Shimano Alfine Disc Brake Internal Gearhub
 

Bangkok touched on this briefly in another post. Hope you don't mind. I thought it deserved its own thread.

Internal gearhub fans rejoice. Shimano has released a disc brake version of its nexus hub to the german market. Hopefully we will be able to buy it here in the USA. Rapid fire shifters also. Here is a link which I google translated from german to english. http://translate.google.com/translat...lr%3D%26sa%3DN

What's the advantage of this over the drum breaks that have been avaliable for centuries?

I've been looking at disc breaks and it seems to me that all they are is weaker and less reliable versions of the venerable drum breaks marketed to pencil necked weight nazis.

I think disc brakes have prety much proven themselves over the years as for as durability and weight issues in the mountain bike arena. Don't think to many weight wennies are going to try a gear hub anyway.:)

How about the fact that they actually stop you in the harshest conditions of winter?

With an Avid BB7 disc brake you can adjust the pads with just a turn of a dial. Can you easily adjust a drum break while stopped at a stop light in the middle of January?

Also changing of disc pads is very quick and easy; it's a five minute job to change a set of pads. Perfect for the commuter who relies on there cycle for daily transport.

Plus you have a front brake.....

Just like far cheaper and less complex coaster brake hubs.
No need for ANY adjustment, NOR any replacement of working parts on a coaster brake model
Just like the OEM front brakes that come standard on any multispeed coaster brake bike sold in Germany (Latvia too?) and could be furnished on any bike. Only difference is with coaster brakes one hand can be safely used for other tasks (drinking beverage, signaling, carrying package, scratching, etc.) than being kept close to the brake lever

The OEM brakes (V or canti) don't stop you well on ice or in wet conditions. Plus the sand that is often used on roads will eat up a rim in a season with rim brakes.

If you don't like the idea of disc brakes, don't use them, but don't trash talk them until you have tried them. I will never go back to rim brakes for winter riding after using discs. I can actually stop in winter conditions with discs.

BTW, for my summer bike I use rim brakes.

The discussion was the brakes on the rear wheel; coaster vice disk brakes.
Please furnish the reason why a more complex, more expensive disk brake is better than a coaster brake on an internally geared REAR hub. The type of brakes put on the front are independent of the rear braking method and the limitations of rim brakes on the front wheel are irrelevant.

I am getting a Sturmey Archer 8 speed for a bike I am building because they do have a have a disk version available. I'd rather have a Nexus. I don't have a very good reason for that except maybe that I remember some of the old Sturmey 3 speeds.

The rapid fire is nice to see, although it would be nice if they would make a shifter that could be used on curved bars.

Off the top of my head: Two negative things about a coaster brake are that they won't work if the chain comes off, and ( the biggie) you can't set your pedal position. If you have to make a sudden turn, and your crank is in the wrong position, you're hosed. Same for being stopped, if your crank is in a bad position, you just have to live with it.

No possibility to slow down as opposed to stop. If you are in the wrong pedal posistion it's very difficult to stop on a dime.

Have you ever used disc brakes. or are you being a blow hard?

Hmm, I've never had a problem stopping under ANY condition in over 50 years of use. Don't know what your stopping problem might have been. How well do hand operated brakes work when your hand has something in it or is otherwise occupied such as giving a hand signal or drinking/eating?

I haven't tried super charging on my family auto either; guess only a blowhard would question the practicality/usefulness of applying expensive racing technology to everyday commuter applications.

Also won't work if the pedals fall off, which is about as likely under normal stopping conditions. And certainly less likely than a brake cable breaking in use, especially under hard application. And even less likely than the braking hand not being in postion to apply hand operated brakes at all in a timely manner.

I wonder why they don't use a geared v-belt instead of a chain. Cars & motorcycles use them for 50k+ miles with no problems. Probably lighter too. Imagine a bike without no outboard grease. Priceless.

Uhhh, how about that disk brakes will stop you in a fraction of the distance that coaster brakes will. Hey, if you like em great. Ride em. Shimano is even coming out with a new group called "Coasting" to better server people who want the simplicity of coaster brakes, but lots of people are willing to put up with more complexity and cost for higher performance. Live and let live. Personally, I don't do a lot of eating or drinking on my commuter bike. I am more concerned about getting where I am going and not getting hit by a car (one reason I like high performance brakes), but if that's your thing, I don't have problem with it.

It seems like most people here don't understand what drum breaks are.

Shimano, Sturmey Archer, SRAM hubs have for a long time shipped with two different types of drum breaks: a hand-operated drum break that works just like a disc break from the perspective of the operator and coaster mechinism drum breaks that are actuated by the chain.

Drum breaks work wonderfully in rain and snow they are fully enclosed, not even with a disc sticking out.

Disc breaks have need to have braze-on mounts built into the fork or the chain/seatstays. So they can only be put on frames specifically designed for them. Many people try to jury-rig them onto frames not designed for it and then the disc detaches from the fork/stays and then they end up in a very big accident.

Drum breaks can be mounted onto any (real) bike frame. They have arms that attach to the chainstay or the fork arm to distribute torque, but this arm does not need a special braze-on mount because all it's doing is distributing torque. The entire breaking mechinism is enclosed in the hub.

Drum breaks as hinted above can also be used on the front. I hear Shimano front drum breaks are ass but Sturmey Archer made and Sun Race now makes a full line of front drum breaks that work swell.

So I ask again, why should I "rejoice" about disc breaks, and what is the advantage over drum breaks?

I don't eat or drink while I'm riding, I ride while I ride, and pay very close attention to my surroundings, especially in heavy city traffic.

Oh Jesus. Not this urban myth.

Yes it is true that a front brake of whatever the sort will stop you in a fraction of the distance of a coaster brake. This is NOT because coaster brakes are weak but because there's not very much breaking power in the back wheel. A drum brake (coaster or hand-operated), a disc brake, a V brake, a caliper, whatever, are all limited by the fact that the back wheel does not have very much braking force. They'll all have the exact same performance in dry weather, although the drum and disc will probably outshine the rim brakes in wet weather.

It is not true that the technology of a disc break has significantly superior breaking power to a drum break for bicycles. Disc breaks supplanted drum breaks for the front wheels of cars (although most cars still have drums on the backs) because of a reliability issue that is not an issue with drum breaks on bikes.

It works like this. All brakes lose effectiveness when they get hot. Yet all brakes (except dynamic brakes, which are a whole different pickle) produce heat when they are used to stop a vehicle. The amount of heat depends on the inertia change involved in the braking, which is a function of the speed of the vehicle and the weight of the vehicle. Drum brakes are fully enclosed and thus, have a tendency to retain heat. When you have a big heavy car that is accelerating and breaking over and over again, the drums get hot and lose effectiveness. This is called "brake fade." Disc breaks are more open and don't retain heat like drums do, so brake fade with disc brakes is much less likely to happen.

But unless you're loading your bicycle up with 300 pounds and coasting down Mt McKinley, you're not going to produce anywhere near enough heat to make your bike's drum brakes fade. Brake fade honestly just isn't a big factor for bicycles because they're not heavy enough and they don't go fast enough. Disc brakes have a purpose in the automotive industry but as applied to bicycles, their only purpose is to seperate the rider from his money. They're yet another technology imported from some other industry to make bikes more expensive. There is no real utility.

I like the concept also except I how would you get the belt on? Belts usually don't have a masterlink. If you didn't have a way to split the belt you would have to split the frame.

^-- there are some folding bikes that use belts.

There's also been driveshafts made for bicycles. They're fully enclosed and are more reliable than chains while being grease free. Unforunatly they're slightly less efficient than chain drives so they've been supplanted.

I love the way a coaster brake looks and they darn sure have brought a many a bike to a halt. That hands free feature Like To Bike mentioned is pretty handy when you are out cruising. They seem to last forever and require very little up-keep. Drum brakes look cool too and work well in nasty weather. About the only complaint anyone ever has against them is they are a little heavy. Disc brakes probably want make you stop any faster than drums but they are a lot lighter. And are proven durable and of course look cool. Then you have rim brakes probably the most common of all brakes. They are the lightest. They might not work as well as the other types in wet or nasty weather. But they will get you stopped. My problem with rim brakes is purely personel. I don't like the way they look. So make mine the smooth uncluttered look of a coaster brake with no front brake or a set of discs front and rear. Since I'm not as tough as you single speed or geary guys make mine with a internal gearhub. Sure glad the manufactures are starting to give us gearhub users a full choice of brakes finally. Now if we can get them to make STI shifters for dropbars for gearhubs. Just my .02 and I have a full jar of change.

Do they use a link or have a way of sliping the belt around the chainstay?

I'm familar with shaft drives.

I didn't really look when I saw it. I imagine they have it designed so it doesn't have to loop around the chainstay. It might have had a detachable chainstay too. It was one of those plastic ones. I wasn't at all impressed.

jordanb asks:

So I ask again, why should I "rejoice" about disc breaks, and what is the advantage over drum breaks?

Carlton answers:

Because the manufactures are starting to pay more attention to the commuter, utility, and gearhub market. These new products give us choices that we have not had before. Now that we have the OEMs paying a bit more attention no telling what they may come up with. They might actually come up with something you like. Remember, at one time there were no internal hubs or drum brakes. If everyone was so set against technology the products you enjoy would have never been produced. The advantage of discs over drums (on bicycles) is mostly in weight savings and ease of removing the wheel.

I hear ya. I'm really not into folders although many riders certainly like them.

Very reasonable answer. You prize performance, I prize value and reliability. I can live with that.

Yeah I know, you don't like tunes either. You enjoy your cycling style? I like to bike but not if it means joining a cult of Asceticism.