[Walt Fricke]

For stock motors, there certainly is no problem to be solved that I can see. Stock flywheel bolts do the trick.

For race motors, I still don't see a problem. ARP advertises their bolts as 200,000 pounds per square inch steel, and suggests a 12mm bolt be torqued to 112 lbs/ft.

I make metric 12.9 bolts to be 186,000 psi steel. Factory torque spec for the 12mm bolts is what - 110 lbs/ft? Same as the ARP.

For the 70.4mm 6 bolt crank I torque the factory bolts to 150 lbs/ft. They don't break, and hold the flywheel in place up to at least 8,500 rpm. So I'm not seeing a problem here either.

I don't see what the bolt head looks like in the ARP catalog. If it is the funny sort of multi-leaf clover head they show for flywheel bolts generally, one would need a special socket, wouldn't one?

Now, if they are less expensive, I could see using them. The factory 12mm flywheel bolts are not cheap (though given what they do, perhaps that is to be expected).

But maybe someone has actually tried these, as they make ones for our 6 and 9 bolt cranks?