My friend is being told by a local prop shop that he shouldn't run a stainless prop on an old MR Drive (pre-alpha). Their claim is that its hard on the drive? Is this true, I've always considered aluminum props as good for a spare but nothing else. Any opinions to this?

The only reason I could think of is that they are such a light weight drive if you hit something it will break the drive instead of damaging the prop. With aluminum the prop will break before the drive, hopefully.

Normally the SS props bite harder than the alu props. But other than that, I can't see what could be a problem. There are alot of variables. If he puts on a small dia. prop like the LaserII, compared to a bigger dia. 3 or 4 blade alu, is one thing. If he decides to throw on a Rev4 or B1 is another. High pitch, low pitch ect. ect. ect. Too many variables to really tell, I think.

Being a lot heavier, an SS prop puts a heavier load on the gears when the drive is shifted into gear, maybe this is what they are referring too. However Alphas have been handling SS props since the day they came out with no issues, the MR can't be THAT much weaker or they wouldn''t have lasted as long as they did

Just another variable. Go with the SS.

we ran SS props on my friends formula 255 for years with no issues...tell your friend to look for a laser prop,if he has through prop exhause it will make the prop slip when going on plane and its alot easier on the drive..