Mr.Matchbox

The workshop manual of my Kawasaki calls for MoS2 grease for the needle bearings of the swingarm. Yes. Really. There is a grease nipple on the Swingarm for this Job.
These needle bearings are under heavy shockloads from potholes and only move maximum 25° angular their whole lifetime.

Did the roller needle bearings in the tripod cups of our car ever make a full revolution when the car is moving? I am doubtfull. It most likely is also only a small left-right twisting movement. Bust as long as we can´t look inside while the car is moving, it´s only guessing. ´

Car Analogy

Thats a good point. Limited rotation. Not like these things are spinning round at high speed.

While we can't look inside, we can say that these needle bearings just go back and forth a small amount compared to bearings that spend their life spinning.

This surely has an effect on what grease is appropriate, tbat doesn't necessarily align with other common needle bearing usage.

BuggyofMildDiscomfort

That's to prevent false brinelling. As you say, the limited angle and oscillation is the key there, it's similar on a lot of suspension arms that use needle bearings. You see similar on many trailing arm setups. It's a case of addressing the brinelling is more important than the life of the rollers.
CV Tripods will generally oscillate back and forth too, being that they change the drive side as they go around (the angle flips top to bottom), but they will do quite a few revolutions on plunging given the shallow feed angle, at pretty high speed - it's why they run bearings and drive wheels in them to start with instead of just having steel stubs.

Mr.Matchbox

false brinelling.... that was the problem discoverd in the 1920s or so when wheel bearings of new cars failed in no time after the cars where transported to the customers with train?

BuggyofMildDiscomfort

Yep, it looks like impact damage but in reality it's tiny movements that push the lubricants out of the way then you get indents from metal to metal wear, especially if the lubes are a thick grease or similar that doesn't flow or creep.

Jarvis

This aligns with what GKN is saying.

"...Molybdenum disulfide contains particles that clog the spaces between the needle bearings and the spaces between the needle bearings and the inner surface of the outer races, causing premature wear."

I assume that the clogging is caused by the high temperature development of tripod bearings.

In addition, GKN clearly states that a molybdenum type cv joint grease (such as the mentioned Redline CV2) should not be used in tripod/plunge bearings and that tripod/plunge bearing grease should not be used in cv joint applications.

cosmomiller

Good thread.

Mr.Matchbox

Redline, via E-mail:

"....Thank you for contacting Red Line Oil, the CV-2 is suitable for use and has been used in needle bearing tripod joints. ..........."

BuggyofMildDiscomfort

And as I said earlier:

"This is part of the issue with comparing greases. Any grease will work to some extent. But which grease will work better is another matter"

Of course it can be used. You could use oil if you wanted. You could use 5th wheel grease. You could use the cheapest 40cwt basestock mineral oil based lithium grease.
It's suitable, it'll go in there and lubricate better than not having anything.
But most likely they're not the best choice.

Mr.Matchbox

O.K., but what would be your suggestion for a better grease as the OEM from Honda and / or the redline?