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NEO2T: spacers and extended thru-axle

Otto-Destruct
over 3 years ago

I'd originally posted this as a question about acceptable thru-axle thread engagement when spacers had been installed on a NEO2T.

Instead, I've since found a solution to the stock axle that came with my bike being too short. Details as follows:

I ran into a few issues that other people had in past, and one nobody seemed to talk about. The first two:

  • rear disc brake unit contacted the lower part of the NEO2T body - this is solved by adding a 2.7mm spacer sleeve to the non-drive-side (NDS) axle adaptor

  • rear derailleur contacted the trainer body while shifted into the lowest gear (largest cog) - this is solved by removing the freehub, the drive-side (DS) axle adaptor, and a small sleeve behind it, and installing both 1.0mm and 0.5mm spacers behind the sleeve before reinstalling the above parts & assemblies

Fixing the above introduces a new problem:

  • the Bontrager thru-axle included with the Domane AL 5 isn't quite long enough to engage fully with the threads on the drive-side drop-out as the effective width is now greater.

Easy solution: install Tacx part T1708, "Trainer Axle for E-Thru, M12 x 1.75" with two of the three included spacers - thick for NDS, thin on DS - using only gentle torque to tighten in place.

Linked album has the whole process and end result: https://imgur.com/gallery/kTYCFdo

  • +1 over 3 years ago

    Bumping this as I updated the original post and added an album detailing the issues. TL;DR: if using spacers on a Tacx NEO to allow for bike component clearance (disc brakes, rear derailleur), you may find your bicycle's stock thru-axle too short. (wider rear dropout spacing)

    Tacx makes several Thru-axles with extended threading that work great. Be sure to match the thread type to your bike. For a Trek Domane AL 5, I'm using the Tacx part T1708 E-Thru-axle skewer (M12x1.75 coarse thread).

  • 0 over 2 years ago

    Hi - Did the small sleeve come out easily or did you have to work on it... mine is completely fixed in place and i've no idea how to get it out with any damage being incurred... ?

  • 0 over 2 years ago in reply to 1937723

    If I recall correctly, I used an o-ring pick with a very fine point to pry it out - might even need two.

    In retrospect, I’d suggest wiping the sleeve with degreaser and gripping with dry nitrile gloves to remove. (re-grease before reinstalling)

    EDIT - the sleeve develops a lot of “stiction” with grease on it but it’s likely not really stuck. You need to get a good grip on it which is tough when it’s got lubricant on the outer surface

  • 0 over 2 years ago in reply to Otto-Destruct

    Hi Otto, thanks for the detailed explanation on the album you posted. I'm using the 2.7mm NDS spacer sleeve for disc brake calipers, along with the DS cassette body spacers to allow for derailleur clearance to the Neo 2T plastic body.

    Unfortunately even with the 2.7mm NDS spacer, there isn't enough clearance for the brake caliper. Specifically the hose and hose fitting (which are mounted on the inboard side of the caliper) smash against the Tacx Neo 2T body. I don't feel comfortable riding that way, and I'm wondering if you can think of a solution. I need probably another 1mm to 2mm of clearance on the NDS for the brake caliper hose and hose fitting.

    One thing I thought of is, maybe I can order the E-Thru trainer axle kit and replace the 2.7mm NDS spacer sleeve with one of the two, 4mm spacers that comes with the E-Thru kit. That would give me 1.3mm more space for the brake caliper, which might be enough. I need the E-Thru kit anyway as the standard axle shipped with the bike isn't long enough.

    Potential problems are 1) this still might not be enough clearance, 2) I don't know if the 4mm E-Thru spacer will fit over the standard TACX 12x142mm NDS threaded end cap, 3) there might not be enough threads left for that end cap to engage securely (ideally there would be another TACX end cap I could buy that has more threads), and 4) I don't know if the rear dropouts will spread this much. I do have a titanium frame so it should be less susceptible to damage from spreading the dropouts, and the frame fits easily with all the spacers I'm already using, but still...

    If you are still on the forum please let me know what you think and thanks!

  • 0 over 2 years ago in reply to northkg
    northkg said:
    3) there might not be enough threads left for that end cap to engage securely

    There almost certainly WILL be enough threading on the end nut: I had to use spacers to keep it from going on too far. It's likely irrelevant though: if the e-thru axle adaptor were THAT short, it would engage with the threading on the frame. (and you wouldn't need the end cap)

    FWIW: my Domane AL frame had a TONNE of extra room to be "spaced out" - in fact, with all the spacers I installed, it wasn't even being "stretched" - it just dropped in place and the axle and nut compressed it. 

    I didn't see if you mentioned: what bicycle are you trying to mount? My advice was specifically on a Trek Domane AL (2021/2022). Different frame geometry will introduce new variables.

  • 0 over 2 years ago in reply to Otto-Destruct

    Thanks @Ottto, I have a Lynskey GR270. I asked Garmin about it and they told me not to use any additional spacers, and that I should remove the disc brake caliper every time I ride the bike indoors. Adding more spacers would force the rear triangle outwards, which I don't feel comfortable with. And it would take too long to re-install and adjust the rear caliper every time I want to ride the bike outdoors.

    At this point I think I am going to cut my losses, sell the Neo 2T, and buy a Wahoo unit instead. It's a shame, such a bad design flaw on the Tacx which is otherwise an overall good trainer. The disc brake caliper interference has been a known problem for years and it's hard to understand why Garmin hasn't addressed it. I even told Garmin I would have gladly spent $150 on a new plastic left side case part if they had one (that has more disc brake clearance). But they ignored me and didn't even respond. So yeah, voting with my dollars and won't be buying any more Garmin products any time soon. Anyway, thanks again for your help.

  • 0 over 1 year ago

    Can anyone comment that has been using a carbon frame, disk brake bike with a Neo 2T long term, with these spacers?  I'm very interested in the Neo, but this spacer fix seems like a very freshman effort to me.  I wish they would reengineer the NDS cover and/or the internals to clear brake calipers.  My engineer's mind is very concerned about the amount of bending that will be put into the seat stays when you tighten down the thru axle and draw that surface up flat to the Neo's OLD dimension of 144.7 mm (142 + 2.7 spacer).

  • 0 over 1 year ago in reply to Windscreen

    no problem at all, trek speed concept (2nd gen) and trek madone disc