biker_reject
Over 1,000 Posts
Can the rear brake lever on the CB drum be reversed from pulling to pushing?
Reversing brake pedal?
- Thread starter biker_reject
- Start date
hardline_42
Active Member
You can flip the lever on the drum so it's pointing up and fab a linkage directly from your rear sets to the lever. This is the easiest way but you'll have to get creative in order to mount the rear brake switch. Here's a shot of Benjie's "El Poquito" CB350 that illustrates the flipped rear lever:
biker_reject
Over 1,000 Posts
Tim said:
I didn't plan my project as thoroughly as I should have. My plan for fabricating my rear sets are hindered by the exhaust canister being in the way of the new brake lever. I thought if I could move a modded stock lever behind the spindle instead of the original forward position, it might work. Only, the brake rod would push instead of pull the drum lever. I might have to do it like the bike from Benjies shown above...
Frankenfe
Coast to Coast
I would not be as concerned about Push or Pull as long as the linkage rod is hefty enough to not bend under pressure in a "Flipped / Push" scenario.
The the bigger questions to me in designing rear set linkage are:
A) Where is the point the force is exerted on the linkage rod in relationship to the swivel point of the swing arm. I would think that if not properly located, pressure/force at the drum will fluctuate under braking as the swing arm moves up and down.
B) The length of 1) the brake pedal from its pivot point 2) the brake pedal linkage lever to its pivot point.
Changes in these from the original lengths will cause a change in pedal travel and necessary force on the pedal to yield the same energy/force at the drum.
While more difficult I chose to go from the new rear set brake pedal forward to the original brake pedal pivot point and then use the original linkage back from that point. this assured me there would not be any issue with swing arm movement and allowed me to address the necessary "force" and "travel" issues by adjusting the lengths of the pedal and levers up to that point. I ended up with a little (8.3%) less force necessary and a little (8.69%) more travel than the stock pedal to apply the force/travel of the original.
These sites may help:
http://www.engineersedge.com/calculators/levers/page_levers_1.htm
http://www.engineersedge.com/calculators/levers/page_levers_2.htm
Here is my brake set up: this "Dual Rod" set up gives me lots of adjustment to find the correct static pedal position, (and I am still working out what that will be for my riding position)
The the bigger questions to me in designing rear set linkage are:
A) Where is the point the force is exerted on the linkage rod in relationship to the swivel point of the swing arm. I would think that if not properly located, pressure/force at the drum will fluctuate under braking as the swing arm moves up and down.
B) The length of 1) the brake pedal from its pivot point 2) the brake pedal linkage lever to its pivot point.
Changes in these from the original lengths will cause a change in pedal travel and necessary force on the pedal to yield the same energy/force at the drum.
While more difficult I chose to go from the new rear set brake pedal forward to the original brake pedal pivot point and then use the original linkage back from that point. this assured me there would not be any issue with swing arm movement and allowed me to address the necessary "force" and "travel" issues by adjusting the lengths of the pedal and levers up to that point. I ended up with a little (8.3%) less force necessary and a little (8.69%) more travel than the stock pedal to apply the force/travel of the original.
These sites may help:
http://www.engineersedge.com/calculators/levers/page_levers_1.htm
http://www.engineersedge.com/calculators/levers/page_levers_2.htm
Here is my brake set up: this "Dual Rod" set up gives me lots of adjustment to find the correct static pedal position, (and I am still working out what that will be for my riding position)
crazypj
Split personality, I fake being smart
Usually the trailing shoe has higher leverage end of cam operating it and leading shoe has lower leverage (by 'length' of cam)
flipping operating lever means the leading shoe has more leverage applied to it and tailing shoe less leverage so you operate one shoe more effectively and one shoe less effectively.
The leading shoe wears out substantially faster with flipped operating lever but brake feel doesn't appear much different due to less effective brake (usually a little more 'grabby')
flipping operating lever means the leading shoe has more leverage applied to it and tailing shoe less leverage so you operate one shoe more effectively and one shoe less effectively.
The leading shoe wears out substantially faster with flipped operating lever but brake feel doesn't appear much different due to less effective brake (usually a little more 'grabby')
Frankenfe
Coast to Coast
crazypj said:
These things always take me awhile to sink in (Usually after reading 5 or 6 times sloooowly) My understanding of the Reverse method was just external, by removing the arm (installed pointing down) from the splined end of the cam shaft and re installed pointing up. I am lost how this would effect the cam since at the external point of the arm the energy is transffered by a twisting or turning motion. Do some people actually turn the cam/shaft 180 degrees?
hey guys,
i had an old 175 that was built into a cafe, and i reversed the peddles around, shifter and brake, the brake side worked fine, no differances in braking but you must put a heavier rod, it will bend the older one. as for the shifter side it works alot better for faster shifts, i found. only thing is it swithes the shift patterns and when you ride another bike after riding yours for awhile, you for get about the switch, and shift in the reverse set up on that other bike.
any way, the reverse set up works fine and its cheap to do.
but to be honest, i will be buying accual rear sets for my cb500.
later.
i had an old 175 that was built into a cafe, and i reversed the peddles around, shifter and brake, the brake side worked fine, no differances in braking but you must put a heavier rod, it will bend the older one. as for the shifter side it works alot better for faster shifts, i found. only thing is it swithes the shift patterns and when you ride another bike after riding yours for awhile, you for get about the switch, and shift in the reverse set up on that other bike.
any way, the reverse set up works fine and its cheap to do.
but to be honest, i will be buying accual rear sets for my cb500.
later.
biker_reject
Over 1,000 Posts
Frankenfe said:I would not be as concerned about Push or Pull as long as the linkage rod is hefty enough to not bend under pressure in a "Flipped / Push" scenario.
The the bigger questions to me in designing rear set linkage are:
A) Where is the point the force is exerted on the linkage rod in relationship to the swivel point of the swing arm. I would think that if not properly located, pressure/force at the drum will fluctuate under braking as the swing arm moves up and down.
B) The length of 1) the brake pedal from its pivot point 2) the brake pedal linkage lever to its pivot point.
Changes in these from the original lengths will cause a change in pedal travel and necessary force on the pedal to yield the same energy/force at the drum.
While more difficult I chose to go from the new rear set brake pedal forward to the original brake pedal pivot point and then use the original linkage back from that point. this assured me there would not be any issue with swing arm movement and allowed me to address the necessary "force" and "travel" issues by adjusting the lengths of the pedal and levers up to that point. I ended up with a little (8.3%) less force necessary and a little (8.69%) more travel than the stock pedal to apply the force/travel of the original.
These sites may help:
http://www.engineersedge.com/calculators/levers/page_levers_1.htm
http://www.engineersedge.com/calculators/levers/page_levers_2.htm
Here is my brake set up: this "Dual Rod" set up gives me lots of adjustment to find the correct static pedal position, (and I am still working out what that will be for my riding position)
Actually, I'm working on building the linkage to do just as you suggest. I cut down the stock splined end and will have a friend weld on a mounting tab. Right now I am having fits trying to fit (ha) the proper length rod to rod ends. Whatever I've tried is just a 1/4"- 1/2" too long!
Swagger
Putting boot to ass since 1967!
First off, far be it from me to go against PJ but I'm looking at a CB450 drum this very moment and the cam is exactly the same on each face. There is no offset face that would give different leverage. The CB125 and XS650 rear that I have here also look to be the same, so swapping the lever position won't have any negative impact as long as you linkage work.
I can snap pics if you need them.
One other thing that I hesitate to bring up but will anyway....
I think you're going to hate your rearsets the way you have them currently. They are awfully low and I think they'll drag pretty quickly if you attempt anything more than a city street corner at near walking pace. You may even drag at that creep-along speed. You'll be far happier if you take the time to raise them a couple inches unless you aren't planning much cornering.
or not...
I can snap pics if you need them.
One other thing that I hesitate to bring up but will anyway....
I think you're going to hate your rearsets the way you have them currently. They are awfully low and I think they'll drag pretty quickly if you attempt anything more than a city street corner at near walking pace. You may even drag at that creep-along speed. You'll be far happier if you take the time to raise them a couple inches unless you aren't planning much cornering.
or not...
Frankenfe
Coast to Coast
Swagger said:
Swagger, I can take your constructive criticism. I knew i was going to get spanked after posting that pic, I tried to head it off when I stated in the original post.
"" Here is my brake set up: this "Dual Rod" set up gives me lots of adjustment to find the correct static pedal position, (and I am still working out what that will be for my riding position)""
I don't think the camera angle helps much either.
I do plan to adjust the pedal up from its current position. I toyed with a number of peg heights when laying out. The problem was, (with foot/ankle in a relaxed position + - 45 degrees to leg) as the peg is raised the toe goes down, so any additional clearance gained by raising the peg is somewhat negated by the toe going down.
But all said you may be right. It won't be the first time I have re-done them.
So as not to be a thread jacker I will entertain comments etc. regarding my Rear Sets and Peg Height on my build thread. http://www.dotheton.com/forum/index.php?topic=20018.msg205757#msg205757
Swagger
Putting boot to ass since 1967!
Don't take it as criticism at all mate, just a heads up. It'd suck to get all ready to fly and end up pogoing off your peg and ending up as a hood ornament.....
Generally speaking, other than a dab to settle the rear end BEFORE you corner, at least at any appreciable speed. Others may do otherwise....
that being said, since the toe of your brake pedal is well inside that of the outer end of your peg, it's more often than not going to be the peg that drags, even with the toe dropped to suit.
Again, build that puppy any way it suits YOU....you're the one that's gotta ride the beasty, just be conscientious and don't get mauled by a Buick....ok?
Generally speaking, other than a dab to settle the rear end BEFORE you corner, at least at any appreciable speed. Others may do otherwise....
that being said, since the toe of your brake pedal is well inside that of the outer end of your peg, it's more often than not going to be the peg that drags, even with the toe dropped to suit.
Again, build that puppy any way it suits YOU....you're the one that's gotta ride the beasty, just be conscientious and don't get mauled by a Buick....ok?
