to quote expert fabricator and 4wheeler, Randy Ellis,
www.randyellisdesign.com "better to lift a tire than flex to the moon and break parts"
all of this extra flex requires running long travel driveshafts that are usually made for agricultural implements. They do not handle speed very well and fling their grease and the splines don't stay tight for a long life.
I had revolvers. I broke two driveshafts running these shackles. I know there was probably a combination of issues at hand:
spring wrap
questionable quality in the fabrication of the drivelines
unloading of revolvers
I ditched them and I didn't break any more of my junk.
Now I'm linked and run driveshafts that only have a little bit of travel that is needed.
The only thing good about revolvers:
they are made of metal and welded together (I like metal parts and I like welding)
Save your money, lift a tire every once and a while, break less parts.
Why be breaking driveshafts because you had to have so much travel. We already subject our trucks to abuse that stresses axles, shafts, shocks, springs, u joints, trannys, motors etc. We rub our driveshafts on rocks, stumps, ledges etc. Why add another fail point and possible area of weakness to a truck?
This is just my opinion. Just my point of view on a crappy product.