We recently moved Petes wheel onto the cage bars to give him more floor space all going really well he still used it as much as ever then I realised I hadn't heard him on it for 2 nights and neither had o/h we took it off and found he had worn the spindle down so much it caused it to have a slight tilt which wasn't so noticeable in situ but Pete obviously felt it, fortunately I'd got the one Pete has for his playpen Note to self : keep an eye on the spindles BTW its a Savic Rolly lasted 6 months from 1st May