U-Tubes (2021) (pair)


Product Specs


Full length of U-Tube: 29.75″ from front to back

Width it adds to bike in the wide setting: 5.25″ on each side towards the front and it tapers to 6″ on each side toward the back of the bike

Width it adds to bike in the narrow setting: 4.5″ on each side towards the front and it tapers to 5.25″ out from the frame towards the back of the bike

Insertion end (part of the U-Tube that slides into the frame): 9.8″ long

Attachment method

Installs into frame with spring pins that are pre-installed.

Bolts and washers are included for those with older bike frames that have threaded bosses.


Our tried and true longtail U-Tubes are an ultra-useful addition to any longtail Xtracycle cargo bike. They support cargo, act as a footrest, and make it possible to tow one or more adult or kid bikes. Now upgraded to attach with push-pins making them easy to install when you need them and remove when you don’t. Price includes a set of two – one U-Tube for each side.

Have more questions? Check out our FAQ page.



The U-tubes are compatible with any Xtracycle longtail cargo bike or conversion kit including: the eSwoop (Shimano / Bosch), the eStoker (Shimano / Bosch), the Swoop (non-electric), the eClassic (Bosch, the Classic XPP, any model year EdgeRunner, the FreeRadical conversion kit, the FreeRadical Leap conversion kit, the Radish, the Cargo Node and the Cargo Joe.

Modification Notes for Compatibility:

For the Swoop (non-electric), 2018 eSwoop/eClassic/eStoker, CargoNode, and all EdgeRunners equipped with the LT2 deck and LT2 v-racks: The U-Tubes will need the spring pin removed and a bolt to install (bolts and washers are included).

For 2021 electric EdgeRunners, LT1 EdgeRunners, Radish, CargoJoe and FreeRadicals: The U-Tubes will work with no modification.

For the FreeRadical Leap conversion kit: The U-Tubes will need the spring pin removed and a bolt to install (bolts and washers are included). The rearmost insertion end of the U-Tubes will also need to be cut. Here are the instructions on how to do this.

Not sure what model bike you have? If the hole in the frame where the bolt or pin would secure the U-Tubes in place has no threads for a bolt and is just a regular hole, the spring pins are needed. If it has threads for a bolt, a bolt is needed.

The U-tubes are not compatible with any RFA model or any non-Xtracycle brand cargo bike.

User Manual

U-Tubes Installation Manual

Link to PDF



Please see the Terms and Conditions page for the Xtracycle Warranty Policy.


Xtracycle Return Policy.


Shipping is free to the continental United States for all accessory products.
For shipments to Canada, Alaska, and Hawaii, UPS or FedEx fees will apply.

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