I have spent a lot of hours over the last 2 years thinking about how I'm going to build the racer and have drawn it out in my CAD system. Everything was going according to plan with some new features in place not currently seen on other mowers out there racing. One of the big changes was going to be to the rear axle where I was going to have negative camber on the rear wheels. To achieve this it required quite a complex rear framework to be constructed but at the last minute I discovered that I had made a mistake on one of the crucial measurements which means that it won't work in the way I intended it to. So back to a 'conventional' rear axle, well not exactly as this one is going to be a 50mm hollow one.
Some other areas of change are the fact that there will not be a T drive, well not as we normally see them used. I am going to be using a centrifugal clutch as I was really impressed with the Bully one I used several years ago. This type of clutch has plates, like a motorcycle clutch, but uses centrifugal force to operate it. The problem I had with the Bully clutch was that it overheated to such an extent that the bearings seized up. Having researched this a lot more now and having been involved in a lot of communication with the designer of such clutches I realise that the problem is that in mower racing the engine speeds are up to a max, of 4000 rpm and that is the normal point of engagement for these clutches. they are, after all, designed for high performance karting where engines are running at up to 10 - 12000 rpm. So to achieve the desired revs, I will be gearing UP from the engine to the clutch then down from the clutch to final drive. This presents a challenge as I need to get the gearing just right. Fortunately I am using a primary belt drive to a layshaft and final chain drive to the axle. It may mean that I have to have a secondary layshaft to get the gearing right but I haven't yet decided on that.
Another novel feature will be front brakes! More on this later.
