I recently purchased some brand new steel half-shafts from a well known vendor. (I went with steel since I plan to put down 550-650 HP and didn't want to go with the carbon fiber ones). I asked the vendor about balancing and they stated it is not necessary for the half-shafts.

I then contacted driveline services and they stated anything that spins over 1,000 RPM should be balanced. So I followed their advice!!!!!

I picked up the half-shafts tonight and there are now (2) Quarter sized washer type weights welded on each end of the tube; (same side), and the yokes had dings from beating out the U-Joints. Apparently they required a lot of weight and the shop foreman showed me that it is not the tube, but the yoke portion that inserts inside the tube that is never of constant thickness.

I am not really happy with the cosmetic appearance since these are planned for a show car, but feel that mechanically this should be done to prevent any driveline vibrations. Apparently, GM never balanced ANY of their half-shafts from the factory. Does anyone know the engineering aspects/requirements of balancing these short half-shafts?

Also, what kind of HP are the aluminum ones good for?

Thanks!

 

On C4's,the only upgrade for the half shafts is stronger units that are less likely to twist and break.

They are not usually long enough to need balancing,but maybe the aftermarket ones you bought benefitted from them.May depends on metal and materials used to make them.

Thats all I can add for now..but wanted to say I never seen a stock C4 half shaft needed balancing because of a vibration.