I think the point here is that there are small variations in threading between parts with the same nominal thread, and TA seem to be playing with these small variations to make a TA pedal that works fine with a TA Cyclotourist crank and OK with French cranks, and Cyclotourist cranks that work fine with TA pedals and OK with English pedals. Whether this is a good idea is debatable, and I have certainly found it confusing since purchasing the pedals, but TA seem to be achieving their objectives, questionable as those objectives may be.
I have read for years that a French pedal will tear the threads out of an English crank, but when you put aside the theory and actually try it, you find it usually isn't true. The fact is, a well tightened French pedal often works fine in an English crank. This happened a lot by accident during the bike boom, when French bikes arrived at US bike shops with French threaded Lyotards which were almost indistiguishable from English threaded Lyotards, threaded into English threaded Stronglight cranks. I bought such a bike brand new and rode it for over year, including frequent club rides, before noticing this when I went to upgrade the pedals. When I related this on the list a few years ago, a lot of people who had never tried this told me it was impossible. Just demonstrates that 5 minutes of experimentation in any field is worth twice as much as a lifetime of theorizing. Not that I would advocate this combination, but most predictions of disaster prove to be exaggerated.
This subject has probably been "beaten to death" unless one is considering buying TA pedals or Cyclotourist cranks. I did both , and I presume this is exactly the sort of forum where others may be considering these products. In that case, it may be of some interest where these products work great, where they work OK, and where they don't work so well.
Regards,
Jerry Moos
Houston, TX
> 14X1.25 VS 9/16X20 have essentially the same thread pitch,it is
> the diameter
> that is different thus hard to thread a ENG pedal into FRENCH while
> other way is sloppy.
> When using an ENG pedal on a FRENCH threaded arm you are
> basically using what is the equivalent to a FULL ROLL tap(which rolls
> threads on instead of cutting them) to form new threads thus I am pretty
> sure you would not see any "SHAVINGS"
> The converse would be FRENCH in ENGLISH you would be pulling
> the threading out and sure might see something come out with your pedal!
>
> There is something inherently creepy about loose threads and I
> would advise against using a undersize pedal with any crankset, that
> said I would think the vision of the resulting injury would cause
> everyone to pause.
>
> BOB FREITAS
> who keeps it to the closest MILLIMETER everyday
> in MILL VALLEY,CA
>
> machinist types who disagree can take it off list or into the
> alley but I think we have beat this thing to death
> twice.................................