Refining a Classic: Tailfin Top Tube Pack Review


Refining a Classic: Tailfin Top Tube Pack Review

Building on the “V-mount” system used in their downtube bike bags, Tailfin introduces their new Top Tube Pack in an array of sizes. Available in a traditional zippered or a “flip lid” design, Ryan Wilson reviews both versions while weighing their respective pros and cons.

Note: the gear in this review was provided for testing, feedback, and review.

Over the last few years, the minds at Tailfin over in the UK have been steadily expanding their line of bike bags, and I’ve had the pleasure of putting many of them through the wringer while out on tour. Last year they introduced a set of downtube bags that utilized their “V-mount” system which uses a V-shaped aluminum base plate combined with a removable rubber boot and a TPU strap to create a super stable connection with the bike, even in places where your frame is lacking mounting bolts. I was immediately a fan of this system and found myself imagining what other types of bags it could be useful for.

When Tailfin sent over a prototype version of their top tube bag using the v-mount system around a year ago it became an instant favorite of mine while riding across Mongolia and Turkey. Even in its early iteration, the side-to-side movement that plagues all of the traditional velcro strap-based top tube bags I’ve tried over the years was essentially gone. Removing that “play” in the mounting setup also made one-handed operation of the zipper noticeably easier.

Choose Your Closure

Jump forward to two months ago, after many small tweaks from the Tailfin crew, I finally got my hands on the final production versions of the V-mount top tube bags to test out on a trip through the Colombian Andes.

In total, Tailfin is offering five variations of the bags, with two magnetic lock flip-lid sizes (1.1L and 1.5L), and three zippered sizes (0.8L, 1.1L, 1.5L). Since I’d been testing out a zippered version for the better part of a year, I decided I’d take the 1.1L flip-lid out to see how it fares against some classic Colombian downpours.

I’ve always been a little bit skeptical of flip-lid designs on top-tube bags. Most that I’ve seen don’t appear to hold the cargo as securely as I’d want when I’m out in the middle of nowhere, leaving important tools bouncing around inside of—and, potentially out of— the bag when riding on rough roads. The lids are typically simplistic in design with a flat flap that just lays over the top and latches down. Tailfin’s top tube bag eliminates these worries by using a 3D welded lid design that wraps down around all of the sides and is then is secured with the simple and fast mag-lock design developed by Tailfin. It all feels very foolproof. Even when overstuffed, I was confident nothing was going to wiggle its way out and no rain was getting in.

If flip-lids aren’t your thing, Tailfin still offers up a classic zippered version (and even includes teal and black zipper pulls if the teal isn’t your vibe… I like it, personally).

Choosing between the two different closures might be the trickiest part of the whole proposition as both have their pros and cons. One thing to consider with the flip-lid version is if you have bulky stem bags you’re using along with a short stem, the positioning of the magnetic latch means that it can get wedged between adjacent bags and becomes just a bit trickier to open without turning your handlebars slightly to the left. I didn’t find this to be a huge issue on my setup, but it’s worth considering when trying to imagine different cockpit bag organization systems you might use and which size bag you’d choose (especially with the wider 1.5L version).

The wider opening of the flip lid does seem to offer accessibility to your bag’s contents more readily; it definitely makes it a bit easier access to things like the stretchy mesh pocket on the left side of the bag (which is ideal for something like a phone) or any item that you have stored right on top. The nature of the taller front edge on the flip-lid means that items that you store in that bottom corner of the bag will be a little bit trickier to get at than with the zipper. In practice, I just loaded this area with things I’m less frequently grabbing, and I put the main items I’m going for all the time on top and it was never an inconvenience.

The flip version will be naturally a little bit easier to operate (and I’m always a fan of eliminating zips, which can be prone to failure with enough dust), but the rock-solid stability of the V-mount makes one-handed operation on the zippered version efficient and smooth as well, so the difference is going to be minor and will really come down to personal preference.

Materials and Build

The V-Mount Top Tube bags feature Tailfin’s usual waterproof hypalon/ripstop nylon, welded construction, and waterproof zips to keep the rain out. It has a lightweight HDPE frame to give the bag some rigidity and reduce bulging from the sides, along with a removable “insole” cushion that is designed to absorb bumps and rattles that can damage sensitive gear. All versions feature a cable management port for charging electronics. Each bag comes with three TPU straps, two shorties for standard tubing, and one longer (36cm) strap for bikes that have a larger junction where the top tube, head tube, and downtube meet.

Mounting Versatility

While the V-Mount system with TPU straps keeps things nice and stable on its own, these bags are made to be used with frames that have bolt-on top tube bag mounts as well. Removing the “insole” from the bag reveals bolt holes that utilize the V-mount base plate and rubber boots to easily attach the bags using bolts instead of TPU straps, thus eliminating any need to have different bags for different bikes. The stability of both mounting options does a good job of significantly reducing the wear on your frame which velcro strap bags are famous for causing.

Two different positions can be used with bolt-on frames, but it’s worth noting that there isn’t a way to move where the TPU straps are positioned on the bag. If you’ve got something in the way like a frame bag strap you can’t move or some sort of cable management obstruction on your frame, you’ll have to adjust the position of the bag a little bit to make it work. Thankfully, this typically shouldn’t be a huge deal because the bag doesn’t rely on being anchored to the steerer tube like most other top tube bags. I found that giving a little bit of space between the steerer and the bag eliminates some of the annoying little squeaks and rubbing noises that can develop over time with these types of bags.

Sizing and Specs

Tailfin is offering three sizes in total: a svelte 0.8L version (zip only) that is optimized for road bikes where knee rub might be a concern; a jack-of-all-trades 1.1L version that will work with a wide range of setups; and, a beefy 1.5L version for bikes where knee rub is a non-issue.

Weights (strap/bolt-on) :

0.8 Liter Zip – 150g/138g
1.1 Liter Zip – 165g/154g
1.5 Liter Zip – 190g/178g
1.1 Liter Flip – 179g/167g
1.5 Liter Flip – 199g/187g


0.8 Liter Zip – $65/£52/€60
1.1 Liter Zip – $70/£55/€65
1.5 Liter Zip – $75/£60/€70
1.1 Liter Flip – $75/£60/€70
1.5 Liter Flip – $80/£65/€75


I always appreciate getting my hands on a new piece of kit from the folks at Tailfin because I know they won’t release a half-baked product just because they need to fill a hole in their lineup. They look at every detail and try to determine if there’s a way to make something better than what else is on the market. If they haven’t figured it out yet, they keep it in the oven until they do.

While I haven’t tried every single one of the hundreds of other top tube bags on the market, and likely any number of them will get the job done, Tailfin offers up a super-refined take on a classic bag that fixes many of the issues present in the existing options.


  • Super stable V-mount system is a big upgrade from traditional velcro systems which are prone to movement.
  • Reduces potential frame wear compared to velcro straps.
  • Removing the need for anchoring at the steerer makes it easier to use with slammed stems and eliminates rubbing.
  • Three sizing options and two closure types for different use cases.
  • Durable and waterproof materials.
  • Can be used with bolt-on frame mounts as well as TPU straps.
  • Removable “insole” provides some shock absorption for fragile electronics.
  • Refined flip-lid design keeps items secure and dry.


  • Not the cheapest choice for sure, but reasonable for the features when compared to other high-end options.
  • Mag-lock closure location on the flip-lid version could be obstructed on certain setups with cluttered cockpits.
  • Can’t adjust the location of the TPU straps on the bag.

You can find more info about the Zip version of Tailfin’s top tube bag here and the Flip version here.