Hi Wasim no i haven't had any success yet but i can still certainly say that the welcab chair we have is totally brilliant but the wheels are a bit soft and if you have anyone bigger than a small adult or child it makes the chair quite hard to push but apart from that its a fantastic system,not sure if you could change the seat but i can recomend buying the factory fitted job,i have heard of replacement hard wheels but just don't know how to source them or indeed where from.