drive line angle

[Jon_P]

anyone know how much of drive line angle we can run on our r65's? i see some with it at rest the drive line is at a pretty steap angle, i understand that a u joint doesnt care but other than the u joint is there any other reason?

[Rob Valdez 79 R65]

I think the G/S series had to go to a second U-joint for this very reason.

I could be wrong.


Builders of race bikes tilt up at the front, not only for additional lean angle, but also to eliminate some of this angle.


Naturally, what is most important is the angle with the bike on two wheels with a rider aboard.

[scuba]

sorry, english is not my native language. please, what is drive line angle mentioned above?

[Ed Miller]

sorry, english is not my native language. please, what is drive line angle mentioned above?

He means the angle between the transmission shaft and flange and the drive line, through the u-joint.  I've never read a figure for it so I'm keeping quiet.  

[Jon_P]

there is alot of movement possible so i was hoping one of the guys with a gs set up would give me an idea what they run. i see the tire hits the lower cross brace if it is to much and if set to low it can also hit the drive shaft tube on the lower cross member if set to low.

[Justin B.]

Jon, that observation almost begs for a smart-a$$ed reply and reminds me of the joke, "Doctor, it hurts when I do this..."  

I know on setting up 4 wheeled vehicles you don't want a whole lot of angle when the suspension is at ride-height.  I'll have to see is I can find any of my old hot-rod chassis building books...

[Chris_in_BC]

On my '81 R80G/S , I have after market forks that are about 2 inches longer than stock. Subsequently I had to get a custom after market rear shock (Works Performance) to balance the bike. To get it all to work I had to flatten the bottom of the main frame member  above the driveshaft bell housing. I also had to grind out the inside of the bell housing a bit to allow the U-joint to clear under all angles of the suspension.
The modifications were done in 1990 with 57K miles on driveshaft. I rode it to the 100K mile mark in 2005 when I had Bruno's in Ontario put in a new U-joint.

No reason, I just thought with the increased drive shaft angle and lots of rough off-road riding that maybe I should.  

Bike now has 135K miles on it and never a problem.  Now if only my legs were longer...

[scuba]

Never thought that I'll be doing this. I started calculating and got some results when I came across this. Some nice guy already did the math. So, knock yourself out.

http://www.4xshaft.com/driveline101.html

I'm gonna have a beer now.
cheers!

[nhmaf]

Note also that quite a few of the paralever-GS bikes required replacement of shafts and U-joints at relatively early mileage intervals.
 :-/

[montmil]

Never thought that I'll be doing this. I started calculating and got some results when I came across this. Some nice guy already did the math. So, knock yourself out.

http://www.4xshaft.com/driveline101.html

I'm gonna have a beer now.
cheers!

Good call on the link. Several years ago, I watched a NASCAR tech program on drive shaft angles and how the angles can impact the u-joint performance. The late Benny Parsons had a mock-up of a u-joint/drive shaft/third member at an over-zealous angle. You could actually hear the universal "pop" as it rotated through a no-go region. Leads to a quick and sudden failure.

I'll join you for a cool one.   Monte