Everett Ogilvie

I wonder why "slipper clutches" are not used (more, or at all) on race cars - they are extensively used on race motorcycles. I read that a few cars have used or tried them but don't know any more than that. To be precise, a slipper clutch slips when the rear wheels try to drive engine speed more than it would naturally be, in other words on a downshift if the wheel speed is closely matched to the engine speed the clutch is normal, but if the difference is too great (they are typically adjustable) it will slip. They prevent wheel hop entering corners on racing motorcycles and they can apparently save an engine by preventing a mechanical overrev in the case of a botched downshift.

I realize most race cars have sequentials these days (and indeed bike trannys are sequentials as well) and I don't know where a slipper would or would not fit in that type of application in a car, but they sound pretty cool for manual transmissions. All serious racing bikes have them so they definitely have merit. Like a fool I have been contemplating owning a motorcycle again so that is why I have been reading about them.

sebdavid

Maybe it's an issue of just how much power a slipper clutch can safely handle?

sperkins

If anyone could use one of these it's me.
I'm the reigning downshift over rev champion.

spazegun2213

My .02 which may be totally wrong, but I have a feeling each motorsport is accomplishing downshifting in a different way. Race cars are nearly all computer control sequentials that will calculate the rpm's needed to match and raise the engine speed accordingly. One would think this extra bit of computing power maybe adds 5lb to a race car? which is next to nothing. However 5lb on a bike, is a LOT of weight. Why worry about another computer, sensors, etc, when you can simply design a better mouse trap (clutch) for bikes and make them just as light... maybe?

But I agree, I've always wondered this and why cars dont have wet clutches as well? I mean, sure it would add another 5 quarts to a tranny for a wet clutch, but they last forever in bikes, and 90% of the time you need to remove the tranny to get the clutch out anyway.

sebdavid

I've seen a lot of sequential transmissions requiring manual blips on downshifts. V8 Supercars is an example, I think.