Brompton Bicycle

Brompton Bicycle, or simply Brompton, is a British company that specialises in folding bicycles, commonly known as "Bromptons".

Bromptons are popular among bicycle commuters.Fact|date=October 2008 Fast and compact folding is seen as the Brompton's key competitive advantage. The Brompton design has remained fundamentally unchanged over three decades, although it has been steadily refined.

History

The idea of folding bikes is not new now and was not new in 1976 when Andrew Ritchie, an engineering graduate but a landscape gardener by trade, decided to try his hand. Contemporary folding bikes from Bickerton in particular had shown that a market existed, but the quality and utility of the product left much to be desired.

Ritchie obtained financial backing from a few friends and founded a company named after the Brompton Oratory, the famous London landmark, visible from Ritchie's flat where the first prototypes were built. Initially he sought to license the design but in the end the drawbacks of this approach outnumbered the advantages and after five years, and a further five of searching for venture capital, the idea remained on the drawing board. Finally Ritchie decided to go it alone and with the backing of thirty friends who paid up front to buy the first production run he began manufacturing the bike himself.

The bikes were well received, others started enquiring, and with rudimentary tooling and as much enthusiasm as expertise the Brompton Bicycle company was in business.

Enthusiasm and hard work were enough for the firm to break even but further capital would be required to expand. Despite the fact that around 500 bikes had been sold, no venture capitalists were interested and production ground to a halt in 1982. However, the company was still solvent, there was still demand for the bikes and Ritchie was convinced that the product had a future so he continued to explore possibilities while doing various other jobs to make ends meet. Finally in 1986, again with backing from friends and former customers (notably Julian Vereker, founder of Naim Audio), enough money was raised to resume production on a larger scale in a railway arch in Brentford. By early 1988 Brompton bicycles were once more in production.

In the years since, the firm has grown to be one of the best-known brands in the UK. The order book is full and a host of imitations have been spawned. The bike has earned a strong following at home and abroad, earning a Queen's Award for Exports in 1995.

Brompton is one of only two mass-production bike builders left in the UK (the other is Pashley Cycles). The company makes one product, the design fundamentally unchanged from the original, but much improved over time. Recent developments include optional part-titanium frames, new styles of handlebar, rather better trolley wheels (see below) and a menu approach to specification, with buyers able to mix and match options and colours.

Bicycles

All Bromptons are basically the same: a characteristic curved main tube with a hinged rear triangle, three-speed hub gears and/or two-speed derailleur to give two, three or six speeds, 16" wheels, a tall seatpost and a folding handlebar stem. The handlebars are aluminium, originally a moustache shape (though with a deep U), with other designs introduced later. There is a hinge in the main tube. In riding position the rear triangle rests loosely on a rubber spring to give some suspension; it is held in place by the rider's weight, and the triangle will pivot down if the back of the bicycle is raised (although on modern Bromptons a clip is fitted which may be set to prevent this). On the left is a folding pedal which reduces the width of the folded package, on the right a standard pedal. Mudguards are fitted as standard; an optional rack and factory-fitted dynamo lighting are available. The dropouts are narrow, which keeps the folded package small but restricts the range of compatible gearing and hubs. Schmidt Maschinenbau manufacture the SON XS hub dynamo for the Brompton. In addition to the frame and dropouts, many other parts are also unique to the Brompton, including brake levers, rear derailleur if fitted, chain tensioner, and handlebars.

The bike is surprisingly rigid given the length of stem and seat pin. Heavy or powerful riders might find the rear suspension disconcerting, but it does dampen bumps, helping avoid pinch punctures that heavy riders sometimes experience.

Specification and Build-to-Order Options

Bromptons retail from around £500 to around £1200 sterling, so most buyers do their research thoroughly and get the right bike first time. Bromptons are reliable and long-lived, meaning that depreciation is lower on Bromptons than many other bikes.

As of 2008, Brompton has more or less abandoned the idea of standard models, their philosophy being that "nothing is standard". The main choices are between M, S or P type handlebars and whether the rider wants single, two, three or six speeds. Other important options are the inclusion of a rear luggage rack, or the presence of hub or bottle dynamo powered lighting systems. The prospective buyer may also opt for a titanium rear triangle, forks and seatpost for a weight saving of around 1 kg.

Riders over about 1.85m or 6 feet tall will require an extended or telescopic seatpost. For safety Brompton recommend that the weight of the rider should not exceed 110kg, and luggage 20kg.

The classic "Type M" moustache bars are somewhat flexible - earlier models were prone to fatigue failure and the tube was subsequently thickened - and a brace is available for those who find this problematic. "Type S" T-shape handlebars are also available, as are a complex "Type P" that offer several different hand positions.

Special luggage is available: panniers and a messenger bag which mount on a quick-release block on the head tube, a trunk bag which mounts on the optional rack, and a saddle bag.

A test ride is advisable to check gearing preference, experienced cyclists usually recommend the 7%, 12% or 18% reduced gearing option, since the standard gearing is suited to a slow pedaling cadence. The simple suspension tends to "bob" a little under load - the two most common fixes are a pair of jubilee clips around the rubber spring or replacing it with an elastomer from a Riese & Muller Birdy. Dual-pivot caliper brakes are now fitted as standard front and rear (replacing the high-leverage brakes formerly fitted as standard at the rear).

A Brompton-branded Brooks leather saddle is available (as seen in the pictures with this article); as is a sportier a Fizik Vitesse saddle. The standard Brompton plastic and foam saddle is light and cheap, but widely regarded as uncomfortable over longer distances. Any standard saddle can be used.

Folding

The fold is in four stages. The bike stands unsupported at each stage of the fold, and can be folded and unfolded in 10-20 seconds by a proficient user. The two hinges, on the main tube and the steerer, are secured by clamping a thick machined aluminium channel over them and fastening a wing-bolt with a large plastic handle. The user stands on the left of the bicycle to fold it. Before folding the luggage must be removed (panniers are quick-release).

First, the front wheel is turned slightly left and the rear triangle flipped under, the wheel touching the bottom of the main tube. Two very small wheels are mounted above the rear light/reflector bracket on the rear triangle, and either a small trolley wheel on the mudguard or two wheels on the back of the rack, if fitted. With the rear triangle folded the bike sits on the front wheel and the small wheels. At this stage the pedals may be freely rotated; the right pedal should be rotated to around the seven o'clock position, that is, low and behind.

Second, the main tube hinge is unlocked, the head tube is grasped and the front wheel swung back (still facing forward) and hooked to the rear triangle with a hook mounted on the left fork.

Third, the saddle is dropped down. There is a quick-release seat pin clamp; a new design is being introduced in conjunction with the new rear frame latch (see above). The seat post when dropped rests on the rear tyre, locking the rear triangle in place. On newer bikes with free-rolling trolley wheels a rubber foot on the bottom of the seat pin stops the bicycle rolling when folded (like every development with Brompton, this is available as a retro-fit).

Fourth, the handlebar stem clamp is unfastened and the bars fold down and are clipped to the right fork. (This can be done before dropping the saddle.)

The folded package is 565 mm x 545 mm x 250 mm (22.2" x 21.5" x 9.8") and weighs between 9 and 12.5 kg (20-28 lb). Most other folding bicycles are significantly longer in at least one dimension.

Once folded the pannier can be re-attached to its block and the integral handle used to pull the bike like a piece of wheeled luggage.

Criticisms

Small wheel bicycles including Bromptons are more sensitive to bumps in the road, than bicycles using large wheels.

Modifications

The Brompton has inspired a devoted following. Brompton fans with engineering expertise have modified the bike; the most notable of these is Steve Parry whose [http://www.foldsoc.co.uk/sp.html SP Brompton] includes a 7-speed derailleur, V-brakes, carbon fibre seat post and suspension handlebar system.

The Schlumpf Mountain Drive [http://www.schlumpf.ch/antriebe_engl.htm] can be fitted in the bottom bracket, giving 2.5 times gear reduction, doubling the number of gears available. The Speed Drive can also be used.

Cycle engineer Juliane Neuss in Germany can supply an add-on kit which turns the Brompton into a folding recumbent bike.

An electric-assist hub motor kit ('nano') adds 4 to 5.5 kg to the weight depending on the size of battery. It was reviewed in issue 60 of "A to B" magazine. On the test route, it ran for 75 km over mixed terrain at an average speed of 22 km/h with a 7Ah Lithum-Polymer battery. The hub is 100 mm wide, so wider forks are supplied, along with an optional modified luggage block which connects to the battery inside the luggage.

Uses

The compact dimensions of most folding bikes allow easy transport in public transport where travelling with a normal bike can be difficult or forbidden.

The bike is not ideally suited to long rides as most models have a restricted range of gears, but with a good saddle it is comfortable enough for ambitious journeys.

References

External links

* [http://www.brompton.co.uk/ Brompton Bicycle]
* [http://www.olivierpascaud.com/brompton.html Brompton factory photographs]
* [http://stein.dommel.be/brompton/chapters/index2.html Brompton Folding Bicycle FAQ]
* [http://www.flickr.com/search/?q=brompton+folding+bike&ct=6&ss=2&s=int Brompton tagged photos on Flickr]
* [http://www.bikethatfolds.com/ A Newspaper Review of the Brompton bike]