We know, there’s no such thing as a stupid question. But there are definitely some questions too embarrassing to ask your local shop or riding buddies. Ask A Stupid Question is our weekly series where we get to the bottom of your questions – serious or otherwise. Hit the link at the bottom of the post to submit your own question!

Finding yourself spending more time pedaling indoors lately? Us too. Not because we’re scared of the cold (we’re still riding outside more days than not), but because it can be difficult to get the same high intensity training when the temperatures are well below zero. That, and sometimes it’s nice to not have to put on 30 pieces of clothing and get your lights charged up to go ride for an hour if that’s all the time you have.

If you are planning on riding the trainer this season, things may have changed since you last hopped on. Things like thru axles if you happened to buy a new bike recently.

That seems to be what David ran into, writing, “With the thru axle trend on road and endurance road bikes, are trainer manufacturers making an interface that will work with a thru axle? For example, I have had a Cycleops Fluid for several years… Using with my quick release road bike.  This year I picked a gravel bike with thru axle and realized i can’t mount to my trainer.”

AASQ #25: How do I put my thru axle bike on a stationary trainer?

That’s a great question, and one I’m sure a lot of riders are facing lately. In terms of retrofitting your bike to an older trainer, your best best will be one of the Trainer Thru Axle adapters that’s out on the market like the ones from Cycleops or Kinetic. These simply replace the thru axle on your bike and are meant for mounting in a trainer. However, not all adapters are created equal – and they are bicycle specific, to a point.

The Cycleops adapters while designed exclusively for their Classic and Pro trainers (which sounds like what you’re looking for), are meant only for indoor use while on the trainer.

AASQ #25: How do I put my thru axle bike on a stationary trainer? AASQ #25: How do I put my thru axle bike on a stationary trainer?

Adapters like the Kinetic Traxle on the other hand, are safe for outdoor use (and most trainers) as well which means you can leave it in your bike if you don’t want to be switching axles every time you want to mount it to the trainer. Kinetic also has an awesome sizing guide that you can print out and use to figure out what specific Traxle you’ll need to fit your bike. The chart highlights the lack of rear axle standards from thread pitch to length which makes it important to get the right size to fit your bike.

AASQ #25: How do I put my thru axle bike on a stationary trainer?

At this point, most trainer brands offer some kind of adapter that works with their trainer and possibly others. There are also brands like The Robert Axle Project that don’t make trainers, but do make trainer compatible thru axles that can also be used inside or out. The Robert Axle Project also has a convenient data base with a lot of bikes that will tell you exactly what axle you need.

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.

Of course, if it’s time to upgrade your trainer there are options there as well which don’t require a new axle. Most direct drive trainers like the Cycleops Hammer which are used without the rear wheel of the bike, are already thru axle compatible. This usually involves different end caps for the “hub” which then allows you to use a standard QR, 142 x 12mm, or even 148 x 12 thru axle.

Obviously, this is the most expensive route to get your thru axle bike on the trainer, but Cycleops does have a rather intriguing deal going on at the moment – trade in any old trainer at one of their dealers and you’ll get 20% off a Hammer or Magnus smart trainer if you do it by January 15th. Only the Hammer would solve your thru axle problems, and even at 20% off it’s still $960 so it’s a bit of a stretch, but it’s out there!

Long story short, yes, trainer manufacturers are keeping up with the thru axle trend and most current trainers out there can be used with a thru axle bike – as long as you have the right adapter.

Got a question of your own?  Click here to use the AASQ form, or find the link under the Contact menu header up top anytime a question pops into your mind! 


  1. Be careful with which thru-axle adapter you pick up though. I have a Tacx Vortex Smart trainer and picked up a Kinetic thru-axle adapter through my local bike shop. The Kinetic axle is too long to fit onto the Tacx trainer. I had to take it back and the bike shop was going to do more research to see what might work.

    • The problem is that some trainers simply don’t open wide enough to fit both the added width at the rear dropouts of most thru-axle bikes and the ends of the adapter that have to stick out from the dropouts so the trainer can grab on to them. Trainers with a cam-style quick release on one side may that only have adjustability on the non-qr side may not have enough range on the one adjustable side to allow clearance.

      Thru axles have been a bit of a moving target like a lot of things in the bike biz lately. There are now four thread pitch options along with the different hub widths.

      • LBS can’t get the Tacx adapter. And I really didn’t even think about it not fitting the trainer. I should have considered it when you take into account the amount of time it took to make sure they had found the right threading to fit the bike.
        We’ll see what they come up with, I’d like to support them, but if it comes down to it I’ll order the Tacx adapter online.

        • I’d say get your axle the same way you got your trainer. Putting it on the LBS to spend time researching something for which there is already a solution then asking them to order something else which may or may not work probably isn’t helping them all that much…

    • Bushman, you can use one of the Traxles with RAT equipped bikes. You will need to remove the RAT insert from the frame, it is held in place by a small screw. Since there are no threads in the frame it doesn’t really matter which Traxle you use. You will need to use one of the spacers that come with the Traxle on the drive side to replace the RAT insert. I have not seen one of the new Cervelo frames yet, but it is probably a similar setup.

      We have actually worked with a couple CX teams that were sponsored by Focus, that is how they did it.

  2. I actually worked with a customer today and taught him how to do this very thing. Please stop throwing local shops under the bus and saying it’s embarrassing to ask us questions. That’s what we’re here for. You should know that Zach. If you go into a shop, or call, and someone makes you feel stupid. Find another shop. There are plenty of good ones with good people who just want to help others enjoy cycling. The AASQ articles have been pretty offensive to me as a person who works at a local shop that works very hard to treat every customer right with no pretentious attitude. I have answered almost every question that you have posted in this series at one point or another for customers within just the last year. There are no stupid questions, just elitist jerks. Sorry for ranting.

    • Hey Kris, to be clear I’ve never really been a fan of the series name. I would prefer it to be called ‘ask us anything’ or something along those lines. But we’re also not calling out shops, just providing a forum for folks to send us questions they may be wondering about. Sorry if the way it’s worded bugs you. I DO know what it’s like to work in a shop and do my best to provide an unintimidating atmosphere so that customers are completely at ease to ask any question they would like. Keep up the good work.

    • This is an excellent point. Why is it embarrassing to ask a shop this question? Perpetuating that mindset is unfortunate and your own personal problem. This isn’t the forum to discuss, diagnose or help with psycolgical conditions.

      The elitist attitude in shops swings both ways and is often originated from the consumers feeling of inadequacy. Yes, many shops just plain suck but there are also plenty who always go the extra mile for their customers. Please don’t pigeon hole every shop employee as being an elitist jerk. Especially when it’s your own personal issue of being embarrassed to begin with.

      • Nothing demonstrates professionalism like throwing the customer under the bus, especially when it’s done using amateur psychology.

  3. Be careful what bikes you are putting in trainers. Specialized stated that they will void the warranty of carbon bikes on trainers and this includes thru-axle equipped bikes.

  4. Make sure you do the proper research on the size of your thru-axle (if you’re reading this page with any level of interest that means you might not know the ins and outs of your thru-axle / including length).

    I learned the HARD way when I bought a CycleOps hammer and found out my Specialized had a silly thru-axle length and it would NOT fit on any direct drive trainer.

    100% ask a shop all these questions before you buy anything!

  5. Don’t put your good bike on a trainer. Trainers destroy bikes. Keep your old bike for trainer use.

    On another subject…thanks alot Bikerumor for running those awesome Erectile Dysfunction ads on your site. How low will you go to make a buck?

  6. I just purchased the kinetic rock n roll and I have a specialized divergent that I can’t use with it. Can you recommend an inexpensive bike to use?

  7. I have a Tacx Bushido trainer and bought but it looks like I simply don’t have enough clearance to fit the bike. Please advise what I can do?

  8. Hello,

    Does anyone know which Thru Axle should be used on a Minoura MAG 850 bike trainer for a Norco Kokanee Bike?

    Thank you!

  9. does anyone have contact info for the FDW magnetic trainer (model FDW-M8-J)? I’m trying to buy it as a gift for a friend (yes I know it’s one of the cheaper ones but reviews seem good and i’m on a budget). Anyway trying to find out if her bike with a thru axle will work with it and if they offer an adapter espeically after reading some of this? I don’t want to get something that will be useless and have to try to resell it (buying from someone who has and never unboxed it). Her rear tire is 142 x 12mm with a thru axle and she has disc brakes. she is new to riding btw…

  10. Any chance someone has produced a list of trainers that will accept a long axel. This information is rarely given in the spec list. I need to be able to fit one that is close to 8in.

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