The helmet hook seems like a bad idea for carrying a spare when you need to... what works good on the VTR? How bout those net thingy's, are those strong enough to hold a helmet? In the past I have just thrown it in a backpack, but that could be real nasty in a crash, and I need a better way.

 

I've used a bungee net on my F3 to hold a spare helmet, and that's worked fine. I wouldn't want it in my backpack, either.

Are luggage sidepacks out of the question?