As usual much thought has been churning away in quiet moments such as when driving to work. I have a challenge in that originally the spare wheel used to be carried within the boot lid on the Riley Falcon. Problem is I no longer have a boot lid (or even a boot) so there is nothing on the car that has fitments to locate the spare wheel – to make matters harder I want TWO spare wheels fitted onto a single mount. Nothing like giving myself a challenge is there.
In the photos above you can see where I want the wheel to be, you can also see that the center of the wheel is above the chassis rail making my life even harder. I had the basic design in my head for fabricating a bracket, now was the time to move that virtual design onto paper then wood then eventually into metal.
My sketches turned out to be designed around supporting the wheel at the wrong height, although the basic idea was sound: two thick metal plates projecting out from the chassis cross tube plus a flat mounting plate welded between the two projection plates which I would shape to match the splined hub carrier. Weld everything to the chassis, bolt on the hub carrier, slide on the wheel(s) – Easy.
But what shape to make the projection plates… A number of new sketches were created, the better looking ones then traced onto low density fibre board (because its seriously easy to cut and shape). Eventually I would settle on the smaller one, middle left in the photo.
The shape in the photo below was trimmed down a few times…
until i settled on this… the finished mock-up… which i could use to trace onto sheet steel and weld up. Technically you could make the whole thing out of one piece of steel which was bent into the same shape. But that calls for VERY accurate bending of very thick metal and I dont think my skill set is up to that standard.
The wheels weigh quite a lot, the weight will also be hanging outboard from the chassis tube so logically the welds on bracket will be stressed by the weight of the wheels and gravity will want to rotate the whole bracket around the chassis rail. The welds will of course not allow it to rotate but they will be under stress and that makes me a little nervous. I am considering fitting a steel tie strap to the top of the bracket that then runs down the back of the chassis tube, under the bottom where it is then bolted onto the tube. That would mean the rotational stress is transferred to that steel strap rather than the welds. This may well be a Victorian engineering principle – i.e. overkill, but i hate the thought of the wheels coming off and dropping into the path of cars following behind me – so better safe than sorry.
The hub carrier will be bolted onto that plate then the wheel slides onto the carrier.
I wont fabricate these in steel just yet as I want the wheel to be fairly close to the body work so I need to wait until my coach-builder has weaved his magic and crafted all the bodywork for me. Funny thing is, once the wheel is fitted you will never see this mounting bracket – so this is a lot of thought and design work for something invisible to the casual eye. In the motoring industry this is where all their development money goes but I only have the one chance.
Next job getting all the switches to work in the center of the steering wheel… there is a lever to advance-retard the ignition, an indicator switch, horn button and a light switch going from off-side-dip-main. This involves a lot of levers,rotating bars, a complex brass tumbler and eventually wiring. I have no idea how ANY of this works or how it comes apart…