Giving NASCAR the Shaft

Automotive Manufacturing & Production, May, 2000 by Jeff Sabatini

There's no guarantee that Dodge's 2001 NASCAR program will use the driveshaft balancing technology developed by Dana's Spicer Driveshaft Division. However, if Mopar is serious about winning, they'll probably be looking into it; almost half the teams running in this year's Daytona 500 were using UV FlexBond. (The technology is also applicable to production vehicles.)

Rather than heat-welding balance weights to the shaft, UV FlexBond allows the weights to be adhesively attached and cured by a combination of chemical means and ultra-violet light. The chief advantage to this process is that it allows driveshafts to be made from thinner gage material, thus saving weight. (Conventional heat-welding processes result in deflection of these thinner shafts.) It also allows for the entire drive system (axle, driveshaft, and some transmission components) to be balanced after installation, rather than balancing each component individually. (While welding balance weights underneath a vehicle is problematic due to space constraints, the adhesive cure process isn't.)

Although these are the reasons NASCAR guys are using the technology, a benefit of particular interest in production vehicles concerns NVH issues. A lighter shaft actually results in an increase in the speed at which powertrain bending resonance occurs, thereby producing a smoother, quieter ride.

Unless, of course, Dale Earnhardt is behind you.