Near the diff side or the wheel side, the sliding pin I meant.

On the actual joint in theme, wheel side. Sorry.

Remember the diff side always stays the same

Sorry, I don't understand. I'm confused where your'e saying the pin actually slides in the RC cvds? Where is the sliding action? If they did slide, I would agree that they function like a real 1:1 cvd.
I'm very open to learn if i'm in error but it looks like the joint functions just like a regular universal. If it does work like a real CVD can someone please be patient and explain with detail the hows and whys.... because I'm honestly not seeing it... the RC CVDs appear to be a very clever and innovative rebuildable universal joint.

is the pin designed to actually make contact with that slot? The pin is in contact with the outer holes on the drive shaft and not the slot.

Just take the barrel and set screw out of the picture and you'll be able to see it

huh? I'm not sure why I would do that. The assembly would not function if you remove the barrel. The rotational forces go from drive shaft->tips of pins-> barrel -> drive axle. Doesn't matter if the axle is straight or bent at the joint, the points of contact (points where force is applied to get rotation) is the same.

I did a search and found a couple posts that reinforce my opinion:Anyways, it's all semantics and a moot point what we call them or how they work. We can have a difference of opinion on wether the rc cvd is truly constant velocity. But I think we both agree CVDs and universals do behave differently when installed.

IMO it probably has more to do with item #4 I mentioned in my original post.

Hahahahahhhah

I havent read that, I will...

I dont mean for you to take the barrel and track the car, just take the parts mentioned above out and hand operate the system and you will see they are cvds

The drive Force really goes shaft-pin-axle, the barrel just holds the system together

They are not constant velocity and you don't want them to be since the diff side is also not a cvd. By having two two axis joints offset by 90 degrees you get the most constant velocity you can at the wheel.

Cvds lock up more under power and braking and that sliding pin gives them more friction than a universal joint which is why they resist being at any angle but straight. I think they are used because they are cheaper for the manufacturer. I would recommend keeping cvds in cars made for them and the same for universals.

Ok, please explain how is it that while at any joint angle and at any point of the oscillating circle, the shaft, the pin, and the axle, are locked in an exact point of the same oscillating circle, they are not constant.

Please explain How can one side of the joint accelerate/decelerate independent of the other side of the joint while the shaft's slot never disengages from the fixed pin in the axle?

Same thing applies to dogbones

This is interesting.
https://www.youtube.com/watch?v=gmV4qwLfOMY

It's a difficult concept to describe. However, this explains brilliantly why the input velocity is indeed different to the output velocity.


Whilst the input and output rotations per minute are the same, each rotation of the output speeds up and slows down, depending on the angle of the plane that the output has to rotate through.

Our 'CVD's' are not constant velocity joints for that, we would need Rzeppa joints. Or something like this:

Constant Velocity Joints - Uber Ball Drive

​​​​​​The fact remains that MIP style 'CVDs' function in exactly the same way as a Cardan joint. Really the only difference is the rebuildable nature of the MIP style joint.

Oh wow, an answer 11 years later with a same kind of video explanation as the last one in 2014.

But let me remind you that today the better brands have a double CVD system to lower the effect.
Red RC » Axon BD10 & T4 lightweight double joint bushing set

Yes, that's about the size of it. The subject of phasing came up on another forum (where it had never been discussed before) and a discussion about the virtues of universal joints Vs MIP style joints were discussed.

I hadn't read this thread until very recently and I noticed nobody had answered the post that stated dog bones, MIP style re-buildable 'CVDs' and universal joints were all constant velocity. Obviously they're not, but it was left unsaid. For 11 years! I bet it boils your p1$$ that it wasn't you that said.

The video I linked to is the best explanation I've have seen on YouTube of how and why such velocity differences occur with our driveshafts but also thoroughly details phasing, too. It's night and day a better video, in terms of resolution quality, sound and explanation.

I agree the double Cardan joint is constant velocity under certain conditions but a standard double Cardan joint alone is not inherently "constant velocity" unless the angles are precisely matched. (I.e. parallel input and output ). These double Cardan joints are marketed as driveshafts for steering, but the reality is that these would make far more sense on the rear of the car, where the wheels are usually non-steerable. In that application, they would essentially be constant velocity - whether the rear suspension be at droop, or under compression (theoretically assuming 0° toe and 0° camber).

At the front of the car they add rotating mass, extra cost, additional points of failure - still without solving the problem of different output velocities when you steer. I struggle to see the advantage on a 1/10th touring car, let alone bigger off road machines with much higher torque put through the system.

That being said, none of my rigs at this time are able to utilise double Cardan joints at this time anyway. One of them soon will use Rzeppa style Uber Ball Drive, which is genuinely constant velocity and a much better engineering solution - if you can make it work at the scales we run at. Certainly at 1/5th scale it works nicely, but they're about £134 a set.

Every day is a school day.

Better late than never.

If CVDs are just rebuildable universal... why would there be a performance difference (other then bearing size)?
is it because the CVDs have more mating surfaces and thus cause more torque induced lockup?
Let me know

Alexander