How can I use my thru axle bike on a turbo trainer?

 ‘What thru axle adapter do I need to mount my bike onto a turbo trainer?’
 ‘My bike has a thru axle, will it still work on a turbo?’

Here at Turbo Trainer Hire, these are some of the frequently asked questions we get asked. We get lots of enquiries from people who have purchased (or hired) a turbo trainer and then find it doesn’t fit as their bike has a thru axel. We hope this blog helps explain how you can still use a turbo trainer if your bike a has a thru axel...

Does my bike rear wheel have a Skewer or Thru Axel?
Thru-axles are newer, they have been in mountain bikes since around 2010 and are now common in road bikes as well. But there are still many bikes that have skewers.

A “quick release”, or QR, skewer is a thin rod that goes into an axle (that is inside a hub). A QR is 5mm thick and is steel. It looks something like this:

A thru axel is a thicker rod, the common rear axle is 12mm in diameter. Like the image below. Thru axles are different because they thread directly into your bike frame. Your bike has a thru axle if the “drop out” is a hole, rather than a U-shaped dropout.  Thru axles provide a stiffer ride, which is beneficial for mountain bikers.


To summaries if you have a thin, 5mm rod, then you have a skewer.  If you have a 12mm threaded piece, then you have a thru axle.


If my bike has Thru Axel, how do I mount my bike onto a Wheel On Turbo Trainer?
You need to check what size your thru axel is and then will you need to purchase a thru axle adapter which fits your bike.


Why do I need a Thru Axel adapter?
Adaptors for use with wheel-on trainers are longer than normal axles that you use in place of your bike's standard thru axle. They extend out far enough on each side that the trainer can firmly lock your bike in place.
Thru Axle adapters simply replace the thru axle on your bike and are meant for mounting in a trainer.


How do I know what size adapter I need?
To check your size firstly pull your thru axle out and measure the dimensions.
There are 3 dimensions you need:

  1. Thread pitch of your axle: Place your axle threads on top of the Fitment Guide image below to find the matching thread pitch. Determine if it is a 1.0, 1.5, or 1.75 thread pitch.

  1. Length of the diameter: measure the end of your axle shaft.
  2. Length of the axle: measure the straight length of your axle shaft. Include the over-locknut dimensions


Once you have your dimensions you need to purchase the correctly fitting thru axle adapter.


Saris / CycleOps have 3 sizes of Thru Axel Adapters, which size do I need?
Saris / CycleOps offer 3 different models:

  1. SAR9707T- This adapter is designed to work with bikes that have a 142x12 thru axle with 1.0 or 1.75 thread pitch
    1. Thread Pitch: 1 or 1.75mm
    2. Axle diameter 12mm
    3. Axle length 142
  1. SAR9733T- This adapter is designed to work with bikes that have 12mm x 148mm for 1.5 pitch Trainer Thru Axle. This also come with a shorter bolt action slider tube.
    1. Thread Pitch: 1.5mm
    2. Axle diameter 12mm
    3. Axle length 148
  1. SAR9712T- This adapter is designed to work with bikes that have 12mm x 148mm for 1.0 or 1.75 thread pitch. This also come with a shorter bolt action slider tube.
    1. Thread Pitch: 1 or 1.75mm
    2. Axle diameter 12mm
    3. Axle length 148

 

Why do some of the CycleOps thru axle adapters come with a short slider?
Essentially, all these adapters just provide a mounting surface on the outside of the axle for the trainer cups to hold onto, and are strong enough to withstand the clamping force of the trainer. There are limits though – mountain bikes with Boost 148mm spacing may require special consideration due to the extra width. In this case, Cycleops sells their 148mm adapter with a shorter slide for the trainer to fit.

 


Can I use a Saris / CycleOps branded thru axel adapter on a Tacx / Wahoo / Kinetic / Elite / other branded turbo trainer or are the Saris / CycleOps branded thru axel adapters specific to Saris / Cycleops?
Potentially, you can use Brand A's trainer with Brand B's adaptors, although Brand A might say that its own adaptors provide the most stability and you will need to double check the sizing.  If in doubt, you're safest sticking with one brand. Make sure you do the proper research on the size of your thru-axle.


What is the difference between Saris & CycleOps branded thru axel adapters?
There is no difference. Saris acquired the CycleOps brand in 2019. The Thru Axle adapter is exactly the same just different packaging and branding!


Are direct drive turbo trainers compatible with thru axel bikes?
Most direct drive trainers like the CycleOps Hammer H2 or Saris H3 which are used without the rear wheel of the bike, are already thru axle compatible and so you don’t need to purchase any special adapters.
You just simply need to fit the correct fitting end caps for the “hub” which then allows you to use a standard QR, 142 x 12mm, or even 148 x 12 thru axle. The different end caps are supplied with  turbo trainer.  The CycleOps Hammer H2 or Saris H3 Includes 6 original end caps which are compatible with 130/135mm quick release skewers and 142/148x12 thru axles.


 

If you have any qs about which Thru Axle Adapter you require then just contact us at hello@turbotrainerhire.co.uk

 
Sporting Regards,


The Turbo Trainer Hire team