Hot
- Waterproof keeps contents dry
- Stays in place on the top tube, doesn’t shift around
- Easily fits cell phone and nutrition
- Narrow enough that doesn’t impede pedal stroke
Not
- Clearance issue when straddling top tube
- Only available in black
https://www.topeak.com/us/en/products/top-tube-bags/1088-fastfuel-drybag
Cost: $54.95 MSRP
How obtained: Review sample from company
Availability: Online, In Stores
RBR Sponsor: No
Sizes: Wedge shape 9”x3.5”x2.3” (22.8×8.9×5.9 cm)
Colors: Black
Weight: 100 g
Top Tube Diameter: Fits 38-52 mm
Head Tube Diameter: Fits 53 – 100 mm
Tested: 5 months (trainer and road)
I like to ride with a bento bag on my top tube for triathlons, group rides and on the trainer. The bag I had been using was rectangular and had a mesh flap that closed with Velcro. While it was very convenient to access items, it didn’t easily fit my iPhone and would sometimes shift during a ride interfering with my pedal stroke. Also with the mesh flap sweat and rain would get on my phone and nutrition.
Then at CABDA I came across Topeak’s FastFuel DryBag. It appealed to me on many points. The wedge shape gave it an aero look and didn’t seem bulky even though it held quite a bit. It was waterproof which would keep rain and sweat off the contents. The deciding factor was would it shift around on the top tube impeding pedaling? So, I asked for a test sample.
Easy To Install
The FastFuel bag was easy to install on my road bike. There’s a single strap that goes around the head tube and one for the top tube. If your bike has integrated handlebar/stem system, there are two straps that go around the top tube and none around the stem. The top tube straps fit a diameter of 38 – 52mm and the head tube strap fits 53-100mm.
Putting It Through Its Paces
I started my testing in late winter on the trainer bike. While on the trainer it was easy to access my phone, energy chews and gels. The sonically welded DryBag technology kept everything dry. After each ride I would wipe off the outside of the bag and was good to go. The hard-shell design kept the integrity of the bag’s shape even when overstuffed. The wide straps kept the bag from shifting and it never impeded my pedal stroke.
By early Spring I was able to transition riding my road bike outdoors. In the Chicagoland area Spring means rain. Unfortunately, I got caught a few times out on a ride when it started to rain. Fortunately for me my phone was in the DryBag and never got wet. A tip is to make sure the zipper is tucked completely under the cover flap to avoid water leaking in.
I did incur one issue during a road ride that I didn’t on the trainer. On the trainer, opening the bag to get something out wasn’t an issue. But then on my first road ride we had a quick refueling stop and I just straddled the top tube. However, I couldn’t fully unzip the bag since my crotch was in the way. If I leaned the bike to the side or dismounted I could unzip the bag fully. I contacted my Topeak rep and found out the samples used for media use were more rigid than the final production models for commercial use. Thus, the bag should be easier to open when straddling the top tube.
I ride a 60cm frame so there may be concern for riders on small frames. It might be harder to access the bag when straddling the top tube since the space between the nose of the seat and the head tube is shorter.
Topeak does make a softshell version of the bag for triathletes – FastFuel TriBag for $45.95 MSRP. This version is not waterproof but does boast a divided main compartment that is padded and mesh side pockets. (The DryBag has a single compartment, no divider). The TriBag also comes in two sizes medium and large.

For those riders that like to coordinate their accessories with their frame color, this bag only comes in black.
Bottom Line
If you are looking for a waterproof top tube bag that is has decent storage capacity and wont impede your pedal stroke, check out Topeak’s new FastFuel DryBag. It’s sleek yet roomy and stays in place.
I debated between the Topeak Fastfuel drybag and the Specialized Burra Burra Top Tube Pack drybag, in the end I went with the Specialized model because it was a tad larger than the Topeak in liters, and it doesn’t interfere with my legs either. Quite frankly I would have been happy with either, I own a Topeak handlebar bag and seat bag and both have been great.
Thanks for the input Fred. I too have Topeak seat bags on my bikes and have been happy with them.
I carry one water bottle in a cage on the down tube and in the cage on the seat tube is a tennis ball plastic can which houses my phone, pack of tissue, snack, etc. Water proof, light weight, and dirt cheap.
I use that same system, Jack. Can’t beat the price plus I can always see whats inside the can.
Yep I’ve seen that before. But I like a bag on the top tube so I can access items while riding (nutrition, phone, etc.)
I have a 43 cm bike and these type bags seem to get in the way when I am pedaling or getting on/off the bike. How do you think it would do on a small frame?
I think you’ll have issues when standing over the top tube. I have a 60 cm frame and it hits me. Pedaling is not an issue as the bag is narrow and stays in place
Hi all,
can maybe somebody comment if this top tube bag fits an iphone 6s ? Difficult to guess because of the curved top edge….
thanks, Roland
I have an iPhone 7 dimensions are 3″x5 3/4″. It fits fine but it lays at an angle to fit. I also push it towards the front of the bag where it is higher.
Hi Sherry,
thanks a lot for this information. Since the dimension of 6s and 7 are almost identical it should fit then.
regards, Roland