ANTONISH wrote: AdamS wrote:
Bmblbzzz wrote:I assume this is a result of parts, in this case stems and bars, being designed in the USA then marketed to the rest of the world. Bar diameters were already described in mm for road (26.0 and various slightly variant designs).
I suspect it's more down to the UK's former importance in bicycle manufacturing. Inch-based British Standards more often than not became international standards. The 26.0mm size is a bit of an anomoly because it is a native metric (italian) size which became the standard for nicer road bikes. Not that I ever had 26.0mm drops, mine were 15/16" and 1".
My favourite is the Italian BB 36 x 24 ( 36mm external diameter - 24 teeth per inch )
It is easy to forget that until sometime in the late 1970s, the UK had the biggest cycle factory in the world, ( being Raleigh in Nottingham) and one of the biggest cycle export industries. Their designs dominated world-wide, pretty much.
Fortunately the US cycle industry has had little international impact on traditional cycle parts. Their contributions to traditional bikes you might find outside the USA are mostly confined to
- the (recent i.e. in the last few decades) popularity of the 559 rim size, which MTBs inherited from cruiser bikes.
- the use of 24tpi track nuts on some coaster hubs (which causes much wailing and gnashing of teeth...)
-Ashtabula BBs in BMX bikes
However more recently you can blame lunatic US-based designers for the endless proliferation of different BB and headset designs which don't work very well and are liable to be 'here today, gone tomorrow' for the most part.
I am told that the weird Campag/Italian threading standards were as a result of the Marshall plan; the Italians received a load of US built lathes etc which would only cut US-style imperial pitch threads.
However it might well go back further than that; whitworth threads used 55 degree flanks (as found in some Italian bicycle standards) and (obviously) inch dimensions. These thread standards were the first to be properly defined (anywhere) and all nations adopted them for a while. It was difficult to buy a screw-cutting lathe that would cut anything else, for a long time. For example I have a lathe manufactured about 1890 in Germany (which sold well at the time, tens of thousands were made and sold over the world) and it uses (and cuts) whitworth screw threads. There isn't a metric dimension in it.
Arguably one reason Germany lost WW1 was that their industry didn't have properly ratified thread standards, so for example parts from standard German army rifles etc wouldn't interchange with others made to the same design but in a different factory. They each used their own ideas for thread standards; they were quite happy if their
bolts fitted in their
tapped holes, with little thought beyond that. Germany produced their first DIN standard for screw threads during
WW1 and it was basically a straight copy of the whitworth standards, inch dimensions and all. Obviously anything designed in Germany before that wouldn't necessarily have used any standard.