does not fit
corvus at REI on 11/28/2008
Rated:

Bought two of these but they did not fit any of our 6 bikes. This product does not fit any seat tube that is large as in all modern bikes, nor did they fit all the seats [as noted is other reviews] found on currently manufactured high quality bikes. I had to use zip ties to get it to fit. The mounting brackets screws strip the plastic they go into easily, had to replace them with bolts/washers. It does have a lot of room for a seat bag but is broken up into two compartments, one would have been better. Alas, I plan on designing my own seat bag as none fit my requirements of having enough room and fitting modern bikes.
Not the best for mountain bikes
H3LLFIRE at REI on 07/01/2008
Rated:

I purchased this bag for use on my Trek 4500 as a way to store my keys, wallet, and BlackBerry. Its side-opening design and expandable lower compartment seemed ideal. Unfortunately it was actually TOO big for my mountain bike. Unless you have a saddle that is pushed back, it'll be tough mounting the bracket on the underneath rails. The velcro loop on the front of the pack that is supposed to wrap around the saddle tube isn't long enough. It made it around the thicker tube of the mountain bike, but not enough to overlap and secure it properly. Lastly, with the pack fully expanded it dropped down too far and skimmed the top of my rear wheel. A shame it didn't work with my bike, but it's still very appealing if you can get it to fit. This bag will likely work well for a road bike with thinner tubing and greater seat clearance.
Works well but can vibrate open
Mike in NC at REI on 12/28/2007
The Expanding Wedge Seat Bag has performed very well for me and I like it a lot, but I did lose a camera because the horizontal zippers around the bottom expansion pocket vibrated open during a mountain bike ride. From now on, I will use a safety pin to keep those two zippers together and securely closed. The top/main pocket has always remained closed and does not vibrate open. I like the hook inside for my keyring since it offers added security. I would buy it again, but everyone should be aware that they need to secure those bottom zippers together.
Perfect Wedge for Bike Seat
Roady1 at REI on 10/10/2007
Perfect design for holding those essential tools and repair items; expands to contain light weight emergency rain cover as well. Quick release feature work consistently well, allowing wedge to fit tightly behind the bike seat, without being unsightly or oversized. Excellent for century rides!
This thing is huge...
Jeremy G. at REI on 09/18/2007
I originally bought this saddle pack to hold things like my tire patch kit, tools, cell phone, etc. I figured the more room I had, the better. The only problem was that it was actually too big for my bike! It's a great product, but make sure it'll actually fit first...
Perfect size
passionate about pedaling at REI on 09/12/2007
This bag was the perfect size for a supported 3 day trip. I could keep what I needed with me & not have the weight of a rack & large bag. I also have the smaller size for just the basics, so snapping this one on in its place was convenient.
Perfect Road Bike Size
Roady1 at REI on 08/29/2007
Light weight, fits well behind seat, easily removable. Excellent size for tools, spare tube and patch kit, plus enough room for a light weight jacket (if you roll it up)!