CVD vs. universal joints

[simplechamp]

Is there any reason to use one over the other? Mainly in terms of how they wear, overall durability, and possible differences when it comes to binding at higher angles.

I notice most 1/8 buggies and truggies use CVDs but some use universal joints. I kind of prefer CVDs because they are rebuildable, whereas universal joints are not (as far as I know). Just wondering why some manufacturers use one type or the other. Maybe there isn't any reason?

And for those who say "they are the same thing", I know the terms are sometimes used interchangeably, but this is what I'm talking about:

CVD:



Universal joint:

[Chadworkz]

CVDs (Constant Velocity Driveshaft) and Universal Joints are the exact same thing, just different names and the different brands use a little different looking style.

Edit: The "Universal Joint" is actually the small piece that the axle and the shaft rotate on.

[simplechamp]

I looked around a bit online, and at the Wikipedia entries on CVDs and universal joints. The section about CVDs talks about what was used before CVDs were invented and it says: "similar four wheel drive vehicles used universal joints, where a cross-shaped metal pivot sits between two forked carriers. These are not CV joints as, except for specific configurations, they result in a variation of the transmitted speed."

I know Wikipedia is not the end all be all information source, but to me that seems to imply that although similar they are two different joint types. The universal joint does not transmit the rotation with a constant velocity. The article also mentions universal joints become more "notchy" and difficult to turn at more extreme angles, so that basically answered one of my questions. The universal joint is a more solid joint, but the CVD is easier to maintain and can handle the higher angles better.

[TexasSP]

I prefer the CVD's because as said, they don't lock up at extreme angles like a traditional U-joint.

While similar in look and design, they both function much differently.

[Chadworkz]

Yea, Constant Velocity Joint CVDs use a barrel, pin, & set-screw...while Universal Joint CVDs use an actual universal-joint, which is a "+" shaped joint made up of a center-section and two cross-pins.

The term "CVD" is commonly used for both types, and they both perform the same job, one just does it better and more efficiently than the other, like was said above.

Constant Velocity Driveshaft type CVDs are best used as wheel-axles since they have to go through various angle changes and multiple axis changes, while Universal Joint type CVDs are best used as center driveshafts since they don't move at all.