Economically upcycling a 1978 BSA (Raleigh) 20 folder

In a recent post I described a 1974 Raleigh 20 FE, in near original condition, that had been in the same ownership for 40 years. The husband of the FE’s owner also had a 20, which was a folding version, badged as a BSA 20, and made in 1978. I rescued both bikes from an almost certain final trip to the local tip. I sold the FE on eBay for less than its replacement lamp cost me. I didn’t mind though, as I needed the space and it saved the bike from a prematurely ignoble end. As for the BSA 20 folder, I decided to keep it and refurbish it.

My aim was not the ultimate ‘hot 20’, which could cost quite a lot of money. Instead I decided to upgrade the less desirable old components, mostly with items from eBay or the spares box, plus a few from St John Street Cycles or Amazon Market Place dealers. The following annotated photo sequence shows the end result, a very rideable hack which, because of its colour scheme, I call Cappuccino.

The 1974 Raleigh 20 FE, described in a previous post, weighed a hefty 37 lb (almost 17 kg) in orignal form but without its rear bag. (That, however, is a pound and half less than my grandson’s modern but relatively inexpensive mountain bike!) The BSA folder weighed 32 lb (about 14.5 kg) in its original form but after the modifications described below, it weighs 30 lb (about 13.6 kg) without bag, despite having the addition of a rear carrier. Further weight savings could be made by replacing the original wheels with new ones having alloy rims, alloy hubs and narrower tyres, and by replacing the handlebars and stem with alloy equivalents.

A general view of Capucciono, complete with the Carradice handlebar bag which, via Klickfix fixings, gets used on several of my bikes.

Above: A general view of Cappuccino, complete with the Carradice handlebar bag which, via Klickfix fixings, gets used on several of my bikes.

Another view of the bike, this time from the left side.

Another view of the bike, this time from the left side.

The handlebar cluster and related components. I decided to keep the original steel stem and handlebars, as they are in fine condition, are nicely rigid and allow lots of adjustment, both verically and fore and aft. The Carradice bag (great for day rides) is easily detachable via a Klickfix bracket on the handlebars and has a handy shoulder strap. The ergonomic handlebar grips (cheap but adequate copies inspired by Ergon) make a big difference to comfort. The Tetro brake levers are also a huge improvement on the cheap steel originals, having far superior leverage, adjustable reach and cable adjustment.

I decided to keep the original steel stem and handlebars, as they are in fine condition, are nicely rigid and allow lots of adjustment, both vertically and fore and aft. The Carradice bag (great for day rides) is easily detachable via a Klickfix bracket on the handlebars and has a handy shoulder strap. The ergonomic handlebar grips (cheap but adequate copies inspired by Ergon) make a big difference to comfort. The Tektro brake levers are also a huge improvement on the cheap steel originals, having far superior leverage, adjustable reach and cable adjustment.

A rider's-eye view of the handlebar cluster, showing the Klickfix bracket, the Sturmey-Archer 3-speed trigger and a bell, tcuked away by the bag bracket. This set-up enables the bike to be stood upside for maintenance, supported well by the handlebar grip extensions and saddle.

A rider’s-eye view of the handlebar cluster, showing the Klickfix bracket, the Sturmey-Archer 3-speed trigger and a bell, tucked away to the left of the bag bracket. This set-up enables the bike to be stood upside for maintenance, with stable three-point support via the handlebar grip forward extensions and saddle.

A view of the handlebar cluster with the bag removed, showing the front of the Klickfix mount.

A view of the handlebar cluster with the bag removed, showing the front of the Klickfix mount.

I decided to ditch the chainset and bottom bracket axle and bearings, replacing them with a cotterless assembly. The chainset was an inexpesnive item from eBay but nonetheless has a proper detachable chainwheel. This enabled me to move the chainwehel to the left hand of teh spider, to get a better chainline. The chainwheel was sold as being for 1/8-inch chain but actually works fine with older style 3/32-inch chains. Also in shot is a MKS all-metal folding pedal, which repalced the very heavy solid bearing original pedals.

I decided to ditch the chainset and bottom bracket axle and bearings, and replace them with a cotterless assembly. The chainset was an inexpensive unused item from eBay but nonetheless has a proper detachable chainwheel. This enabled me to move the chainwheel to the left hand of the spider, which was very important to get a reasonable chain line. The chainwheel was sold as being for 1/8-inch chain but actually works fine with older style 3/32-inch chains (e.g. for 6-, 7- or 8-speed derailleurs). Also in shot is an MKS all-metal folding pedal, which replaced the very heavy solid bearing original pedals and enables the width of the bike to be usefully reduced very easily for transit or storage. I dispensed with the hockey stick chainguard and its mounting bracket, filing off the sharp corners of what was left of the fixing point on the strut behind the chainwheel.

Raleigh 20s and their badge-engineered brethren have ultra-wide (78mm) bottom bracket shells and are Raleigh-threaded. This is very limiting when it comes to converting to a cotterless set-up, especially at a reasonable price. I reduced the width of the bottom bracket shell, on the chainwheel side, by 5mm. This enabled me to fit a relatively inexpensive Oxford 73mm-wide threadless bottom bracket cartridge.

Raleigh 20s and their badge-engineered brethren have ultra-wide (78mm) bottom bracket shells and are Raleigh-threaded. This is very limiting when it comes to converting to a cotterless set-up, especially at a reasonable price. So I reduced the width of the bottom bracket shell, on the chainwheel side, by 5mm. This enabled me to fit a relatively inexpensive Oxford 73mm-wide threadless bottom bracket cartridge. The letters and numbers stamped onto the bottom bracket are not a serial number but the postcode of the previous owner.

This shot clearly shows how the chainstays of the Raleigh 20 series were flattened and wrapped around the bottom bracket shell (to which they were brazed) before continuing forward to form bracing struts, brazed to teh underside of teh main beam.

This shot clearly shows how the chain stays of the Raleigh 20 series were flattened and wrapped around the bottom bracket shell (to which they were brazed) before continuing forward to form bracing struts, brazed to the underside of the main beam.

A wider view of teh same area.

A wider view of the same area. Note the struts, which join the main beam below the frame hinge on the right of the picture.

Another view of the MKS folding pedal.

Another view of the MKS folding pedal and surrounding area. Note the frame hinge on the left and the TI ‘made in Britain’ sticker at the base of the seat tube.

A similar view but showing the pedal in folded mode. The difference may not sem much but a pair of such pedals can reduce the stored width of the bike by about 5 inches (12.5 cm)

A similar view but showing the pedal in folded mode. The difference may not seem much but a pair of such pedals can reduce the stored width of the bike by about 5 inches (12.5 cm).

Another view of the folded pedal, with the frame hinge at top left.

Another view of the folded pedal, with the frame hinge at top left.

The wheels are in very good condition, the original Sturmey-Archer rims being true and almost perfect cosmetically. The front hub and rear hubs are also fine and the spoke tension is OK. So rather than spend a small fortune on new 451 wheels, I decided to keep the originals and just fit new inner tubes and new Schwalbe Kevlar-protected whitewall tyres. Yes, steel wheels have porrer wet weather braking but I don't intend riding this bike much in the rain. Also, I upgraded the brakes, about which more below.

The wheels are in very good condition, the original Sturmey-Archer rims being true and almost perfect cosmetically. The front hub and rear hubs are also fine and the spoke tension is OK. So rather than spend a small fortune on new 451 wheels, I decided to keep the originals and just fit new inner tubes and new Schwalbe Kevlar-protected whitewall tyres. Yes, steel wheels have poorer wet weather braking but I don’t intend riding this bike much in the rain. Also, I upgraded the brakes, about which more below.

This bike did not have a carrier (rack) but I found this original Swiss-made Pletscher on eBay. This carrier was fitted to quite a few Raleigh 20s and fitted perfectly. It has a sprung parcel clip and I have added a couple of old-style toe-clip straps, which are often handy for securing items of luggage (such as a rolled up jacket).

This bike did not have a carrier (rack) but I found this original Swiss-made Pletscher on eBay. This model of carrier was original equipment on some Raleigh 20s and fitted perfectly. It has a sprung parcel clip and I have added a couple of old-style toe-clip straps – often handy for securing items of luggage (such as a rolled up jacket).

Another view of the carrier.

Another view of the carrier.

And yet another shot of teh carrier, but this time including the new longer and alloy mico-adjust seat pillar. This replaced the original steel seat post, which, for no good reason, was slightly shorter than the standard Raleigh 20 item. The saddle is quite a nice one from the spares box.

And yet another shot of the carrier, but this time including the new longer and alloy micro-adjust seat pillar. This replaced the original steel seat post, which, for no good reason, was slightly shorter than the standard Raleigh 20 item, and which had an old-style steel saddle clip. The saddle now fitted is quite a nice one from the spares box. The original, supplied with the bike, was a very cheap vinyl-covered mattress saddle, with no main chassis springs – unlike the relatively plush Brooks item fitted to the FE described in a previous post.

Another view of the saddle and seat pillar.

Another view of the saddle and seat pillar. Also in shot is the Sturmey-Archer AW wide-ratio 3-speed hub. As can be seen, this was made in the days when they still fitted a lubrication point, so it’s easy to add a few drops of oil from time to time. The AW is a very efficient hub but the original gearing of Raleigh 20s is on the high side. So, although I kept the same number of teeth on the chainwheel (46), I fitted a larger rear sprocket (17 tooth). This lowers the top gear to 71-inches, a great gear for pootling along at a reasonable speed, without hunting between top and middle gear. Middle gear is now reduced to 54-inch, fine for many moderate slopes. Low gear drops to 40-inch, enabling easier hill climbing. For most people, reducing the gearing in this way is one of the easiest and most worthwhile upgrades you can make to a Raleigh 20 or derivative.

The original pressed steel callipers are not great, so i replaced them with these

The original pressed steel calipers are not great (poor leverage and flexible arms), so I replaced them with these Tektro R365 dual-pivot brakes. The leverage at the caliper is much better (aided also by better brake lever leverage), they are quick-release and incorporate adjusters for brake block clearance and cable tension. As the brake fixing bolt that passes through the fork crown is retained by a threaded sleeve (rather than a standard nut) it is necessary to enlarge the hole through back of the crown slightly. Also, these calipers fouled the forward extension of the original mudguard. This was easily resolved by trimming back the mudguard. Visible in this picture, against the lower steering bearing, is the chrome-plated stop that prevents the forks being reversed. I took the opportunity of fitting new balls to the lower steering bearing. (The upper bearing is solid nylon, which damps the otherwise rather light steering. It can be replaced with a ball bearing unit, if desired.)

Despite the long reach of these brakes, the fixing hole for the rear brake calliper needed to be elongated downwards by a few millimetres to get the brake blocks low enough to avoid the risk of them rubbing on the tyre sidewall during braking. Slightly longer brake arms would avoid this problem.

Despite the long reach of these brakes, the fixing hole for the rear brake caliper needed to be elongated downwards by a few millimetres to get the brake blocks low enough to avoid the risk of them rubbing on the tyre sidewall during braking. Slightly longer brake arms would avoid this problem.

A close look at a 1974 Raleigh 20 FE

The Raleigh 20 was the archetypal British city bike of the 1970s and Raleigh’s biggest selling product line in the middle of that decade. The company made up to 140,000 a year and the bike was in production from the late 1960s to the early 1980s. You can read more about it here: https://hadland.wordpress.com/2012/06/24/raleigh-twenty-r20/

Recently I acquired a 1974 Raleigh 20 FE (‘Fully Equipped’) that had been in the same ownership for 40 years and was in almost completely original condition, apart from modest wear and tear. It is a testament to the fitness for purpose of the product that the owner kept it and used it for so long. Here is a photo tour of the bike in question.

A general view of the 1974 Raleigh 20 FE

A general view of the 1974 Raleigh 20 FE.

A front view. Originally the bike would have had a plastic clip to hold the three front cables together more neatly but these clips tended to fall off and were not really necessary.

A front view. Originally the bike would have had a plastic clip to hold the three cables together in front of the head tube more neatly but these clips tended to fall off and were not really necessary. The headlamp shown here is a replacement but differs only slightly from the original, which still worked, despite having a missing ‘glass’. All Raleigh 20s had a restrictor to stop the bike being ridden with the forks reversed. In models fitted with integral lighting, the stop was combined with the headlamp bracket.

Rear carriers (racks) varied between Raligh 20 models. Some had none and some had a Pletscher alloy carrier with a sprung parcel clips. The FE had a tubulr steel carrier with a plastic tray. This helped hold the removable holdall (shopping bag) that came with the bike. It's rare to see the original holdall still with the bike.

Rear carriers (racks) varied between Raleigh 20 models. Some had none and others had a Pletscher alloy carrier with sprung parcel clips. The FE had a steel carrier with a plastic tray. This helped hold the removable holdall (shopping bag) that came with the bike. It’s rare to see the original holdall and this bike had lost its one. At the front and back of the tray you can see the elasticated cords that held the holdall in the tray. The rear lamp is combined with the rear reflector in the neat and very robust unit fitted to the rear mudguard.

The chain stays were falttened to wrap around the underside of the wide (78mm) Raleigh-threaded bootom bracket, to which they were brazed. The stays then carried on forward and were brazed to underside of the main beam. The result was a very stiff frame. Note the Raleigh heron's head motif stamped into the steel chainwheel. The peadls were Raleigh's own low maintenance type, which used non-adjustable, solid, sintered metal, oil-retaining bearings instead of cones and ball bearings. The end caps often fell off.

The chain stays were flattened to wrap around the underside of the wide (78mm) Raleigh-threaded bottom bracket, to which they were brazed. The stays then carried on forward and were brazed to underside of the main beam. The result was a very stiff frame. Note the Raleigh heron’s head motif stamped into the steel chainwheel. The pedals were Raleigh’s own low maintenance type, which used non-adjustable, solid, sintered metal, oil-retaining bearings instead of cones and ball bearings. The end caps often fell off, as can be seen here. The hub is a Sturmey-Archer Dyno-Three AG3, combining a 3-speed wide-ratio hub gear and a Dynohub alternator to power the built-in lighting.

The rear hub seen from the left-hand side of the bike. The wider section of the hub houses the alternator. The hub gear was operated by a twist-grip on the handlebar. This had a friction clutch within it to automatically take up  slack that might develop in the gear control cable. There are instructions for re-setting this function elsewhere on this website.

The rear hub seen from the left-hand side of the bike. The wider section of the hub houses the alternator. The hub gear was operated by a twist-grip on the handlebar. This had a friction clutch within it to automatically take up slack that might develop in the gear control cable. There are instructions for re-setting this function in the ‘Gears’ this website.

This bike is fitted with Raleigh's Design Centre Award-winning self-adjusting brake levers. In common with automotive drum brakes, these detetcted increased brake lever travel and, via a ratchet mechanism, automatically tightened the cabled to compensate. Sadly, this was all too complicated for many bicycle mechanics and the levers were soon dropped.

This bike is fitted with Raleigh’s Design Centre Award-winning self-adjusting brake levers. In common with many old-style automotive drum brakes, these detected increased brake lever travel and, via a ratchet mechanism, automatically tightened the cabled to compensate. Sadly, this was all too complicated for many bicycle mechanics and the levers were soon dropped.

A proper metal heron's head Raleigh head badge, riveted on by hand. None of your cheap self-adhesive stickers in those days!

A proper metal heron’s head Raleigh head badge, riveted on by hand. None of your cheap self-adhesive stickers in those days!

The type of saddle fitted to Raleigh 20s varied somewhat but was always a plastic covered sprung type. A cheap version, sold under another Raleigh-owned brand name, such as BSA, might well have a vaery basic, unbranded saddle. This FE, however, is a high-end model and has a Brooks fully-sprung mattress saddle.

The type of saddle fitted to Raleigh 20s varied somewhat but was always a vinyl-covered sprung mattress type. A cheap version, sold under another Raleigh-owned brand name such as BSA, might well have a very basic, unbranded saddle, with no main springs. This FE, however, is a high-end model and therefore has a Brooks fully-sprung mattress saddle.

A view down onto the top of the main beam. As the label shows, the bike was sold in Newbury in the days when that town had 4-digit phone numbers. Some time later, in an office over a shop in Newbury, a company called Vodafone started life. Now most phone numbers are so long we can't remember them!

A view down onto the top of the main beam. As the label shows, the bike was sold in Newbury in the days when that town had 4-digit phone numbers. Some time later, in an office over a shop in Newbury, a company called Vodafone started life. Now most phone numbers are so long we can’t remember them!

This view shows, among other things, the twin bracing stays formed by extending the chain stays around the bottom bracket and up to the main beam. You can also see the Raleigh pedal, complete with logo moulded into the heavy solid rubber body.

This view shows, among other things, the twin bracing struts formed by extending the chain stays around the bottom bracket and up to the main beam. You can also see the Raleigh pedal, complete with the Sir Walter Raleigh logo moulded into the heavy solid rubber body – and the typically missing end cap!

The final picture shows the bottom bracket area from the left-hand side. The fixing for the very robust and reliable propstand is brazed to the underside of the bottom bracket. A nice touch on the Raleigh-branded 20s (as distinct from the versions sold under other Raleigh-owned brand names) is the cotter pin nuts bearing the Raleigh monogram.

The final picture shows the bottom bracket area from the left-hand side. The fixing for the very robust and reliable propstand is brazed to the underside of the bottom bracket. A nice touch on the Raleigh-branded 20s (as distinct from the versions sold under other Raleigh-owned brand names) is the cotter pin nuts bearing the Raleigh monogram.

A Motorised Raleigh 20

Here’s something you don’t see everyday. It’s a UK street-legal moped based on a Raleigh 20 and was created by consulting engineer Chris Sawyer. It has a Cyclemaster engine and front suspension. Apparently it works quite well and it demonstrates the rigidity of the folding version of the bike. Many thanks to Chris for permitting use of his photo.

The folding Raleigh 20 converted into a moped by Chris Sawyer
The folding Raleigh 20 converted into a moped by Chris Sawyer

A New Class of Cyclists: Banham’s Bicycle and the Two-wheeled World it didn’t Create

Bruce D Epperson is, among other things, an eminent American cycle historian. His paper ‘A New Class of Cyclist: Banham’s Bicycle and the Two-wheeled World it didn’t Create’ should be compulsory reading for anybody studying the history of cycling in the United Kingdom in the 1960s and 1970s. It appeared in the journal Mobilities, Volume 8, Issue 2, 2013.

Here’s the abstract:

While not uncommon for innovator and innovation to merge into a single identity, it is more unusual for this to occur between object and critic. But it did happen in the 1960’s with a novel small-wheeled bicycle, the Moulton, and the British architecture and design critic Reyner Banham. Banham believed the Moulton would give rise to a new generation of middle-class urban radical cyclists who would eventually come to rely on bicycles for their transport needs. While this did not happen, the Moulton’s attention-getting technology did lead to a revived market in bicycles among young, newly affluent consumers who bought small-wheeled utility bicycles as fashion statements and status symbols.

The article is particular relevant to those interested in the history of Moulton bicycles, the Raleigh cycle company and the Raleigh 20 series of small-wheelers – Raleigh’s biggest selling product line in the mid 1970s.

The article can be purchased online here from the publisher, Taylor & Francis:
http://www.tandfonline.com/doi/pdf/10.1080/17450101.2012.659467#.VRKlAGbEigc

Web of Science provides more information about the article, including contact details for the author:
http://cel.webofknowledge.com/InboundService.do?product=CEL&SID=Y2fRMQ6UGNkDsTUOM53&UT=WOS%3A000317828900005&SrcApp=literatum&action=retrieve&Init=Yes&SrcAuth=atyponcel&Func=Frame&customersID=atyponcel&IsProductCode=Yes&mode=FullRecord

 

Tony

 

The rarely seen Moulton Stowaway joint that looks like a hinge

Alex Moulton hated the idea that his bicycles would be considered as folding bicycles. He always made the point that his aim was to produce a better bicycle, not a folder. A small proportion of the 1960s Moultons were separable for stowing in the boot of car, as were the majority of his post-1983 spaceframe machines, but Alex never, ever, made a folding bicycle.

A number of people have adapted Moultons into folding bicycles but Alex never did. The question that many Moulton researchers and enthusiasts have asked themselves is “Did he ever, in secrecy, produce a folding prototype?” More than 20 years ago, when I first saw a colour slide in the Moulton archives of the bike featured here, I thought for a few seconds that I had found evidence of just such a machine. But it did not take long to establish that this, too, is a separable machine, albeit a unique variant on the theme.

The original Moulton Stowaway joint, used in a minority of production F-frame Moultons in the 1960s, was very unforgiving if the bike was ridden without the joint bolt being fully tightened. Just one short ride with the bolt loose would distort the joint, making it looser in the vertical plane when ridden yet harder to separate.

In the 1970s, Alex Moulton made a little known attempt to improve the Stowaway joint. The only known example exists in a prototype Mk 4 Moulton. (The Mk 4 was a development of the Mk 3 that never went into production.)

Alex’s aim was to produce a joint that was fail-safe and that would not be damaged if ridden without being fully tightened. The resulting design is shown in the photos below. The front section of the main beam has a primary hook at the lower end of the joint end. This hooks over a peg on the rear section of the main beam. The top of the front section of the main beam bears upon a “hooded” forward extension of rear part of the main beam, thus holding the two parts of the main beam loosely together.

Rather than just relying on the primary hook joint, there is a pair of secondary pivoting hooks within the front section of the main beam. These hook around a peg that runs through the central axis of the rear section of the main beam. To complete assembly of the bike, the frame’s short “carrying handle” is swung into its horizontal position and fastened around the seat tube, just above the squashball suspension unit, using a bolt with a quick-release lever. A cam on the underside of the carrying handle, near its pivot, locks the secondary hooks in position. The combination of the secondary hooks and the bracing effect of the carrying handle make the joint tight in the ridden mode.

To separate the frame, the carrying handle is unbolted and swung forward, which releases the pair of secondary hooks via the cam in the carrying handle. The two parts of the frame can then be separated by releasing the primary hook.

In conclusion, this prototype joint is certainly a belt and braces job but is very complicated, expensive to manufacture and relatively heavy. It is not surprising that it never saw the light of day.

Mk4 special joint 1

Mk4 special joint 2 Mk4 special joint 3 Mk4 special joint 4  Mk4 special joint 6Mk4 special joint 5

More pics of Le Petit Bi

Elsewhere on this website you will find my article about Le Petit Bi, the 16-inch wheel French folding bicycle designed in the 1930s by A J Marcelin of Paris. Riders included the philosopher Jean Paul Sartre and the artist Francis Picabia. Below are some additional pictures to supplement those in the original article.

The first is a press advertisement for the first version of the bike, showing it in ready-to-ride and stowed modes. The advert is undated but probably from about 1939.

The second picture is of the later version of the bike, as patented during the later stages of WW2, which featured a hinged frame. (There is a lower resolution version of this image, which was used in a press advertisement discovered by Bob Cordon Champ, in the main article.)

Lastly, there is a photo (ex-Cycling magazine) of their reviewer Alex Josey testing the bike. He erroneously ascribed the bike to the aviator and intelligence officer Louis Armandias, who merely brought the demonstrator models to London from France on behalf of a friend of his father.

Press advert for the original version of Le Petit Bi
Press advert for the original version of Le Petit Bi
The later version of Le Petit, which featured a hinged frame
The later version of Le Petit, which featured a hinged frame
Alex Josey of Cycling magazine road-testing a hub-geared version of  Le Petit Bi during WW2
Alex Josey of Cycling magazine road-testing a hub-geared version of Le Petit Bi during WW2

 

Rolling resistance – theory and practice

In theory, the rolling resistance of wheels decreases as the diameter of the wheel increases. This is on the assumption that all other factors are equal: the tyres are of identical cross-section and carcase construction, with equal internal air pressures and equal external applied loads, rolling at low speeds in still air where no significant aerodynamic effects apply, on smooth hard road surfaces, with the wheels on hubs with insignificant bearing friction.

Yet it is clear from observation and testing that, under some circumstances, some smaller diameter bicycle wheels can roll as easily, or even more easily, than some larger diameter wheels. This does not mean that the theory is wrong – merely that one or more of the “other factors” is not equal. The easiest factor for the average rider to control is tyre pressure. It’s a fair assumption, confirmed by everyday observation, that most cyclists ride on tyres that are at sub-optimal pressures. So, pumping up the tyres of a small-wheeler to the maximum recommended by the tyre manufacturer may well be enough to allow it to roll more easily than many other cycles with larger wheels. Choosing a small diameter tyre with a supple carcase will also help. At racing speeds, wheel aerodynamics and unsprung mass of the whole bicycle and rider ensemble can also enter into the equation and may, for example, favour a well-designed small-wheeler with suspension.

Between 1998 and 2002, British engineer John Lafford carried out rolling resistance tests on various tyres, ranging in tyre bead seat diameter from 305 mm to 622 mm (i.e. nominal wheel diameters of 16-inch to 28-inch). The manufacturers and product types, cross-sections, tread patterns, state of wear and tyre pressures all varied quite considerably. His full data may be found here: http://www.legslarry.beerdrinkers.co.uk/tech/JL.htm

Below is a chart generated directly from John Lafford’s data using Microsoft Excel. The vertical axis shows the various tyres tested, ranked by bead seat diameter – biggest at the top and smallest at the bottom. The horizontal axis shows rolling resistance – the less the better. The straight, backward-sloping, black line is a computer-generated trend line which reflects the general truth of the theory that rolling resistance decreases with tyre diameter. But it is immediately apparent that the rolling resistance of any particular tyre diameter may vary considerably, confirming the variance due to those “other factors” that may not be equal in reality. Hence we find some of the smaller tyres under certain conditions have actual rolling resistances lower than some of the larger tyres.

Rolling resistance of bicycle tyres of differing diameters using data from John Lafford's 1998-2002 tests.
Rolling resistance of bicycle tyres of differing diameters using data from John Lafford’s 1998-2002 tests.

The Duemila (updated 2015-05-24)

The Italians have never produced a really good small-wheeled bicycle, despite their considerable engineering tradition. They have, however, occasionally produced interesting machines that provide a talking point – even if the riding experience is less than exhilarating.

The Duemila, made in Padua, was a case in point. The interesting aspects were the exceptional fore and aft adjustment of the motor-scooter-style saddle and the integral front carrier, created by the unusual fork configuration.

Below is the front of an English-language brochure for the bike, showing how all the family could ride it – though ideally not at the same time. There is no evidence that the bike was ever marketed in the UK, which at the time (mid to late 1960s) was not part of the European Common Market, as the EU was then known.

The back of the brochure is shown below. This shows not only the adult version but the children’s model, the Duemila Minor.

The photo below, which I took in Bruges (Belgium) in the summer of 1970, shows the only Duemila I have ever seen.

The father-in-law of Imke Tietje from Hamburg inherited a Duemila and a picture of his machine is shown below.

Christian Barf kindly sent the photo collage below, which shows details of his own Duemila, including the fold.

Christian Barf kindly sent this brochure page, which shows details of the Duemila, including the fold.

The Mysterious Minifold

The Minifold, ready to ride – if you dare

American-born Tim Whitty owns the well-known Cyclecare bicycle shops in Kensington, London and Purton, Wiltshire. In 2003, at the Purton shop, he came across a fascinating little folding bicycle. It is badged as a Minifold, which sounds like the sort of name with which any folding bicycle enthusiast would be familiar. It isn’t. Neither Tim nor I, nor any folding cycle enthusiast we know, has ever heard of a Minifold.

In Tim’s photos of the bike, shown here, there’s a tape measure extended to 36 inches. This indicates that the bike is not much more than 3 feet long, which is a little less than 1 metre. The machine’s frame is unusual and interesting, in that it is primarily of cast aluminium but with several cast steel parts. As you can see from the picture below of the bike in its folded condition, the cranks fold in an unusual way: they hinge inwards, so that the pedals do not protrude.

The Minifold folded – probably what it does best

The folding handlebars are somewhat reminiscent of certain French folding bicycles of the 1960s and this impression is bolstered by the old French-style reversed brake levers. The seat support structure, with its shallow-angled, hinged, square-section seat tube and bifurcated support strut, is quite novel. Square-section seat tube is, in itself, unusual, though not without precedent. The wheels and brakes are the sort of equipment that might have been used on a Raleigh child’s bike in the 1960s. Braking is provided by a combination of cable, rod and stirrup, whereas the wheels and tyres are 12-inch, wide section. The whole machine has the look of something created in the late 1960s or early 1970s.

Tim’s guess is that this was a sophisticated and expensive prototype. He thinks that the ride was found to be unacceptable and that the Minifold project was therefore abandoned. This view is supported by the good condition of the machine and the fact that the original tyres show little sign of wear.

Why did it turn up in Wiltshire? A couple of old time cyclists from the Purton area have looked at the Minifold and suggested that, in view of the constructional techniques and materials used, there may be an aerospace connection. There was a Vickers (later British Aerospace) aircraft factory nearby in east Swindon and, though this no longer exists, there are still companies in the area that have their roots in the old Vickers operation.

So, if you have any further information about the Minifold, please get in touch.

Viking’s small-wheeler

How a bicycle became a moped then a bicycle again

The Viking small-wheeler

Alex Moulton’s famous small-wheeled bicycle was launched in November 1962. Raleigh, who had reneged on an agreement to manufacture the Moulton, were stunned by its success and in July 1965 launched their response – the balloon-tyred RSW16 (Raleigh Small Wheels 16″ diameter). CWS, the Co-operative Wholesale Society, responded to the RSW by producing a somewhat similar machine, the Co-op Commuter, but which had a mixte frame. That is, instead of having a single main beam linking the seat tube and head tube, it had a downtube and twin laterals – a pair of small diameter tubes running from the head tube via the seat tube to the rear wheel dropouts.

In May 1967, three months before Raleigh bought out the original Moulton bicycle concern, the Nottingham-based company launched a motorised version of the RSW16 – the Raleigh Wisp. Clarks Masts of Binstead, Isle of Wight, then decided to make a rival to the Wisp, as a way of diversifying from yacht mast manufacture. What better basis than the nearest pedal-powered rival to the RSW16? Clarks therefore contracted CWS to produce a slightly modified version of the Co-op Commuter to which the Isle of Wight company attached a small petrol engine of their own design. Thus was born the Clark Scamp moped. Opinions about Scamps differ. One writer has described them as “horrible things which flexed alarmingly when you rode them and were hopelessly underpowered so you had to pedal like mad to get up any incline.” J.S. Lycett, however, argues that the Scamp was “quite a usable machine and undeserving of a poor reputation.” He has an interesting article about the machine on the Moped Miscellany website.

The Raleigh Wisp, a motorised RSW16. Part of an advert in a trade magazine.
From ‘Motor Cycle & Cycle Trader’ 26th May 1967
Promotional cartoon showing general arrangement of the Clark Scamp moped. From J.S.Lycett’s article cited in the text

The Scamp had a gear-case in the rear wheel, with the engine mounted on the side of the gear-case. The petrol tank was in the upstand of the luggage rack, below the saddle and above the rear wheel. The tyres were 16 x 2″ moped type. A Sturmey-Archer BF 90mm hub brake provided stopping power for the front wheel, whilst a simple long-reach calliper brake provided rather less for the rear. According to Lycett, the Scamp would cruise at about 26 mph (43 kph) and climb moderate hills without pedalling if “taken at a run.” He considers that it “falls naturally into place between the clip-on cyclemotor and the NSU Quickly type in the evolution of the moped.”

However, neither the Raleigh Wisp nor the Clark Scamp were commercially successful. They faced fierce competition from superior Japanese imports. Clarks produced only some 3,500 Scamps before they ran into financial difficulties. These were not helped by failures of the Scamp’s starting mechanism, caused by breakage of a plastic pawl on the centrifugal clutch. In 1968 Lloyds Bank therefore appointed a receiver/manager who disposed of nearly all the finished machines and all the spares. (See Ken Mettam’s short article on the Moped Miscellany website.) The descendant company, Clarks Masts Teksam Ltd, is still based at Binstead and specialises in “mobile mast installations for every purpose”, especially mobile communications. They have representatives in Belgium, Germany, Switzerland, France and South Africa – but no parts for Scamps.

Viking Cycles had gone into liquidation in 1967. One of the directors, former Team Viking manager Bob Thom, together with others, formed a new Viking company. They wanted to continue production of the clubman-type cycles with which the name Viking was synonymous. Viking Holdings of Wolverhampton built a good relationship with the nearby Co-op Federation Cycle Factory in Birmingham and especially with its managing director, Harry Simonds. Consequently, the Co-op built some frames for Viking.

After Lloyds sent the receiver into Clarks, the Co-op was left with a surplus of frames and other parts (other than the engine) for the Scamp. Bob Thom managed to get about 200 of the frames, which were finished as pedal cycles and sold as Vikings. Anybody expecting a small-wheeler with a dash of Viking lightweight sportiness was in for a shock. These machines were essentially unpowered Scamps: the tyres were Avon Moped Grips, the CLB handgrips included a twistgrip throttle and the saddle’s vertical adjustment was minimal. Even the rubber-sleeved fixing pins for the fuel tank were there. Despite the lack of variable gears, the Viking weighed in at a formidable 35 lb (approx 16 kg).

The Viking small-wheeler is a very rare machine with a chequered history, but interesting nonetheless. It is one of the less successful ripples that flowed from the splash made five years earlier by the Moulton.

(The Viking head badge illustration is courtesy of John Gleave. All photos of the blue Viking small-wheeler are copyright of Tony Hadland.)

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