Having read all the contributions justifying mounting the rear brake forward of the bridge, I remain entirely unconvinced of any of the arguments.
OK..so that position makes it easier to adjust the brake blocks if the bike is being set up with panniers and racks..But surely the reality is that the blocks are set up accurately before the bags are strapped on...and I dont see that readjusting them is a regular, daily or weekly matter, not even when touring loaded up. There have been enough bikes produced over many several decades by very savvy safety conscious manufacturers who, had they been convinced that it was safer and functionally more expedient to have the rear brake mounted forward, would have done so in a flash.
On touring bikes and road models requiring mudguards, it is necessary for the brake's arms to be longer ie larger clearance ones...these longer arms in turn act as longer levers which when they oscillate or vibrate under the strain of braking transmit more strain on the pivot bolts. In the 20s and 30s possibly earlier, manufacturers always used systems of anchors or straps to prevent the long brake arms from being forced to move in the direction of the rotating wheels. One massive manufacturer. Automoto ,actually developed a front brake for every-day bikes, that bolted onto the back of the forkcrown. This was not done for aerodynamics but in order to limit the amount of bending and forward movement that could occur in the brake under the strains of braking. Manufrance, another very large manufacturer,also introduced such a brake and continued to use it well into the 1950s until the Mafac Racer became ubiquitous.
In a week in which another relatively unspectacular-looking Rene Herse frame has notched up an immense selling price on Ebay, I am convinced that if there was/is any advantage in having forward-mounted rear brakes then such pioneers of the heavily laden touring bikes ie Herse, Singer, Sabliere Pitard, Charrel etc etc would have locked into this style many years ago.Only Routens adopted it, even going so far as to facillitate the easy flow and movement of the rear brake cable to the straddle wire by passing it through a fine steel tube that pierced the seat tube of the frame. Odd..or what?
I notice that when Jack Taylor used two brakes on the rear bridge, the forward brake was a normal side-pull caliper one...the other being a brazed on cantilever. I am not certain about this...but I assume that the forward brake was the ancillary one, possibly for coasting, operated by the stoker. On two occasions I have used double brazed on cantievers on the rear of touring bikes, fore and aft of the brake bridge.. These have been interlinked by a system of metal rods that actuate both brakes at the same time, the rods also acting to limit any untoward tendancy to vibrate by the forward brake;they were worked by one Mafac tandem lever The system worked well when properly set up but has disadvantages such as tending to apply too much friction to the rim causing it to heat up. Fortunately we never caused a tyre to explode. I have to admit that there are better combinations of two brakes at the rear...but this system looks very neat and can be very efficient, particularly if the person pulling the brake lever understands its constraints and limitations.
Norris Doubting Thomas Lockley
Settle UK