There isn't a hollow axle to my knowledge that uses the standard D rings. However Niftech does sell one, but requires that you use their proprietary Rocket Rings. The Niftech axles are definately truer and smoother, and the pricing is about the same. But where they get you is their Rocket rings. Instead of $2.50 for a pair of standard D rings, you'll be forced to buy their Rocket rings at $15 a pair.