Französische Fahrräder: Unterschied zwischen den Versionen

==Typische Abmessungen und Abweichungen zu "Standard"maßen==

{{:Unterschiede Maße BSA und Französisch (Tabelle)}}

AVA Death Stem  

Many higher-quality French bicycles of the '70's came with AVA brand bars and stems. These have a reputation for failure, and should be replaced.

If you convert from a French stem to a standard one, you will also need to replace the handlebars, which are a different diameter.

The threaded parts of a French headset are non-standard, but the press-in parts are conventional. If you have a worn-out headset, it is most likely the lower races that are damaged. If you have trouble finding a French headset, you can replace the bottom races with ones from a standard headset, and keep the old parts on top.

French headsets use a different type of keyed washer than others. Instead of having a groove machined in the threads, the rear part of the threads is filed flat. French headsets commonly used a serrated keyed washer, with matching serrations on the threaded bearing race. This makes French headsets slightly harder to adjust, but once they are adjusted, they hold their adjustment better than conventional designs.

French-thread bottom bracket cups use 35 mm x 1mm threads. They are getting hard to find. If you have a French bicycle with sound bottom bracket cups, you may want to re-use them, even if you wind up changing the axle. Since French bottom brackets are normally the usual 68 mm width, British/I.S.O. bottom bracket axles will sometimes work.

See the selection of French bottom brackets and parts at Harris Cyclery.

The usual cotter diameter for French cottered cranks is 9 mm, rather than the 9.5 mm more commonly used on British and Asian bicycles.

Older TA and Stronglight cranks each had their own unique thread for for the crank extractor, and you will need to get the correct puller for the crank you are working on. TA used a 23 mm extractor, Stronglight used 23.35 mm until 1982, when it converted to the standard 22mm diameter. You must use the correct crank extractor. Be especially careful not to use a TA extractor on a Stronglight crank. It will thread in, but it may strip the threads in the crank.

Older Stronglight cranks used bolts with a 16 mm head. The common Park crank bolt wrench [unfortunately no longer made] will turn these, but most other socket wrenches will not fit inside the extractor hole. Use only bolts with a 14 or 15 mm head in a crank with a smaller extractor thread diameter.

Since the down tube and seat tube are slightly smaller in diameter on French bicycles, clamp-on front derailers, cable guides and stops, and down-tube shift levers may in some cases not clamp tightly enough. This is not usually a problem in practice, but does cause trouble occasionally. You could shim the tube with a couple turns of vinyl electrician's tape.

Older French bicycles used a different, smaller diameter where the pedal screws into the crank, 14 mm x 1.25 mm.

The vast majority of French bicycles imported into the U.S. used standard 9/16" x 20 tpi crank threading, but if you find an older bicycle that was bought in France, you may run into this problem. The French-thread cranks can be tapped out to 9/16". This is much easier (and more worth the trouble) with aluminum cranks. Start the taps from the inside of the cranks, so any possible thread damage occurs where it doesn't matter. French pedals will often be marked "G" (Gauche=left) and "D" (Droite=right).

French-thread freewheels used a smaller diameter attachment to the hub. Neither the freewheels nor the hubs are interchangeable with anything else. Fortunately, they are quite rare: virtually all French bicycles sold in the U.S. had standard British/I.S.O. freewheel threads. In any case, unless you are restoring a collector's item, you will do well to spread the rear dropouts, and upgrade to a modern rear wheel with a cassette hub and index shifting -- see my article on frame spacing.

DESCRIPTION

Some French bicycles (and many early Treks!) came with Maillard "Helicomatic" rear hubs. This was the first cluster that could be removed without a big, powerful tool. It came with a cute little pocket-size tool that incorporated a spline wrench for the cassette lockring, a spoke wrench, and a bottle opener. The Helicomatic was a nice idea on paper, but poorly executed. These hubs are losers.

These hubs were prone to bearing problems as well. Due to clearance requirements, they couldn't fit the normal 9 1/4" bearing balls, so they used 13 5/32" balls on the right side. These didn't hold up well. The cones tended to wear rapidly, and replacement cones are no longer available to fit these hubs.

Most of the French bicycles that flooded the U.S. in the '70's had plain rear fork ends, and used rear derailers with bolt-on adapter claws, secured by the rear axle.

The better models, those with Reynolds 531 or other high quality tubing, commonly featured Simplex forged fork ends, with built in Simplex-type derailer hangers. These are not the same as the Campagnolo- and Shimano-type hangers used on modern bicycles. It is possible, however, to modify Simplex hangers. They have an unthreaded mounting hole, which may easily be tapped out to the standard 10 mm x 1 mm thread used by modern derailers. Standard derailer hangers also have a step at the bottom edge which limits the forward swing of the derailer. This can usually be supplied by judicious use of a file. Its angle may differ depending on the derailer. If the derailer hanger can't be made to work, you might remove it and braze on one that does, or use an adapter claw.

French spoke gauge numbers are lower for thinner wires, while the U.S./British gauge numbers are larger for thinner wires. The crossover point is right in the popular range of sizes used for bicycle spokes:

Fortunately, though, the thickness of most spokes is by now labeled in millimeters. When in doubt, measure! Spoke threading also may differ, so always get new spoke nipples to go with new spokes.

Most French bicycles imported into the U.S. before the mid '80's used 630 mm (27 inch) wheels. This size was never in use in France, and was only supplied on export models.