Fitting an AeroPack to the Cannondale Topstone

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A guide to fitting the Cannondale Topstone

A guide to fitting the Cannondale Topstone

Since its release in 2019, the Cannondale Topstone has remained a rider favourite for gravel rides and bike-packing trips. Lots of Tailfin customers use this bike and a few Tailfin staff own one too. Search ‘Topstone’ in our reviews to see just how popular it is.

The Topstone has been available in alloy, carbon, and e-bike versions for several years, and the frames have undergone minor changes since their introduction. As a result, at first glance, it may be confusing to set up the Topstone. This guide will show how to fit an Alloy AeroPack to the Carbon Topstone, and the mounting principles shown apply to all other Topstone models too.

The bike shown is a 2025 Topstone Carbon 3, in size 54.

Configure your Tailfin Order

In this example, we’re showing the Alloy Cargo AeroPack without Pannier Mounts, but our Carbon versions (and our Racks) are also compatible with the Topstone. The Kingpin suspension system used on some Topstone models has a relatively small amount of movement. Both the AeroPack and Rack are safe to use and can pivot to accommodate this movement.

See our comparison guides here to help choose which setup is best for you – based on your riding plans. For simplicity, we’re using the Universal Thru Axle on this bike. It includes the threaded ends for all Topstone models and is just as strong as our other axles.

Before placing your order, also use our Axle Guide to determine if any additional adaptors are required. Cannondale has changed the frame on the Topstone model over the years, so it’s important to check.

You may wonder why we recommend using a thru-axle for the Topstone. In short, it’s the strongest option. Although some Topstone models feature rack mounts, not all do (some are intended only for fenders/mudguards). By attaching your Tailfin system to the axle, the stresses on your frame are almost eliminated. It is the mounting approach we recommend above all others.

If you’re not sure on the axle required, there is an additional check you can complete. Check for any text printed on the frame’s mech hanger. On Topstone carbon frames, you will see ‘UDH’, ‘Single Lead’ or ‘Double Lead’ printed.

UDH =
1.0mm x M12 Thru-Axle and a **UDH Adaptor**

Time to assemble

Use our assembly guides to put together your AeroPack. You’ll need a Torx T25 tool and a torque wrench to do this

Fit the new axle

Now your AeroPack is assembled, just one part remains – fitting it to your bike. To do this, you’ll need to install the new Tailfin Thru-Axle. In this guide, the Universal Thru Axle is shown.

Follow the steps below to install the new axle:

For UDH-equipped Topstones like this, remove the original part and fit the new adaptor. See our video guide **here**

Join the two parts of the Universal Thru Axle together

Fit spacers to your new axle. If the original axle has a conical head, ensure you use a conical spacer

Install the new axle and tighten to 8-10Nm with a 5mm Hex key.

To remove the Universal Thru Axle unscrew from the **driveside**

You can leave the axle fitted even without the AeroPack attached. It’s normal for threads to show on the drive-side – it is just as safe as your original axle as the number of axle threads engaged with the frame is the same. To remove the Universal Thru Axle loosen from the driveside of your bike

Attach your AeroPack

The last step is to attach the AeroPack to your Topstone. It’s often easier to do this standing behind your bike.

Connect the Fast Release Dropouts around either side of the axle.

Secure the Seat Post Connector in place and ensure it’s locked shut. See our quick guide here on how to correctly attach the Seat Post Connector.

Now you’re ready to ride!

Optional Extras

The Topstone featured in this guide is a size 54. On small frames, a traditional seat pack could cause problems and either significantly limit the size of the bag or, worse, rub on the tyre and rapidly wear a hole through the bag.

The AeroPack can overcome this by including the AeroPack Extender with your order (or Long Top Stay if purchasing a Rack). The Extender pushes the bag further away from your saddle and helps maximise the space available for the AeroPack’s bag. For best results, we also recommend packing smaller/softer items at the front of the bag when using a dropper post.

We also recommend including the Extender if you have less than 10cm of seat post outside your frame and/or lots of saddle setback.

The AeroPack Extender has been fitted to the AeroPack shown in this guide

Additional products

The Cargo AeroPack has an 18L internal capacity with an extra 3L using the side mesh pockets. The model shown in this guide can also carry additional items on the sides too. If you need extra storage, consider these options below;