Mine used to do this but I tried two modifications(this assumes you have stndard brakes).The first was to remove about a third of the rear brake pad area, this stopped the back locking up before the front, unfortunately it does so by reducing rear braking effort, far better to increase front braking effort. This is expensive and means either a big brake kit from Caterham or Alcon calipers from James Whiting. The second remedy was new tyres - Yoko 32R's, 185 on the front and 205 on the back on standard 13 inch wheels. Less oversteer, more traction out of corners, a more compliant ride and better rear arch filling aesthetics. Must be why some racers use this set up.