toyokogyo12aturbo
toyokogyo12aturbo New Reader
6/4/08 7:47 a.m.

If one were to build a car that required a high angle for a driveshaft, could they use CV joints? I've heard U joints shouldn't be used past 3-4 degrees and CV joints less than 12 degrees. Have you ever heard of anyone using CV joint b/t the trans and final drive? I've be a little concerned that a standard CV/ axle wasn't designed to turn such high speeds. Have you ever seen a high speed CV joint or a CV joint being used in a drive shaft?

stumpmj
stumpmj HalfDork
6/4/08 8:17 a.m.

I've seen them used in high articulation applications (like crazy rock crawlers) but that's all that I know of. Of course, those are hardly what I would call high speed.

Is there any particular reason that you think a normal U-jointed driveshaft wouldn't work in your application?

toyokogyo12aturbo
toyokogyo12aturbo New Reader
6/4/08 8:46 a.m.

I'm trying to make something like that old indy roadster with the offset engine. Since the drive shaft is so short and the offset would be several inches. The angle will be quite severe (as much as 45 degrees) So the limiting factor on how far over it goes it the driveshaft angle.

GameboyRMH
GameboyRMH Dork
6/4/08 8:47 a.m.
stumpmj wrote: I've seen them used in high articulation applications (like crazy rock crawlers) but that's all that I know of. Of course, those are hardly what I would call high speed.

Yeah I've seen them used in rock crawlers as well, sometimes at angles of around 20 degrees!

I wouldn't worry about a U-joint at less than 8 degrees or so, I've seen some trucks that have them at angles like that. Some older Land Rovers also have U-joints operating at nasty angles. I've never heard of a CV joint in a driveshaft.

Jack
Jack SuperDork
6/4/08 9:12 a.m.

The TR7/TR8 use CV's instead of U-joints on the driveshaft. Yup, way ahead of thier time. They work, but often get replaced by U-joints when they fail, due to the costs involved.

jack

Wally
Wally SuperDork
6/4/08 9:49 a.m.

The indy roadsters used an offset rear axle so the driveshaft was in a straight line. Depending on the rear you want to use it may not be that expensive. I thonk the Legend and dwarf type cars use a corolla axle with one tube shortened.

stumpmj
stumpmj HalfDork
6/4/08 11:00 a.m.

^^^ What Wally said. You'd be relly hard pressed to make anyhting live with that much offset.

Strizzo
Strizzo HalfDork
6/4/08 11:05 a.m.

www.highangledriveline.com

they make high angle driveshafts, some that can work at over 40 degrees

Hocrest
Hocrest New Reader
6/4/08 8:04 p.m.

Subaru used a CV type joint in the center of the driveshaft in the SVX. They use standard U-joints at the end joints though. I read that they did this to reduce noise and vibration.

thatsnowinnebago
thatsnowinnebago New Reader
6/4/08 11:23 p.m.

look at double-cardan u-joints, I think they do pretty big angles ok

toyokogyo12aturbo
toyokogyo12aturbo New Reader
6/5/08 12:11 p.m.

I've seen some of the double-cardan u-joints on rock crawlers 'n such, definitely under consideration (but with $$ and speed considerations). I'll have to look at the SVX thanks for that tip, too. Shaun.

foxtrapper
foxtrapper SuperDork
6/5/08 6:16 p.m.

If you'll notice, the wheels on fwd cars turn to a good angle, well beyond 12 degrees, and use CV joints.

CV joints work well at higher angles because the rotation stays consistent. With u-joints, it becomes uneven, surging as the u-joint rotates around. The more severe the angle, the more severe the surging.

famous
famous None
6/5/08 8:22 p.m.

Another low cost option to reduce the offset from the transmission to axle might be to use the front axle from a small 4x4 in back. you'd even have the option of live axle or independent suspension depending on the donor vehicle you chose.

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