Sheldon Browns Fahrrad mit 63 Gängen: Unterschied zwischen den Versionen

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In the 1940s and '50s, high-quality bicycles were very rare in the U.S. One of the few keeping the flame alive was a Boston dealer named Charlie Hamburger, who had a shop near South Station. I have never met him, nor spoken with him, but he is reputed to have been a perfectionist, who accepted "Only The Best". In addition to being possibly the first to import Campagnolo components into the U.S., he brought in frames made to his specifications, mainly from France. I have heard that René Herse was one of his major sources, while other models came from Peugeot. He sold these frames under the trademark "O.T.B" (Only The Best.)

Sheldons O.T.B.

My introduction to the marque came in the early-1970's, when I was working at the Bicycle Revival in Cambridge, Massachusetts. A customer came in with an O.T.B. that he wanted to sell, and I bought it. He had helped Charlie Hamburger clean out and close down his shop, in 1957, and had been given a bike of his choice as payment. He had selected the frame, and equipped it with parts of his choice, setting it up for touring.

Der Rahmen

The frame is made from Super Vitus tubing, according to the decal on the seat tube, with moderately ornate lugs. Although it was labelled "model course speciale" (special racing model) the geometry is more what would be considered touring geometry nowadays; 72 degree angles, 22" top tube, 23" seat tube. Its most unusual feature is the seat stays, which are the narrowest I have ever seen.

It was painted an orangey red, with darker red pinstriping. The paint was in such poor condition that I repainted it myself, a rather amateurish brush job, but it doesn't look too bad from a distance.

Originalaustattung

When I bought this bike, it was an 8-speed with what was then called "alpine" gearing. (The meaning of this term has changed subsequently, largely due to the efforts of Frank Berto, who uses it in a rather different sense.) It had a "Rosa" cottered crankset, 48/30, and a Cyclo freewheel 14/16//19/26. These were shifted with Simplex derailers, the front being the type operated by a simple lever mounted on the seat tube. Other equipment included Lam sidepull brakes, and some very nice Fiamme 622 mm (700c) clincher rims.

Sheldons Fahrrad Nummer 1

After a few modifications, this became my main bike. I installed Sun Tour VGT derailers, Mafac centerpulls (state-of-the art at the time!), a Brooks Swallow saddle, wheels with Campagnolo Record hubs (high-flange rear, low-flange front) Weinmann wood-filled rims, Clément Criterium Seta tubulars, and converted it to a 10-speed, with a TA 51/26 crankset, and a 14/16/18/21/24 freewheel. This gave me a good cruising range on the 51, with the 26 used as a granny. Until I built my own frame, this was my pride and joy.

O.T.B. 74

otb drivetrain

An unusual feature of this bike was my home-made handlebar end shifters, made by mounting a down-tube shift lever just inside the end of the handlebar, so that it hung down inside the bar. These shifted in the opposite direction of normal barcons, and I rather preferred it that way. I've never been much of a racer, but the one time I raced this bike, in a citizens' race that involved a substantial off-road stretch on a hiking trail with lots of exposed tree roots, I got to pass a lot of people, thanks to the fact that I could shift while they couldn't. It also helped that I was a pretty experienced off-road cyclist, because I was in the habit of riding this bike around local hiking trails, singletrack, etc. The low gear really helped in those conditions, though the silk tubulars were not the ideal tires.

Another unusual setup detail of this bike was the pre-æro "æro" brake levers. (Installed after the photo above was taken.) These were conventional Weinmann levers, except that I ran the cables out the bottoms of the levers, rather than the tops. This was a very cool-looking effect back before the invention of modern "æro" levers, and also provided handy access to my handlebar bag (everybody used handlebar bags, back then!)

30 Gänge

After I built the Brown, which was conceived as an Italian-style criterium bike, I got more adventurous with the O.T.B. I converted it to 630 mm (27") clinchers and made it into a 30-speed, by attaching a 14-24 cluster to a Sturmey-Archer AW 3-speed hub. I rode it this way for several years, until I got the mountain-biking bug in the late '70's, and needed to pirate the 30-speed rear wheel to put on my kidback tandem.

Der letzte Aufbau

Being a firm believer that nothing exceeds like excess, I eventually turned my O.T.B. into a bit of a project bike. When Specialized introduced the Saturne X-22 rim, the first really light, narrow 559 mm (26" MTB size) (unless you count the handmade, cut-down Bontragers) I bought a pair of them, a pair of Panaracer 26x 1.5 radial tires, and built her up as a 63 speed machine. My hope was to make a bike that would do everything, on- or off-road. The frame had pretty good clearance to begin with, and the smaller diameter of the 559 mm rims/tires was easy to accommodate, as long as the tires were not too wide to fit between the chainstays.

The Panaracer radials turned out to be extremely unpleasant to ride (they are fast and efficient, but they always feel flat, there is a lateral floppiness that is just intolerable, at least with the narrow rims.) I replaced them with Specialized Streetstompers, which worked pretty well on and off road. I found that I did not enjoy riding this bike off road too much, however, so I replaced the Streetstompers with Specialized "Fat Boys", which are still in use. (Has any tire ever had a less appropriate name than the "Fat Boy?" When you consider that, at the time it was introduced, this tire was the skinniest tire available for this rim size, what could they have been thinking?)

It isn't easy to fit seven sprockets onto a Sturmey-Archer hub! P.T.B. hub

63 Gänge

The O.T.B. currently sports a Sturmey-Archer AW 3-speed hub, with 7 sprockets, driven by 3 chainwheels: 3 x 7 x 3 = 63. When people hear that I have built a 63-speed bicycle, the first question they ask is "do you really need all those gears?"

The answer, of course, is "no.", but I don't actually need all the gears on a ten speed either. In fact, most of my riding is done on one-speed (fixed-gear) bikes. Nobody needs 63 gears, but it was an interesting and amusing mechanical challenge to put it together, and it does give a very wide range, with close spacing between ratios. There are probably gears that this bike has never actually been ridden in!

Actually, I guess I was just ahead of my time, because a similar setup is now offered by Sachs, a 3-speed hub which is designed to take a 7-sprocket cassette. Nevertheless, as far as I know, I am the first to succeed in getting 7-sprockets to work on a Sturmey-Archer hub!

The toughest challenge of this was getting enough axle length. I used the longest Sturmey-Archer axle available, but even that was far too short for a normal installation on the right side. I used a conical countersink drill bit to countersink a hole into the adaptor claw, then I bevelled the edges of the special axle nut so that they would fit into the countersink. This only gives 5 or 6 threads of engagement, but since the countersinking prevents the axle from being able to slide forward, that is enough. Axles on internal-gear hubs have a tendency to rotate if not secured solidly, so I took extra pains on the left side to use the appropriate anti-rotation washer, and two nuts, both tightened quite snugly.

The cluster is a Sun Tour "Ultra 6" unit, which is threaded onto a threaded (old-style) Sturmey-Archer driver. This means of attachment leaves the freewheel rather far from the spokes, so far that there is room for a seventh sprocket. I have mounted the extra sprocket by bolting it (a 28 tooth) to the 24 tooth sprocket on the freewheel. (On my 54-speed tandem, I did a similar modification, turning a 5-speed 14-28 freewheel into a 6-speed 14-36, using an old T.A. chain ring as a rear sprocket.

Die Bremsen

When I substituted 559 mm (26") wheels for the original 622 mm (700c) size, the brakes would no longer reach the rims. For the rear brake, I used a BMX-type sidepull caliper, but for the front I wanted to retain the existing Mafac centerpull. I was able to do this by making an extender for the brake.

I used two short strips of aluminum bar stock (3/4" x 1/8"), and drilled 6 mm holes in each the end of the strips. I bolted the upper ends of the strips to the fork crown, using a long bolt running through the crown where the caliper would normally mount. One strip was in front of the crown, the other in back of it. The caliper then mounts through the lower holes in the two strips. I have a stack of washers between the bottom ends of the strips to hold them apart. This lowered the caliper by the distance between the holes in the strips.

I have a separate page on Home-made Drop Bolts, which explains this in more detail.

Doppelt angesteuerte Vorderradbremse

When I installed a clip-on ærobar, I found it a bit scary to go fast with my hand so far from the brake, so I rigged a second brake lever. This lets me use the front brake either from the normal bars or from the clip-on. I made a special yoke for the front brake, which has a cable stop with an adjusting barrel, instead of an anchor bolt. There is a single cable running in housing from the ærobar brake lever, looping down so that it comes up to the yoke from below. When the ærobar lever is squeezed, this housing pushes up on the yoke from below. The cable runs normally from the yoke to the normal brake lever. One of the levers has an anchor bolt in it, to secure the plain end of the cable.

The lever on the ærobars is a freestyle-type lever, which has a "stopper" button, allowing it to be locked up to serve as a parking brake. This handy feature has been included on several of my bikes. It helps keep the bike from falling over when it is leaned up against a wall or other object. It also provides a bit of protection against opportunistic thieves when doing quick errands in low-risk areas.

Quelle

Dieser Artikel basiert auf dem Artikel My O.T.B. - Only The Best von der Website Sheldon Browns. Originalautor des Artikels ist Sheldon Brown.


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