1981 Lotus (Tsunoda) Super Pro Aero

Model VS-18
Serial no. MM04212


Purchased from Tom Jordon on 25 April 2014 for $900 as a complete machine. Back on the road 7 December.

One of the most dynamic eras in racing bike design and development, the 1980s saw the widespread introduction of carbon and alloy frames, oversized steel tubing such as on the Masi 3v, "low profile" frames and various efforts at aerodynamic design culminating in one of the great innovations and commercial flops of the decade: the "aero" frame designed around Shimano new Dura-Ace 7300 Aero component series. Arguably the finest aero racing model of its time and the first introduced to the US market, was the Lotus Super Pro Aero of 1981-83.

Founded in 1979 by Sidney Star, Lotus featured a complete line of lightweight cycles made in Japan by the well-established (dating to 1905) Tsunoda Industries, one of the country’s largest contract builders. Lotus was more than a marketing outfit and Star worked closely with Tsunoda, Pacific Cycles and framebuilder Yamaguchi and possibly Maruishi to develop a comprehensive range of top quality lightweight cycles for the U.S. market. Favoured by then prevailing exchange rates of the dollar and yen vs. British and European currencies, Lotus coincided with a shortlived heyday of Japanese designed and built racing bikes and new component concepts by Shimano, Nitto, Araya and Tange.

Concurrent with the development of Shimano revolutionary aerodynamic Dura Ace 7300 and 600 AX series of components (introduced in autumn 1980), Tange designed a new aero profile oval tubing set, Aero Dynamic Cro-Mo D.S.G. (double straight gauge) with an existing fork design tweaked to give an aerodynamic contour to the blades and a new fork crown. Tsunoda was the first to design a frame out of it and in fact made all of initial aero frames which in addition to being sold under its name were rebranded for SR, Shimano and others.

Sidney Star embraced the aero concept for Lotus and was the first to introduce it to the United States market on a commercial basis after a one-off frame was made (in one day!) for the New York Bike Show in January 1980 by Jim Merz for display at the Shimano stand. Three prototypes were built in 1981 for Lotus’ sponsored attempt to break the transcontinental record from Santa Monica, California to New York by Jim Black in June, and painted in a striking pink livery. One of these still exists in a private collection.

Although the record attempt was not successful, huge interest in the aerodynamic concept saw the first production models introduced to the U.S. Market in September 1981 as the Lotus Super Pro Aero. These differed from the prototypes and other Tsunoda aero machines in being made of Tange Aero Dynamic Cro-Mo Butted tubing while retaining the all chromed fork and rear drop-outs of the prototypes, a refinement not seen on other Tsunoda made frames.

Painted in a brilliant polychromatic champagne gold, they had the complete Shimano Dura-Ace 7300 Aero component set except for the stem and bars which were the even more revolutionary Nitto Crystemblue two-piece bolted on face plate stem, the first of its kind, and mated to aerodynamic ADX bars with flat contours and designed to be ridden only on the drops. Among the first aero section V rims, Araya Aeros, were fitted. The Dura-Ace AX set was revolutionary in many ways with such unique concepts as concealed aero brake cables, a completely new Para-Pull brakset that was aerodynamic in profile and unique in its “clamshell” operation and Dyna Drive pedals which positioned the shoe at the same line with the pedal axis providing a more stable pedaling platform, lowering the centre of gravity and directing more of the power into the stroke. The wheel hubs were engineered to let the bladed spoke heads all face the same direction and a new cassette style 7-speed freewheel was introduced. Indeed, there was not a single component of the Lotus Super Pro Aero, including the frame, that was not totally and quite breathtakingly new and novel.

Not unexpectedly for a whole new concept in frame and components, the Lotus Aero Pro was not without its faults. Its biggest drawback was weight. As the oval shaped Tange Aero Dynamic tubeset had less lateral strength and rigidity compared to conventional round tubing, the side walls were thickened which added weight as did the beefy but still aero profile seat and chain stays. Even with the butted version of Tange Aero Lotus used, they weighed about 22.5 lbs or two pounds more than their contemporaries. In the end, the 10% increase in weight mattered more in the market place than the claimed 21% decrease in wind resistance since the added weight was palpable and the aerodynamics less perceptible to the rider. The heavy frameset was not helped by the equally chunky Shimano AX series components and earned these machines the unwelcome moniker of “Aero Slugs”. Further, they never found any acceptance in the pro peloton except those sponsored directly by Shimano as well as some amateur riders.

These were expensive and difficult machines to mass manufacture and were, in fact, individually handbuilt. Although the Tange aero tubing had a lugset, the initial Tsunoda machines were fillet brazed with only the bottom bracket of lugged construction nor could existing jigs be used for construction. The distinctive oversized flared airfoil headtube found only on the lugless models was achieved through labour intensive handfinishing using Bondo.

Built to showcase Shimano's entire AX aero component system, it was said that they sold the complete component set at cost to Tsunoda to offset the expensive frame production cost lest the retail price be uncompetitive. And in the end, the overall success of the machine depended on the performance and appeal of the components. As is too well known, the entire AX effort was, to use that early 21st century term, an "epic fail" on almost every level. While the Dura Ace AX chainset and pedals were admired for their stiffness, design and performance, the derailleur and brakes were fussy, over-engineered and hard to adjust. Shimano invested a fortune in development, tooling and elaborate brochures to sell the concept. From a sales perspective, the aero concept didn’t even translate into a “craze” other than a self-generated one.

An undoubted triumph of Japanese engineering, design and fabrication skill and flagship of the nasceant Lotus line, the Aero Pro retailed for $1200.00 in 1982 ( $2852.00 in 2013 dollars) putting it at the very top-end of professional racing bikes at the time. For 1983, the Super Pro was offered in an alternate Raspberry Pink metallic and the decals were changed. That year Lotus introduced the Aero Sports using lugged Tange Aero Dynamic Cro-Mo D.P.G. tubing and Shimano midrange 600 AX components and costing $800.

By mid 1983, the whole aero thing had pretty much run its course and Lotus withdrew both the Pro Super and Aero Sports at the end of the model year. The following year, Shimano stopped production of the entire AX series. Even so, the concept widely influenced other components including Campagnolo's C-Record and aerodynamic elements in component design would remain a force through this day. For Shimano, the sales flop of the AX series more than paid off in the end as it gave the brand a market presence and respect for innovation it did not enjoy before. For Japanese made bicycles, the boom was ended when the exchange rate of the Yen vs. the Dollar shifted and they cost as much to produce as European machines before the decade was over. “A Glorious Failure” perhaps, the Lotus Pro Super Aero represented a high point in Japanese racing bike design and manufacture.

The Restoration
A nice original condition example of the Lotus Super Pro Aero, this was acquired as a complete machine. The paint, chrome and "stickers" were all in remarkable good, original condition. Return to the road took much longer than anticipated owing to difficulty sourcing the early Araya Aero rims in the original polished alloy finish. The saddle was replaced with a NOS correct Kashimax Aero one, NOS brake shoe pads, NOS “aero” plastic headset cover and the elusive aero brake cable tidy, Cat-Eye cello bar tape, Shimano aero bottle and cage and a longer 100 cm version of the rare Nitto Crystemblue stem. Except for the Czech Tufo narrow section 19mm Jet Pro tubular tyres, the machine is of entirely Japanese manufacture.

The Ride
For a commercial flop, this is a darned nice racing bike, beautifully made, a delight to look at and appreciate that when it was introduced every bit of it was entirely new in concept and appearance. Every component, even the little aero shaped cable tidy, plastic headset cover and the wonderful water bottle is beautifully designed and aesthetically pleasing. It is a bit disconcerting at bit since from the rider position the thin aero profile of the main triangle is most apparent and the frame almost disappears underneath you. I don't find the ride nearly as whippy as some and indeed the frame seems very stiff and ride somewhat harsh. The superbly rigid cranks and brilliantly engineered Dynadrive pedals combined with the rigid rear triangle give it a nicely responsive response to the pedal stroke. The most aerodynamic aspect of the machine are the gorgeous Nitto stem and 'bars which swoop down and forward and are flat profile on the tops, compelling one to "ride on the drops" giving remarkable efficiency in air flow and pedal efficiency. I usually ride on the drops so this seems natural, if one doesn't, I suspect it takes more getting used use to. The much maligned Dura-Ace 7300 brakes and derailleur are far better than I imagined although having 7-speeds to use seems rather a lot... remember this was one of the very first commercially made racing bike with 7-speeds as standard and the first with a "cassette" rather than freewheel. Distinctive, different and delightful, the Lotus Pro Super Aero might finally find appreciation some 34 years after its introduction. It certainly has with this owner.

Frame
Material: Tange Aero Dynamic DB Cro-mo oval tubes frame and forks
Finish: (original) metallic champagne gold with chromed front fork and rear drop outs
Size: seat tube 62 cm (c to c ), 63 cm (c to t) top tube 57 cm (c to c)
Chainstay length: 41 cm/16.25" (c to c)
Wheelbase: 39.5 inches (c to c)
Bottom bracket height: 10.75"
Angles: 74˚ (head) 73˚ (seat)
Fork offset: 2"
Rear spacing: 126 mm
Lugs: conventional on bb only, fillet-brazed head and seat
Fork Crown: Tange 160 Aerodynamic full sloping
Dropouts: Shimano EF (June 1980) forged date code rear and Shimano front
Braze-ons: gear lever bosses, chainstay gear cable stop, bb cable guides, chain rest, top tube brake cable clips and pair of bottle cage bolt bosses on downtube
Frame features: aerodynamic oval tubes, lugless filet brazed, recessed brake bolts

Components
Rear derailleur: Shimano Dura-Ace AX RD-7300 214 g.
Front deralleur: Shimano Dura-Ace AX FD-7320 88 g.
Gear levers: Shimano Dura-Ace AX SL-7321 B type braze-on 64 g.
Chainset: Shimano AX FC-7300, BCD 130mm, 43t x 52t chain rings, 170 cm cranks date code FD (April 1981) 632 g.
Bottom bracket: Shimano AX BB-7500 English thread, 68-112 spindle
Headset: Shimano AX Dura-Ace SM-HP10 English thread with AX plastic aero cover
Stem: Nitto Crystemblue 100 mm 22.2 quill 25.4 clamp 330 g.
Handlebars: Nitto Adb-X aero 39cm, Cat Eye blue cello plastic tape and plugs
Brakes: Shimano Dura-Ace AX BR-7300 Para-pull 334 g.
Brake levers: Shimano Dura-Ace AX BL-7300 aero with original brake hoods 107 g.
Brake/gear cable housing: Shimano Dura-Ace AX original grey
Seat pillar: Shimano Dura-Ace AX SP-7300 C type 28.6mm 244 g.
Seat binder bolt: Shimano Allen grub screw style bolt
Saddle: Kashimax Aero AX-4A 350g
Pedals: Shimano Dura-Ace AX PD-7300 214g (incl clips and straps)
Toeclips and straps: Shimano alloy clips and blue nylon straps
Rims: Araya Aero 1 700x18.5 32-hole polished alloy 300 g.
Hubs: Shimano Dura-Ace AX FH-7370 Freehub 32-hole with Dura-Ace quick release skewers, FA (Jan 81) front and FC (Mar 81) rear date codes. 596 g.
Spokes: Araya bladed stainless steel
Tyres: Tufo Jet Pro sew-ups 700x19
Cassette: Dura-Ace AX Oro Uniglide seven-speed 13-14-15-16-17-18-19t
Chain: Shimano Dura-Ace Uniglide Oro CN-1700
Accessories: Shimano aero bottle and cage SM-BT10 132 g.
Weight: 22.6 lbs