There is quite a weight savings going with the Triumph Speedmaster 3 wheel conversion. Another reason I went with this donor was because it utilized a chain drive. The chain drive is simple to maintain and lighter weight vs the Goldwing type setups that I have played around with in the past. Utilizing a chain drive gives you the ability to adjust gear ratios at will. This strategy was used in the famous 376mpg Opel car back in the day =
376 MPG | The Story of the 1959 Opel P-1
I like the flexibility the chain drive affords in adjusting the gear ratio to suit my needs. Most cars are limited in there gearing range. This setup will help me dial in the best final drive ratio for the little two cylinder Kubota.
Going back to weight savings the Triumph Spitfire actually has pretty light weight components in the rear as far as traditional cars go. Also there are quite a bit of aluminum race parts available to lighten the load further. These aluminum parts are not cheap and the dollars really start to rack up fast as you begin transforming the rear end with all of these beautifully light weight components. I would have eventually transformed everything into aluminum and spent a fortune in the process. So the alternative to spending a small fortune on the Spitfire rear end was the 3 wheel option.
I figured I could actually cut more weight with the 3 wheel option and do it at a fraction of the price. The other reality is that the Speedmaster also offers aluminum components such as the rear swingarm at a fraction of the Spitfire alloy parts prices. Aluminum sprockets for the Speedmaster are widely available and aluminum fully adjustable shocks can be had for $200. You already have a really light weight dual piston brake caliper in the rear so no need to mess with that.
I have yet to determine how much weight savings will be had with the Speedmaster setup due to the fact there is still some key components to obtain but so far it is looking pretty substantial with the opportunity to further sweeten the pot with alloy parts in the future. Once I get all the parts on hand I will update this post with some pretty good weight comparisons.
GH
