How Tailfin designed its perfect top tube pack

Not all top tube packs are created equal

By Katherine Moore

Published: Thursday, 06 April 2023 at 12:00 am

Best known for its unique carbon-framed pannier racks, Tailfin has been working its way meticulously through other bikepacking luggage essentials to bring its engineering-led approach to new products.

“Our number one core principle is innovation,” explains head of product design and brand Rob Phillips.

“We only release products once we have developed a product that outperforms our expectations in every requirement.”

This ethos explains why the brand’s new range of top tube packs took more than two years to research, prototype, test, refine and produce.

What makes a great top tube pack?

""
Top tube packs are a great way to store essentials, but they can be a hindrance more than a help.
Tailfin

Sitting atop the top tube, just aft of the stem, top tube packs are a great way to store essentials, snacks and electricals, especially when hitting the road or trail for multi-day bikepacking excursions.

Always within easy reach, top tube packs are ideal for storing items you need to access quickly.

Yet, as anyone who has used an ill-fitting or poorly designed top tube pack will tell you, sometimes they can be more of a hindrance than a help.

Through its research, Tailfin identified a number of common issues with top tube packs.

Instability

A top tube pack needs to be fitted securely so it doesn’t flop from side to side, especially when climbing out of the saddle or riding over rough terrain.

If a front stabilising strap is required, these are often incompatible with slammed stems.

Bulging and knee rub

If a top tube pack bulges out to the sides when filled, it’s more likely to be unstable and lead to knee rub.

In the worst-case scenario, this can result in muscle injury if you change your cycling style to compensate for a bulging top tube pack.

Frame rub

""
If a pack is unstable, straps can bite through paint.
Tailfin

Attachment straps can bite through paint, especially when combined with the movement of an unstable pack. The problem is exacerbated in wet or grimy conditions.

Waterproofing issues

Even if waterproof material is used, water ingress needs to be prevented through stitching holes and openings such as zips or flaps. This is key for storing electrical items safely.

Attachment style

While bolt-on top tube packs have become more popular, some people have to choose between strap-on or bolt-on, meaning these packs are less easy to move between bikes with different mounting options.

Solving problems

""
Tailfin set out to solve the common issues with top tube packs.
Tailfin

Taking these known issues on board, Tailfin set out to solve them, creating its first line of top tube packs. Here’s how.

Curing instability

Tailfin has used its patented V-Mount solution to provide a secure fit.

A rubber boot prevents movement. A rigid internal pack structure, which Tailfin calls its ‘taco shell skeleton’, helps maintain the structure of the pack. Everything can then be cinched down using optional frame-friendly straps.

These combine to give a solid attachment but also prevent any unwanted movement as you’re riding, claims Tailfin.

The sturdy Nylon, TPU and HDPE construction can also withstand knocks from the rider, staying in place perfectly should you accidentally hit it with a knee while riding over more challenging terrain.

Minimising knee rub

""
The teardrop shape reduces volume where the pack is most likely to interfere with a knee.
Tailfin

Tailfin analysed knee tracking data from a wide range of riders to help design its top tube pack.

Tailfin says these observations freed it up to divide the design process into two channels. Firstly, it could create packs that would eliminate knee rub for those who suffered from it by focusing on body-mapped shaping. This led to a teardrop shape, which reduces volume where the pack is most likely to interfere with the movement of the knee.

Secondly, it could develop packs of different sizes that incorporate the knee-rub minimising design.

Tailfin worked to develop a small pack for riders with a narrow stance or with knee tracking that typically moves laterally inward – both of whom are more likely to have issues with knee rub.

The 0.8-litre top tube pack, in Tailfin’s words, should enable more riders who’ve struggled with a top tube pack to use one for essentials, employing a tapered 3D design. The result is a pack that is small but can still fit a full-size iPhone.

The 1.1-litre and 1.5-litre capacity packs are also tapered in profile to minimise knee rub while offering greater storage potential.

Frame protection

""
The V-Mount design avoids unwanted movement, which can cause rubbing.
Tailfin

 

The V-Mount attachment system prevents any unwanted movement, which can cause rubbing. The pack can be mounted using either screws or the included TPU straps.

Waterproofing

Tailfin has used a welded construction, rather than stitching, to make the top tube packs weatherproof.

According to Tailfin, this eliminates any tiny holes where you might otherwise see water ingress.

The materials themselves are waterproof too, from the brand’s signature Hypalon/Ripstop Nylon outer shells to the other fixtures used and quality zips, which, unlike many other zips, remain waterproof even under strain.

Tailfin top tube pack range

""
The Tailfin Top Tube Pack comes in three sizes.
Tailfin

The Tailfin top tube pack range comprises five models.

The pack is available in three sizes: a slender 0.8-litre, a mid-range 1.1-litre and a larger 1.5-litre capacity.

All three sizes are available with a zip opening, and the larger two sizes are also available with the magnetic flip-top design.

Three different straps are supplied with each pack, so they will fit everything from skinny steel tubes on a road bike to chunky carbon frames.

""
The top tube packs have a large internal pocket for a phone.
Tailfin

There are also two different sets of holes for screws, giving you multiple options for direct mounting the pack.

The shaping of Tailfin’s top tube packs differs according to size in order to eliminate knee rub, and each features a teardrop structure at the front to give a more aerodynamic interface next to the stem and to blend aesthetics.

Internally, there’s a large pocket designed to accommodate most smartphones, together with a cable management port at the front.

Tailfin says many packs will flop around if they have an internal pocket holding a phone. So, designing a soft, protected pocket with the stability to have a phone upright was essential,    together with a cable management port at the front.

A cushioned insole helps to protect valuable items such as battery packs.