Vincent brake design
There exist quite a few problems with Vincent brakes and from what I have read in MPH, Phil Irving the ingenious designer pointed that out many years ago himself stating he made them too small in the first place.
Being of a seven inch single leading shoe design, they may have been okay or even good at their time, but in todays traffic the vast majority of them are mediocre if not plainly bad. There are many club members around that found different ways to bring the brakes up to task, I have listed the most common modifications on the ” brake mods” page.
There are also members that have built their own brakes, really good and beautiful looking ones like Paul Packman’s 4ls 7″ brake. He sent me pictures of his brakes a year ago and they are a piece of art indeed..
After more than 60 years, now most of the brakes have been partly or fully replaced with remanufactured parts, but usually only the brake shoes and worn out drums get replaced. A real problem after such a long time are the brake plates that are possibly buckled, the pins bent and they are simply not good for further use. Even if they are okay they still tend to flex when the brakes are applied hard and much of the power applied when gripping the lever hard is simply used to bend the plate rather than increasing the braking power.
Shoes tend to be bent or twisted and are of such a weak design that again the shoe gets distorted in a vain attempt to increase breaking power. The geometry of the brake shoe and braking compound fitted to it, probably reflect ease of fitting and manufacturing of that era. The shoes and the location of the brake compound fitted to them are not designed to have powerful brake or a high brake shoe factor. Due to the geometry the trailing shoe is first and harder engaged during braking than the leading shoe who actually does most of the work to slow you down. There are ways to overcome this problem -mainly by reducing the compound length on the trailing shoe- but you are actually working around an inherent design problem.
The best thing that can be generally said about a sls brake is that the braking power is the same in reverse direction. Good for cars and especially for outfits stopping on a steep hill.