Crazy idea? Brake by wire - not cable!

[Clancy]

Just saw the post on the Argonaut w/SRAM e-tap with hydraulic brakes.

Made me think of the simplicity of set-up except the hydros.

Which made me think.... possible one day to do break by wire as in new cars?

Or, Bluetooth breaking with hydraulic discs?

Imagine the ease of set-up

[batman1425]

Imagine the force of impact when the transmitter/receiver drop their pairing mid ride from interference or battery loss. I'm sure such systems could be made to be nearly as reliable as cable or hydro system, but the consequences are quite different from losing shifting performance. It will take quite the body of evidence to convince people that e-braking is as safe and "better" than the already very good cable and hydro systems.

[JWDR]

Imagine the force of impact when the transmitter/receiver drop their pairing mid ride from interference or battery loss. I'm sure such systems could be made to be nearly as reliable as cable or hydro system, but the consequences are quite different from losing shifting performance. It will take quite the body of evidence to convince people that e-braking is as safe and "better" than the already very good cable and hydro systems.

Safe enough for cars but not for bikes, got it.

[54ny77]

no thanks. call me a luddite.

[batman1425]

Safe enough for cars but not for bikes, got it.

Cars have a bit more liberty with respect to the size and weight of a safe and effective brake by wire system. Integrating that tech into a bicycle where weight and aero are major concern will vastly impact the viability of it in a bicycle application application.

Additionally, the current brake by wire applications in hybrid and electric vehicles frequently have mechanical/hydraulic backups in the event of a electronic system failure.

[mt2u77]

I'm amazed at how much faith is put in WiFi/Bluetooth reliability. Those devices operate in the ISM band, where there are literally no limits on radiated power and no requirements to play nice with bandwidth consumption. There are lots of legit industrial, scientific, and medical equipment that will blast any Bluetooth signal away for a half mile radius. Even without such interference, signal quality is unreliable and subject to a lot of buffering to keep things flowing.

As an engineer in the field, it will be a cold day in hell before I let Bluetooth control my brakes. A dedicated band, with enough redundancies designed in, and automotive level reliability standards, would be a slightly less cold day in hell-- but the bike market is way too small to merit that type of investment.

[Mark McM]

Just saw the post on the Argonaut w/SRAM e-tap with hydraulic brakes.

Made me think of the simplicity of set-up except the hydros.

Which made me think.... possible one day to do break by wire as in new cars?

Or, Bluetooth breaking with hydraulic discs?

Imagine the ease of set-up

Are the electronic braking systems in cars and trucks wireless, or do they use hard-wired connections?

For the cars and trucks, there is a significant amount of electric energy continuously available to operate the brakes. For a bicycle brake by wire system, what energy source do you propose?

[batman1425]

Are the electronic braking systems in cars and trucks wireless, or do they use hard-wired connections?



For the cars and trucks, there is a significant amount of electric energy continuously available to operate the brakes. For a bicycle brake by wire system, what energy source do you propose?



Every one I have seen is hard wired.


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[Nooch]

Are the electronic braking systems in cars and trucks wireless, or do they use hard-wired connections?

For the cars and trucks, there is a significant amount of electric energy continuously available to operate the brakes. For a bicycle brake by wire system, what energy source do you propose?

Next development, etap/di2/eps powered by dyno hubs...

[batman1425]

Next development, etap/di2/eps powered by dyno hubs...



That's one application where this might work, regenerative braking from a dynamo hub, but you would still have to supplement with a mechanical system of some kind.


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[54ny77]

This all sure makes cycling sound like fun.

:rolleyes:

[bicycletricycle]

I think that the rear brakes on formula one and some hypercars are fully electronic. They have gone this way so that the systems can integrate in the regen braking smoothly. Apparently it is really hard to get them to "feel" right.

I am not sure if they still have a physical hydraulic system, perhaps the "electronics" just actively manipulate the hydraulic pressure being created by the drivers foot.

I think brakes that don't work when your batteries run out seem silly. They would have to make them so that they locked up if any of the systems failed (like air brakes). That would be interesting :)

[Mark McM]

I think brakes that don't work when your batteries run out seem silly. They would have to make them so that they locked up if any of the systems failed (like air brakes). That would be interesting :)

I don't think that idea would be safe at all - you don't want to be driving down the highway at high speed and suddenly having your brakes lock up.

Instead, this issue is more likely to be addressed by redundant systems - which even mechanical systems have. Current cars have to independent hydraulic systems (that work on diagonally located wheels), plus a cable operated emergency brake.

[bicycletricycle]

Air brakes on trucks auto lock when the system looses pressure, I think.

I don't think that idea would be safe at all - you don't want to be driving down the highway at high speed and suddenly having your brakes lock up.

Instead, this issue is more likely to be addressed by redundant systems - which even mechanical systems have. Current cars have to independent hydraulic systems (that work on diagonally located wheels), plus a cable operated emergency brake.

[Mark McM]

Air brakes on trucks auto lock when the system looses pressure, I think.

Only the parking brakes. The normal operating brakes use air pressure to apply the brakes (and won't work if pressure is lost).

[oldpotatoe]

Safe enough for cars but not for bikes, got it.

Car electronic braking systems aren't 'wireless' but hard wired. Mixing programs.

[bicycletricycle]

Next development, etap/di2/eps powered by dyno hubs...


http://www.chapmancycles.com/2017/03/dynamo-powered-di2-light-touring-bike-v2-0/

[JWDR]

Car electronic braking systems aren't 'wireless' but hard wired. Mixing programs.

You did see where the Op proposed two different methods? With one of them being wired and one being wireless?

[MesiJezi]

Mechanical braking has redundancy in the fact that the front and rear brakes are two discreet systems. If one fails, the other is theoretically still usable.

I would consider using hard wired electric brakes only if the front and rear braking were controlled separately and had separate power sources. I would also require that the calipers be "normally open" so that in case of failure or loss of power you would not come to a sudden stop...

Not sure it there is much to be gained, except for aesthetics. You would lose some feedback through the levers, FWIW.

[batman1425]

plus a cable operated emergency brake.

I'll add a 3rd option - electronic emergency brakes which typically work via a servo and cable, or are integrated directly into the caliper. In cars with an integrated setup (Volvo i believe does this among others), if the car were to experience a total electrical drain or complete system failure with the E-brake on, the only way to move the car would be to cut off the caliper. :eek: But as you say, functional redundancy.

[batman1425]

You did see where the Op proposed two different methods? With one of them being wired and one being wireless?

Neither of those setups have functional redundancy as described by the OP. Car brake by wire systems do.

Modern passenger vehicle brake by wire systems are typically an electro-hydraulic hybrid system where actuation of the pedal causes initiates motor to push on the master cylinder, which has certain benefits in automotive applications - most notably regenerative braking. You lose the vacuum booster, and a bunch of plumbing among other things. That said, they still have have a physical linkage between the pedal and the master cylinder, so in the event of a complete electronic failure, you still have some control over the braking system. And as others have mentioned, the car typically has another alternative emergency braking system.

In a bicycle application, there is little value to an electronic system if it requires mechanical redundancy for safe operation.

[ojingoh]

In a bicycle application, there is little value to an electronic system if it requires mechanical redundancy for safe operation.

Another way to look at it is the car has no viable options for mechanical force applied by the passengers directly. You are not Fred Flintstone. Cars have to utilize other systems - electrical, hydraulic, electronic - to apply the force. On a road bike simple mechanical leverage is fine, hydro if you must.

I've driven cars with non hydro brakes, and I dont think i want one in 2017 unless it's a track toy. :hello:

[cmg]

no need to worry, whatever you hit will stop you.. ....

[pbarry]

no need to worry, whatever you hit will stop you.. ....

Good one! :beer:

[Clancy]

no need to worry, whatever you hit will stop you.. ....

This post is worth the original posting. Brilliant!

[Mark McM]

Another way to look at it is the car has no viable options for mechanical force applied by the passengers directly. You are not Fred Flintstone. Cars have to utilize other systems - electrical, hydraulic, electronic - to apply the force. On a road bike simple mechanical leverage is fine, hydro if you must.

I've driven cars with non hydro brakes, and I dont think i want one in 2017 unless it's a track toy. :hello:

On a related note: In the debate over disc brakes vs. rim brakes on bikes, many point to the switch from drum brakes to disc brakes in cars. But what they fail to consider is that disc brakes did not become common on typical passenger cars until power brakes became common - without power assist, it takes far more foot pressure to operate disc brakes than drum brakes. I've driven non-power assist drum brake cars, and non-power assist disc brake cars, and I wouldn't want to drive a large non-power assist disc brake car on a regular basis.