Keywords: cyclops thru axle,indoor bike trainer,wahoo thru axle

Indoor trainers & thru axles

Gerard Vroomen - 26-Jan-2017
We get a lot of questions about if/how OPEN bikes can be used on an indoor trainer. And our answer was always as simple as it was unsatisfying: "We have no idea, we never ride indoors, we ride outside regardless of the weather." 

But I understand that for some of you, this is important, so I asked our good friend Jeff Frehner, an OPEN rider and president of Powertap/Cyclops, for his expert opinion on the matter.

His top recommendation would be the Cyclops Hammer. This is a trainer where you remove the rear wheel, and it is compatible with thru-axles both 142 and 148mm wide (so for the U.P. and ONE+ respectively). This is how it looks, you can see the cassette body where you would install your cassette of choice, and then you install the bike with this trainer as the "rear wheel" (the setup shown is for QR frames but it works for thru-axle too):

Of course this is the top of the range, if you own or want to buy a less expensive Cyclops, then you can use the thru-axle adapter on it. This converter is also suitable for 142 and 148mm thru axles and looks like this:

And in combination with a trainer and an OPEN U.P. it goes together very easily and looks like this (thanks to Jeff for taking this photo in the Cyclops warehouse):

As you can see, the frame easily clears the trainer and the thru-axle fits in the trainer rock solid.

But wait, there's more. For some reason OPEN has become the bike of choice for industry insiders, and so we have not one but two executives at Wahoo Fitness who are great friends of the company. Mike Stashak and Ingo Urban recommend the KICKR, also a direct-drive trainer where you take off your rear wheel. Here is what it would look like all set up:

It's got nice features like Zwift integration (they recommend a 2.1" tire for any Zwift workouts). You just need to get the thru-axle adapter (142mm only, so for the U.P. but not the ONE+ at this point though I would assume 148mm can't be far off - my unverified thought completely).

I hope this is helpful to you, if you have any more questions I can try to answer them but remember, this is a topic Andy and I know little about!

Comments & Questions

Thanks guys for this post! I think in general Open riders agree with your approach of always riding outdoor. But one upside of using the UP (or One+) also for indoor training, is that we get to use and know even more our best machines :)
BTW I use Tacx and I found a way with some adaptors as well. Maybe it takes a bit of trial and error, but not too bad at the end.
Post #1 of 22. Posted by stef on 26-Jan-2017 17:23:52 GMT in reply to blog [0<--1418]
I'm facing a similar situation. I use a Tacx Vortex Smart Trainer can you give a bit more detailed description how you solved the issue. Maybe it’s less try and error for me ;-). Thanks a lot
Post #10 of 22. Posted by Holger Weißen on 06-Dec-2018 08:29:56 GMT in reply to post #1 [1418<--16119]
I got the Tacx thru-axle adaptor (12mm) and used that on the not driver side, but then found in a shop another 12mm bolt, shorter, to screw in on the driver side (or course, removing first both the original UP components from the rear wheel).
However, I ended up selling that trainer now, and got one where you remove the wheel - not as cheap but better ;)
Post #11 of 22. Posted by Stef on 06-Dec-2018 09:19:26 GMT in reply to post #10 [16119<--16120]
Thanks for your quick reply.

I will go for the “Tacx T1711 Trainer-Achse M12x1,00 für E-Thru” and look were I will end up.
Post #12 of 22. Posted by Holger Weißen on 06-Dec-2018 10:05:13 GMT in reply to post #11 [16120<--16125]
Also good for bike fits. I don't ride indoors, but I couldn't get the bike fitted with a TA
Post #2 of 22. Posted by IC on 26-Jan-2017 19:15:17 GMT in reply to blog [0<--1419]
Do you know how strange it is seeing a U.P. on an indoor trainer (for me anyway) The very reason I purchased this bike and built mine the way I did was so I could ride it in all conditions. I'm assuming at this point the above pic is from the guys from Lauf in Iceland and not someone ANYWHERE else ;-)
Post #3 of 22. Posted by KP on 26-Jan-2017 21:50:00 GMT in reply to blog [0<--1421]
Never put favorite bikes in trainer except for a race warm up or fitting. Always keep good bikes ready to roll. Don't burn your good tires on the trainer. Buy old used junk frame, fit it to your geometry with old/used parts, put it trainer. Leave it there. If you must use your good bike, use rollers, not trainer.
Post #4 of 22. Posted by bsmith on 26-Jan-2017 22:33:33 GMT in reply to blog [0<--1422]
Will you still honor warranty if rear seat stays break? Many vendors won't due to excess stress on rigid trainer.
Post #5 of 22. Posted by Patrick on 27-Jan-2017 08:46:13 GMT in reply to blog [0<--1424]
Our seat stays are designed to withstand that use, so no problem. Seat stay failures I have seen are more of the "cyclist meets tree" variety.
Post #7 of 22. Posted by Gerard Vroomen on 31-Jan-2017 09:54:08 GMT in reply to post #5 [1424<--1432]
So the president of cyclops recommends a cyclops trainer..... fascinating!
Post #6 of 22. Posted by Matt on 27-Jan-2017 09:51:13 GMT in reply to blog [0<--1425]
And the people from Wahoo a Wahoo trainer. The point is not that they do, but which ones.

As I was trying to explain, we get many questions from people if there is any trainer that will work with our frames and if so, how to best set it up. Since this issue involves a combination of trainer shape and frame dropout shape, it's not as straight-forward as finding a trainer that is thru-axle specific as it may still not fit a particular frame. Hence the people from Cyclops and Wahoo were kind enough to check their trainers with an actual OPEN frame, the only way to figure this out.

If other trainer companies (or any OPEN consumers who happen to own them) check their trainers with our bikes, we will gladly add them to the list. But I can tell you for sure that I'm not going to buy 10 trainers to figure out which fits, when I think riding on a trainer should be a valid defence when pleading insanity in court.
Post #8 of 22. Posted by Gerard Vroomen on 31-Jan-2017 09:59:49 GMT in reply to post #6 [1425<--1433]
Post #9 of 22. Posted by Matt on 31-Jan-2017 10:41:33 GMT in reply to post #8 [1433<--1437]
Hello guys, looking to buy a simple trainer for my open U.P frame like the cycle ops on the third picture. If i'm not mistaken you do not mention the reference for this one?
thanks for the tip
Post #13 of 22. Posted by Bass on 14-Dec-2018 17:23:51 GMT in reply to blog [0<--16137]
I have a trainer Élite Direto and a Open UP Classic
I need of an adapter for the Rear axle ?
Post #14 of 22. Posted by Campisi Francesco on 01-Feb-2019 01:57:35 GMT in reply to blog [0<--18212]
This is an ancient post, but commenting here in the hopes someone interested in the same thing sees it. I am looking for the best thru axle to use for my UP on an old Kurt Kinetic while leaving it easy to keep riding outdoors. I want to be able to squeeze in the occasional indoor session while not overly weighing down the bike or dealing with a poorly made axle. I came across the Robert Axle Project ( Their axle finder includes Open as a manufacturer with UP and WIDE listed as options. Any feedback on these or better recommendations?
Post #15 of 22. Posted by Jason on 21-Nov-2020 08:16:46 GMT in reply to blog [0<--22761]
I know several customers who use the Robert Axle Project axles for their trailers (so with an L, not an N) on the UP, and they seem happy with it. I don't have any direct feedback on their other products.
Post #16 of 22. Posted by Gerard Vroomen on 23-Nov-2020 05:00:43 GMT in reply to post #15 [22761<--22762]
Thank you for the reply! I am ordering the trainer axle from them to give it a shot. The part number that their "axle finder" gives for the UP is TRA213 "12mm Thru Axle for Trainer: 160 to 172mm with 1.0 Thread" and I'll post feedback here for anyone else that may be interested.
Post #17 of 22. Posted by Jason on 23-Nov-2020 12:41:01 GMT in reply to post #16 [22762<--22763]
Using axles like this means you will remove the proprietary female thru axle bit on the drive side of the frame. For years I have assumed this bit made the OPEN frame incompatible with "wheel on" trainers. Seems like the answer is to just remove that last screw that holds the derailleur hanger on. Mind blown. I also have a Kinetic. Kinetic makes a thru axle adaptor of various thread pitches although I have not been able to make them work. Will post if they are also viable options.
Post #18 of 22. Posted by jeff on 27-Nov-2020 10:30:36 GMT in reply to post #16 [22762<--22768]
OK, to post a follow-up, the TRA213 from the Robert Axel Project works well with some caveats and modifications. Yes, as per Jeff's comment, you have to take out the screw cap that holds the derailleur hanger to the frame, but then you use the drive side trainer axle cap that threads into inner threads of the thru axle to resecure the whole rear end of the bike. The instructions aren't really made for the OPEN so you have to figure out the taking out the screw cap yourself and you definitely shouldn't use the nylon washer, but none of that is too confusing. The first issue is that the RAP drive side trainer axle cap is 0.75" instead of 20mm in diameter like the OPEN screw cap. That is only a 1mm diameter difference, but it reduces the actual clamping area by about 20%. Further, the 20mm M6 bolt that they use to secure this cap has only about 5mm thread engagement in the axle. I bought a 30mm M6 bolt (I went with A2-86 instead of A2-70 to increase strength while keeping it in 18-8 stainless) and a 20mm stainless washer to upgrade the connection. I emailed back and forth with RAP about this and they seemed indifferent to my concerns saying that while they understood what I was saying, plenty of people were using it as they provide it without issue. I rode with it as is for a while and although I am happy to report no catastrophic failures for a month of occasional trainer use, I did notice some wear on the frame insert from the undersized drive side trainer cap. This convinced me to finally switch things up. The McMaster-Carr part numbers for my upgrade are 90035A126 and 94316A330 if anyone else wants to do the same. I'm happy with it at this point. I wish RAP had taken my concerns a bit more seriously, but I think they make a very good product otherwise.
Post #22 of 22. Posted by Jason on 12-Jan-2021 18:51:27 GMT in reply to post #16 [22762<--22842]
I have a Tacx Neo and trying to get my Open Up on the trainer for winter. Has anyone done this and if so can you tell me the correct thru axle / QR setup ? Many thanks in advance.
Post #19 of 22. Posted by Mark Curphey on 08-Dec-2020 21:57:17 GMT in reply to blog [0<--22784]
Hi Mark, if you look at the earlier comments on this post, you will find some people discussing the Tacx setup. Their trainer can interfere with the flat mount caliper (on any frame) but there are some spacers available.
Post #20 of 22. Posted by Gerard Vroomen on 09-Dec-2020 07:00:41 GMT in reply to post #19 [22784<--22785]
Hi! Just got a wahoo kickr and was wondering if the stock thru axle on my Open U.P. is ok to use on the kickr, or do you suggest using a separate thru axle on it?
Post #21 of 22. Posted by Ian on 28-Dec-2020 05:15:29 GMT in reply to blog [0<--22814]