The Spares Company
Club Shop/Regalia
Parent Website
Contact Officials
Machine Registrar
Club Secretary
Membership Secretaries
MPH Editor and Forum Administrator.
Section Newsletters
Technical Databases
Photos
Home
What's new
Latest activity
Forums
New posts
What's new
New posts
Latest activity
Information
Bike Modifications
Machine Data Services
Manufacturers Manuals
Spare Parts Listings
Technical Diagrams
Whitakerpedia (Vincent Wiki)
The Club
MPH Material Archive
Flogger's Corner
Obituaries
VOC Sections
Local Sections
Local Section Newsletters
Miscellaneous
Club Assets
Club History
Club Rules
Machine Data Services
Meeting Documents
Miscellaneous
Essential Reading
Magazine/Newspaper Articles/Letters
Adverts and Sales Brochures
The Mighty Garage Videos
Bikes For Sale (Spares Company)
Log in
Register
What's new
New posts
Menu
Log in
Register
Install the app
Install
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Speet Brake Installation Query
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Gary Gittleson" data-source="post: 110612" data-attributes="member: 3625"><p>Sorry, but I must disagree with some of this. When 10 lbs are applied to the primary side, that force will move two things at once, the brake cam lever on that side and the balance beam in the opposite direction which in turn applies a force to the other brake, thus distributing the 10 lbs into two halves. The brake cam lever will never see all of the 10 lbs. They are halved because the balance beam has its pivot in the center. Had it been off-centered, the splitting would have been proportional to the ratio between the lengths of the two sections, right and left. </p><p></p><p>Another way to look at is to imagine fastening a clamp to the cable on the primary side just below the balance beam and trying to squeeze the clamp and balance beam together. That's what the setup is really doing. That pulling together is obviously dividing the force evenly between the cable below and the beam above.</p><p></p><p>Still another way to think of it is this. Imagine two springs attached parallel to each other to a fixed object and a bar joining their other ends. Suppose we pull on the bar in the center with 10 lbs of force. Will each spring see 10 lbs? Whatever force they experience, they will apply in return. If so, wouldn't their forces add together and pull back with 20 lbs? If we can do that, we are well on our way to building a perpetual motion machine. If we pull with 10 but feel 20 then we are pulling with 20 so should feel 40..... It's obvious that the two springs will work together and return the same 10 lbs of pull: opposite and equal. Therefore, each spring will see and oppose 5 lbs assuming they are of the same strength.</p><p></p><p>In any case an important point is that if we are to use the balance beam to actuate brakes designed for direct pulls, we will introduce a doubling of the handlebar lever movement the system was designed for. That's why Nigel had to modify the lever. The standard lever has less leverage than what the Speet brake requires because in the standard setup, there's a mechanical advantage provided by the balance beam. And that's why if we use the balance beam with the Speet brakes, we need to shorten the levers at the brakes <em><u>to reduce the leverage there to compensate for the extra leverage provided by the beam</u></em>.<u></u></p><p><u></u></p><p>Another way to automatically evenly distribute the force is to use a whiffletree or whippletree <a href="https://en.wikipedia.org/wiki/Whippletree_(mechanism)" target="_blank">https://en.wikipedia.org/wiki/Whippletree_(mechanism)</a>. I think I've seen such a setup on a bike somewhere, as well as disparaging comments regarding them. I don't remember where I saw that. Any thoughts about that?</p><p></p><p>Gary</p></blockquote><p></p>
[QUOTE="Gary Gittleson, post: 110612, member: 3625"] Sorry, but I must disagree with some of this. When 10 lbs are applied to the primary side, that force will move two things at once, the brake cam lever on that side and the balance beam in the opposite direction which in turn applies a force to the other brake, thus distributing the 10 lbs into two halves. The brake cam lever will never see all of the 10 lbs. They are halved because the balance beam has its pivot in the center. Had it been off-centered, the splitting would have been proportional to the ratio between the lengths of the two sections, right and left. Another way to look at is to imagine fastening a clamp to the cable on the primary side just below the balance beam and trying to squeeze the clamp and balance beam together. That's what the setup is really doing. That pulling together is obviously dividing the force evenly between the cable below and the beam above. Still another way to think of it is this. Imagine two springs attached parallel to each other to a fixed object and a bar joining their other ends. Suppose we pull on the bar in the center with 10 lbs of force. Will each spring see 10 lbs? Whatever force they experience, they will apply in return. If so, wouldn't their forces add together and pull back with 20 lbs? If we can do that, we are well on our way to building a perpetual motion machine. If we pull with 10 but feel 20 then we are pulling with 20 so should feel 40..... It's obvious that the two springs will work together and return the same 10 lbs of pull: opposite and equal. Therefore, each spring will see and oppose 5 lbs assuming they are of the same strength. In any case an important point is that if we are to use the balance beam to actuate brakes designed for direct pulls, we will introduce a doubling of the handlebar lever movement the system was designed for. That's why Nigel had to modify the lever. The standard lever has less leverage than what the Speet brake requires because in the standard setup, there's a mechanical advantage provided by the balance beam. And that's why if we use the balance beam with the Speet brakes, we need to shorten the levers at the brakes [I][U]to reduce the leverage there to compensate for the extra leverage provided by the beam[/U][/I].[U] [/U] Another way to automatically evenly distribute the force is to use a whiffletree or whippletree [URL]https://en.wikipedia.org/wiki/Whippletree_(mechanism)[/URL]. I think I've seen such a setup on a bike somewhere, as well as disparaging comments regarding them. I don't remember where I saw that. Any thoughts about that? Gary [/QUOTE]
Insert quotes…
Verification
What was Mr Irving's Christian Name?
Post reply
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Speet Brake Installation Query
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top