Here’s another interesting take on motorcycle brakes that give you an almost unobstructed view of your wheels while still providing excellent stopping power. Called the 360 Brake from Baldwin Wilson Development Corporation, they work on the same principle as a clutch and pressure plate, in this case two full circumference brake pads squeeze the rotor and all parts fit inside a slotted hub assembly that keeps everything out of sight while allowing cooling air to take away heat.
The 360 Brake is designed to work on wider forks and can also be used in the rear, including applications on single sided swingarms, but the system takes up a fair amount of space around the hub and seems aimed more at the custom market where size or space issues are not the problem they would be on more standard street bike applications. The company website does say they they are working on a smaller version for narrow forks which should fit most metric cruisers.
According to the company, tests show shorter stopping distances than with standard brakes and less fade, however, I think you need to remember what type of bike and riding these are designed for, these are not for any high performance sportbikes, so keep that in mind before everyone jumps in to say they’re no good because they’re not used in MotoGP. As even the company states, the brake “performs well within the design parameters it is engineered for.”
I think they are an interesting variation on current setups and may work very well but if you’re looking for a brake free view of your wheel and still want high performance, perimeter brakes might offer a better solution.
Thanks for the tip, Jim!
Links and more photos below:
Link: 360 Brake
Related: Wilwood Stealth Perimeter Brake System
Related: Perimeter Disc Brake Rotors
Pete P. says
Changing the pads gonna be a beatch!
John McDowell says
If I read the diagram correctly, the “axle” not shown needs to be “fixed” to the fork so that it can not spin. Then the braking parts can work. So how well does the axle take the braking forces versus the standard fork leg and caliper?
I would like to see some performance tests first. Or, is the “Rotor Hat” and / or the opposing “Caliper” get fixed to the fork?
jaredthegeek says
This looks sort of similar to the motor brake on Crown electric forklifts/stock pickers….only in that application the brake sits atop the main drive motor and is not hydraulic but spring/solenoid powered. Not powerful and tends to lose braking capacity with repeated applications.
I’m somewhat skeptical but curious nonetheless.
Sean says
I’ve always wondered why we don’t simply increase the size of the pads to increase stopping power. Anybody know why?
chris says
this seems like it could have potential for street/sport bike applications. as long as it is determined that the axle and bearings could take the beating, think how many “brake plates” you could fit in there. it seems like there’d be more weight than on a conventional setup, but the plates would be much smaller so it’d most likely offset. not to mention the weight would be very compact near the axle (where it has the least impact on gyroscopic and unsprung weight). i’m thinking of something similar to a clutch plate type limited slip differential. it’s got issues sure, but like i said, it’s got potential.
GenWaylaid says
I recall that the top-of-the-line Lambretta scooters had a similar setup in the late ’60s. They used a full-circumference pad pressing on a small brake rotor. From what I’ve heard, the rotors didn’t cool well and had a tendency to warp.
Heat build-up and the associated fading and rotor warping are potential problems with any compact disc setup.
Roberto says
Commercial airliners use brakes similar to these, with stacks of multiple disks and pads.
Alex says
Have a look on airplane brakes, then you know that this idea is not that new at all 😉
todd says
I’m not quite sure how the relationship of pad size to friction pans out. From what I understand of physics, to get the same surface pressure on a braking surface that is twice as large you would need twice as much pressure (all about PSI). There is something called “coefficient of friction” but someone will have to help me understand how it might relate to variations in PSI and area for friction materials. Does an increase in area equal an increase in friction even if the PSI is reduced?
An increase in “rotor” diameter would give a proportionate increase in braking leverage with a given amount of friction and force. Also, increasing force seems to increase friction; more stopping power. -An increase of friction directly causes an increase in temperature. If there is no increase in friction (i.e. stopping power) then there would be no increase in heat generated. However, an exposed rotor of large surface area is much more capable of dissipating heat than this enclosed system. Typically a clutch runs in a bath of cooling oil, which I do not think is applied here.-
We cannot reasonably add leverage at the lever (longer lever or smaller master cylinder diameter) so the leverage is usually applied at the wheel in the form of larger diameter rotors. Since this system is much smaller in diameter that leverage is lost but that loss in leverage might be made up for if friction increases relative to area, which seems to be the case.
If both surface area and pressure provides additional stopping power for a given amount of leverage why not just increase the pressure? I think BMW is one of a very few who have utilized servo-assist (power) brakes in motorcycles. Is this option soley rejected because of reduced braking force when the system is off – pushing around the garage or engine failure? If so I can imagine a few ways to retain residual power for the system when the bike is not running. Is it the added cost and complexity, lack of public acceptance? Thanks for the help understanding the fundamentals.
-todd
xbob says
whats the cost for this brake system?
aaron says
why do we need more stopping power? if you can lock the brake or lift the rear wheel with one or two fingers, added braking force is not required. fade is largely gone in current sportbikes, so we’re left with feel/response as the reason for the latest improvements like monobloc calipers and radial mounting. at the highest levels, i think most engineers are happy with the status quo regarding brake performance. most performance gains now are found in altering the braking systems for lower unsprung weight and less rotational inertia. ease of manufacture and reducing complexity are other elements that dictate new design – hence the failure of bmw’s system to catch on.
aaron says
todd – you are close in your line of thinking. it’s force, (lbs or newtons) not pressure (psi or Pa). in theory, friction has nothing to do with area – the equation is Force of friction = coefficent of friction*normal force. strictly speaking, surface area doesn’t affect friction. the coefficent is determined by the two materials in question and their surface finish. normal force is force applied 90 degrees to the surfaces. the theory is messed up when the materials change with heat (carbon brakes) or are deformable (sticky tires – more surface area means more grip – frictional formula be damned!)
I think that the larger the rotor/caliper/pad, the more area there is to dissapate heat. there is also less heat input per gram of material, so there’s less distortion in the braking elements and less heat passed along to things like brake fluid.
todd says
My question on adding power assisted brakes was for the benefit of smaller rotors. Smaller rotors would give less unsprung weight and lower inertia for better handling and faster, more direct steering feel. Moving the calipers towards the fork axis also reduces the tendency of head shake allowing one to forgo a damper all together for even lighter steering feel. I think the trend though is towards larger and larger diameter rotors in the same vein of wider rear tires.
In respect to these Baldwin brakes adding an electro-mechanical or vacuum assist servo would give these all of the benefits stated above with the potential for even greater stopping power. Cruisers are typically very heavy bikes and they are getting faster.
Isn’t PSI the same thing as force over area? You lost me on that one.
-todd
aaron says
psi IS force over area. but the formula requires just the force to determine the force of friction. the area is not required to determine this.
just speculation here, but I think that if more force were applied to smaller rotors, they would need to be much stronger to cope with greater shear forces. the wheel would also need to be built stronger. more weight, and I get the impression that assisted brakes don’t have the feel or response of standard ones.
guitargeek says
Expensive, complicated, unproven, etc. I figure there’s a reason Brembo hasn’t come up with anything like this. And what is the motivation? So other people will be able to see your expensive wheels, ie “vanity”.
I don’t know about you guys, but I LIKE the look of big clunky brakes.
FORM FOLLOWS FUNCTION.
todd says
so the moral is: larger brake pads do not provide additional stopping power.
It’s funny, I remember always reading about full width drum brakes and how they were superior. I guess it was because they were larger in diameter too or had twin leading shoes. Maybe the benefit was in their ability to resist fade due to the greater surface area. Thanks for clearing up the force / friction thing.
-todd
Sean says
I agree with guitargeek, form always follows function. Or at least, it should. Mind you, if you’ve got a “custom” chopper then it’s the other way around. I like the look of big, chunky USD forks, a minimalistic mudguard, radially mounted calipers that grasp brake pads almost as large as the rim itself. That, my friends, is a functional front end setup, designed to take you from twice the legal limit to cop friendly territory in as little time as possible.
GenWaylaid says
There’s one big disadvantage to small-diameter rotors. The braking torque they can produce is limited by their small lever arm.
On conventional brake rotors, the lever arm of the applied force is a little more than halfway between the inside and outside edges of the brake pad. The coefficient of friction is the ratio between the frictional force dragging the rotor back and the normal force of the brake pad pushing down on the rotor. The total braking torque is the lever arm times the coefficient of friction times the force exerted by the brake pad. The pressure on the rotor is the force exerted by the brake pad divided by its area. Only the part of the rotor immediately under the pad is being heated by friction (the heating is proportional to the energy dissipated, or braking torque times the rpm of the wheel) while the rest of the rotor is flying through the air and cooling off again. Hence drilled rotors, which stir up more airflow for better cooling.
With a compact, multi-disc setup the lever arm is closer to 70% of the way to the outer radius, but it’s still not very large. That means more force has to be applied in order to get the same braking torque. If you tried to apply all that force to just one small-diameter disc it would lock up. Instead, many discs are stacked to divide the force between them. The braking torque is still the lever arm times the coefficient of friction times the force exerted by the brake pads. The pressure, however, is the force divided by the total area of ALL the discs in the brake. The heating is similarly divided among the discs, so both pressure and heating rate can be brought back down to normal levels despite the high force being applied. Unfortunately, all of the discs’ area is being used for braking and is being heated, so there’s not much area left to dissipate heat. If you used the brakes like an airplane does, for one intense burst of a few seconds, then they’d have plenty of time to cool. Repeated application is likely to cause problems.
So, to recap, a compact multi-disc brake can provide the same stopping torque as a conventional disc brake, but only if the force applied is much higher to counter the smaller lever arm. This force gets divided up among the discs, so pressure and heating are not problems, but heat dissipation is because there’s so little contact with cooling air.
todd says
To make things worse, they’re mounted on a 21″ rim stopping a 700 lb bike… with a 300 lb rider….
-todd
tauno says
i am going to try it on the front of my 2006 american ironhorse texas chopper. at any significant speed, i rely on my rear brake. tend to use the front at slower speed or after rear has been applied.
i also remember that in the 50’s and 60’s we used to build choppers w/o front brakes. if i remember, on long bikes, (picture fonda’ chopper) there was very little weight over the front wheel, and front braking made the tire skip/bounce.
i spoke to an airline pilot friend and he says they were great re reliability and stopping for commercial aviation. he was going to try and get some maint. record data for me.
if it works on the front, i’ll probably try it on the back.
why, you say?? why not say i!
Red Gear says
Cool…. Where can I buy it?