Half-shaft weight data

[treynor]

Another in my occasional series "everything you wanted to know about your Viper... and more"

Stock half-shafts from a '01 GTS: 14.8 lbs each.
UNITRAX medium-duty "800 HP" half-shafts: 17.4 lbs each.

 

[GTS Bruce]

I guess what we need are some hollow light weight high strength tubes. Bruce

 

[MES]

Do you have any pics of the medium duty half shafts? I ended up getting the heavy duty 1,000+ HP rated shafts and am wondering what the difference is? Due to the small rotating radius I don't think the weight will make much difference. I did notice much less wheel hop with the HD shafts, maybe because of the extra weight on the suspension. Anyway here is a pic I snapped comparing the two.

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[treynor]

I didn't snap any pictures of the UNITRAX mediums, apologies. They look very much like the stock half-shafts, including the rubber bellows in the center, but they are a bit larger in diameter. I have the UNITRAX heavy-duties on my yellow RT (need 'em -- after all the mediums are only rated for 800 HP

) and they are as you have pictured.

The rotating mass is largely irrelevant because of the small diameter and, subsequently, small polar moment of inertia of the half-shaft. The addition to unsprung weight is potentially more significant, although I personally can't tell the difference.

 

[cstegall]

Ben,

Great info. and it has raised a question...I am in the same queue with Doug only my work is just a Level 1 w/intercooler system. IYO...do you think I will need to change out the Half-Shafts on my car after the DLM work?

Thanks,

Clark Stegall

 

[treynor]

Clark,
It's not the horsepower, it's the torque (especially at launch) that kills half-shafts. If you intend to ever put drag race tires on your car, IMO stronger half-shafts make sense. With street tires the data seems to be mixed -- I have heard tales of stock shafts breaking on street tires, but only a few.
In my case, I'm going to be taking the Daytona to a few drag races this year and running ET streets, so uprated half-shafts are almost a requirement.