Chain cassette noise Hello fellow cyclists,

I just bought a new Home Trainer that has a Shimano 105 Cassette.

My Bike has an Ultegra drivetrain with less than 600km (375mi).
I have checked the wear of the chain which seems clearly well off the .75

 

Yet I get a clicking/ratcheting sound. Video at slow speed almost no load (hand cranked):


                
            

Video at higher speed with bigger load:


                
            

What would you do ?

Thanks a lot !

EDIT:
With this view, the alignment seems right and an indexing problem less likely ?

Here

Also, it seems the noise comes from the chain/cassette separation on top:

Here
The most likely scenario is that the freehub/cassette on your trainer do not line up exactly the same as they do on your normal wheel, and you need to make small tweak to your indexing.

In your second video, it definitely sounds like it is trying to change gear.