I can't imagine why the kickr, or any trainer, would cause your hanger to bend.
That said, if your shop has physically re-aligned your hanger several times, that has probably weakened to the point where just basic shifting, on or off the trainer, might be pulling it out of alignment?

If your rear derailleur cage is straight, then I would def. just start with their first suggestion, get the high quality wheelsmfg replacement hanger.
If your rear derailleur cage is also bent, then go with both of their suggestions.

I agree, unless you are banging the bike against the trainer mounting it, I don't see how it could happen.

Hangers do wear out and need replacement.


Are you saying your shifting is fine on the wheel, but off when on the trainer? Have you adjusted your derailleur to the trainer specifically once mounted? One of my bikes is always out of sorts on the trainer and requires a good bit of adjusting.

Another possibility it that you are having an issue with your quick release (or more unlikely an improperly aligned cassette) on either the Kickr your road wheels.

If your QR doesn't stay locked in place the shifting alignment will be out of sorts and something has to give. When the derailleur is under tension and your QR isn't tight the system will place tension on the hanger and it can bend it. I have found that the heavy duty QRs that come with trainers aren't always the most secure and there is amble room for user error if you are consistently putting a bike on and off the trainer. To make matters worse you get brake rub when things start coming loose on the road which lets you fix things before any real damage begins but you won't get this on a Kickr.

A cassette that isn't spaced correctly or is a bit loose can also mess with drive train alignment.

The LBS has provided good suggestions but they will likely address the symptoms rather than source of the problem.

Different cluster on the trainer, chain to short.

I agree this is something to look at. If your LBS has only seen the bike and not the Kickr they won't know the context to the problem.

Derialleur hanger bolts on my Propel have a tendency to loosen. Replacing wheel after a race I found that the hanger was only held on by the wheel skewer. I got new bolts and used plenty of blue loctite. No problem since. Worth checking.

oooh I like this idea--what clusters are on both?

Both are Ultegra 11-28. I could never get the stock Kickr casette to work well. If anything the chain is too long right now.

The kicker mounts the cluster in a slightly different position to most hubs.
Generally on a manually shifting system it will be 2 to 4 clicks out on your rear derailleur adjustment.
When you tune your di2 system to run properly, first gear is now past the mechanical end stop and as the shift cannot be completed the system drops it back into second gear to stop battery drain or damage.
The bike shop only ever sees your regular rear wheel and tunes it to that.
99% of hangers are out of alignment when they are bought into a shop and this is the only thing the shop can find wrong as you have not conveyed all information to them.

The answer is to not use first gear on the trainer or to back out the end stop enough to allow it to complete the shift and run correctly on the trainer knowing that if you do tweak the hanger a little bit on the road one day that you are just a little bit closer to having a bad day and tearing off the hanger and derailleur in the back wheel spokes.

I’m not sure what information I’ve withheld from them. I could care less how well the bike shifts on the Kickr since I’m only doing ERG. This issue is that the shop is tuning to the road and then after riding on the Kickr the road alignment is screwed up again. I’ve given up on trying to get the Kickr to shift perfectly as it isn’t worth the time.

I have had this same issue with my Gen 1 Kickr & my Ultegra 6770 di2 derailleur...
what I found was that it was bending the derailleur hanger ever so slightely. So i made the switch and swapped out for an oversized pulley hanger and jockey wheels from Premier and just don't shift on the Kickr anymore (i use erg 99% of the time anyways)

It appears to me that is is due to the frame on the bottom side of the Kickr - which future versions (Kickr core) seem to have eliminated.

Check that the kicker has been set up with the correct axle parts, I have seen a couple with a wrong mixture or spacers/ adaptors that lead to the bike being simply clamped in and not actually have any axle sticking out for the dropout to rest on on the drive side.
You need the adaptor set on r130 for a standard rear end.
If this does not make sense to you, then read the instructions or let the shop sort it.
But they cannot diagnose the problem if you do not take your kicker to the shop with your bike and get it sorted out.

Hangers are generally made of aluminum so they bend and break before the carbon of the dropout is damaged. Structurally the hanger is barely up to the task of securely positioning the derailleur on a good day. As soon as a shop straightens your hanger it becomes so weak that it flexes and easily bends. Every additional time they straighten it it just gets worse. I got a titanium hanger for my Litespeed and the bike shifted like a champ from that day forward. I would suggest just getting a new one.

All new bikes should come with at least one spare hanger, but since they don't you should just plan on replacing them when the shifting performance stats to go south.