I haven’t found one, but there are simple solutions. I use a standard small saddle bag, strap the two straps to the seat rails and then use a zip tie to secure the bottom of the bag around the non-round seat tube. Works very well and keeps the bag very secure.
Jandd Mountaineering has made some versons of their Mini Seat Wedge with an extended velcro strap that wraps around an aero post like you see on a P3 or P2. They were sold mostly by Nytro.com or under Craig Turner’s brand X-Lab (Craig founded Nytro and went on to found X-Lab).
In lieu of finding one of those, any of the Jandd brand bags can be easily modified with some hook and loop sewn onto the strap that extends around the seatpost.
It’s velcro seat straps are long enough to go around the elongated seat post no problem. However, if they weren’t, they could be easily extended with a small piece of velcro one-wrap.
This stuff is great. One side is the hook and the other is the loop. It is awesome for holding things in place, and does a great job of extending velcro straps that are too short.
I bought some velcro with tape on one side & put the 2 sides together and made an extension for the velcro on my existing bag. Works like a charm. That way when I switch it to my road bike I just remove the extension and throw it in the bag.
I have two different saddle bags that I use on two different aero seatposts. In both cases I just pulled the seat rail straps nice and snug and left the seatpost strap off. No issues.
I would add the Sci’ Con to the list. The have 3 models that attach directly to the saddle rails. No fooling with velcro if you need to swap between bikes.
Zip lock bag and gaffer’s tape. Shove as much between the seat rails as possible, and use a couple of thin (1/2 width) strips of gaffer’s tape to hold it up.
I gave up on looking for a good bag that was tight against the seat. Gaffer’s tape doesn’t leave residue and is reusable.
I take it you are using the setback Transition post? I’m very fortunate that my seat position allows me to use either one, but I decided to go with the straight post because I could fit a bag back there much easier. I only use a bag for HIM/IM when I need to carry a tubular, but my Jandd Tire Bag II has served well during those times.
I got nothing against some creative tuckin’ & tapin’, but when I need to do repairs during a race, I don’t want to mess with untaping, cutting zip-ties and all that crap just to get to my gear. Plus, then you have to reassemble & secure that hodge-podge to get back on the road. To me, a simple bag is much easier to deal with, even with the loss of style points and very minor drag penalty.
Some bags have longer velcro to accommodate aero posts (my Jandd does), so look for that… Otherwise, as someone mentioned earlier, you can always bridge short straps with another velcro strip. Good luck!
I have two different saddle bags that I use on two different aero seatposts. In both cases I just pulled the seat rail straps nice and snug and left the seatpost strap off. No issues.
Same here, but I only have one saddle bag. The two seat rail straps have held firm on my Cervelo since 2008.
I have two different saddle bags that I use on two different aero seatposts. In both cases I just pulled the seat rail straps nice and snug and left the seatpost strap off. No issues.
You’re a candidate for the Arundel bag that was previously mentioned. They replace the seat post strap with a leather patch, so the clamp hardware doesn’t wear a hole through the front of it. Works well (except if your saddle is really far back, then the leather patch is too high and you have to unstitch and restitch it lower…which I did).
I carry my flat kit in a water bottle. It’s waterproof, cheap; and can be stored in a jersey pocket, easily transferred between bikes, lashed under the saddle (velcro strap used for computer cables), or placed in a spare cage.
I experimented for a while with zip-tieing a Gorilla Cage tight under the seat to try that bottle setup (then can use for either hydration or as a tool kit) - it worked great - easy to set up & use, and the Gorilla cage was totally rock solid back there.
The only reason I didn’t keep that setup was because I needed something bigger than a bottle for tubular during longer races. Otherwise, the single bottle tucked under the seat is a great way to go…