Thru axle for wheel-on classic trainer

Hi, I have purchased a bike that has a 148x12mm thru axle on the rear wheel. This doesn’t fit my smart zwift turbo trainer and I can’t find a product to allow me to use my bike on the smart turbo. Has anyone got any advice? I need an axle that will have correct fittings at each end to allow connection but zwift don’t sell these nor do the bike manufacturers.

Hi @Rich_Scott1 welcome to Zwift forums and Zwift more broadly.

Shuji at Zwift HQ here. Can you tell us who makes the bike and which model it is?

Also want to confirm you’re talking about the Zwift Hub trainer. These were sold either with 1) a multi-speed gear cassette or 2) with a single-speed Zwift Cog. Which version do you have?

Either way - the trainer should have come with several different axle adapters for either a quick release axle frame or a thru axle frame like yours. Were all those adapters included? This is how you’d install the correct adapters.

TLDR: use the thru-axle that came with your bike.
The 148 mm specification refers to the inside width of the frame, but the total axle length varies quite a bit from bike to bike because the frame’s dropout thicknesses vary from brand to brank, and model to model.

If you would like one-on-one assistance with installation, please don’t hesitate to contact our Support colleagues, who’ll be happy to help with anything you might need.

Thanks - the bike is Ribble r872 disc and the trainer is


Ah gotcha, you have a wheel-on classic trainer, not the direct-drive Zwift Hub. Totally different situations - what I wrote doesn’t apply in your case.

You are correct - you will need a different thru-axle with extended nubs on both ends so your trainer can grip them securely. Robert Axle Project is a US-based manufacturer of specialty thru-axles for different applications including the one you need. There are probably others based in the UK or EU that you can Google.

EDIT: When buying a replacement thru-axle - you will need to pay close attention to the total overall length of the axle as well as the thread pitch (there are 3 industry-standard thread pitches used, plus some proprietary ones). Use the tools that Robert Axle Project provide to determine what your Ribble requires.

This is what you want, it adapts the through axle to a 5mm skewer

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