[T17]

I queried the chassis spur hole with Schumacher and got this response from none other than Tom Cockerill himself in respect of the Cat K1 Aero:

The Spur gear does have a hole in the chassis beneath it. However, I’ve never seen this allow any damage to occur to the spur gear. On the flip side of the hole, it can also be said to allow debris out that would otherwise have got stuck between the gear and chassis. The reality of it is spur gears are normally only damaged from 1 of 2 things, the motor moving or sand grains getting in the teeth of the spur gear. No matter how well sealed a spur gear is, sand will always find a way in, as it happens on 2wd’s which a fully enclosed gear cover!