Sunday, 24 November 2013

Rebuilding a Brompton Folding Bike

My 2000 vintage Brompton L5 had had a hard life in a boat locker and was already in a sorry state when the 5 speed Sturmey Archer finally gave up on a hill in the Isle of Man . A quick Google revealed that there was an 8 speed conversion available from Kinetic bikes in Glasgow so an order was placed and a general refurbishment undertaken.

Stripping down for stove enamelling proved to be a little challenging as the countersunk screws which secure the pivoting rear frame are Locktited in and had to be drilled out. The pin and bearings were in perfect condition so I tried to order replacement screws and spacer washers from a Brompton agent. This proved impossible as Brompton only supply a complete kit. I complained to Brompton who put me in touch with the head mechanic, however his information later proved to be incorrect, as the design of the spacer washers and possibly the pivot arrangement had changed and they appear to have no records of production amendments. Little did I know that this story was to repeat at every stage in the re-build.

I found an excellent stover in Burton on Trent, T Ward Ltd, who filled the corrosion and produced a superb result in rhubarb and custard colours. The finish was incidentally much better than my wife's recently purchased Brompton Superlight.

I reassembled the swinging frame first and added the current locking catch which prevents the bike folding when lifted plus a harder rear spring.

I needed a new headset and selected the lighter alloy version from the spares list. Again this did not fit as the spigot length was longer than the counterbore in the steering tube. Fortunately I was able to put the cup in the lathe and reduce the length to suit (but should you have to do this)?

I then moved on to the seat pin. This is retained by a plastic inset which I renewed as the old one had broken on removal (it is glued in place). The packet arrived containing two bushes, a common occurrence with Brompton spares, along with instructions for fitting. The resulting bore was significantly too small for the seat pin and required reaming to fit, which was not mentioned. Not everyone has access to a 1 1/4" reamer but fortunately I was able to borrow one and finished the job.

The kit from Kinetic proved excellent with an amended chain tensioner, smaller chain set, and comprehensive fitting instructions. All went well. This pic shows the Kinetic modification in the folded position.

This is the bike in running mode with the new smaller chain set to achieve the required gearing. There is a low 1st and high 8th with 6 closely spaced intermediates, about perfect for commuting and touring.

I moved the the handlebar group and found that the new brake cables not only did not fit the levers but there was an instruction that the levers must be replaced at a cost of £27. This is presumably owing to a design weakness but typically Brompton ask the client has to pay

The job was finished with a new seat, bar grips and lights.

Despite their dreadful failings in client support Brompton are an excellent example of the adage "design is all" as the original concept is still way ahead of the nearest rival.

 Re-united with it's sister Superlight for a shake down run on Derby's cycle lanes.

I am delighted with the end result being a unique customised folder which is ideal for commuting.

I am astonished by the ineptitude of Brompton, who clearly have no concept of legacy support, and may even be lacking the necessary data, if not, it is certainly withheld from clients. I suppose this is par for the course for a darling of the Tory party, who have featured them several times in a pathetic attempt to persuade us we are still in the forefront of manufacturing industry and innovation. Unfortunately my experience is also in line with Tory philosophy of sell it now with little care or concern for the future.


londonman said...

You should be justly proud of that refurbishment. Top notch.

neoshed said...

Brilliant job mate.

I can't say as I'm surprised at the lack of support or parts. They're probably surprised each month that they're still in business.