Calling all mechanical engineers: Innovative coaster brake arm attachment methodology
#1
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Calling all mechanical engineers: Innovative coaster brake arm attachment methodology
I really hope this has been discussed already and there is a solution in place out there somewhere...but my initial search yielded no results.
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?
#2
Super-duper Genius
I really hope this has been discussed already and there is a solution in place out there somewhere...but my initial search yielded no results.
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?
It would be easy for frame builders to add a little brazed-on boss under the chainstay, and for the hub manufacturers to design the brake reaction arm with a quick release of some sort... if there were any demand for this sort of stuff.
The truth is that coaster brakes are not popular enough among the type of cyclist who would care about these features. The cheesy clamp and screw that come with most coaster hubs are sufficient. They’re super cheap to build, and they work.
To answer your question more directly, I have not seen an elegant/efficient alternative. But I agree one would be nice, for the “enthusiast” coaster cyclists.
#3
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Suppose the chainstay attachment had two parallel plates with the coaster arm fitting between them. A simple hole just big enough for a quick release pin; those pins with a locking ball and a button to unlock the ball. I forget where I have seen them as simple pins but wheelchair users have been using hubs with those pins for quick releases for decades.
If you could find the right pin, making the attachment from sheet steel wouldn't be all that hard. (https://www.mcmaster.com/quick-release-pins)
Ben
If you could find the right pin, making the attachment from sheet steel wouldn't be all that hard. (https://www.mcmaster.com/quick-release-pins)
Ben
#4
aire díthrub
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Only two types of bicycles I know of come with coaster brakes, typically: children’s bikes and cruisers. Both of these are considered ‘cheap’ bicycles. Where I live, coaster brake beach cruisers are extremely popular, but you can pick a new one up for 100 bucks or often much less, brand new. There’s simply no profitable market for any company to improve upon a design that ain’t broken, as they say. You could reach out to any number of custom frame builders to see if they could design something for you, but their time and talent won’t come cheap. Chapman cycles immediately comes to mind: Chapman Cycles ? Custom frames built in Rhode Island this guy is a creative genius, and I’m sure could come up with something. But you’re not going to likely find anything already designed because, well, you’re looking for a solution without a problem, basically.
#5
I have a fairly speedy bike with single speed coaster hub. It's a Schwinn road frame with narrow rims and 28mm tires. A wing nut for the reaction arm makes it pretty quick to remove / replace the rear wheel on my coaster brake hubs.
#6
elcraft
I always envisioned a slotted plate , open at the rear, attached/ brazed to the bottom of the the chain stay. Sort of a reverse facing horizontal drop out. The reaction arm would have a bolt or stud going through the end ( at the spot here they normally have the attachment hole) that would sit in this slotted plate. The reaction arm only needs to prevent the hub innards from turning; it doesn't need to be bolted down. The normal axle bolts could be loosened and the hub slid first in one direction to release the reaction arm pin/ stud/ bolt, and then in the other direction to free the wheel from the frame. So simple,- no quick release or bolt needed on the reaction arm. The slot, in this plate, would only need to to be long enough to accommodate the range of available reaction arms.
#7
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I always envisioned a slotted plate , open at the rear, attached/ brazed to the bottom of the the chain stay. Sort of a reverse facing horizontal drop out. The reaction arm would have a bolt or stud going through the end ( at the spot here they normally have the attachment hole) that would sit in this slotted plate. The reaction arm only needs to prevent the hub innards from turning; it doesn't need to be bolted down. The normal axle bolts could be loosened and the hub slid first in one direction to release the reaction arm pin/ stud/ bolt, and then in the other direction to free the wheel from the frame. So simple,- no quick release or bolt needed on the reaction arm. The slot, in this plate, would only need to to be long enough to accommodate the range of available reaction arms.
#8
elcraft
Only the slotted plate faces the rear. The reaction arm faces the usual way. Sorry about the crude drawin See the image.
Last edited by elcraft; 06-28-19 at 05:57 PM. Reason: clarification
#9
aire díthrub
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wouldn't it have to have the same amount of forward/aft adjustment as the dropout as to allow proper chain tension and full use of the dropout? Very simple and elegant design though. A nice forged piece would work very well. Looking at this design, I’m somewhat surprised this hasn’t previously been envisioned by a frame builder somewhere at some point.
#10
elcraft
I wonder why no one has come up with this before, myself. The amount of drop out length does not need to be equal; hub goes into drop out with chain not necessarily on the cog, then the pin on reaction arm engages into the slot. Then hub can be moved forward enough to slip chain onto the cog and then, back deeper into the drop out for the chain tension. Of course this idea could also be used with rear facing track style drop outs , as well.
#11
elcraft
I met Mr. Chapman at the "Builders Ball" show in the Boston Design Center. He was there with Richard Sachs and Peter Weigle- Chapman's work compared favorably with theirs, despite their more legendary status. I actually got into my career of gold/silversmithing because of my desire to build lugged bicycle frames. But the paradigm changed, while I was in school, to lugless welded designs.
This idea for securing a reaction arm is part of a series of frame issues that I have contemplated for more than thirty years. Many of the other ideas, I have seen implemented already. This one hasn't been addressed mostly because rear hubs using reaction arms weren't exactly commonly used by high end builders...
The shift towards more specific frame/ drivetrain options; IGH's, SS/FG, and Dual Drive (derailleur with IGH), and belt drive arrangements, has been a welcome development. A custom frame may actually be set up for something other than derailleur drive trains, by design.
This idea for securing a reaction arm is part of a series of frame issues that I have contemplated for more than thirty years. Many of the other ideas, I have seen implemented already. This one hasn't been addressed mostly because rear hubs using reaction arms weren't exactly commonly used by high end builders...
The shift towards more specific frame/ drivetrain options; IGH's, SS/FG, and Dual Drive (derailleur with IGH), and belt drive arrangements, has been a welcome development. A custom frame may actually be set up for something other than derailleur drive trains, by design.
#12
Clark W. Griswold
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There is no need to develop coaster brakes any more. It would be one thing if they had good braking power but they don't. I would prioritize good braking power and quality over a purely clean look. You can get a very clean look these days with internal routing for cables and you can use disc brakes which would keep the drive side cleaner and also give excellent braking and more tire clearance.
Chapman Cycles does excellent work and I always wanted a Circle A before they closed and now want a Chapman at some point, especially seeing one live in person close up and talk with the owner.
Chapman Cycles does excellent work and I always wanted a Circle A before they closed and now want a Chapman at some point, especially seeing one live in person close up and talk with the owner.
#13
Senior Member
I really hope this has been discussed already and there is a solution in place out there somewhere...but my initial search yielded no results.
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?
Has anyone developed a more modern coaster brake arm attachment method, perhaps building on the quickrelease concept? I'm thinking of a some device that would bolt to the brake arm, and then attach to the chainstay via a sturdy quickrelease lever of some sort. That way you could have the lever on multiple wheelsets and quickly interchange. Would also speeden up the flat change process.
Thoughts?