Good brakes?

[spad4me]

I just ordered a rear hub brake .
.Brake Rear Roller BR-IM70-R M10 NuVinci: Staton Inc
Then I found a thread about Kool Pads .
I am going through the wally world brand of cantilever brake pads like crazy.
I was going to buy a 130 dollar front wheel and brake hub to go with the rear brake hub. .
I am going to try the rear hub and front and rear set of kool pads.
I allready utilize the fromt wheel brace and levered brake arms.

 

[reb1]

Make sure you get the salmon colored ones. They use iron oxide in the compound. You should use a good quality V brakes like a shimano type or better. There is a product called a travel agent that will increase the amount of cable your brakes pull and will give more solid stopping. Using a brake booster will also help by keeping the brake bosses from spreading out when you apply the brakes.
http://www.cambriabike.com/shopexd.asp?id=40902-Travel+Agent+Brake+Pulley+With++Adjuster

There is also a very good article on adjusting the brakes. Adjusting Direct-pull Cantilever Bicycle Brakes ("V-Brakes ®")

 

[Goat Herder]

You know there is gotta be a reason why true motorcycles don't use rim brakes.

 

[reb1]

Motorcycles are built heavier and intended for higher speeds. Bicycles are built for efficiency with human power.
Drum brakes have been available for many years. The types of bicycles that use these brakes have just recently started to be marketed in the US. These are still not as powerful as a good rim brake. They are used by commuters in Europe mostly where there is flatter ground and not at high speed.
Disk brakes did not get popular until recently. There are only a couple of them that I would consider for tandem or motorized bicycle use and these are very expensive.
A major problem with having stronger safer drum or disk brakes is the weight. For drum or disk brakes you need a stronger fork and rear stays. This adds weight and reduces the comfort of the bicycles that do not have shocks. All except a couple of the disk brakes available will fail due to heat coming down a steep canyon with a tandem bicycle. This is because they did not make the rotors heavy enough. I use hydraulic rim brakes and a drum on the rear that is used for a drag to control speed and keep the heat of the rims and allow me to rest my hands when coming down a canyon.

 

[Goat Herder]

Motorcycles are built heavier and intended for higher speeds. Bicycles are built for efficiency with human power.
Drum brakes have been available for many years. The types of bicycles that use these brakes have just recently started to be marketed in the US. These are still not as powerful as a good rim brake. They are used by commuters in Europe mostly where there is flatter ground and not at high speed.
Disk brakes did not get popular until recently. There are only a couple of them that I would consider for tandem or motorized bicycle use and these are very expensive.
A major problem with having stronger safer drum or disk brakes is the weight. For drum or disk brakes you need a stronger fork and rear stays. This adds weight and reduces the comfort of the bicycles that do not have shocks. All except a couple of the disk brakes available will fail due to heat coming down a steep canyon with a tandem bicycle. This is because they did not make the rotors heavy enough. I use hydraulic rim brakes and a drum on the rear that is used for a drag to control speed and keep the heat of the rims and allow me to rest my hands when coming down a canyon.

Why are disk brakes the common staple of a down hill competition bike? If you want good brakes guy's use what they are using! Not some tiny rotor set up.

I have been riding with both Hayes hydraulic with 203mm rotors , and Avid BB7s 203mm as well . They work flawless in rain snow or shine. There are a bunch of folks using rotors that are too small for down hill competition or a motor. Plus there are some shotty calipers out there as well? MINE ARE NOT

Ok gotta ask why do you need a hydraulic set up for V brakes? That weighs too much?

I beg to differ on your weight scenario.

Disk brakes don't weigh any more than hydraulic V brakes. Especially the Avid BB7s I use with 203 mm rotors that are not hydraulic.


Ok Here is another one I have had V brakes hot enough to see smoke come off the pads. Giving the different tension on the spokes that lead to having to re true the wheel ever so slightly. I just don't think that ever was a good design. We are not talking about bicycles anymore.

I have yet to warp a rotor as I have used the correct size for the application. My wheels have never been so straight!

Besides, from an engineering standpoint, aluminum is a lousy brake surface. Little rubber pads wear out fast! If they are hard enough to last? Your rim is wearing out sintered metallic pads on steel rotors last a lot longer. [Quoted from elsewhere]

Why do race cars use disk brakes and not drum brakes? snork

Can someone show me a down hill mountain bike with V Brakes that is practical? snork

When v brakes have their death grip on the rims and you are going through a corner or bumps that does terrible things to a spoke set up[think warping]. They are better served to let flex naturally. That also allows better traction over terrain. True nice handling down hill bikes and motorcycles work this way and the wheels stay straight.

These are the true pinnacles of design!

Another important thing to say here is we are not talking about bicycles any more...Seriously.
Some of us joined the forum and put motors on them. snork


I can take my Morini build, the bike and I combined at about 375 pounds if I am not carrying any thing. I can stop on a dime all day long . The Morini is a very playful motor! So I do a ton of near panic stops. I have well over 2000 miles on my disk brakes and have not had to do squat to them!! Nada thing at all whatsoever except for very slight cable adjustments that took 2 seconds if that..

For the record I don't run small rotors either[think down hill competition]. BB7's 203mm rotors Love them and there grab and feel to me has totally been fine tunable.

Just saying......

Disk brakes have been around for awhile now. The sad thing is all the folks using undersized rotors. The technology is not that new

Until Wall mart sells a bike with real brakes.........Ha now that was funny!

 

[Goat Herder]

Now I am not all that familiar with drum or coaster brakes. I still suspect my favorite brake will always be disks in 203mm rotors.

 

[Kevlarr]

More expensive tandems use a very heavy duty drum brake and it's not part of the hub.
Precision Tandems - Arai Drum Brake Information

Now your first mistake is buying $6 Bell brake pads 'cause they're just rubber and nothing else. Better brake pads make a world of difference.

 

[Chalo]

Why are disk brakes the common staple of a down hill competition bike? If you want good brakes guy's use what they are using!

The bicyclists who use their brakes the hardest are not downhillers-- when you're headed downhill on a normal length bicycle, you can't even use all that much braking power before the bike will tip up.

Tandemists have the most demanding braking application in the cycling world. They are packing twice the normal amount of weight on two wheels, and their bikes have very long wheelbases. They won't tip up under hard braking, so the brakes can be applied harder than a single bike's brakes.

Tandemists mostly use rim brakes. The ones who are serious about mountain riding generally have two rim brakes for stopping, plus at least one drum brake for steady drag on downhills. Disc brakes are generally acknowledged to be inadequate to cope with the heat loads a tandem can impose-- good ones will stop plenty hard for a time, but then they can overheat and fail.

Chalo

 

[Goat Herder]

Your still horking rim's I don't see any real motorcycles or cars with rim brakes. While folks continue to use undersized rotors and inferior calipers the comparison is null and void. Use the right disk set up for the right job. My observations were made on a extreme circumstance. Hot rod motor very heavy bike at a suspected total weight of 375 pounds.

I beat this thing and tried it out thoroughly. There was no fade for me to worry about.

Disk brakes will always get a bad name from folks using a inferior set up just like rim brakes will.

 

[Chalo]

When v brakes have their death grip on the rims and you are going through a corner or bumps that does terrible things to a spoke set up[think warping]. They are better served to let flex naturally. That also allows better traction over terrain. True nice handling down hill bikes and motorcycles work this way and the wheels stay straight.

This is spectacularly fanciful thinking. With a rim brake, force is transmitted from the tire, to the rim, to the brake. All the spokes have to do is position the rim, which is what they always do. Hard rim braking does not have a significant effect on spoke tension.

With a disc or drum brake, force must be transmitted from the tire, to the rim, through the spokes, through the hub shell, and on to the drum or disc rotor. The spokes see substantial changes in tension from braking, and the hub must be quite a bit stronger and stiffer than a hub used with a rim brake.

The Buell Lightning motorcycle used a brake rotor attached to the rim, and it was not just to allow the rotor to be bigger. The idea was that if braking force didn't have to be transmitted through the hub and spokes, the wheel could be made lighter but still reliable.

Chalo

 

[Goat Herder]

All the disk brake applications I have used my rim's were never straighter. we are talking about motorized bicycles now. I have gotten my rim brakes hot enough to see smoke come off the pads with fading to boot. There was always rim straightening to do because of it.

 

[Goat Herder]

The best bicycle disc brakes are available for your single bike or tandem right now.

 

[Chalo]

Your still horking rim's I don't see any real motorcycles or cars with rim brakes.

You don't see a lot of real motorcycles or cars using lightweight wire spoked wheels, either.

There are a lot of other factors in play:

-- Serviceability (The wheels can be removed without disengaging the brake.)

-- Manufacturability (A wheel does not have to be as precise or uniform if the rim is not a braking surface.)

-- Replacement cost (A new set of alloy wheels at brake job time would be expensive.)

-- And simple technical considerations (A brake caliper large enough to wrap around a car or truck tire and stiff enough to support the necessary brake pad forces would be huge, massive, and expensive compared to a disc or drum. Dumping motor vehicle amounts of braking heat into the rims would cause fluctuations in tire pressure.)

For bicycles, rim brakes are the proven solution. The strongest brakes available (in gross power dissipation) are rim brakes. Disc brakes have gotten quite good, but they still weigh more, cost more, and fail earlier under high load than rim brakes. Discs are easier to damage and harder to repair than rim brakes.

When you need a strong bite on the brakes from a small amount of hand force at the lever, hydraulic discs can be just the ticket. But just because they are best in this one regard does not mean they are better in other regards.

Here is a summary of instrumented tests on disc and rim brakes done by a German cycle magazine:

CHRIS' TANDEM TIPS: Rim brakes, disks and overheating - hard data

The two rim braked wheels they used were normal, not heavy duty wheels-- and yet they held their own against the best and most expensive disc brakes available at the time of the test. Relatively hefty aluminum deep rims like the Velocity Chukker or B43, which were not available at the time these tests were conducted, would provide more heat sinking and better heat rejection though greater surface area, and thus would easily exceed the thermal capacity of any disc brake.

Chalo

 

[Goat Herder]

When you need a strong bite on the brakes from a small amount of hand force at the lever, hydraulic discs can be just the ticket. But just because they are best in this one regard does not mean they are better in other regards.

Here is a summary of instrumented tests on disc and rim brakes done by a German cycle magazine:

CHRIS' TANDEM TIPS: Rim brakes, disks and overheating - hard data

The two rim braked wheels they used were normal, not heavy duty wheels-- and yet they held their own against the best and most expensive disc brakes available at the time of the test. Relatively hefty aluminum deep rims like the Velocity Chukker or B43, which were not available at the time these tests were conducted, would provide more heat sinking and better heat rejection though greater surface area, and thus would easily exceed the thermal capacity of any disc brake.

Chalo

That test is null and void compared to the disk brakes I have suggested. To make it clear as long as folk's keep using inferior brakes rim or disk this will be a problem area to understand. 203 mm is where my studies and observations came from. Do you have hard data for them? Lets get with the times!

Hayes hydraulic with 203mm rotors , and Avid BB7s 203mm have been phenomenal for me no up keep or anything. They just keep on working. It just kills me here on the forum looking at so many bikes with undersized rotors and while I question the calipers as well.

The best bicycle disc brakes are available for your single bike or tandem right now.


You avoided my question about horking rim's that's my favorite word now snork!!

In my observations I've have gotten my rim brakes hot enough to see smoke come off the pads with fading to boot. There was always rim straightening to do because of it.

In my observations the straightest wheels I have to date under extreme braking are my disk set ups.

It was explained to me upon a time by down hill biker techs in a bike shop that my wheels were going to be straighter this way. I think that going through turns etc there may be something to that. I dunno got to think about it. What they told me I have slept since then.

 

[reb1]

I purchased the Arai drum when I bought my tandem in 1990. The original rim brakes were called self energizing brakes. I believe the CPSC put the company who made them out of business claiming they were too dangerous for the front of a single. They were meant for tandem use. In 2001 I needed to replace these brakes and was never happy with the rear brake that came on the tandem, due to cable stretch with the rear brake. I purchased the Magura HS66 brakes. Fluid does not stretch. These brakes bring the tandem to a stop better than any cable brake available. The drum brake is not hooked to a brake handle. It is hooked to a thumb shifter and I lock it in place. I use the drum to control my speed and keep my hands from getting tired when I come down a long grade. The drum brake is heavy but it keeps heat off of the rim. Several years before I purchased my tandem I was returning from a weekend ride with several other riders. We were headed toward Provo. We had just passed Sundance and a couple on a tandem went down. There had been several cars in front of us slowing then speeding up as the corners came up just before this happened. While we were waiting for an ambulance the ride leader pulled the front wheel out and took the tire apart. The tube had begun to melt in several places. When I am coming down a grade with a cart I use the drum to keep the speed down. I like around 35mph. This allows me to still have good control in an emergency stop with the rim brakes. My brakes can stop me the wife and a large cart full of groceries. The combined load can whey from 500 to 700 lbs. There is a big difference between racing a bicycle down a hill and managing your speed coming down a long grade with two people and gear.
I am researching motorizing the tandem. I will need to rack mount a motor but have it hook into a freewheeling crank. I will also need to fabricate a chain guard to keep my wife from winding up in the chains. I still intend to pedal with the motor helping.

 

[jimraysr]

I was concerned with breaking power when I realized the my all up weight was around 350 - 375#.

The easy fix for my Schwinn Searcher was Magura Hydraulic brakes. Light weight, no reservoir, mineral oil fluid, no moisture problems, easy conversion, no changing wheels, no interference with Manic hub adapter and drive for Honda. Finally easy to remove and install on the next bike frame.

The difference is hard to believe, but a friend who rides mountain bikes tells me hydraulic disc brakes are as much a change for the better as cable to hydraulic?

Really happy with the improvement.

Jim

 

[Goat Herder]

Well just to clear any confusion the disk brakes that I have experience with are an absolute joy at the hand calipers. They take very little pressure at all to energize. With the Avid BB7 being very easy to energize I have encountered no cable stretch issues at all. The Hayes hydraulic being like a breath of air on a nat's [flying insect] posterior to energize.

Both to me are a joy the over all control and feel is very discernible with easily managed control.

In fact most folks I know used to throwing the typical death grip at a rim brake get quit a surprise out of how well the 203mm set up will stop that I run I currently run.

These are the only Disk breaks that I am the most familiar with. I think they hold water pretty darn good as test go. On my Morini build I have over 2000 miles of abuse. I am still on the original pads as well.. Although I suspect they are due.

I have friends running Avid juicy type brakes with 160mm'ish rotors their not impressed until they try my 203mm set ups. I hated the Juicy set up that came with one of my new bikes that I bought they had 170mm [I think can't remember] on them and were terrible.

I have another friend running a mechanical disk brake of some kind with a 160mm'sh as well. He hates it and loves my set ups.

I got them both envious..

Both of these guy's for the inferior brakes they are running the typical cable stretching death grip to stop ensues. lol.

 

[reb1]

I agree with you on the ease of pulling the lever. When I setup the hydraulic rim brakes on the tandem, I wished that I had done it sooner. My hands used to throb coming down steep potholed dirt roads with the cabled rim brakes. I use a Paul V brake with a travel agents on my single. I am sure this would work fine for the front on the tandem other than taking more hand mussle to operate. The problem on a tandem is the distance to the rear brake. Cables stretch more than fluid compresses. Tandems are different and you can get major braking out of the rear brake instead of locking up the rear if you have a good enough brake. I am stopping for two plus gear and these brakes make this easier.
I do not know about the miles but I have had my hydraulic rim brakes on since 2001 and because I have driven work vehicles do not keep a money pit of my own. I have changed the pads if I remember correctly around 5 times. This is done with my fingers. I have not ever pulled them apart other than when I had to put a longer line for the rear brake when they were new. The HS66 was discontinued in 2001. If I smack up one of my brake handles or need HS66 specific parts I will need to go to the HS11 or HS33 and change over to MTB bars. They have been made since 1989 and are in the 2011 catalog.
I agree with the larger disk. Santana carries a tandem specific disk that is 10" and thicker. You can use it as a regular or drag and not have it fail. I believe this one uses a cable to the hydraulic actuator. There is an industrial model designed for gas powered off terrain vehicles that is used on heavy trikes and pedal cabs. It is called the Magura Big.

 

[Goat Herder]

Reb1 you have a good point about the distance incurred with a cable brake to the rear. I had not thought about that. Do you have any links to the heavy duty disk brake you mentioned? I am very curious about that. I would very much enjoy to read up on it.

 

[Chalo]

That test is null and void compared to the disk brakes I have suggested. To make it clear as long as folk's keep using inferior brakes rim or disk this will be a problem area to understand. 203 mm is where my studies and observations came from. Do you have hard data for them? Lets get with the times!

Magura Gustav M discs (which performed best in the test but failed at 1100W dissipation) are still just about the stoutest available. At that time the used (I believe) 180mm rotors. An equally sturdy 203mm rotor would offer 13% more braking leverage and heat rejection with the same caliper. That means it fails at 1240W instead. It's not an overwhelming difference.

In my observation, 203mm rotors tend to be spindlier than the old Gustav M rotor, larger but with no more surface area. Magura now offers the Gustav M with a 210mm rotor.

There is no substitute for heat capacity to dump energy into, and surface area to reject it from. A 203mm stainless steel rotor weighs about 180g and has a specific heat of .5 joule per gram per degree C. A Velocity B43 rim weighs about 770g and has a specific heat of .9 joule per gram per degree C. And the rim has much higher thermal conductivity, and it has many times the surface area, so it can absorb a lot more heat and reject it many times faster than a disc rotor.

That's why disc brakes can work so impressively at modest loadings, but fail long before rim brakes that seem unimpressive by comparison. They're perfectly adequate for normal size riders on normal weight bikes moving at normal bike speeds. Turn up the energy levels from there, and you can have problems.

Hayes hydraulic with 203mm rotors , and Avid BB7s 203mm have been phenomenal for me no up keep or anything. They just keep on working. It just kills me here on the forum looking at so many bikes with undersized rotors and while I question the calipers as well.

The difference between a 160mm rotor and a 203mm is 27%.

I find a 165mm rotor to be more than adequate for the rear brake on my mountain bike. I use a 9" (229mm) hard anodized aluminum rotor on the front. The thick aluminum rotor has more heat capacity, as well as more surface area to reject heat and more mechanical advantage at the caliper. But that's appropriate for a front brake that can apply at least three times as much braking as the rear.

You avoided my question about horking rim's that's my favorite word now snork!!

In my observations I've have gotten my rim brakes hot enough to see smoke come off the pads with fading to boot. There was always rim straightening to do because of it.

Because the physics are contrary to your experience, I chalked that up to peculiarities with your equipment. I already showed you how a good rim can soak up seven and a half times as much heat as a 203mm rotor, and pass that heat to the air several times faster. And I have shown you tests that demonstrate disc brakes fail at lower energy levels than rim brakes.

Disc front wheels are dished, therefore weaker than equivalent symmetrical front wheels. Disc rear wheels have narrow flange spacing, therefore less stiffness than conventional rear wheels.

So I have to conclude that your rim braked wheels were simply not the equal of your disc braked wheels.

It was explained to me upon a time by down hill biker techs in a bike shop that my wheels were going to be straighter this way.

Those guys are not immune from getting things wrong. In this case, they were wrong. A disc braked wheel must be built with a stronger rim and/or more spokes to be equally as strong as a given non-disc wheel. Fortunately, most of them are built that way.

Chalo