Cvds are constant velocity. The sliding action of the pin in the joint makes it a true cvd. Same case with a dog bone, the sliding action in it makes the same effect. The end result is better traction on the track.

Universals are more reiable and have a bit less friction in them, but again they oscillate at any angle. At a mínimum trying to break static friction between the tire and track surfaces. In other words, less traction.

Cvds are the upgrade when made properly, even kyosho has a cvd upgrade for their car, and the better performance item, until they are worn, which they lock/bind - but again the unis bind too, and as a standard feature of the design. Unis cannot be made bind-less, that is the nature of them. The trade is a bit more friction and reliability.

Both units new for the big race event the cvds kill a u-joint. 20 races later, different story.

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