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I am thinking about disconnecting my front brake altogether because it's either on or it's off, and there's no in-betweens. As a result I've been over the handlebars about five times now and it's getting to be a bit of a pain.

Does anyone know if its possible to soften the brakes so the front acts more like ABS?

Grigory Rechistov
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William
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    What model of brakes? – Argenti Apparatus Oct 06 '19 at 22:57
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    Disconnecting your front brake is a dangerous way to solve this problem. You have done the right thing by asking for guidance/help. Please do follow the suggestions in the answers below. – Criggie Oct 07 '19 at 02:34
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    Have you or has anyone else ever modified the braking system in any way? – Criggie Oct 07 '19 at 02:36
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    ABS is not a softening mechanism. On the contrary, it will increase braking power by preventing slipping of the tire: static friction is stronger than sliding friction. That said, slipping with the front wheel would often lead to a fall anyway which is probably the main reason to have ABS on a bike. – Peter - Reinstate Monica Oct 08 '19 at 07:06
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    What kind of riding are you falling over the bars on? If you are doing lots of steep trails, then going over the bars from front braking is likely a technique/body position issue. If you're going over the bars on relatively tame slopes, then something is probably wrong mechanically. I have had rotors that would get caught on the edge of the caliper block, as the caliper was misaligned. – Ben Oct 08 '19 at 09:41
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    @Criggie can agree. Once had a front brake that disconnected itself - end result was my running into a solid metal barrier. – Baldrickk Oct 09 '19 at 13:30
  • It may seem elementary, but do you use more than 1 finger on the brake lever? its absolutely not necessary. – Watermelon Nov 01 '19 at 05:21

6 Answers6

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It's hard to say exactly what the cause is, but I see two main possibilities:

  1. Mechanical causes

    1. Brake pads. If the pads are very close to the rotor when at rest, and have minimal motion to close on the rotor then that may be enough to wedge them. Try inspecting the brake pads and if worn, replace them. Brake pads are consumable. Thin brake pad material will reduce your "modulation" zone, same as hard brake pads on rims do. Could consider swapping your pads front to rear caliper temporarily as a test.

    2. Pistons. If your pistons are a little gunked up at the sides, they may not be retracting fully. This may be limiting the distance that the pads have to travel to be hard on the wheel.

    3. Rotor wear and damage. Spin the front wheel off the ground and look closely at the rotor—it should not wobble or divert side-to-side, and the friction surface should not have burrs or obvious wear.

    4. Fluids. I doubt these are the cause of your issue. Low fluid, or air bubbles will exhibit as spongy-feeling levers and you don't have that. (edit) though @t_bacon points out that if the system is over-filled it will be slightly pre-pressurised, which will be pushing the brake pistons out a little all the time. It's definitely worth checking if the fluid is over-filled, by opening the bleed screw and see if fluid squirts out at all.

  2. Technique

    1. When braking, your lever should have a range of motion before the brakes are wedged hard-on. How tight you squeeze your fingers controls the level of braking effect.
      There's a great answer at What does "modulate" mean when referring to brakes? Just visualise your flatbar lever instead of road brake levers, the concept is identical.

    2. Body position for fast braking should be "arms straight and arse back" If you try and stand up on the pedals while hard braking your center of mass is higher and theres a moment-of-rotation which robs your rear wheel of traction and imparts a forward force on the rider.

One suggestion would be to swap bikes with a friend and try some carpark laps on another bike equipped with hydraulic brakes, and to get that other rider to try your bike brakes. Decide if its a problem endemic to your bike vs technique, and go from there.

Michael come lately
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Criggie
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    +1 however, I would argue the statement that fluids definitely won't be the cause of the issue. I have, after bleeding my brakes, had times where the fluid system is overfull meaning that it takes very little lever pull to full on lock the brakes. This is generally caused when the brakes are bled without fully retracting the pistons into the caliper body, thus allowing additional fluid into the system. Simple fix is to just open the bleed valve, push the pistons back in to push out any excess fluid then close the valve again. – T_Bacon Oct 07 '19 at 08:45
  • @T_Bacon excellent point about being over-full of fluid. I've added that with your name on it :) – Criggie Oct 07 '19 at 10:08
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Don't - its dangerous ( Majority of braking force comes from front brakes) and in many countries illegal to ride on the road without 2 operational brakes.

Likely you are using too much force and not enough control. You need to learn to feather brakes rather than jam them on, while shifting the weight back and lower.

Another possibility is you are using front brakes when you should not be - e.g. down a very steep drop. If the slope is extremely steep, you need to go in slow, roll it out while on the slope, and brake once it levels out. Using the back brake only for control can help, but avoid using the front. Again, weight back and low helps with control.

Its possible the brakes are grabbing, which does make it harder to feather them properly, but this should not put you over the bars.

mattnz
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    The advice about using only the back brake on steep descents could be misunderstood. In the majority of cases and for most riders, you are using both front and back brakes at all times, even in steep descents, like steep rock rolls. If your body position is centred over the wheels in relation to the orientation of the bike, modulating both brakes gives you the most braking potential and bike control. I wouldn't want new riders thinking they can't use their front brakes on slopes as that is going to lead to bad habits and avoidable spills. – Ben Oct 08 '19 at 09:56
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    For what it means, I have had some cheaper bikes where the brakes were... pretty much unfeatherable regardless of skill, as in there was essentially no distance between "no breaking at all" and "locked front wheel". Ive seen both cases where this was shoddy design and cases where it was something damaged or maintained badly. I suspect from the OPs description their bike has one of these issues... – Vality Oct 08 '19 at 21:30
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It is unusual to see a hydraulic brake described as on/off, as they are usually well known for their modulation.

However I have had an experience of this before with a friends bike. He was regularly locking up the rear wheel, and initially I put it down to inexperience as a new rider - until I rode the bike myself and found the brake to be extremely 'grabby' and hard to control.

The problem was resolved by simply bleeding the brake.

Andy P
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    If you read MTB forums, you'll notice two types of riders, those who love Shimano brakes for the their power or those who hate Shimano's rapid "bite" (i.e., on/off feeling). As someone who likes to ride steep stuff, I like Shimano's bite. In other words, any brake has the right amount of modulation on the right trail ;) – Paul H Oct 07 '19 at 20:29
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To answer the last part of your question: yes, ABS systems for bicycles exist (a quick searching of the Internet is enough to see that). However, they are not widespread and are mostly for OEM city bikes where there are no expectations about rider's skills. As a result, maybe not something readily available for an end user to buy.

In absence of ABS, and somewhat repeating other answers, here is what I'd suggest to do.

  1. Get better with your braking technique. Generally the best thing to do is to keep learning about your bike, get to know your trails and to measure your abilities proportionally. Maybe you are trying to ride features for which you are not yet ready as a rider?
  2. Change brake pads to resin type, if you have metallic ones. Metallic brake pads have higher grip.
  3. Change front rotor size to one smaller. If you have 180 mm, go to 160 mm (if your fork is compatible with smaller discs).
  4. Adjust leverage of your brake lever to make it less pronounced. Only few high-end levers have this option, however.
  5. Change your front brake to a less powerful or try different brake vendor. Do you happen to run downhill calipers on an XC bike? Some people feel like a Shimano system is more intuitive to use than SRAM's, others feel like Magura brakes are too powerful, and others disagree etc. Even setting up a mechanical disc brake can be a thing. Think again though if trading stopping power for a sense of security is worth it.
Grigory Rechistov
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    If you are referring to the inline/cable stop springy thingies, those aren't really ABS, but Braking Performance Worseners. I still haven't figured out why do they exist. – Wsal Oct 07 '19 at 09:58
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Different brake pads have different amounts of "grab." You may consider changing the type of brake pad you use in your disc brake. Sintered or metallic pads are generally considered to have less initial "bite" than organic pads.

Greg
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This feels like something is not quite correct with the front brake. Sorry, I've missed if you've provided the make/model, but theoretically, modern hydraulic disc brakes should allow complete modulation through the braking phase rather than an all or nothing approach. That suggests contamination, sticking piston(s) or calipers, etc.

You could also check your riding position. Placing your saddle backwards a few mm, whilst retaining comfort, would place your centre of gravity rearward, meaning pitching forward is reduced. This can also be obtained by lowering your saddle slightly too, again, within the confines of comfort and efficient riding.

Lucero79
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  • In my very limited experience, a hydraulic brake will "stiffen" as it warms too, to the point the brake lever gets pushed out by the expanding fluids. If OP simply locks the hand in one position then that will force the pads on harder as they heat. – Criggie Oct 09 '19 at 08:33
  • True, but heat will also create fade meaning for each relevant amount of pressure, the braking performance will decrease in a braking heat cycle. – Lucero79 Oct 09 '19 at 09:20