khs aero turbo

esse artigo saiu na Bicyclist Magazine, de setembro de 1996, publicada pela Petersen Publishing Company. transcrevo-o inteiro aqui, já o achei em meia dúzia de blogs. é sobre uma bicicleta lendária dos anos 90. antecipou em 10 anos o que se veria nas Cérvelo P3: o seat tube curvo. não conheci nenhuma bike de cromo com o chain stay tão curto, com a traseira tão curta. esta bike anda! e como anda!

tenho um quadro desses aguardando a pintura e a montagem. quando terminar, mostro aqui. lembrando que “khs” é a abreviatura de: Knowledge Health Strenght.

Steel Bikes – KHS Aero Turbo 1997

“Courtesy Bicyclist Magazine, Petersen Publishing Company” and feaured in the September 1996 issue

KHS Aero Turboby Patrick Brady
Studio photography by Lynne McCready

Imagine a bicycle designed for a novice rider. Picture a ride that can teach the rider a thing or two about sprinting, allows its owner to concentrate on power output and not handling during a time trial, and can climb with the sort of quick agility that makes you wonder if you could be a pro. Give it a price tag that won’t break the bank but is still enough to hold up under racing. Imagine all that in one bike and you’d come up with something like the KHS Aero Turbo.

KHS approached three masters of the fast bike: Boone Lennon, Lennard Zinn and Steve Hed, and hit them with the idea of designing a fundamentally aerodynamic bicycle that could be brought to the masses, a bicycle that would function nearly as well as a dedicated crit bike and could still time trial as well as a dedicated time-trial bike. Lofty expectations? Definitely.

In Nordic skiing nobody buys a combination skating/diagonal ski because it’s too long to skate on and it’s too stiff and short to kick and glide on. You’d end up with one pair of skis good for, well, nothing. It just so happens that bicycles don’t have to suffer from the same pitfalls skis do. According to Zinn, the Turbo’s primary designer, it is possible to create a bicycle that gives nothing up in handling in two of a rider’s most commonly encountered race situations such as time trials and criteriums.

The Wish List

Zinn, Hed and Lennon went into the project with a few requirements in mind. For Zinn the bike had to handle well – there didn’t seem to be much point in making a bike aerodynamic if the rider couldn’t hold the position or if it felt squirrelly through the corners. Hed wanted a machine that gave the rider an aerodynamic advantage just by climbing aboard. The final hurdle was making sure the rider was in an aerodynamically efficient position in order to capitalize on the bike’s assets (Lennon’s department).

Normally, this trio’s main focus is to get a rider across the finish line as fast as possible, but for this project they decided to up the ante. In the face of the shrinking road market, they believed the creation of a multipurpose road bike might entice some new enthusiasts into the sport. Citing the prohibitive nature of having one bike for each discipline, Zinn explained they wanted to make a bike that didn’t immediately create a need for more and, in an effort to short-circuit dealer stock issues, they decided to offer the Aero Turbo in just three highly adaptable sizes.

On paper, offering just three sizes – 52, 55 and 59 centimeters – might seem unfairly selective. But a closer inspection of KHS’ methods indicate some very strategic planning. The quest for an aero bike led to the use of a shorter-than-average head tube. That was coupled with a flat (instead of down-sloping) top tube and a seat tube that extends 2.5 centimeters above the ovalized top tube.

Our test bike measured 55 centimeters from the center of the bottom bracket to the top of the seat tube. When measured in the more traditional method (from the center of the bottom bracket to the top of the top tube), the KHS suddenly has a very stubby 52.5-centimeter height. While that may seem odd, the presence of a 23.5-centimeter seatpost shows the bike for what it truly is: versatile.

Our 55-centimeter bike can fit riders who would otherwise ride bikes ranging from 53 to 57 centimeters. The top tube measured a very traditional 54.5 centimeters (relative to a 55-centimeter seat tube) and with the proper choice of stem could fit a range of riders. Our test bike came equipped with a 130-millimeter stem.

If I were buying this bike for myself, I would have settled on the 59-centimeter model. Had I changed the stem of our test bike to a length more appropriate for me, I would have been looking at something on the order of 160 millimeters and, in my opinion, would have ruined the ride of an otherwise nice handling bike, but I’ll get to that.

Autopilot

Drawing from his experience of designing a special fork for the bike John Stenner used in winning the national time-trial championship, Zinn designed the bike so the rider would be positioned farther back on the bike relative to the position of the wheels on the ground. It was Zinn’s intent to shift as much weight as possible from the front wheel to the rear, thereby making the bike less skittish under weight shifts.A bike less prone to changing direction under movement by the rider does require more rider skill in order to corner quickly. Zinn noted that Stenner’s ability to countersteer made him incredibly fast in time-trial turnarounds. “If you can countersteer,” Zinn said, “you can corner [with this bike] as fast as anybody.” (See “Pro Riding Secrets,” Aug. ’96 for tips on countersteering.)

In order to make these changes, the rear wheel had to be as close to the bottom bracket as possible. With 37-centimeter chainstays the rear wheel was slotted into place rather tightly. There might be a bike on the market with shorter chainstays (and still uses a 700c wheel) but I haven’t seen it. The absence of a chainstay bridge was immediately noticeable, but the stays themselves left enough clearance to run a tire as wide as 25c.

With a rear end tighter than that of a volleyball player on a Malibu beach (male or female), this bike was given a longer-than-usual front center in order not to give the bike an unusually short wheelbase.

Time Well Spent

I’ll admit my first mile on this bike was perhaps the strangest experience I’ve had relative to bicycle position. To call the 75-degree seat tube angle steep would be like calling the air in L.A. hazy. I swore to myself that the saddle needed to be back farther – like the next county. The sensation of being so far forward didn’t leave me on the first ride but it did somewhere along the second. Out on my first hammer session on Pacific Coast Highway (PCH to the locals), I ceased to feel that I needed to be farther back relative to the bottom bracket.I was aware I had adopted a toe-down pedal stroke á la Armstrong, but it didn’t bother me. What’s more, my position on the bike seemed to benefit from maintaining a high cadence. Resting my palms on top of the 105 STI brake hoods allowed me to stretch out nicely and motor on a bike I shouldn’t have felt so confident on. I say shouldn’t because I believe an element of confidence on a given bike cannot come from within. Normally, I believe knowing a bike intimately is requisite to riding with the kind of confidence Sean Kelly exhibits.

I’ve had some experiences where I felt as if I knew what I needed to put into the bike in order to get back out what I wanted. That hasn’t usually come to me on a bike I’ve been on for a week or even a month, but I got that from this bike by my third ride. Sprinting felt intended; I never skipped the rear wheel, which I’ve certainly done on bikes I was less familiar with. I felt so powerful climbing out of the saddle, I began to wonder if maybe I’d misjudged my fitness level (maybe I am better rested than I thought).

My one reservation concerning the KHS Aero Turbo concerns distance: I wouldn’t take it on a ride longer than, say, 50 miles. Even so, KHS general manager Steve Richey and Zinn wouldn’t disagree with that assessment. Richey admitted, “With that rear wheel tucked in under the rider, it’s going to transmit a little more road shock than usual.”

Regardless, every ride I took on the Turbo was enjoyable. I hate finicky bikes so I appreciated the use of Mavic MA2 rims, the 105 group and the locking FSA headset. I’m apt to carry a bunch of tools with me (which I hate doing) if I don’t trust a bike. This bike was reliable in a way that let me leave some tools behind.

The fact that this bike attracts a lot of looks is less a testament to its workmanship than its unusual design. As a TIG-welded steed, the tube joints aren’t much to look at. The welds themselves are solid – no signs of undercutting – but then again, nothing to get excited about either. But the bike as a whole is impressive, especially when you consider most $1199 bikes offer a lower-grade mix of components.

Because of its unique appearance, this bike might not be a potential buyer’s first choice to test ride, but it will be the most distinctive. I never thought I’d like this bike in that deep-down fundamental way. I never thought I’d get excited trying it on new terrain, but it happened. I relished each new revelation: Oh, it sprints! It climbs! It motors.

Anúncios

6 Respostas para “khs aero turbo

  1. love bycycle go green. awesome post, keep on going

  2. Algum quadro similar chegou a ser fabricado depois? Se não, qual a razão???

    Abs!

    • sim e não. logo em seguida o mercado aderiu ao alumínio de forma massiva, e claro que com o alumínio, um quadro com uma geometria tão agressiva seria muito difícil de rodar. embora haja quadros de alumínio com traseiras bem curtas, mas nem tanto.

      é comum haver quadros não exatamente com o tubo vertical curvo, mas dobrado para dentro para encaixe da roda. a litespeed tb teve algumas edições da ultimate com o tubo ligeiramente curvo, mas não tão pronunciado.

      mas com a fibra de carbono surgiram diversos quadros com geometrias até mais agressiva. quadros para triathlon e ou/contra relógio, usando o tubo vertical com a parte de cima a 90 graus, e a óbvia curva embaixo encaixando a roda. a cervélo tem modelos assim.

      o grande detalhe é que fabricar em cromo com essa geometria às vezes contraria o atual consumidor dos quadros de cromo, que procura geometrias que privilegiem o conforto. quem quer quadros bem rígidos está bem servido com os quadros da cannondale, que não precisam de uma traseira tão curta para serem tão rígidos. pinarello dogma também é bem rígida, sem recorrer ao tubo curvo.

      por outro lado, com a especialização das bikes não se constróem mais bicicletas tão versáteis. a khs aeroturbo ao seu tempo poderia ser usada em contra relógios, triathlon, e brincar na estrada em provas mais curtas. hoje se usa uma bicicleta pra cada coisa.

      a minha tem a função óbvia de ser um foguetinho pra andar na cidade, e não pras longas distâncias na estrada. para prevenir a tentação de jogá-la na estrada (e arrepender-me 150 kms depois) coloquei um selim leve e desconfortável depois de muito tempo, pelo menos para mim: fizik arione.

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  3. Sim, sim… Por isso que mencionei ‘similar’. Seat tube mais ou menos aerodinâmico com um ‘rebaixo’ pro pneu traseiro já vi em outros materiais, principalmente carbono. O que a KHS tem de único é o tubo redondo e curvado, se bobear nem poderiam copiar então.

    E, de fato, um quadro atual de cromo *e* super-rígido seria contraditório. Sorte de quem tem 😉

    • joão, bikes com tubos curvos há desde a década de 30, principalmente em bikes para uso na paris-roubaix. as contra-relógio dos anos 70, 80 e 90 abusaram dos tubos curvos. algumas não tinham um tubo reto sequer, salvo o tubo da caixa de direção. ainda vo fazer um post sobre essas bikes.

  4. Pingback: aero, e turbo! | as bicicletas

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