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Tom Goldman · 09-30-2009, 02:44 PM

I had a similar problem on a car I built with a 3 1/2" 57" shaft. ......I was advised that it was right at the critical legnth for that diameter@ 7000 rpm........The less expensive solution ,if you have the room ,is to go to a 4" diameter shaft. ....I believe the critical speed on a 4" 57" shaft is closer to 7600rpm .....I did find I could tune the vibration out to a slightly different rpm by altering the pinion angle,altho that is only a crutch for the real problem. .........Not saying other shafts are'nt as good,but I've had better luck with Mark Williams shafts ,than other brands..........try this link for more info http://www.markwilliams.com/driveshafttech.aspx .........Tom

09-30-2009, 02:44 PM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,476 Likes: 891 Liked 882 Times in 236 Posts	Re: Driveshaft vibration I had a similar problem on a car I built with a 3 1/2" 57" shaft. ......I was advised that it was right at the critical legnth for that diameter@ 7000 rpm........The less expensive solution ,if you have the room ,is to go to a 4" diameter shaft. ....I believe the critical speed on a 4" 57" shaft is closer to 7600rpm .....I did find I could tune the vibration out to a slightly different rpm by altering the pinion angle,altho that is only a crutch for the real problem. .........Not saying other shafts are'nt as good,but I've had better luck with Mark Williams shafts ,than other brands..........try this link for more info http://www.markwilliams.com/driveshafttech.aspx .........Tom __________________ Tom Goldman 1500 SG , 1506 STK Last edited by Tom Goldman; 09-30-2009 at 02:47 PM.