Fitting a CargoPack (formerly known as the AeroPack) to the Cannondale Topstone

A guide to fitting the Cannondale Topstone

Note: This guide references our AeroPack, now available as the CargoPack system or as part of our modular Pannier Rack range.

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.

Cannondale Topstone
2025 Cannondale Topstone Carbon 3, size 54

Configure your Tailfin Order


axle selection page showing the Tailfin Universal Thru Axle

 

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
Single Lead = 1.0mm x M12 Thru-Axle
Double Lead = Speed Release Thru-Axle

Time to assemble

Tailfin AeroPack Assembly

Fit the new axle

 

Follow the steps below to install the new axle:

Remove the original thru-axle

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

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. 

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 Tailfin 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;

Cannondale Topstone with Tailfin AeroPack