Driveshaft

I've seen Stock aluminum shafts fail in stock big block trucks, and we had a guy running a cheetah with dual fuelers and a bunch of nitrous on the pull track with a stock shaft...... Hopefully it doesn't crack your tail housing when it fails.

Get a built aluminum shaft, steel is no bueno for a street truck. PM me if you're interested in an aftermarket aluminum shaft.
 
Steel is fine for a street truck. Been running one from Greensburg Machine for many years on my CC/SB with zero issues....at less than half the cost of aluminum.

I don't know where this love for aluminum comes from...other than the people pushing a sale...
 
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nwpadmax said:
Steel is fine for a street truck. Been running one from Greensburg Machine for many years on my CC/SB with zero issues....at less than half the cost of aluminum.

I don't know where this love for aluminum comes from...other than the people pushing a sale...
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The "love" for aluminum comes from building driveshafts for the past 15 years and understanding the market as it changed and why it changed. When I was trained, we had a max 72" ckits rule for 4" tubing in light duty applications. I cut my teeth on building steel replacements for the aluminum shafts from the 90s that were graphite wrapped and used to rot from the salt getting in between the wrapping. When GM went from a poorly spec'd lopsided 2 piece to an aluminum single in the CCSB and ECLB trucks back in 02 it kind of caught my attention. So I checked the calculators and engineering guidelines to understand what was going on.

A CCSB has a center of U joints dimension approximately 71", you plug that into the safe operating speed calculator and you come up with a safe operating speed of around 3600rpm, given stock gears, that RPM is reached at 95 mph on 33 inch tires and lower speeds as tire size gets smaller. Driveline tubing is predominantly rolled and welded tubing, some is DOM. You can pull 15 sticks of driveline tubing out of the crate and each piece would balance differently and have a different amount of run out. This make the true critical speed almost immeasurable. So you take a driveline that is built with an adequate safety factor, blow a dent in from road debris, or run it with a bad U-joint and the shaft should reasonably withstand that vibration. Take one that is built outside the safety factor, and maybe that ****er makes 30 quarter mile passes at 115MPH with no issues, well some time goes by and you have some run out from a loose U-joint and a vibration, that vibration then contributes to a critical speed failure. A critical speed failure typically folds the shaft up in the center and does a **** ton of collateral damage.

Realistically, I would feel better about stretching the safe operating speed numbers on a steel shaft in a race truck over a daily driver.
 
^^^

I understand what you're saying and I agree with your math. However...the thread is about sledpulling. 5000 rpm / 1:1 / 2.72 = 1838 rpm. Zero issue. And it's conservative because most "street" Dmaxes won't turn 5000 ever.

So I think you should rephrase as "steel will work fine for sledpulling in low range, however, if you are also going to drag race it, be aware of these critical speeds."
 
nwpadmax said:
^^^

I understand what you're saying and I agree with your math. However...the thread is about sledpulling. 5000 rpm / 1:1 / 2.72 = 1838 rpm. Zero issue. And it's conservative because most "street" Dmaxes won't turn 5000 ever.

So I think you should rephrase as "steel will work fine for sledpulling in low range, however, if you are also going to drag race it, be aware of these critical speeds."
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I was pretty clear about aluminum in a street truck..... And went further to explain my stance on the limitations of a steel shaft.

Plenty of street dmax pullers see street and dyno time.
 
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