Reviber mini exercise bike

[imfromwales]

Has anyone used one of these please? I have bad knee joints and was thinking of buying one
See photo

Ive thought about them a lot but I have a feeling that they'll either lift off the floor when you're trying to use it and also I think you wont really be in the right position to do themovement and it could cause damage to your knees

I tried a cheap one and couldnt get on with it. It kept moving about all over the place and it was difficult to find the right sitting height.
Now I have a recumbent exercise bike which is excellent, esp if you have dodgy knees!