The medium version is perfect if (like me) you want to carry 2x-tubes, 3x CO2, inflator, tire levers and a mini-tool. Mounting is easy and stable (go w the strap & buckle option). Bag size will not bump your legs if properly mounted.
I bought this one to have as a backup of another of the same make, model, and size. The seams are separating on the other one and there is noticeable wear where the velcro seatpost strap makes contact with the bag material. Still, I'm buying another one because I like the size and overall design of this bag. And, I suppose, the devil you know is better than the devil you don't know.
It's a wedge pack, so not much to say other than it functions exactly as I hoped. Attaches very securely without fuss, no movement or rattling. Small, but holds two tubes, two C02 cartridges, a C02 inflator, patch kit, multi-tool and one misc. item (energy bar, keys etc.). Simple and clean design. I'm so far very happy.
After years of fussing around with various size and attachment methods, I've settled on this pack as the most versatile option for single day rides on road or cross bikes. Size small is the right size. Medium is too big unless you want to fit 2 29'er tubes - otherwise a small will fit 2 cx tubes with room to spare.
Don't bother with Velcro or custom attachment methods (fizik).. go with straps and clips like the topeak.
Downsides not at all waterproof. Pack can bump legs depending on position.
The Topeak Aero Wedge Pack-Strap is an excellent seat bag with room for 2 tubes, tire levers, CO2 cartridges, nitrile gloves and a multi-tool in a size medium bag without even having to use the expansion feature. The straps allow quick & easy transfer from one bike to another and make for a very secure attachment. The zipper opening is sturdy & reliable and it is easy to attach a clip-type tail light to the back of the bag. Over the years I have purchased 5 of these for the bikes in our family and they have proven to be both durable & reliable as well as being an attractive unit. They also have kept the contents dry when I have been caught in a rainstorm. Highly recommended!
Really like the aero design and the room inside for tubes tool and inflator. Simple to attach with the strap and stays put. I had a previous model that had a click-in kind of slot attach under the saddle, but the strap on this much better.
I have used this large bag for 2 years, mostly road and gravel road riding. If the zipper gets muddy, it is difficult to work. And the mesh divider on the flap tears with use.
The medium is tight for anything more than a tube and a few tools. It's virtually impossible to squeeze in a wallet and cellphone. But my biggest frustration is the placement of the zipper. With the bag snugged up tight under the seat (which I assume is how it's supposed to work) you have to squeeze your fingers between the bottom of the seat and the bag to open or close it.
This saddle bag is very nice and has a lot of room to put a few inner tubes, multi tool, and your CO2 inflator and cartridges. It has an expandable zipper around the middle if you need to add more stuff. I would have given the bag a 5 star rating, but I don't like the long straps that dangle on both sides. Perhaps they could have put a bit of Velcro on both straps so they won't dangle and flap in the wind.
I was looking for a large bag to replace an old performance wedge. This fits pretty much everything for me. Tube, 2Co2's, levers, keys, cell, patch kit, gloves, small wallet, eye glasses, and pretty good size first aid kit. I like the straps under the bag because it holds my pump (mini-morp).