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There's a new braking system put out by a company named SureStop that controls both front and rear cantilever (side-pull) brake systems with a single brake lever. They seem to be mainly appealing to the safety / children / new bike owner's market.

They say their technology can prevent end-overs as well as skid-outs.

How do they do this? It appears to be more complex than a dual-cable brake lever -- i.e., there seems to be some fore-aft balancing magic that's going on.

Bonus question: If the rear pad loses traction against the wheel (for example: it wears down to its nubbins, slips off the rim, or the rear brake cable breaks), does the user lose all braking - front and rear? Does this then violate the redundant brake regulation in bicycle consumer sales laws?

For example, Japan's JIS 9301:2010 regulations requires "separate braking systems operating on the front and rear wheels respectively" and SureStop says that they are compliant with this standard. Because the front and rear brakes are linked in SureStop, it's unclear to me how they are "separate."

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    I have no relation to this company but saw them on TV and wondered how they were doing it, technology-wise.
    – RoboKaren
    Apr 17, 2017 at 4:56
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    In many countries, bikes must be equipped with two independent brakes (Safety in case of mechanical failure). Before installing check local regulations as the design has single point failure modes of normal brakes yet only one. IMHO, teaching riders bike skills needed to ride a bike safely properly is a far superior option to a solving a problem that does not really exist.
    – mattnz
    Apr 17, 2017 at 6:13
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    Should perhaps be renamed "UnsureStop" in light of the uncertainty about what it actually does. ;-)
    – David Richerby
    Apr 17, 2017 at 12:05
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    Complete garbage. The front brake is crucially important on a bike; you don't want it entangled in any compromising contraption involving the rear brake. When you squeeze the front brake lever, you want all the action to go to the front brake. I wouldn't even dream about installing this on a bicycle.
    – Kaz
    Apr 18, 2017 at 1:23
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    "how does it work?” not at all. one of the worst pieces of bicycle technology I've come across. they recently updated the lever to have more cable pull (more than a standard v brake) in order to try to improve the braking ability
    – Paul
    Apr 18, 2017 at 20:54

5 Answers 5

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You've got a brake lever and a rear brake both with typical mechanical advantage characteristics. One of the rear pads has a spring-loaded sliding mechanism where forward momentum captured from the back wheel when braking causes it to slide forward and actuate a cable going to the front brake, which is controlled only in this manner. (The head of the cable is in the moving pad, and the stop for its housing is a stationary part of the pad. Movement between the two generates the cable movement, same as a brake lever.) Some assumptions are built-in about weight distribution and total weight on the bike, and the manufacturer chose a distance for the slidey bit that will keep the front brake from ever being able to lock if those assumptions are correct.

Maximum braking power is decreased compared to a normal system owing to the aforementioned one-size-fits-all design assumptions, which have to be conservative for the system to do its thing, which in the scheme of things probably makes them less safe for most people, not more. They are adequately powerful for most purposes when set up correctly. Their marketing/product material touts the line that they're a pure, unequivocal upgrade over conventional systems, which is not correct because they reduce the overall amount of braking power available.

Another safety drawback, especially for novice or fearful users that might be most drawn to the system, is that not adjusting the rear brake's barrel adjuster as the rear pads wear will create a situation where the entire bike has inadequate or no brakes much faster than in a conventional two-lever setup. For a rider that simply will never use their barrel adjusters, SureStop is much more dangerous. Compounding the issue is that the front brake has its own adjuster, but using it properly is a little more complex than normal (see their videos for more explanation.)

Another way of looking at how it works and the effect on power is that you've got a normal rear brake you can set up and use however you want, and for your front brake someone put an arbitrarily sized block of material between the lever and the bar so the lever will always bottom out against it at a certain point in its travel.

Any loss of grip between the rear pads and rim, or any mechanical failure of the rear brake, will keep the front brake from operating, rendering the bike brakeless. In other words, the system eliminates one of the key safety features of other bikes with two brakes: redundancy in case of mechanical issues, especially in emergency braking situations where cable systems in particular are stressed the most.

A theoretical advantage of this kind of system is for one-handed users, especially if the one braking hand available has compromised strength. Unlike split levers, they don't have the drawback that they're dividing one hand's braking force between two different brakes, since they're making use of otherwise-wasted energy to actuate the front brake.

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    Yep, bad news if anything like that happens. Also in the case of a rider who neglects their barrel adjusters, they'll run out of brakes completely that much faster. (This is actually the big issue with them I've seen in action.)
    – Nathan Knutson
    Apr 17, 2017 at 18:42
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    The analogy was a way of explaining how the total range of movement of the front brake is limited by the range of movement of the sliding pad, which is designed to be short enough that locking the front brake is impossible under all circumstances. It's the same as if the brake was hooked up to a lever with limited travel.
    – Nathan Knutson
    Apr 18, 2017 at 5:45
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    Interestingly, on their page noting compliance testing, they do say that it meets the requirement for independent braking. I have no idea how: surestop.bike/testing
    – RoboKaren
    Apr 20, 2017 at 15:16
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    The European version lists stopping distances for both front and rear brakes and rear brake only. It sounds suspiciously like front and rear could be controlled separately, which contradicts the entire point of the contraption.
    – ojs
    May 7, 2017 at 19:43
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    and the manufacturer chose a distance for the slidey bit that will keep the front brake from ever being able to lock if those assumptions are correct -- actually, the front brake can never lock, on surfaces with "normal" traction. If the front starts to lock then the bike will tip forward, removing weigh from the rear wheel, and hence removing activating force on the front brake. This is automating the scheme some bikers claim to do manually by "feeling" for rear wheel slippage and releasing the front when they sense it.
    – Daniel R Hicks
    May 7, 2017 at 20:08
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The idea is to stop out the front crashes. The company used to be called Slidepad.

The one lever does not directly actuate the front brake. A conventional rear V brake other than a Slidepad on one side. The brake pad is on a slide. The Slidepad is the actuator (lever) for the front brake. The force of the rear wheel on the brake pad is used to actuate the front brake. As the Slidepad slides forward it simply pulls on the front brake cable. The cable comes out the back so sliding forward pulls on the front brake cable. If there is no braking force on rear wheel then no braking is transferred to the front. As soon as the rear wheel starts to come off the ground braking to the front wheel is reduce and if the rear wheel comes off the ground then no braking to the front wheel.

It mounts to conventional V post. I think you could even use a regular V brake in the front.

It certainly has a purpose and is not a gimmick but I feel like it is over advertised. They state as effective as dual braking but it does not transfer optimal braking to the front wheel. On Shark Tank they said brands are afraid to put them on any bikes as then people would ask why are you using unsafe brakes on other bikes? They certainly did not share that independent brakes are required in many countries.

The company has been around since 2009. They did not get much traction as a component and formed a child safety bicycle Gardian for both revenue and to prove out the product.

Any experienced rider would prefer independent control. On a steep downhill need to use the front brake.

The flaw is that the front has the most braking power and yet the front is now limited by the braking power of the rear.

Sometimes you only want to use the rear for just light braking. The front comes on and gives you more braking than you want for that situation.

video

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  • On Shark Tank it appears what Mark Cuban invested in is Guardian not Surestop.
    – paparazzo
    Apr 17, 2017 at 14:15
  • "The front is now limited by the braking power of the rear." There is no requirement that the front brake be less powerful than the rear. The amount of brake force transferred to the front is determined by the "gear ratio", as it were, of the cable from rear to front -- the force applied to the front can be many times that applied to the rear. And note that there's really nothing preventing the regular front brake lever from being left in place, to allow "emergency" braking or all-out front braking if needed.
    – Daniel R Hicks
    Apr 17, 2017 at 17:38
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    @DanielRHicks Gear ratio? I guess you could do a lot of things. The stated question is Surestop and that is what my answer attempts to address. Comments are not for discussion.
    – paparazzo
    Apr 17, 2017 at 18:12
  • The point is, there is not enough info to know what fraction of rear braking force is transferred to the front. (Note that it could be greater than 100%.)
    – Daniel R Hicks
    May 7, 2017 at 11:50
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    +1 but discounting the possiblity of a slippery rear rim doesn't seem like a good idea. Causes include: muddy water flicked up by the front wheel, overly generous application of chain oil, worn out rear pads because they're overused, etc.
    – Chris H
    May 8, 2017 at 12:27
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Based on these images from http://surestop.bike/

enter image description here and http://surestop.bike/wp-content/uploads/2016/12/single-lever-test.jpg and enter image description here

We can see clearly:

  • There is one brake lever on the handlebar
  • There is a V brake on each wheel
  • There is a brake cable from the single lever to the rear wheel which passes across the top of the V brake arms, and then back into another brake cable which returns to the front wheel V brake.
  • Pictured bikes all have rear derailleurs, which means no coaster brakes.

So I surmise (And some of this may be wrong)

  • The brake lever controls the back brake, which in turn controls the front brake
  • If the rear-to-front part of the brake fails, rider is left with back brakes only.
  • If the rear brake system fails, the bike has no effective brake at all.
  • This system is incompatible with the cycling laws of New Zealand, Australia and anywhere that legislates a minimum of two discrete and independent braking systems.

The inner brake cable could simply be super long and run all the way through the entire system and be terminated at the front brake, but that's too simple. I suspect there's some secret sauce in the rear brake that moderates the cable tension to the front brake, but their website photos don't show that area of the bike.

If you disagree with any part of this answer, please make comments.

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    The UK is another place that requires two brakes, and this appears to be from a European standard. Without access to the standard itself it's unclear whether two brakes operated by one lever would count, but probably not as the regulations state that the front brake may be operated by the right hand and the back brake by the left. theguardian.com/environment/green-living-blog/2010/aug/25/…
    – Chris H
    May 7, 2017 at 11:15
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    What's unclear is how the rear assembly transfers force to the front cable, and how much it can transfer, and how well regulated. While I am sure that there are schemes of this general nature that would work well (I favor using a disk brake for the rear), this one seems a bit hokey.
    – Daniel R Hicks
    May 7, 2017 at 11:53
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    Those pictures also indicates the target market: non/beginner cyclists. It's pictured on the quintessential BSO (which won't be maintained properly making this more dangerous).
    – Chris H
    May 8, 2017 at 12:22
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The question of HOW the system works to prevent head-over accidents is quite simply answered:

The front brake is actuated by force generated from the forward motion of the rear wheel. If the rear wheel stops moving then the front brake is released.

When one brakes hard with the front wheel the momentum of the rider will tend to tip the bike forward, lifting the rear wheel. Even before the rear wheel lifts completely, it will lose traction and begin to skid. The rear wheel stops turning and the front brake is released (or at least moderated, in situations where traction is not completely lost).

The effect would be very much like ABS braking on an automobile, and the classical panic stop head-over accident would be essentially impossible. (Of course, one could still hit something or fall into a hole and go head-over, but such a scenario has nothing to do with brakes.)

Skid-outs are a hair more complicated, and likely the effect would only be significant in certain scenarios -- mainly those on dry pavement where the problem was over-braking on the front, vs scenarios where the pavement condition was a large factor.

(But I get the impression that the real intent of the question, or at least of the responses, is to beat up on this idea rather than attempt to understand it.)

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  • That's a nice description of the system. I'm sure the question is well-motivated (see Bicycle designed for one-arm usage?) but I'll admit to commenting mainly to slate it as now I understand a little about it I think it's a horrible idea.
    – Chris H
    May 8, 2017 at 12:38
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    Yes, at first I thought this system would be a panacea for my problems, but have abandoned it since it can't be retrofitted and since it seems like a Bad Idea all around.
    – RoboKaren
    May 8, 2017 at 14:55
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I've got the James Hudson. I came up to a busy corner, hit the brakes and kept right on going. I agree with these people that are saying these aren't what they're cracked up to be. I'm thinking of having them switched out to conventional breaks. I do appreciate the Endo protection because I have done that before, but it's not worth risking my life ending up in the middle of traffic. The bike is at the shop now with the certified dealer. He had them set so close to the rim that I had to totally deflate the tire to take the wheel off. So much for quick release! I couldn't even get the noodle to unhook. In concept it seems like a good idea, but the reality is when they fail, you're screwed.

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    I don’t know if redundancy helps all that much. When I brake I’m counting on my front brake working correctly. I usually don’t plan enough safety margin into my braking maneuvers to do them with the rear brake only.
    – Michael
    Mar 28, 2022 at 18:53
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    @Michael: a good point, often overlooked. Redundancy is hard. People tend to think having two of something is safer than having one, but if you need both to work it is worse. For brakes, you might notice a failure at one point, somehow survive that time, and ride more conservatively to get home, so even if you don't always ride in a way to withstand an instant brake failure you are probably better off.
    – Ross Millikan
    Mar 29, 2022 at 4:59
  • This doesn't answer the question of How do the brakes work. Unless "not very well" is considered an answer.
    – FreeMan
    Mar 29, 2022 at 14:06

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