>Please straighten me out if this is incorrect.
>
>My understanding is that the rise on Randonneur bars
>flanking either side of the stem was to give additional clearance
>for pulling up those curved Randonneur brake levers.
The reason for the rise of the Randonneur handlebars is to provide a more comfortable position BEHIND the brake hoods. Due to the upsweep, the bars fit the palm of your hand perfectly there.
However, in order for this to work properly, the bars must be shaped a certain way. The old AVA Randonneur handlebars did this best:
http://www.vintagebicyclepress.com/
The new Grand Bois "Randonneur" handlebars are a copy of this shape
http://www.vintagebicyclepress.com/
Many other "Randonneur" handlebars have the upsweep, but don't have the subtle shape to provide the extra-comfortable hand position. For example, the Nitto Randonneur bars and some GB "Randonneur" bars I have seen didn't offer any additional comfort over a standard handlebar.
The "Randonneur" shape is quite old - as you can see in "The Competition Bicycle," Nicolas Frantz used them in the 1928 Tour de France. It was only after World War II that the shape was called "Randonneur," from what I can tell. By then, racers had moved to other shapes.
Disclosure: Vintage Bicycle Press sells Grand Bois "Randonneur" handlebars.
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com