A Visit to the Brompton Factory

Having enjoyed some success with our Bromptons as unlikely but effective tourers, Maggie and I took the opportunity to visit the Brompton factory.  Tours are run twice a week, and cost £25.  The tour lasts about two hours, and we both enjoyed it; we had both encountered small engineering factories of this type in our student days, and this must be one of the few still operating as a successful business in England.

The tour started with a visit to the museum, and it was gratifying to find that the third exhibit was identical with the Brompton that Maggie had ridden to the factory - I had bought it in 1991, and, despite the attentions of two generations of Gladwyns, it still goes well.

Raw materials and components entering the factory are steel tubes, castings, rims, spokes, tyres and build kits such as gears, saddles and handlebars.  Machining, brazing, painting, assembly and testing are carried out on site.  There is a pleasing mixture of manual craftsmanship, computerised machines and well-organised processes; rigorous testing is also carried out at the component, sub-assembly and finished machine levels.

Brazing the frame components is the foundation of the design; very high levels of accuracy are required and Brompton offers apprenticeships to brazers.  It takes about eighteen months for a skilled brazer to become fully proficient at producing the complex bottom bracket and main tube structure.

Automated brazing machines are used for less demanding elements of the frame structure, such as the handlebar stem and the pivot clamps, which are machined from castings on site.

Wheels are made using bought-in rims and spokes on a substantially automated machine.  There is some manual intervention, but the truing and testing are computerised.  It gives a very strong wheel.

Painting is done on-site, there are no photographs of this due to the risk of triggering the fire system, but the process is modern with the same mix of computerised automation and manual finishing for the difficult nooks and crannies.  Finished components are then brought together at the assembly line.  This was running with 14 stations for the model being built when I was there, other models may require additional steps.  A single set of actions is carried out at each build station, with the finished sub-assembly being moved on its trolley to the next station when complete.  Cycle time yesterday was 3.5 minutes - viz. a complete bike every 3.5 minutes; as you will see from the counter at the end of the line, the builders were ahead of target.  There are two lines; the factory has space for four.  49,000 bikes were built and sold last year - every one is to prior order.  80% of sales go for export.  A passing remark by our tour guide was that China has 23 cities with more than ten million inhabitants; Brompton currently has dealerships in two of them.  So there is considerable opportunity for growth there, and in other growing economies around the world.

The star of the show is the electric Brompton.  I rode one, and it goes well, but I don't think it has a place in my world - not yet, anyway!

A very enjoyable and interesting afternoon, and I thought that Brompton were generous with their time and access.  I'd recommend it, if this sort of thing interests you - there are not many other places in Britain where you can see bicycles being made.  Brompton is in Greenford, just by the Grand Union Canal, so a very congenial cycle ride from London.  

Mark