Based on bikes in my collection (mostly Italian from the 1930s thru 1970s) my theory is as follows:
Originally, longer-reach brakes allowed plenty of room for fatter tires, fenders, and mud clearance. As roads improved, skinnier tires could be used, and less mud would accumulate around the brake areas.
Shorter fork blades and short-reach front brakes go hand-in-hand.
Although short-reach brakes give better braking performance, they won't work with the early front-opening horizontal dropouts. Early on, "horizontal" meant nearly that - parallel to the road. The dropout openings were far from perpendicular to the seat stays, which meant that, as the wheel is moved forward for removal or adjustment, the tire gets closer to the brake bridge. Unless you let the air out of the tire, short-reach brakes would not allow the wheel to move forward enough for removal.
I've noticed that on my 1940s bikes the dropouts are more horizontal, less so in the 1950s, and even less in the 1960s. As the dropouts approached perpendicular to the seatstays, short-reach rear brakes became practical. The dropouts on my 1980s bikes are nearly perpendicular to the seatstays, and all have short reach brakes front & rear.
This is just a guess, but some of this may have to do with the influence Tulio Campagnolo had on racing bikes during the 1940s and 1950s. His "sliding hub" shifters might not work as well if the dropouts are too steep i.e. perpendicular to the seatstays... you'd have to "lift" the bike further when shifting to a larger cog. Sorry, but it's hard to explain without visuals. It seems like the switch to short-reach front/long-reach rear brakes came during the 1940s, same time as Campagnolo drop-outs and sliding hub shifters. After the cambio Corsa and Paris-Roubaix shifters disappeared, the dropouts could begin to get steeper.
So... short reach in the front because they work better, long reach in the back because short reach wouldn't fit until horizontal dropouts got steeper.
Only my two cents...
Middletown, Ohio, USA
> Gentlemen and ladies,
> I'm risking your scorn by asking what may be an old chestnut of a
> question, but I have tried the archives and can't find an answer.
> We've noticed a design "feature" on many frames from many countries and
> built over several decades: the rear brake reach is longer than the front.
> It seems most common on older ('60s) frames where centerpull brakes are
> spec'd, but certainly not exclusive to them.
> What's the purpose (or purposes) of it?
> And if it was a good idea back in the 1950s to early 1980s, why not now
> (other than the obvious, economy and simplified manufacturing)?
> Thanks in advance (for any info and for your indulgence)
> Alan Goldsworthy
> SF, CA, USA