Zumo and correct assembly of adaptors?

[U509193]

I've just got a brand new Elite Zumo trainer to replace my old and broken Evo, but I've got a question about the assembly of the adaptors....

I'm using quick release hubs and the spacing between the frame is 135mm and have a 9 speed shimano cassette, so following the instructions I've:

1. Used the two cassette spacers and assembled my cassette onto the trainer.
2. Installed the non drive side adaptor (that slots in the hole) and used the additional 5mm spacer on the same side.
3. Fitted the QR spindle.
4. Fitted the bike to the trainer.

So, that's all gone OK, but what was puzzling me was the drive side adaptor or lack of one. There is a flat cylinder face but it doesn't have the "hatched" surface you usually see for gripping against the frame, in fact it's smooth. Is this the way it's is supposed to be?

I've not got any other adaptors left for the QR set up, so I'm assuming it is.....

Drive side...

IMG_20231114_215211_(500_x_500_pixel).jpg (103.34 KiB) Viewed 6881 times

No drive side...

IMG_20231114_215304_(500_x_500_pixel).jpg (74.31 KiB) Viewed 6881 times

...it looks a little bit close on the drive side to the frame, haven't tried running it in the highest gear, but will do tomorrow to see if it's OK.

[U509193]

OK, so I decided to replace both cassettes (on my road wheel and on the zumo), they both needed replacing and a new chain at the same time can't hurt. After doing this and checking that all worked OK on the road wheels I put the bike back on the zumo and noticed something......
.....as soon as I started turn the peddles the chain dropped down from 9th gear to 8th,without touching the shifters. I think that the two spacers the manual says I should use is wrong:

IMG_20231116_202306_(500_x_500_pixel).jpg (62.31 KiB) Viewed 6872 times