Just when you thought it was safe to install pedals...
Most of us thought that worrying about matching threads on pedals and cranks was not a concern with new equipment, but yesterday's thread casts serious doubt on that.
Jan measures the new TA pedals, which are supposed to fit French or BSC cranks, at 13.80 mm, 0.43 mm less than English NR, and even slightly smaller than old French TA. Yet Peter says these pedals thread snugly into new "BSC" TA cranks, even requiring the use of a wrench to thread them all the way in. This implies the the TA "BSC" cranks are not infact 9/16 = 14.28 mm, but more like 14 mm, the old French standard.
It would appear that the ISO (English) standard we thought prevailed for the last 15 years is not so standard after all. But perhaps this is only TA, upholding that time honored French tradition of being different for the sake of being different. I must admit I have a sneaking admiration for the French "contrarian" attitude, which is one reason I like (and collect) French bikes. This reminds me of Mark Twain's line in his famous dialog "Sympathy for the Devil": "....I find this a very peculiar attitude. It is un-American. It is un-British. It is French!!!!"
I find it hard to believe that there is such a wide variation in crank thread between Campy and Shimano cranks. Since there are dozens of pedal manufacturers in many countries making pedals to the ISO standard and selling them for use in either Campy or Shimano cranks, a wide descrepancy would almost certainly have been noticed long ago. One assumes then, that it must be TA, which after all is no longer in the mainstream of the indusrty, which is doing things differently. One wonders if threading a third party modern pedal into a new TA "BSC" crank takes unusually high force on the wrench and in fact "taps out" the cranks. Anyone tried this lately?
Meantime, it would appear caution is in order in installing TA pedals, or in installing pedals in TA cranks, as the TA threads may not be as marked. One may have to revert to the method needed with 70's era equipment when both standards were common and some components were not marked. Namely, try cautiously threading the pedal into the crank. If it goes in easily by hand without using a wrench, it may be too small and should be used only with caution, and always kept well tightened. If it won't go in easily by hand, try a wrench with very modest force. If it goes all the way in , it should be fine. If the pedal tightens up after only a couple of turns and if modest pressure on a wrench is not sufficient, the pedal is too large. Don't force it unless you want to do a crude impromptu job of retapping the cranks. Unfortunately "modest" force applied with a wrench is a subjective thing, but I think most people used to working on bikes, especially those who have encountered French threads before, can judge this adequately.
The strange curent TA attempt to make pedals that supposedly fit either French or BSC cranks makes me wonder about the markings on old Lyotard pedals. Some are marked "R" & "L" and are almost always English. (I hesitate to use an unqualified "always" about anything done by the French.) Other Lyotards were marked "D" & "G" i.e. Droite=Right & Gauche=Left, and were almost always French threaded. But a significant number (I have several) were not marked at all. I now begin to wonder if these had a thread intermediate between French and English that could be used for either or maybe even had French thread, but would work OK with common French Made BSC cranks of the time if well tightened, and were deliberately left unmarked so French bike manufacturers could use them on either French or BSC cranks. This might have been of benefit to the French bike manufacturers, as, at least in the Bike Boom years, they tended to be rather inconsistent with equipment, using whatever was in stock, and often using up inventories of old parts before switching to a different or revised model. Just slapping pedals into cranks wthout worrying about threads would have sped up the assembly process.
Regards,
Jerry Moos
Houston, TX