as the lightened steel spool (16lbs). I told him I had no problem swapping it out for the steel one if it was stronger but he continued to insist it wasn't necessary.

I tend to believe the racers actually using the parts more so than the manufacturer so I'm kind of torn now. Anyone using a Dana with a aluminum spool and had problems?

[FED 387]

Many of the problems with both aluminum spools and 9 inch Ford aluminum differential cases has to do with deflection of the parts under hard accleration(hole shots)---If you think about how you install either a Dana/12 bolt or Ford 8.8 ring gear you are actually spreading the housing a few "thou" to do it. and if you have an alum spool instead of a steel one the aluminum will deflect more than the steel will---Vehicle weight ,engine HP,type of trans (stick/auto) trans brake or not and rear end gear ratios all come into play here and actually have everything to do with if the parts will live in your application---If you have ANY doubts call the spool manufacturer tech line and get their recommendations---What works in my car may or may not work in yours----Ask the tech people they will not lie to you--asking around on forums like this one can confuse some people---Go right to the source ask em they are more than happy to help--Comp 387

[Adger Smith]

Strength also has to do with the ratio you are using. A 6.50 gear with a very small tooth count pinion is more prone to fail due to deflection than a 4.56 with a bigger pinion. Yes, the alum will deflect more than steel, but the ratio is the deciding factor. Think about what is happening when the ring gear moves away from the pinion. The contact area gets smaller and moves to the thinner/weaker part of the gear. As I said in my previous post the Alum deflects too much for the gear ratio I'm using. It might not for the gear you are using.

[Rod Greene]

I ran the MW aluminum spool and 40 spline rifle drilled axles in my Demon for over 15 years leaving the line at 7000 plus in a car the weighed 3300 + most of the time. Never broke anything. Never even cracked a tooth. I ran 5:57 or 38's. Nothing better than MW.

[Jim Caughlin]

FED387, I don't agree with you about 'Ask the tech guys, they won't lie to you'. Maybe not lie but they will error on the way too heavy duty side. Virtually all of my drivetrain components were opposite the advise of their manaufacturers who assured me they would either break outright or wear prematuely. Weight and friction loss are too big of an issue in Stock and SS to take their conservative 'don't want our brandname badmouthed if I'm wrong' attitude. I've learned a lot over the years by looking at cars that have been in my shop and their undersized light duty 'mistakes' which seem to have held up for years without breaking. None of us want to break parts at an inoppertune time but look at the fastest cars and you will see some pretty flimsy parts, I don't think it's by accident. The smart and fast guys are more than happy to tell you that 1350 ujoints, power robbing 9" Ford rearends and all of those cool looking heavy duty parts are the hot setup.

Jim Caughlin
SS 6019

[mopar jeff]

Originally Posted by 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,
Thanks for your detailed explanation, and I was only referring to the part about Stock/SS guys not looking for every last hundredth or thousandth. I would imagine most people when building or changing a car, weigh the options and try to squeeze anything extra they can. That is how you become the fast car of the class. Any class that is going to potentially be heads up would obviously do that if funds permit. No ill will intended at all, just making a statement.
When I built my rearend, I would have put an aluminum spool in because I have a low horsepower combo. The only problem was that no one makes one for the Ford 8.8. So I went with the lightened steel one instead. Maybe I wasted some money on all that good stuff back there, but at least I tried, and I can't ever put the blame on not buying the best stuff. Take care and thanks for your input.

[GTX JOHN]

I have had same MW alum. spool in Demon most of the time for last 15 years.
I replace the R/Pinion around 75-100 runs when it get noisy which is about twice as often as the other cars with steel spool. No visible twist on MW axles that were in the car when I bought it (35) but they are not drilled. 1.36 @ 60 weighing as much as 3500 but usually 3350.

Rod: Putting that very Dana you were talking about into my Demon today!

I guess that old rearend doesn't owe me anything at this point.

[Jim Kaekel]

Thank you to every one for your thoughts and opinions.