Thanks for the info. I purchased the camelbak large bite valve but I was unable to make it work. I'll try the Platypus.
I'm also going to replace the magnets with the "rare earth" variety. I just need to figure out how to get them out and back in. Also, it's difficult to find a good size selection of the magnets locally. You can buy them online but matching up the sizes is more difficult when you buy online.
Thanks again for the recommendation.
BTW, I was having major issues getting water out through Specialized's bite valve that comes with their bladder. It's pretty small and the water would just barely come out, especially when you're out of breath on a hard uphill. Replaced the rubber bite valve itself at the end with a Platypus hyper flow and now it is MUCH easier to drink. Just pulled off the rubber bite valve and pushed the Platypus one on so the magnet setup remains untouched and thus still functions 100% as designed. The opening is much larger. http://www.rei.com/...yper-flow-bite-valve
I might end up replacing the whole tube with an Osprey replacement. It's a higher flow (than Specialized's bite valve assembly, still a little lower flow than the Platypus Hyper Flow) and comes with a magnet on the end near the bite valve so you can use Specialized's aero bar magnet. Basically a copy of the Specialized setup except with a larger tube, higher flow bite valve, and rotating bite valve. It also has its own second magnet that I believe is stronger than the Specialized setup, so it would be trivial to rig the Osprey magnet to your aerobar for better holding strength. http://www.rei.com/...-tube-and-bite-valve