Drive Train

 

The manufacture of the drivetrain was left to the end of the manufacture phase. After the entire frame was made and steering mechanism was set up the bicycle was ready for the installation of a drivetrain. This was done by making use of Bike Station’s offer of technical assistance, near the end of the project and taking the nearly complete bicycle there and fitting the majority of items with the specialised tools and personnel they had available free to us. Going to Bike Station also allowed the inexperienced team to get advice and any parts which had been neglected within procurement. This approach proved to be successful, to a great extent, however several problems were encountered. A major one being the limited time within their laboratory with this risk being limited by doing all the jobs that required the specialised tools such as the gearing system.

 

The initial drivetrain concern, was during frame construction when the bottom bracket shell, due to be punched into bottom bracket, was to small and a loose fit. However this was overcome by the use of a strong adhesive and this allowed the group to utilise the overhang of the shell in order to avoid the pedals hitting any of the seat stays. At this point, the crank arms and pedals were then professionally fitted and the rear wheel gearing system was then considered.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A further problem was established by this stage, due to the misalignment of the stays during welding and the low tolerances taken by the technicians. The result was that the stays were welded at the wrong angles. Practically, this meant that the rear wheel and chain ring were misaligned longitudinally and laterally, and that the chain could not pass between the two without rubbing over the right seat stay. This resulted in another change of design, as the group conceded to go for a single speed bicycle due a lack of space for any additional gears by the rear wheel, let alone a derailleur. This was combatted by mounting the nylon covered keeper from the neodymium magnets onto the seat tube at a calculated height. This keeper provided a slight pressure on the chain to keep it aligned with the chain ring, and enable the bicycle to function properly.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Brake levers had to be modified to fit over the ovular handlebars, and two side-pull calliper v-brakes were fitted to the front fork and rear brake mount using standard fittings. Inner brake cables were inserted into an outer casing and fed through the brake system and tightened accordingly, thus completing the drivetrain of the bicycle.