Originally Posted by
Landgolier
Right, but they're not skidding or otherwise applying big impulse forces to the cog, especially against the threading.
exactly. you can ride safely on the track without a lock ring, frankly. hell, being stronger on a track just makes the cog tighter.
Originally Posted by Landgolier
I don't know that I buy Shants' critique of the 6 bolt disc brake system versus the level splines. I'm not exactly a pro downhill MTB racer (unless hill bombing for beers counts), but as far as I know shearing bolts off is pretty rare on those systems, and locking up a disc brake puts larger forces on the rotor than anything buffered by muscle and knee cartilage ever will. Also, shearing the bolts is probably a good thing, as the next most likely failure mode would be catastrophic hub asplosion. Also, with the level system the hub splines taking the shearing force are Al while the cog is steel, which is not exactly teh recipe for durability, and again, has a pricey failure mode.
edit: it should also be noted that the first bike disc brake designs used a reverse thread lock ring like a track hub. Not surprisingly, these stripped out a lot, and the 6 bolt rotor system was developed to replace it.
I will definitely admit that the 6 bolt system is likely sufficient and am comfortable with backing off a bit in the degree of my criticism of it, but I don't agree with your critique of the knuckles. Each of the three knuckles is quite thick and is about an inch long. You're not going to be shearing one off, especially with any forces distributed between three of them. One thing I really like about the knuckles is that, by taking rotational forces off of the bolts, the threaded bolts themselves only have to deal with the minimal lateral forces. Their only job is to keep the cog on. Given that I seriously cannot imagine a circumstance under which a knuckle would shear, I like the fact that I'll never end up with a sheared off bolt stuck in my hub. I hate dealing with those damn extraction sets.
basically - while the 6 bolt system probably won't be doing anyone harm, i think the level system is designed with more variables in mind.