I found this very informative and interesting. It's something I've never been taught or even thought of before. The more you know... 
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Driveshaft Velocity
- Thread starter t01blaze
- Start date
t01blaze- That's fantastic information. I knew MATHEMATICALLY what would happen to a driveshaft as operating angles increased, but I had never seen it done visually/audibly.
I have always set my cars up to have operating angles of the driveshaft u-joints close to eachother on both ends (and with the u-joints in phase). And that shows exactly why that's important.
In the real world, I would only add that you CAN NOT have u-joints operating at 0* angle for extended periods of time. The roller bearings inside them require SOME movement of the u-joint to keep lubrication (grease) getting to the various parts or it will just grind the rollers into their races.
It doesn't need to be much angle- a couple for degrees will do it, but it must be present. And, of course, as close to equal operating angles of the u-joints on both ends as possible.
The factory does a really good job of keeping the angles correct. One of the reasons why you should be very careful changing the pinion geometry much from stock.
For a street driver you want the u-joint angles very close to equal with the rear pinon pointing just a smidge further down. For drag race you might want to point the pinion down even further because under heavy load it's going to try to "climb" the ring gear and go more nose-up. So you point it a little further down at rest so that it comes back up to equal under high load.
I have always set my cars up to have operating angles of the driveshaft u-joints close to eachother on both ends (and with the u-joints in phase). And that shows exactly why that's important.
In the real world, I would only add that you CAN NOT have u-joints operating at 0* angle for extended periods of time. The roller bearings inside them require SOME movement of the u-joint to keep lubrication (grease) getting to the various parts or it will just grind the rollers into their races.
It doesn't need to be much angle- a couple for degrees will do it, but it must be present. And, of course, as close to equal operating angles of the u-joints on both ends as possible.
The factory does a really good job of keeping the angles correct. One of the reasons why you should be very careful changing the pinion geometry much from stock.
For a street driver you want the u-joint angles very close to equal with the rear pinon pointing just a smidge further down. For drag race you might want to point the pinion down even further because under heavy load it's going to try to "climb" the ring gear and go more nose-up. So you point it a little further down at rest so that it comes back up to equal under high load.
Tore mine in 2 equal size pieces when I let off at the stripe at 120 mph . That was my lesson in Drive Shaft Terminal Velocity.
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