The featherbed frame was a motorcycle frame invented by the McCandless brothers and offered to the British Norton motorcycle company to improve the performance of their racing motorcycles in 1950. It was considered revolutionary at the time,"As opposition companies strove to develop completely new machines with multi-cylinder engines, far more powerful than the Norton single, Bracebridge Street was content to find new speed in 1950 with a revolutionary new frame which steered and handled so superbly that it immediately earned the now forever-famous tag Featherbed". Sixty Years of Speed, 1967 a Motorcycle News publication, pp.41-42 Accessed 26 January 2018Motorcycle handling and chassis design: the art and science by Tony Foale. 2006 and the best handling frame that a racer could have."Introduced in 1950, the featherbed Norton frame, designed by Rex McCandless, of Belfast, became, and still is, the standard by which handling and steering of all racing machines is judged". Sixty Years of Speed, 1967 a Motorcycle News publication, p.41 Accessed 26 January 2018The Café Racer Phenomenon by A Walker. 2009 Later adopted for Norton production motorcycles,Motorcycle Mechanics, August 1966, pp.36-37 Featherbed stripdown. "Developed from the one-time, world-beating Manx Norton, the Dominator 'featherbed' frame is still regarded as the ultimate in steering, handling and roadholding." Accessed 8 February 2018 it was also widely used by builders of custom hybrids such as the Triton, becoming legendary and remaining influential to this day.Motor Cycle, 23 April 1964, pp.494-497 Norton Featherbed Twins by John Ebrell. "The famous featherbed frame, beloved of specials builders. Its absolute rigidity makes a big contribution to the legendary Norton roadholding". Accessed and added 4 February 2018Do not mourn the Featherbed! Motorcycle Sport, August 1978, p.218 "The Featherbed Nortons were some of the all time greats, but to ascribe to the shape of the frame some magic properties is to detract from the design of the whole bicycle, its weight distribution and geometry and to give to the frame's progenitors some of the credit due to the likes of Ken Sprayson, who knows a thing or three about its development." Accessed 10 January 2018
The Featherbed inspired other frame builders who based their own products on similar principles, including the 1960s heavyweight Münch Mammut,Motor Cycle, 3 February 1966, pp.142-143 On the Four Winds by 'Nitor'. "Engine is from the NSU Prinz car and may be specified in 43 or 52 bhp trim. In my picture you can see how well it fits into a featherbed-style frame". Accessed and added 2014-09-28. Re-accessed and quotation added 8 September 2018 a lightweight version for a 250 cc BSA C15 engine,Motor Cycle, 24 November 1963, pp.696-699 All the rage by John Ebrell. " ...Ilford's CeeR-Speedshop. For £29 they'll supply the C15 rider with a featherbed-type duplex frame". Accessed and added 2014-09-28 and the 1970-conceived Dresda frame.
The Featherbed was replaced by the Norton Isolastic frame in 1967 for the then newly developed Norton Commando which used a rubber-mounted engine and gearbox,Norton By Mick Woollett. 2004. although Norton continued to offer the Mercury with a Featherbed frame until production ceased by 1970. Replicas of the frame continue to be produced by specialist companies.Classic Bike, October 1989, p.80 Barber Engineering advert (Norfolk, England). Replica frame builder. G50/7R, Featherbed and Seeley Mk3. Other frames to pattern." Accessed 10 January 2018Andover Norton Frames and Auxiliaries made to factory drawings Retrieved 2014-09-28
Origins In 1949 brothers Rex and Cromie McCandless offered Norton a new frame to support their successful 500cc race single. Rex McCandless was a self-taught Belfast motorcycle engineer and raced competitively with his brother on a Triumph Tiger 100. He had made several improvements to the Triumph, notably an innovative new frame with a swinging arm fitted with vertical hydraulic shock absorbers from a Citroen car. BSA bought several of his converted motorcycles but Norton saw the real opportunity and contracted him to work exclusively for them from 1949. The Norton Motorcycle Company were concerned at the reliability of their plunger (or "Garden Gate") frame, as several had broken through the stress of racing. Norton engineer Joe Craig solved the problems by making the frames heavier but handling suffered as a consequence.
Norton commissioned the McCandless brothers to design a complete frame, incorporating a swinging arm. McCandless' finished design was expensive, as it required over forty feet of the best Reynolds steel tubing. It was a welded twin loop with a swinging arm fitted with their own design of shock absorbers, with a heavily braced cross-over headstock. In two months a prototype motorcycle with the new frame was on the test track and it was tested on the Isle of Man in the winter of 1949. It performed well and Norton decided that the Norton works team would have motorcycles with the new frames. The Norton works was not well equipped so the sif-bronze welding was undertaken by the McCandless brothers who produced the eight frames for the racing team by hand. Production featherbed frames were made under Ken Sprayson's direction at Reynolds, who became known as 'The Frame man'Do not mourn the Featherbed! Motorcycle Sport, August 1978, p.218 "No one would argue that there was a better roadholding bike in the 50s than the Norton. That it was capable of taking more power than the Dommie engine could give was proved not only on the race track by the Manx version and the Domiracer but also on the road by those who put Triumph engines in them." Accessed 10 January 2018
The patent Norton applied for a patent for the design on 13 October 1949 and it was granted as reference 664,667 but the completed specification was not published until 9 January 1952. The Featherbed frame was simply constructed: This invention relates to a new or improved frame for a motorcycle which comprises two substantially parallel rectangular loops each formed from a single length of tubing, and the ends of the tube forming each loop cross and are welded to each other at the top front corner of the loop, the free ends of the tube which extend beyond the crossing point being welded to the side of an inclined head tube adjacent to the top and bottom thereof. The assembled frame is extremely strong for its weight and designed to provide the maximum resistance to any stresses applied to the frame by road shocks or by the driving torque of the power unit.
The Featherbed name Harold Daniell was a successful Isle of Man TT racer with three victories and several placings in the Tourist Trophy races and the Manx Grand Prix.IOMTT.com Harold Daniell results database (retrieved 5 November 2006) After testing the new Norton frame in 1950 he declared that it was like "riding on a featherbed" compared with riding the "garden gateGarden gate is a reference to the plunger frame Nortons of this era"—and it has been called the featherbed frame ever since.
Racing success Further testing took place at Montlhery race track with four motorcycles running flat-out for two days. The new frame stood up well to tests and saw its UK launch at Blandford Camp in Dorset in April 1950. Geoff Duke had won the Senior Clubmans TT and the Senior Manx Grand Prix in 1949 on the earlier type Nortons, so was a clear choice for Norton to really put the new Featherbed-framed race bikes to the test. Duke won the race on the new design and several racing successes followed with Norton winning first three places in the 1950 Senior and Junior TT's. In the Friday Senior TT Duke set a new lap record of 93.33 mph and also broke the overall race record, finishing in two hours, 51 minutes and 45 seconds; he had previously finished second to Artie Bell (Norton) in Monday's Junior TT. (Harold Daniell's Norton was third.) When it came to the bends on the twisting Island course the new frame gave the Nortons a distinct advantage.
Featherbed frames were also successfully modified for use in off-road racing or motorcycle scrambling.Off-Road Giants!: Heroes of 1960s Motorcycle Sport by Andy Westlake In the 1950s, Ron Hankin designed a featherbed-inspired Moto Cross frame for Les Archer junior, having curved downtubes to allow for greater front suspension movement without fouling the wheel on the frame, and with heavy bracing around the steering head tube. The frame was used with Manx Norton engines prepared by tuner Ray Petty, and also with a 500 cc Norton Dominator engine.That was the year... ...Les Archer became European MX champion Classic Dirt Bike, 7 April 2017. Retrieved 8 February 2018
Featherbed variants
Manx racer in Reynolds 531 Weight and strength were key factors in the design of the featherbed frame for the Norton racing team's Manx. 16-gauge Reynolds 531, a high-tensile manganese-molybdenum steel alloy, was used as it allowed the frame tubes to be made thinner for the same strength, as well as making for a more responsive frame. All the joints were Sifbronze welded, – a relatively low-temperature flame-braze – except for the sub frame which was initially bolted-on but welded in later versions.
Norton International In 1953 the Norton International was relaunched with a new version of the Featherbed frame made from grade A mild steel.
Domiracer 'Lowboy'
In 1956, Norton development engineer Doug Hele was tasked with creating a 500 cc overhead valve road-based racing machine to challenge the larger-displacement side valve 750 Harley Davidsons run in the same class at AMA-organised Daytona 200 races. Initially unsuccessful, the project was turned into creating a road-based race engine as a replacement for the ageing Manx Norton racer engine. Hele designed a lighter-weight, lower frame with slightly shorter wheelbase, based on Featherbed principles having slightly altered frame runs and shortened telescopic front forks which became known as Lowboy. The project was named Domiracer, and one was successfully raced to third-place by Tom Phillis in the 1961 Senior TT race."Undoubtedly a successful experiment but it did not go into production. In 1961 Norton prepared a special 500 ohv twin based on the Dominator roadster and Australian Tom Phillis raced it into 3rd place at 98.78 mph with a fastest lap of 100.36 mph. The frame was a lower-built version of the famous featherbed". Machines of the TT, Sixty Years of Speed, 1967 a Motorcycle News publication, p.42 Accessed 1 February 2018Story of the Domiracer, Classic Racer, Autumn 1988, pp.52-57 Accessed 4 February 2018 In 1962 the factory developed a Lowboy with a 350 cc Manx Norton single-cylinder engine and a 650 cc version using the Dominator 650SS engine but with a full-height Manx frame, both as tried by Derek Minter.
In 1962 the race shop closed and was sold to Paul Dunstall, who had already developed his own Norton Dominator-engined race machine campaigned by Fred Neville (deceased 1961) and Dave Downer (deceased 1963). Dunstall successfully developed 500, 650 and 750 versions, later producing a Lowboy frame kits sold to the general public. After the Dunstall organisation closed in the early 1980s, other specialists offered the Lowboy frame.The Minter Line Motor Cycle, 4 October 1962 pp.406-409. Accessed 28 January 2018Dunstall Lowboy frame kit, part number 1060, undated catalogue "The Dunstall Lowboy racing frame assembly allows you to build your own compact light and competitive racing 750. The kit is designed to accept the 750 Norton engine, but the 650 or 500 will fit just as easily." Accessed 28 January 2018Classic Racer, Summer 1989, p.11 Mick Hemmings advert, Accessed 28 January 2018. "Domiracer Lowboy Frame Kit. As used by Tom Phillis and designed by Doug Hele. Will take Manx or Twin engines c/w wide tubular singing arm, taper rollers."
Single and Twin cylinder roadsters in Featherbeds