This is the Trixie wheel - it's no cheaper than the Wodent Wheel really and the Wodent is the better made wheel - they last for a very long time.
It could be the wheel rubbing, as Nancy says - especially if it is running 'not true' - with a kind of scissors effect that might not be noticeable.
Amazon.com : Trixie Exercise wheel, plastic, ΓΈ 20 cm : Pet Supplies