What makes good brakes? Pistons, rotor or feedback?

Years back when we made track cars we used the best brakes possible for the budget. Things where easy back then. As many piston in the caliper as possible and the largest diameter rotor. Then add pads - green stuff I think was the tits back then. good brakes could be sourced from a handful of vendors. But the rule of thumb was the more the merrier.

But for e-bikes I feel things are a lot more complicated. We can't just use dirt bike brakes and be done with it. We got to think about weight as well. So what makes great brakes? I notice them monster calipers with 8 pistons or 6 pistons are all but vanished - guess weight penalty made them obsolete? The same with them big diameter rotors. Gone and forgotten. Even then big oversize'd tandem bike rotors are gone. AFAIK Hope still got a 224 mm rotor left and that is the biggest rotor around.

So when choosing brake parts what do I need to look for? What makes great brakes? Those 6 pistons calipers from Hope was too big and too heavy? Or did they maybe not improve braking or the brake feel enough to justify the added weight?

What is a great combo of today for brakes and why should people choose just those parts? I see this in context of heavy weight high powered e-bikes, that needs great stopping power. I don't care about saving 100 grams of weight. Stopping power and brake feel is what is important.

How do you want to define "good brakes"? That's an extremely ambiguous term, and the answer you get is going to change dramatically depending on what angle you're looking at this from.

I define good brakes as brakes with the ability to give me the best feedback and modulation at the edge of control while maintaining consistent operation over my desired speed range, with a wide operating temp range, under extremely harsh conditions, and with minimal maintenance.

And under that definition, V brakes win for lower speed bikes. Cable disk brakes win for bikes at higher speeds under 125 pounds. I'd want a hydraulic brake for a heavier bike.

The larger the rotor, the greater mechanical leverage you have but that becomes irrelevant if your pads overheat and glaze or brake fluid boils. So, the rotor and caliper both need to be to shed heat quickly & effectively to prevent that from happening.

Magura & Shimano both have nice 4 piston brakes out now and are quite impressive on 203mm rotors. They're both mineral oil which is nice to work with compared to 4 pot DOT fluid options like Hope & Hayes.

To deal with heat at the rotor, there's all kinds of techniques chosen like thicker rotors, floating rotors, hollow ones, stainless/aluminium/stainless sandwich & heatsinks.

Well I would define good brakes as brakes that are able to bring me to stop fast as possible while still give good feedback/feeling when using the leverage.

I mean I can see that weight was more important for the riders when the 6 pistons calipers from Hope was released - back in 2007. But today there are a whole different market. The e-bike. With 100-150 + lbs of dead weight. 330 gr or 400 gr will not do any difference in my mind.

The best brakes for DH riders that are competing against others might not be the best brakes for use on a heavy e-bike. We could easily do with more hardware. Larger rotors that deals better with heat, more pistons without loosing any sleep due the added weight.

I would not consider V brakes for e-bike, nor wire operated disc brakes. For heavy e-bikes and even heavier rider I consider only hydraulic disc brakes. Has anyone tested the mono 6 kit from Hope when it was still widely available? It is still possible to get if looking, it got 6 titanium pistons, larger pad surface and caliper surface and also has a 250 mm rotor. Would it be worth the extra cash to find one of them fir high powered e-bike?

It's strange with MTB brakes it seems more pistons = better generally, more power, more modulation. But then I look at my 2006 KTM 250 brakes, there is only one very large piston per caliper.

However, I have a value oriented but high quality DH brake on my ebike - the shimano zee and it's fantastic on my 90lb ebike, easy to lift the back wheel up even with the 25lb hub motor. With regen braking, I have overkill brakes already, will never come close to overheating even with steep downhill descending.. and with a hard pull my bike seems to stop very nearly as quick as my non-electrified MTB. With extensive downhill off-roading on pedal bikes experience I would suggest to not underestimate the power and heat dissipation of any current mid to high end downhill MTB brake for ebiking. They are built to handle extremely steep and lengthy continuous descending, and very hard braking.

Rotors make a big difference. I trust shimano 'ice tech', which as voicecoils was commenting, has the aluminum steel sandwhich on the braking track, and also uses a floating design. As well you can now get brake pads with heat sinks built into the back plates. Shimano, Stop components and uber-bike are some brands making these. If you really want the best heat dissipation you can even go for shimano's highest end rotor the RT99, which has even more heat fins and shedding capability.. center lock mount only though, no 6 bolt version unfortunately.

A very heavy rider, and a very heavy bike doing long descents without regen, then I would suggest looking for something better than standard MTB options.

Kyle201 said:

It's strange with MTB brakes it seems more pistons = better generally, more power, more modulation. But then I look at my 2006 KTM 250 brakes, there is only one very large piston.

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Blame a lot of that on marketing. More pistons allows a longer, thinner pad to be used. That's an advantage when a normal shaped pad isn't enough, but there are many downsides as well. more pistons means more fluid movement, and more seal drag. That cuts down on the amount of feedback you get from the brake and reduces your ability to modulate the brake effectively at the limit.

1 piston is going to give much better feedback, allowing much better modulation. But you need to make the disk bigger with more surface area so you can fit a wider pad. That adds weight, but it does help with heating and more even pad wear.

@Macribs, Not sure why you dismiss cable operated disk brakes since they are vastly superior than hydraulic bicycle brakes in many regards.

Keplers super commuter was built initially with both discs being upgraded to the largest reasonably priced diameter rotors. The rear had a tendency to lock up with even the lightest level pressure, so he downsized to the next common diameter, and it "felt right" after that. When braking (as I'm sure you already know) the weight of the bike + rider shifts forward, so the front brakes perform most of the braking and heat dissipation.

I'm probably not a good person to post on this subject, I'm still using a spoon brake...

@Drunkskunk Well I might just be ill informed or prone to fall for marketing schemes. But I always seen hydraulic disc brakes as vast superior to the cable ones. For one thing brake fluid also takes ups heats - as long as kept under boiling point that is a good thing as it aids in heat removal. There was a time when all but the race ready snowmobiles used mechanical wire operated disc brakes - well they did work but after trying hydraulic brakes we never looked back and not once have I missed them old wire mechanical brakes.

All dirt bikes and motorcycles I have ridden over the years have used hydraulic. Except for the cheapest mopeds. Never once when ridden have I found myself thinking, gee I wish I rather had wire operated disc brakes.

What are so great about them wire disc brakes? Except maybe higher markup for vendors? I can't see one place where they excel over hydraulic brakes - well the price of course but that is it. Even when service is closing in you get early warnings with hydraulic brakes. With wires they will just snap one day and you could be left in a tight spot.

I might be wrong as I have not ridden wire disc brakes on bikes.

So what front caliper and rotor combo can compare to the obsolete Hope Mono 6?


@spinningmagnets you might be old fashioned with the brakes but your saddle sure is all that
Btw I should have written that I am looking for big ass brakes for the front primarily as the rear does less work.

Downhill brakes are designed to be consistent over the whole run, which means no overheating. See the latest Shimano Ice-tech's, they've got air cooling ribs all over them.

So yes design goals for downhill are not the same as for a 100+lbs e-bike on pavement, for that one you would need even more max force and even more heat dissipation.

For the record bigger rotor offers LESS feel they just dissipate heat better and have more braking force. Using 203mm discs on a 30lbs street bike is WAY overkill, in fact it might not even be within the design parameters of the fork they were put on.

But practically speaking what's your choice other than the best downhill brakes you can get? You got bicycle hubs and forks and dropouts. Put a good dirt bike brake on a bicycle fork and it'll just snap the fork leg off and probably rearrange your face in the process. I don't see any other practical choices than whatever you think is the most efficient downhill brake system that's in your budget.

regen braking

Hehe you have little faith in todays forks I think any fork that can withstand numerous 3-6 feet drops might just have more to it then you think.

That being said I will keep within DH brakes - I might however go for the even larger rotor and 6 piston caliper from Hope if I find one locally. I will check out the Shimano's. The better solution will be a set that has widely available parts.

whatever said:

regen braking

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Yeah regen is fine and dandy but is not what you want when you need it the most. Plus regen can put more strain on the axle.

What's your use case? As in, how hard are you riding? Do you experience any specific problems with your brake system?

Think about it this way: a downhill bike is already optimized within the razor's edge for weight savings. There's nothing on a spendy modern bike that is "overbuilt" anymore, whatever could be removed, largely is already not there. Flip side, there aren't that many people out there who ride hard enough to be anywhere close the strength limit of a downhill bike.

I see all kinds of contraptions here that a fast rider would absolutely destroy within the first 100 yards of riding. Prime example is those "rear racks" that mount to the seat tube, carrying 10+lbs of batteries, or bottle batteries that mount with two tiny M5 bolts to a super thin aluminum downtube. But yet folks ride like that for years and they're fine because they aren't aggressive riders and don't put that much hurt on their equipment.


Oh yea. Don't skimp on brake pads. If you want fade-free brakes the first thing to look for is the most robust brake pads you can find in the right shape. The difference can easily be 50% or more in fade resistance. Just don't go overboard and get some crazy race pads that only work if they're pre-heated to 100 degrees already

Use case - well thing is with added weight of the rider and a heavy e-bike many daily situations has a potentially for being high stress for brakes. Long descends. Repeated hard braking due to traffic. What I mean you don't need to ride to the max to put some work on your brakes. Weight alone will do that.

It is easy to forget that we e-bikers are not DH riders. I mean we add weight in all places but the front end and I guess that is partly why I started this thread. Realizing DH riders fear extra grams as they race downhill where every seconds counts. First of all our bikes are way heavier to begin with. Often the rider too I guess I was frustrated over what seems almost obsessive scare of any added weight. As I said earlier back in the days of cheap racing bigger was better. If your budget allowed for 8 piston caliper, 8 piston caliper it was.

Then I see that several multi piston calipers are obsolete and out of production for this bicycle market. I guess my rant was that if those Mono 6 was released today they could have actually found a place in the market. Big fat e-bike riders with big powered e-bikes. Hope was just a decade early with them brakes.

You might be right or (IMHO, most likely), it's all in your head. Sure heavy bike and all but I dare you get a good modern Shimano downhill brake system and try to get it to fade. Folks have "tattoos" made via pressing skin to brake rotors, and no that doesn't mean brakes had any fade.

More pistons doesn't necessarily mean more brake power or better fade resistance. I think those 6-piston monsters died off simply because brake pads got so much better over time and can operate fade-free at higher temperatures, so there's no need for all this complexity. Plus things like ice-tech that actually do make a difference not just look good came about.


PS: For the record my bike clocks in at about 40lbs and I'm entirely content with stock 160mm wimpy brake system. We got hills here but there's no hill out there to be a concern. I'd roll down Haleakala Highway on these brakes any day.

I guess this whole thing can be spun around and put differently.

If you're adding 100lbs of very powerful electric propulsion to a bicycle, why do you expect anything to work on it? Sure the tribal knowledge says it might work out Ok but really. The frame wasn't engineered to take big torque from the motor, it wasn't engineered to carry the weight of the battery (there's a big difference between human soft weight and hard weight of the battery), etc. etc. So singling out just the brakes is not fair. The whole thing is stressed out quite a bit and it's a minor miracle we don't see many snapped off head tubes, twisted off chainstays etc.

The only logical explanation for all this is bikes were designed for much higher loads put on by downhill riding (yes, including brakes), so street riding these things keeps parameters within design envelope and everyone's happy.

Yeah I failed to mention that I have a frame that was purposed build for e-bike. From solid steel. I also got mc wheels and tires.
What I do have is dh hub up front so that dictates the brakes up front. You are right all this might very well just be in my head. I have little to none experience with the DH brakes and I based this thread entirely on previous experiences regarding brakes - but on totally different scenes. From motor cycles and snowmobiles to race cars.

I will listen to your feedback and will start out with normal DH quality brakes. If I should find them fade or having trouble stopping 400 lbs of moving bike and rider I can start looking for those monster Mono 6.

But man those calipers and brake pads they looks so darn tiny. It is really hard to wrap my head around this. Those tiny brakes will stop a 400 lbs rider/bike combo even from speed at 60 mph or more.

Lukes Deathbike used a dual-crown fork from a motorcycle with only one disc. He abused it with frequent hard braking in the several races he rode it in, and heat wasn't an issue. Of course the components were heavy compared to bicycle gear, but one disc was all that was needed when the right system is applied.

The Greyborg framekit people stock a special order front wheel with dual disc mounts, and their fork has dual caliper mounts. The claimed benefit is that the dual DH bicycle brakes are lighter than a single motorcycle disc system.

I believe the Greyborg system is designed for hydraulics, but...If dual cable-operated discs appeals to you, there is a brake handle with two cables available.

macribs said:

Yeah I failed to mention that I have a frame that was purposed build for e-bike. From solid steel. I also got mc wheels and tires.
What I do have is dh hub up front so that dictates the brakes up front. You are right all this might very well just be in my head.

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No sorry I think you're damn right to be concerned given your situation. That's pushing it!

If you really wanted to do something about this, it'd probably be easier to custom build brackets and find a motorcycle hub that is narrow enough to transfer the whole moto setup over to your bike.

Actually even better would be to make a custom steering stem and transfer the whole motorcycle front end. That's actually not that difficult.

Hmm, the best brakes I have ridden with, were the kind that were properly adjusted. Any kind. But that's for dorking around riding. Race riding you need motorcycle grade shit, to run like a motorcycle.

They do need to be able to lock up the wheel to not suck of course, and locking it up too easy does make it tricky so that's not good either.

A ride that will cook off and fade your brakes, then adding regen would help a lot. Not grab handle regen, but push button only when you want it regen. Easy to grab two handles, and still feather a push button regen with your thumb.

But yeah, you can't do strong regen with a shitty torque arm, or soft axle. And regen is not where you want your best brakes, the front wheel.

I'm not saying cable brakes are better, what I am saying is that hydraulic brakes aren't better. There are tradeoffs for each. What made Cable operated brakes the right choice for me was the need for a brake that worked in extreme riding conditions, at both low speeds and high speeds. My monsterbike has blistered the paint off a caliper. had that been a hydraulic caliper, I would have boiled the fluid and lost all braking. But since I had a cable brake, I only had some moderate brake fade and plenty of warning that I was going to be in trouble if I kept riding so hard.

in 30 years of riding and working on bikes, I have never had a cable snap. I have never known anyone who had a cable snap, and I have never heard a creditable story of a cable snapping. they can take around 2000 lbs of static tension. brakes use around 20 pounds of tension. When they do start to fail, it's by fraying, and there is all kinds of early warning sines long long before the last strand would snap.

I have seen hydraulic lines fail, but in fairness it was usually due to a wreck or a snag on the trail.when you snag a hydraulic line on a 1/2" branch on a downhill run, it will get ripped right off the bike and leave you with no brakes. When you do that to a cable brake, well...
ok, you end up waking up in a ditch wondering why your bike's tire is in your face, only to then realize that the bike is dangling by the brake cable from a tree branch directly over your head. True story.. But I still had working brakes!

On a bike much heavier than mine, a motorcycle disk brake with a hydraulic caliper would make sense. Same as it does on your snow mobile, and on a medium to large sized motorcycle. A bicycle brake caliper is a toy by comparison.

The advantage of Hydraulic brakes is lighter weight, less hand strength needed, and less maintenance
The advantage of mechanical brakes is a more heat tolerance, and wider operating perimeters, plus higher fault tolerance.
Neither have an advantage in stopping power or modulation inherent in their design.


As for rotors, a smaller rotor will generate more heat. a larger rotor will shed more heat.
I know that makes it sound like larger is better, but it's not that simple. Disk brakes need heat to operate correctly. If you can't get the heat up, the brakes won't be effective, and will either act "grabby" or will feel like you have severe brake fade, where they won't want to grab at all, depending on the compound of pad you are using.
Right now I have a 224mm Hayes H9 on the front of my bike because I need to shed as much heat as I can. But I have a 203mm rear brake because I couldn't get enough heat in the rear to brake effectively with the H9. And I'm considering going down to a 185mm to improve my low speed performance.

I thought about maybe getting made a custom sleeve of some sort for the right side stanchion of the Fox 40, but I run it by a co-worker and he seemed to think dual brake set up would put too much stress on the fork. So I gave up on that.

I've been looking into dirtbike fork, pit bikes front ends etc. But I gave up on that due to all added weight up front. I also decided against dirtbike front hub/brake set up due to weight and possible fatigue of fork.

Those Shimano Saint 820 looks like 4 piston calipers, with lots of added mass for more cooling. I could try those combines with Hopes 224 mm floating rotor. Heat should be taken care of, shear stopping power from caliper, pads and pistons I am still unsure about.

What you all think, 400+ lbs too much weight for stopping from high speed for such a setup?

I really hope someone that has ridden the Hope Mono 6 kit drops by this thread - it would be nice to hear first hand experiences about them brakes. It seems those are the biggest calipers and rotors that is still possible to find. From researching this topic I did find another 8 piston set - but that looked like vaporware. Could not find anything but press releases.

Brakes seems to be the last place to skimp - better try to get it right the first time.

macribs said:

...shear stopping power from caliper, pads and pistons I am still unsure about.
Brakes seems to be the last place to skimp - better try to get it right the first time.

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A common misconception is that better brakes have more stopping power.
Untrue.
Stopping power is a matter of your tire's grip on the road. At the edge between turning and skidding, you have achieved the absolute maximum braking force your bike is capable of. So any brake that can skid the tire is capable of 100% braking force. any brake that couldn't skid the tire belongs in the trash.
Good brakes do 2 things beyond simply skidding the tire.
1)handle heat. either they shed heat well or they tolerate it well, they need to be able to handle heat.
2)modulate well. You'll stop faster if you can hold the wheel on the edge of skidding without actually skidding it. Good brakes allow you to feel what the wheel is doing and modulate the braking force as needed to hold the wheel at that edge of traction.

Drunkskunk I think we are saying the same thing with different words. When I wrote shear stopping power I was not talking only about the ability to lock up the wheel. I was talking about the ability to lock up the wheel repeatedly if I so choose without fading due to too much heat.

Brake feel I am onboard also there.


So again - The bike will be heavy 100+ lbs and I am 300 lbs. So will that Shimano / 224 mm rotor work over and over without boiling the fluids or glazing the pads? Again powerful e-bike top speed > 60 mph and weighing in >400 lbs.

If not I think the only option left without going motox front end would be to find a set of Hope mono 6.