Had a conversation on the trail recently about using overload clutches to reduce ujoint breakage, consensus then was that they were too expensive and bulky.

But check these out:

http://www.mcmaster.com/catalog/108/html/0899.html


http://www.mcmaster.com/cgi/item.cgi?searchstring=6524K45&tab=find&qty=&disppartnum=&mcmid=782616896&ItemLinksString=%2D1&notadd=


The 400 ft-lb model might work OK on the front driveshaft, at least for those of us without V8s, and 5" OD isn't tooo bad.
$100 is almost reasonable, would be less if you could find the original mfg and buy direct.

I don't know whether it would cause more breakage than it prevents due to sudden unloading, or unload unnecessarily when both ujoints are loaded equally, etc. But I think somebody with an experimental streak ought to try it.

I don't think even a Sami motor would have a problem putting more than 400 ft-lbs to the driveshaft.

Pete

4 ft/lbs * 100:1 gearing= 400ft/lbs
If the motor produces 200 ft/lbs at a normal rpm,add in gearing, I think the clutches would always be spinning (slipping):confused:

Ooops, I guess I dropped a zero in my really complicated calculations.:rolleyes:
(I was also figuring on the torque split ft/rr.)

Nevermind.

...Right idea, wrong location, I think.

...Put it at the front x-case output. It'll have the same effect... But instead of dealing with 100:1, it'll be 20:1 (with 5:1's in the diff, for example)...

But another problem is the fact that its not in ft-lbs, it's in INCH-lbs... I can't remember, but:

1 ft-lb = 144 in-lbs, I think (because the radius is squared in a torque equation)...

...so a 400 in-lbs disc would be good for like 2.7 ft-lbs... Pretty useless.

But that Pneumatic one would be interesting. Especially if you had one on the front and rear... Front or rear drive at the flip of a switch...

But another problem is the fact that its not in ft-lbs, it's in INCH-lbs... I can't remember, but:

No, the last model, "friction torque limiter", lists max torque in ft-lbs. (Unless I'm going totally nuts.)

But that's right, if it's in the shaft the diff gearing doesn't count.

But it's still useless:

20*100 ftlb (my 4banger)=2,000 ftlb, too much even if half goes to the rear axle.

Kinda close, tho, dang.

1 ft lb = 12 in lbs.

Pete