The way it was explained to me was that the axles are so short in the front ,it puts too much leverage on the bearings and will wear them more than if the wheels are on like they are supposed to be. I have had the front end appart on one of these and the axle is only 3" or so long. It will make it very hard to turn also. I had one swapped for a while and it will rip the wheel out of your hand if you hit something while turning. It almost broke my hand.