After the above with a cable not cordless.
Won’t be using it that much so don’t want to be buying batteries all the time.
Needs to be rear wheel for use on the turbo trainer.
Do they exist?

Yes, they do. Some come with a rear sensor in the box, some you need to get a rear wheel sensor as an extra.

Try Sigma or Cateye

Cateye Mity 3 with a long lead. They do exist. Batteries seem to last forever on them.

Cateye strada is what your after they do one that is for the rear wheel, I use it on my turbo bike.

Cateye Strada Cadence will do the job.

Yep, I had the Strada Cadence. Good piece of kit too. Until the wire got caught in the crank 🙁

Stupid question of the night – why can you not use a wired front wheel speedo on the back wheel?

Stupid question of the night – why can you not use a wired front wheel speedo on the back wheel?

I dare say you could. If you mount the computer on your seat or something! Otherwise I reckon it’s unlikely to reach.

Or just extend the wire. It won’t show much if you extend from as close to the computer as possible and re attach by the seat post. It’s only 2 very thin wires.

Got cat eye Strada on my turbo, perfect

Sigma does a rear wheel mount for theirs.