Genetically Modified Bromptons


Front suspension

Mark Lewis, May 1998:
[...] I've had a few ideas about how a suspended front fork could be achieved.
The neatest would be to use the standard forks with a modified suspended steerer tube. This would have two closely fitting tubes one inside the other fixed together through a small suspension block sitting in the middle (probably like the Cannondale front suspension [...] came out about five or so years ago and is now marketed under the 'HeadShok' name. Have a look at their website at . They sell forks for standard MTBs with the suspension unit built into the steerer tube. It looks very neat and sounds like a better system (at least in theory) than the standard twin fork suspension that almost all mountain bikers seem to have. I've never actually seen anyone riding a bike with one of these forks so perhaps they aren't as good as the makers would have us believe?)
The outer tube would be threaded either end for the headset and be fixed somehow to the handlebar stem. The inner tube would turn with the outer tube by a series of grooves and corresponding ridges in the faces of the inner and outer tubes (or a better system would employ bearings to achieve this). This would allow the inner tube to move up and down suspended by a suspension unit in its centre. The front fork crown would be fixed to this inner tube with some kind of rubber seal between the two sliding tubes. If the internal suspension unit relied on a compressed volume of air to provide the bounce it could easily be constructed with a standard high pressure tyre valve to allow the air to be be pumped in with a normal bike pump to vary its response. More importantly, and with the addition of a locking mechanism to prevent the inner tube's vertical movement, air could be let out completely to allow the front fork to be locked into its highest position for normal folding.
It would then look very similar to a normal folded Brompton. For short rides the unfolded bike could be left with the headset suspension locked for a normal ride or released and inflated for a suspended ride!

Brompton Recumbent Conversion Kit

Leonard Rubin's UFB ("Ultimate Folding Bike" or "Super-Brompton") project

Len is too busy to update his web-site, so here's the last news heard on Brompton-Talk:

Here is the history of the project:

Leonard Rubin, Oct 97:
The Super Brompton project, as it has been dubbed, resulted in the fullfillment of a lifelong dream: a 20lb., 24-geared (20"-100"), hydraulically-braked, super-performance urban assault vehicle that folds instantly to disappear before your very eyes, enabling one to always have a magical "pocket taxi" at hand without the back-breaking inconvenience normally associated with carrying a folding bike around all day long in an out of buildings, buses and trains!!!

For the British market, which seems to have expressed a definite preference for the heavier and less efficient, but aesthetically and practically appealing internally geared hubs, I am building a new prototype using a Sturmey Archer 7 speed hub. Unlike the quite expensive titanium rear triangle I will be producing for the US market, my thought is to make the rear triangle for that out of steel (4130), to reduce cost. It will still result in a modest weight savings, and when combined with some of our other superlight components and custom replacement items, could still result in a very light bike.

I braze on a front derailleur hanger to the frame, which produces the lightest, most beautiful and trouble-free setup. However, this involves tremendous precision, and is a delicate and time-consuming operation, involving a lot of pre- and post-operation work, so it is not less expensive than Channell Wasson's ingenious bolt-on system (it is a helluva lot lighter though!!!).

To the many, many people that have expressed interest in my replacement wheelsets, titanium telescopic seatposts, titanium bolt-kits, full Super Bromton coversion kits, etc. I can say here that they are all finally available, and that I am so busy designing, fabricating and working to pay for all this R&D and merchandise that I have no time for advertising brochures, pricelists and that sort of thing.

If you are seriously interested in lightening up your bike and or improving the performance, drop me a line ( or Len Rubin 3123 Shelter Creek Lane, San Bruno, CA 94066), or call (650) 737-0303, and we'll discuss a specific custom solution. A last word: it is neither easy nor cheap to achieve the contradictory goals embodied in a truly lightweight and simultaneously strong and comfortable collapsible bicycle -- it's all but impossible! So please don't expect or bemoan that these custom solutions are more expensive than off-the-shelf stuff! That said, I welcome your inquiries (or enquiries for the rest of you).

{Leonard Rubin, Jan 98} I hope to have the first run of the new PRODUCTION Titanium rear triangles ready to show by Folder Forum III. They will initially be spec'd for our own ultralight high-performance wheels (and conventional high-performance derailleur drivetrain, using Titanium Shimano freehub bodies and Titanium cogs), though I know that many in the UK have a "rationalized fetish" for the lead-weight/molasses-filled internally-geared hubs (which you can't PAY cyclists around here to ride!) but the unparalled performance, amazing weight (and recent cost reductions through clever CAD re-engineering) may make believers out of some of you Brits yet. My latest 24-speed, hydraulically braked SuperBrompton tipped the scales at 20lbs. and I'm just warming up!

Aluminium Brompton clone?

Kong Wai Ming, Nov 1998:
At the Tokyo Cycle Show from 5-7 Nov 98, There was a aluminium brompton prototype on display. I was told that it weighs less than 9 kg and could be in production from April 99. Also, the new Taiwanese brompton can carry the optional baggage system.

Electrically powered Bromptons

Wish lists