2015 Specialized Diverge Comp Smartweld won’t fit the Zwift Hub

I just got my Zwift Hub and setting it up I notice my bike is not compatible with it and maybe not any direct drive trainer.
My bike is a 2015 Specialized Diverge Comp Smartweld with a QR rear wheel. The spacing is 135mm. What I have realized is the derailleur hanger on the bike is a little unique (pics included). The hanger has a bend or shift in it which makes the spacing on the drive side wrong. My bike has 5 mm of space from the cassette cap to the hub flange where as the Zwift Hub only has 2mm from the cassette cap to the flange.
When I install my bike in the smallest cog on the trainer the chain is rubbing the derailleur hanger and when you rotate the pedals it shifts over to the next cog. It is essentially shifted over one gear.
I am not sure if anyone else has tried a Diverge on the Zwift Hub or other direct drive trainer and was able to make it work. If I knew some one with a machine shop I could have them make me a new drive side adapter that is 3mm longer.

Also, anybody had any luck putting a mountain bike on the Zwift Hub? I have a 2022 YT IZZO that has a SRAM X01 12 speed drive train. I know I would need a XD hub to make it work. Just wondering if using a mountain bike on Zwift is worthwhile?


Mark Gauding

The 3 pics are, derailleur hanger, second bike on the trainer, third normal bike with wheel installed.

Is there a spacer under the cassette? If so I would try using a smaller one, or none.

With mountain bikes, it depends on the gearing. Looking at the YT Izzo on their website, I would guess that the high gear is too low to work well with Zwift, unless your power output is quite low. If the bike supports using a larger front chainring that would help. Availability of the XD freehub seems to be poor.

Thanks Paul.

I checked for a spacer but there was not one being used.

Also thanks for the info about the mountain bike. May just have to return the Zwift Hub.


Does the Hub come with any spacers? Even sticking a washer between the dropout and the cassette might get you the space you need.

Before returning it I would ask a Specialized dealer about the problem, preferably by showing them the bike on the trainer. They may already know the answer.


I was thinking about that. Not sure if it would leave a whole lot for the dropout to sit on.



I was thinking the same thing. Was going to go to my local shop where I bought the bike and see if they can help. They are a Specialized dealer.


Is that a cup and cone bearing in that hub, or a cartridge? If it’s a cartridge, maybe a spacer underneath the cap? I’d have to get my hands on it to be more helpful I think :slight_smile:


Here is what is included with the Hub trainer. This is the drive side adapter for QR.


What does that thread onto? (good pics though, that is definitely helping)


This is what it threads onto to hold the hub on the Zwift Hub.


That could be where you could get your ~2mm from. A spacer down in the freehub. There’s a reasonable amount of threads in there, might be that the adaptor could still be threaded on well enough if a spacer of some kind kept it from threading in all the way.

Letting your LBS look at it is still the best way to go, but that might be at least one place to have them look.

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Thanks! I will have to see if I can find a washer that is close that I could modify to fit in there.

Will get to the LBS on Tuesday since they are closed on Monday.:grin:


No problem :slight_smile: It may not work at all of course, lol. The risk is that the adaptor has to be threaded in enough to, you know, keep the bike from falling apart :smiley: But the shop might have other solutions too–might be that a different hanger could work. Good luck!

I have the same issue as OP. I’m using a BH Ultralight (not sure if the frame is 2012 or 2016) on a Wahoo Kickr. The BH dropout is offset inward just like OP. Works fine with the rear wheel on, but the dropout rubs against the chain when on the trainer and in smallest cog. First thing I did was to grind a couple mm of the inside of the dropout. This worked, but is sort of a hack. I got a new dropout and currently have a 1/2" washer on the QR holder/guide/flange, which bumps the dropout outward just enough to clear the chain. It does reduce the surface for the dropout to sit, but it feels stable and is held in place by the skewer.

Thanks Mike!

I may try the washer fix. Also thinking of going to a local machine shop and see if they make a new drive side adapter that is 3 mm longer.


You were grinding down the dropout, or the derailleur hanger?

See your Specialized dealer. They made an optional replacement hanger that was the normal shape - the one fitted depended on which hub was being used, Specializeds own (SCS) or anyone else’s.

Of course, that would make it more difficult to swap between trainer and wheel but if it’s a dedicated trainer bike or you’re going to be leaving it attached for a whole Winter, that might not be an issue.



Thank you for that information! I will be going to my LBS who are a Specialized dealer. Hope they have have that hanger or can order it for me.


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Sorry - meant to say hanger. It’s aluminum and grinds easily. Could grind, sand, and paint and it’d be fine.

The washer seems ok too. I’d show photos but I’m traveling until Saturday.