Most people who build Astromechs have experimented with the front wheel system they use and I am no exception, however, I know think I have found the ultimate system. I have played around with two wheels, roller wheels, flat profile, elliptical profile, skate wheels and so on. The system I finally decided on was a single front wheel at 4" with a spring and damper system fitted to the back of the center foot to keep both the foot level and absorb shocks through the front wheel. The shock system has been working fine for some time now, what has been a minor problem is the rate at which the very soft center tyre has been wearing out. The soft rubber had to be formed into an elliptical shape to add fast turning, the flat profile wheels and tyres were rubbish and put to much strain on the main motors and center foot mountings, especially when run on rough surfaces.When I had two wheels fitted I used smaller in-line skate wheels which were great but had the problem of being to small. I had looked at 100mm scooter wheels in the past but most of them where made from tough plastic which would take be backwards in terms of ride and noise. What I recently came across on ebay was 100mm scooter wheels made from a really nice very, very hard wearing but soft 84a compound polyurethane. After testing these wheels on most surfaces they are idea and the best bit is that the profile is ideal allowing very fast turning even on very deep pile carpet. The only downside is these particular wheels were only available in bright pink but considering Emy is a girl, not so much of a problem and best of all they were only £3.00 each. Looks like my center foot problems are now solved..