Driveshaft Specialist Inc - Warning

[GT_Rich]

Just a heads up to anyone shopping for an aluminum driveshaft. Driveshaft Specialist Inc (http://www.driveshaftspecialist.com/default.html) will be a top Google search result if you're shopping around for driveshafts. Nice enough folks, good turn around time. Unfortunately, they do not understand critical speed calculations on the shafts they sell. They will quote a critical speed based on the tube length only and not the welded shaft assembly. There's usually about a 10% reduction in critical speed for a finished driveshaft with u joints and a slip joint.

I have a long wheel base car and I run 4.10 rear gears. so I needed a 56" long driveshaft that could turn at least 7,000 rpm. They quoted a shaft speed of 7100 for what they would build me (3.5" alum). Well, it hits critical speed at 6300 rpm and creates a sharp and sudden vibration. Enough to crack the tail housing on my trans.



I brought this to their attention and the best offer they could make me was to buy back the shaft they made for $175 and I would have to pay $50 in shipping to get it to them.

I'll have someone else build the 4" aluminum shaft that should have been recommended to me in the first place.