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Old 11-29-2012, 02:12 PM   #94
RallySport Direct
 
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Drives: 2014 Widebody Cosworth FR-S
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Quote:
Originally Posted by twincamRob View Post
Well looking at that pic it looks like 'our' carrier bearings are smaller than what I'm used to seeing (S chassis, DSM, etc...) so I retract my statement about "most of the weight reduction being from removing the carrier bearing".

But it goes without saying that a less 'exotic' 1 piece steel or aluminum driveshaft will have pretty close to the same savings for far cheaper.
An aluminum shaft will be cheaper and lighter, but it will be larger. I don't know how much room an aluminum shaft would leave for exhaust clearance, but it won't be much if any.

A steel driveshaft is going to be too heavy to for a 1 piece shaft and you need a carrier bearing to support that kind of weight. Aluminum and steel will be quite a bit cheaper, but carbon fiber does have quite a few advantages.

We actually did a writeup that covers both aluminum and carbon fiber driveshafts and the differences between them. I will post a few highlights from our overview.

Carbon and Aluminum Drive Shaft Overview

  • CF has a smaller OD, which means direct replacement with no modifications. Some applications require modification to heat shields or transmission tunnels to allow adequate clearance for the larger OD Aluminum shaft.
  • CF shafts are capable of higher speeds
  • The CF shaft can twist about 2X as much compared to the aluminum counter part before it fails from sheer stress
  • When the CF shaft fails, the fibers will come apart and un-wind. When an Aluminum shaft fails…well you have a 14lb sledge hammer spinning at over 1000RPM going to town under your car

Aluminum does have a couple advantages over carbon fiber though
  • An equivalent CF shaft will be about 5-10% heavier then a Aluminum counter part
  • Aluminum shafts are only about 30-50% of the price of the CF unit
Let us know if you guys have any questions about this
Thanks,
Zach
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