These wheel's are too small & too many teeth (36t against 33t). Also, the teeth on the ones on Aliexpress are a straight cut. Whereas the ones on the Carrera's are slightly angled. I'm on with some lads who are trying to see if they can 3D print me some off. These "should" work "if", the bearing in the middle is press fitted & the wheel is not moulded round it. I can't see this being the thing. Ian @ On Yer' Bike! M'bro