Another B.T.R. Build.......

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Mr.B.

Mr.B.

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Oct 21, 2008
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Upper Mississippi River valley
I don’t know the specs for either.

But I’m using a old Tomos moped front hub (90mm X perhaps 1”) on my rather heavy build and I can’t imagine any drum better short of a actual motorcycle brake.

-Kirk
 
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cobrafreak

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Feb 16, 2011
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The only other front drum brake that is going to out perform the 90mm S/A is the drum brake of a Honda CB110 motorycycle, the one that Big Boy Cycles uses. It's massive.
 
Mr.B.

Mr.B.

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Oct 21, 2008
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JohnThomas Sorrels

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Dec 28, 2011
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So yours would be the BS-100? 83mm diameter, 18mm wide? That's not much bigger than the Motobecane/ Puch size, anyone know of a way to calculate braking power based on shoe size? I wish I could find specs on the S.A. 90mm shoes.
 
Mr.B.

Mr.B.

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Oct 21, 2008
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Upper Mississippi River valley
Yep, mine is the BS-100

I did have a couple of issues with mine, but not because of design quality.

I had cut more than half of the securing strut off for cosmetic reasons and then foolishly mounted it behind the fork. First time I hit the brakes hard the retaining strap slipped and the weakened strut bent and flopped to the front of the fork.

That bent the backing plate, caused the stud the shoes rest on to go out of alignment and eventually lead to the shoes binding.

Even though my bike is extra heavy and the hills near my house are extra steep after repairing the Tomos I’m still comfortable with it.

However If I were to start over, I might very well use a brake from a small motorcycle as Cobra Freak suggested- Nothing wrong with overkill when it comes to brakes!

-Kirk
 
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JohnThomas Sorrels

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Dec 28, 2011
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Last...





I'm still debating the front brake in my head. I don't really want to go motorcycle brake because of the different axles, etc. The Sturmey Archer looks a lot narrower than moped brakes so the braking surface between an 80mm moped hub and the 90mm S.A. hub might be really close. Anyone with the Sturmey Archer want to take it apart and measure?
 
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cobrafreak

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Here is the size difference between the S/A 70mm and 90mm drum brake. When I was using the 70mm I had to plan my stops ahead of time because if I didn't it was too late. The 90mm is more than just 20mm larger. The drums and shoe area have much more contact area. Much better stops with the 90mm.
I have the moped hub that you have and the S/A 90mm was bigger. I didn't measure it, but realize the rear brake is just about 10 or 15% of the total brake effort. The
 
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JohnThomas Sorrels

New Member
Dec 28, 2011
212
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0
Ramona/ San Diego
cobrafreak said:
Here is the size difference between the S/A 70mm and 90mm drum brake. When I was using the 70mm I had to plan my stops ahead of time because if I didn't it was too late. The 90mm is more than just 20mm larger. The drums and shoe area have much more contact area. Much better stops with the 90mm.

I have the moped hub that you have and the S/A 90mm was bigger. I didn't measure it, but realize the rear brake is just about 10 or 15% of the total brake effort. The
Click to expand...
Could you measure the width on the 90mm shoes?
 
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cobrafreak

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Feb 16, 2011
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My hubs are in bikes at the moment so I cant measure anything. Just get the 90mm S/A for the front. They are the finest bike hub brakes in the world. Made in England by people who ride in the worst weather around :)
 
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JohnThomas Sorrels

New Member
Dec 28, 2011
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Ramona/ San Diego
cobrafreak said:
My hubs are in bikes at the moment so I cant measure anything. Just get the 90mm S/A for the front. They are the finest bike hub brakes in the world. Made in England by people who ride in the worst weather around :)
Click to expand...
I probably will, you have the dynamo hub don't you? If so does it power just a front light or do you have rear lights also?
 
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cobrafreak

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Feb 16, 2011
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I have both front and rear Dyna-Hub lights. I'm using SuperNova E3's because they were the brightest hub powered lights available at the time and were compatible with S/A. A little pricey, but I don't regret it. They are real vehicle lamps which are 33 Lumens at 50', Super bright. Cars flash their lamps at me at night sometimes. One nice thing About SuperNova E3's is that they have a capacitor in them that stores power from the hub so when you stop you have 10 minutes of low power mode lighting so people can still see you in the dark. There are others though. I saw a list on a bike website of which lamps work best with which brand of Dyna-hubs. I would recommend you seek out a compatibility list before you buy because each brand of lamp has a different voltage and wattage requirement.
 
Joe_Knesek

Joe_Knesek

New Member
Oct 22, 2011
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Lyndhurst, Ohio
John the Sturmey Archer 90mm hub will give you plenty of stopping power. My son & I rode a tandem bike equipped with an XL-FD model & it stopped on a dime from a 50 mph downhill run. Our combined weight was about 375 pounds.

I'm building a BTR using the same motor & ordered an XL-FD for the front & the Motobecane for the rear.

Your hub looks like it's actually the Lelue hub since it does not have a cable stop on the brake plate. Did
 
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JohnThomas Sorrels

New Member
Dec 28, 2011
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Ramona/ San Diego
I think you're right about the Lelue hub, I noticed earlier that it looks more like that one on their website and emailed them with a picture to make sure, either way I'm happy with this hub as it uses the same brake shoes, is 36 hole, and has a lot of different sprocket sizes available. I checked out your build, any recent progress?
 
Joe_Knesek

Joe_Knesek

New Member
Oct 22, 2011
40
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Lyndhurst, Ohio
JohnThomas Sorrels said:
I think you're right about the Lelue hub, I noticed earlier that it looks more like that one on their website and emailed them with a picture to make sure, either way I'm happy with this hub as it uses the same brake shoes, is 36 hole, and has a lot of different sprocket sizes available. I checked out your build, any recent progress?
Click to expand...
Not really. I'm still waiting on the Chromoly tubing I ordered. I may have time to tear down the motor this week and ceramic coat the head and cases in graphite black. I also plan to coat the piston with a ceramic dry film coating. The rest of the bike will be powder coated in black chrome.
 
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JohnThomas Sorrels

New Member
Dec 28, 2011
212
0
0
Ramona/ San Diego
UPS dropped off the tires I plan to use for this build today. I went with 21" M.C. rims which will hopefully be in later this week. The tires are Shinko SR244 Dual Sports, these things are beefy!



A little detail of the sidewall...



4 ply, more than a 1/4" thick!

 
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