As I was ploughing through the literature/websites dealing with these kind of bikes, I found it hard, not say impossible, to see how people where building up their front & rear wheels. At least it was very difficult for me out here , without physical access to any hardware to see how I could make such off-the-shelf components come together to complete wheel assemblies, fitting the front and rear forks with brake discs and drive sprocket and the whole nine yards. And on top of this my natural aversion against wire spoked wheels. Aversion because I, in spite of my engineering background, never had understood the mechanics of such things. Wire spoke wheels are just too inexact for my taste, but again this is because I don’t understand them and not because there is something wrong with them. Just like wood. I don’t like to work with wood because wood changes dimensions with e.g. humidity, wood cracks and so on.

I like solid metal, be it steel, aluminium or titanium or bronze. These materials you can drill and mill and turn and grind into various shapes, dimensions and tolerances and there they stay, no matter the temperature or humidity or whatever. Within limits.

As I was despairing about the wheel situation I remembered that there used to exist Italian cast wheels called Campagnolo. Just a little bit of Googling brought me to the website of the company MARVIC, where they showed that they were making just what I was looking for: Front and Rear wheels cast in a magnesium alloy. I sent them an email and got a prompt reply, in perfect English, saying that they thought they could help me. They emailed me a set of drawings showing the outline of the hubs and asked me to fill in the dimensions I wanted

The rear wheel was trickier. Here I had to consider more parameters: distance between the swinging arm legs, distance between drive chain and wheel centreline, rear tyre width and dimensions of the rear brake caliper. The tyre size was given since I had just chosen the same as the big guys were doing. The other given was the drive chain distance from the swinging arm centreline. When I drew this up I quickly realized that the chain would not only not clear the tyre sidewall but probably cut a hole through it as well. Clearly, if I was going to clear the chain from the tyre, the chain most move outwards but at the other end of the chain is the gearbox and the output sprocket which of course has to line up with the rear wheel sprocket. I spent a couple of sleepless nights trying to figure out a solution. Finally I decided to send an email to Kenny Cummings at New York City Norton to ask him how he deals with the problem. In a not too friendly reply he confirmed my calculations and said that his solution was to put 3 mm washers between the LH engine plate and the engine as well as the attachment brackets on the frame. Was I happy to hear that not only was I right but also that there was a solution? I emailed Bruce Vernon at TT Industries, the people that make my gearbox, and asked if he could move the drive sprocket 3 mm outwards in any way and he came back with an elegant solution. He will mill off 3 mm from the gearbox LH housing attachments and thereby the gearbox is moving 3 mm outwards and the problem should be solved.

Now I could fill in the dimensions for the rear wheel hub and send off to Marvic but then they came back and said they could not do it because of an interference issue between the rear sprocket shock absorber and the wheel sprockets. Again sleepless nights as I had already ordered the rear wheel brake disc and caliper and put all my eggs in the Marvic basket. Luckily they came back after a few days and said that they had found a solution so now the rear wheel issues were away from the desk. I just had to make a last minute design change after having woken up at night realizing that I would not be able to fit or remove the brake caliper without mounting/removing the brake disc at the same time. Marvic did the same change on their drawing so now we should be cool.

I have struggled from the first moment with selecting colour for the wheels. They will have to be painted or powder coated because the magnesium alloy needs protection from wind and weather. The original Campagnolo wheels were painted in a golden colour but Marvic makes them in black or grey or orange or whatever the customer likes. I can go by material and say that all components made from Magnesium should have the same colour and since the front fork sliders and yokes and gearbox housing are all magnesium and are coming in black I should also get the wheels black. Or I get them aluminium grey to match the brake disc carriers ? Maybe I will flip a coin………. Finally decided on aluminium/silver paint.

And here is the bonus. The Marvic company is located in a town in Northern Italy called Brunello. This is famous for its red wines like Brunello di Montepulciano: I am planning to personally pick up the wheels and then maybe a couple of cases of red…….


Both wheels are 18 inches in diameter and the tyre widths were chosen by just looking at what other people do: NYC Norton, Minnovation Racing and Gearhead Racing are good examples. Most of them seem to favour Dunlop tyres, because they will let you go faster than on any other brand. However, first of all I cannot imagine me going faster around bends than any tyre will allow, and secondly Dunlop has a rotten website from which I could get no engineering information.

On the other hand, AVON TYRES have a fantastic website www.avonmotorsport.com which gives you everything you need to know when doing what I am doing. Even the number of revolutions per kilometre which comes in handy when calculating which sprockets to us to attain certain top speeds – for example.

I will use a SM23 size 130/70VB18 on the rear wheel and a SM22 size 110/80VB18 up front.