That's some serious riding! :-)
Originally Posted by
TinkerinWstuff
I use a hiking pack that's vented on the back and has front straps to keep everything in place. Zero complaints. Mountain Fourteener by Camelback. I usually ride without the bladder and put it in for hikes in the mountains. Holds a change of clothes and I leave shoes at work.
CamelBak Fourteener 24 Hydration Pack - 100 fl. oz. - REI.com

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FB4K - Every October we wrench on donated bikes. Every December, a few thousand kids get bikes for Christmas. For many, it is their first bike, ever. Every bike, new and used, was donated, built, cleaned and repaired. Check us out on FaceBook: FB4K.
Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.