Coaster to Drum Conversion PICS and Video

[bikebuilder]

Someone asked me to explain how to do this. This particular brake setup is the easiest to modify. The one on my bike was more difficult. The center mass or the "ball" on this one is in two peices. All you have to do is weld the two peices together so that it cannot reset it's self while riding. Reassemle the hub and weld a lever on to where the gear used to be with holes front and back. front for the hand lever and the back for a spring. Make sure that the lever you weld on is in the best position possible to work with the hand lever.

The one on my bike had the ball in one peice already but did not have that little peice sticking out between the pads to hold it in place. This would allow it to reset. So I had to weld a little nub on the ball.

This conversion works pretty good. I can leave black marks with the one on my bike. The one I put together for "little brother" 195lbs would lift the back tire off the ground.

You can see it in use a little watch the video linked in the rat-rod swingbikes post

http://ratrodbikes.com/forum/viewtopic.php?f=6&t=9333

 

[UncleKudzu]

Re: Coaster to Drum Conversion

wow, an answer complete with illustrations! thanks a million, bikebuilder!

surprisingly, there's not really an answer anywhere as to whether or not a coaster brake would work up front. i asked here and at my buds over at motorbicycling.com and generally searched everywhere. seems like a good idea to me, and you're saying that it works well with a hand lever?

i'll have to cogitate on what what's happening in the hub that calls for welding, but thanks again for answering this!

 

[UncleKudzu]

Re: Coaster to Drum Conversion

ok, after thinking about this i have a question: why isn't the forward motion of the wheel enough to throw the hub back into "drive" after braking? you can brake and coast, brake and coast with the hub on the rear, so why not on front? i'm not understanding why any internal weld is needed.

 

[bikebuilder]

Re: Coaster to Drum Conversion

That is what confuses most people, and why it never works.

The area with all the dots on it is the main focus. On the bike I ride this was one peice and the "nub" where the blue dot is did not exist. I made one. On this one the "ball" is in two peices which allows it to reset so in a rear coaster situation it can be activated at all times. when using it as a drum brake if you let the brake reset. you will get one good stop and then it will reset. The brake arm where the gear used to be will change position and you won't be able to activate it again. Back to this brake. I will just have to remove the spring holding the ball together and weld the two peices together along the green dots. I fully anticipate lifting the rear wheel on the bike this brake is going to be on. The key is that the the part above or behind the area with the dots does not change it's relationship to the cable and lever.

 

[UncleKudzu]

Re: Coaster to Drum Conversion

man, i can't thank you enough for the illustrated instruction, bikebuilder!

the hub i just worked on has the one-piece clutch/ball thing and two shoes that float between it and the cone on the brake side. i'm not sure how the resetting takes place in that arrangement, but you've given me a way to think about it.

 

[bikebuilder]

Re: Coaster to Drum Conversion

You need to basically weld some extra metal on the ball and make the peice marked by the blue dot. You want the ball to move side to side but not rotate.

 

[bikebuilder]

And here's the video. I am using old levers and I only used the front brake to stop. I think with a newer lever and a bigger coaster brake it would work even better. This was a really small brake.

 

[Joe Monstermaker]

I'm definitely gonna give this a go. Thanks for the info, especially the heads-up on modifying the coaster, I hadn't thought about how it would rotate in relation to the brake arm.