I have this 1938 Shelby with a 37 dated Morrow coaster hub. http://ratrodbikes.com/forum/viewtopic.php?f=6&t=72124
I cleaned up and rebuilt the bike and rode about 50 miles ...to observe that the brakes were the worst I have ever ridden.
Never to fear... I set out to remedy the shortcoming. 8)
This is a "brake cylinder hone".... there was a time when automobiles had a part called a brake cylinder ...and this tool was used to resurface the walls of the cylinder in a rebuild process.
Here we see it in operation... our purpose is to break the glazed mirror smooth surface on the inside of our hub.
At left is the original 37 dated "brake shoe". At right is a later 46 dated brake shoe. You can see they changed the design in later years to include a lot of "surface texture". The lengthwise grooves are meant to allow the braking action to sweep the grease and oil off the breaking surface and into a recess where it will not impede the breaking action. We are going to add some of these features to our early brake shoe.
A vintage bicycle repair manual recommends adding 3 grooves per segment to improve braking performance. Here is the tool I have selected to perform that operation.
Here is a visual hint of how I will cut the grooves
Here are the resultant 3 grooves per segment
After cutting the grooves I sanded (sparingly) lengthwise with some 36 grit sandpaper to add more surface texture. Here is the final result.
The hub was reassembled and testing ensued...The "after" result is much, much better than the "before" result. The bike was formerly unsafe to ride; and now brakes within a normal range of expectations.
I cleaned up and rebuilt the bike and rode about 50 miles ...to observe that the brakes were the worst I have ever ridden.
Never to fear... I set out to remedy the shortcoming. 8)
This is a "brake cylinder hone".... there was a time when automobiles had a part called a brake cylinder ...and this tool was used to resurface the walls of the cylinder in a rebuild process.
Here we see it in operation... our purpose is to break the glazed mirror smooth surface on the inside of our hub.
At left is the original 37 dated "brake shoe". At right is a later 46 dated brake shoe. You can see they changed the design in later years to include a lot of "surface texture". The lengthwise grooves are meant to allow the braking action to sweep the grease and oil off the breaking surface and into a recess where it will not impede the breaking action. We are going to add some of these features to our early brake shoe.
A vintage bicycle repair manual recommends adding 3 grooves per segment to improve braking performance. Here is the tool I have selected to perform that operation.
Here is a visual hint of how I will cut the grooves
Here are the resultant 3 grooves per segment
After cutting the grooves I sanded (sparingly) lengthwise with some 36 grit sandpaper to add more surface texture. Here is the final result.
The hub was reassembled and testing ensued...The "after" result is much, much better than the "before" result. The bike was formerly unsafe to ride; and now brakes within a normal range of expectations.
