Technical Self Aligning Throwout Bearing?

Hopefully this isn't a ridiculous question... but, what is a self aligning throwout bearing?
What situation would call for one?

I don't think this is necessary for my vehicle(SBC, ST10, Mcleod Super Street Clutch). But, I hate to assume things. Like my 6th grade math teacher said "When we assume, that makes an ass out of u and me".

Thanks in advance.

 

Never heard of them till now...

Hays Self-Aligning Throwout Bearings
Designed specifically for installations with clutch to transmission misalignment resulting in noise and vibration, Hays self-aligning throw-out bearings minimize these conditions. Clutch alignment can also vary due to normal wear and tear. Self-aligning bearings with their rugged performance characteristics are also a functional upgrade from standard bearings on older cars, when applicable

 

I could be wrong but this sounds like a solution looking for a problem.

 

Throw out bearing or pilot bearing? makes more since (not really).

 

That's kind of what I was wondering. But, I'm sure no expert, so I thought I'd ask around.

 

I wondered the same thing and it has something to do how the races inside the throw out bearing work together, from what I remember. I got the self aligning one, figured it could not hurt.

 

I'm wondering if the self aligning ones are weaker?
I sent a message to Summit asking about the self aligning bearings. I told them vehicle, motor, transmission, and horsepower and they have replied "you don't need it". They didn't explain why. Just said to stick with the heavy duty Hays bearing I have used in the past.

 

Pretty common in the modern comfort stick shift cars and truck clutch systems now days.
You do want a bearing face that will work with the fingers on your pressure plate.

 

Pretty common in older Jeeps and Fords
Arrow pointing at face offset that self corrects

 

I am currently using a Hays 70-104. Are there other brands that are equal to or better than the Hays bearing?
I have seen a Mcleod and a Centerforce that look the same and have virtually the same hype. But, I didn't know if they were comparable. Just wondering if I can save a buck without sacrificing quality.

FYI this is a moderately high hp application(529.7 @ 6100)

 

I can't get my head around what misalignment this bearing design is intended to address ?

 

Throwout arm moves in an arc, clutch plate movement is linear .

 

Throwout bearing slides on the trans snout so it's movement is already linear. The arm engages the back of the slider where there's nothing to "self align".

 

I figured it was to align with the fingers of the pressure plate if they happen to be slightly off center.

 

I think that's true. I believe the bearing is allowed to float a little laterally so it can align with the clutch if the crank and trans axis are not perfectly in line. Obviously they should be in line, so this seems to be a work around for an imperfect situation.

 

On a "Long" style pressure plate as in Fords, the three arms can be at different heights. At least on the old ones you could adjust them individually for height, but the self aligning feature would be useful if the adjustment weren't quite exact.

 

Since the throwout bearing rides on the transmission snout/ collar, there's no way for it to align anything. If you want to make sure the input shaft on the trans. is centered with the crankshaft, you can get adjustable dowel pins that are eccentric and will move your bellhousing enough to get it perfect. I believe Tremec will not warranty their trans. unless you made that measurement...