How to brake hard reliably

[kolmog]

So I figure I've got some of braking down pretty good... Get into a sitting position, focus weight on heels... But there is yet a big problem that would stop me from braking hard reliably, which is what happens if you hit a bump.

When you hit a bump while braking, at least on a non suspension wheel, the following happens:

1. The wheel is pushed up and leaves the surface
2. Your feet are pushed up and some of that upwards motion from the wheel is transferred upwards to your feet, but not underneath your center of gravity
3. Your body will rotate back slightly so when you come back down you will be lower than you were before the bump
4. The wheel will probably have lost a bit of speed to the bump also, so your feet will land further forward than where they were pre-bump.
5. Too far forward and you'll be rewarded with a very sore bum

Any solution to this? I figure there must be one, otherwise it would be impossible to brake hard riding trails...

 

 

[kolmog]

[rcgldr]

You need to leave some margin for dealing with bumps. If the bump leans you too far backwards, and you're too close to the limits of motor torque to rebalance you, you'll end up falling off the back. I don't know if cutout is a potential issue if overleaning backwards.

[kolmog]

41 minutes ago, rcgldr said:

You need to leave some margin for dealing with bumps.

But if you have margin for bumps you can’t brake hard...unless you have something to keep your feet in place, thereby reducing the need for margin?

[Tawpie]

Been there, done that. So now I run a little slower but if the bump is suddenly bigger than I thought it was going to be I tend to stop braking, try to take the bump in a more 'normal' position, then recover and resume braking. If you're hard on the brakes and the wheel catches air, it'll want to spin all the way to full speed reverse and/or want to rotate backwards and that makes for a bad landing... being neutral in the air is best I think.

Mostly what @rcgldr said... leave some margin. When its bumpy, there really aren't very good brakes. I don't like them, but jump pads might help keep your feet closer to the pedals.

Edited February 1, 2022 by Tawpie

[mike_bike_kite]

Suspension would help to keep the wheel in contact with the trail. Not sure how it would help in practise though especially under hard braking.

[kolmog]

20 hours ago, mike_bike_kite said:

Suspension would help to keep the wheel in contact with the trail. Not sure how it would help in practise though especially under hard braking.

More if the bump would be absorbed so your body position wouldn’t be affected as much, presumably. 

[.....]

No real solution. You cant lean back really hard to brake really fast, and assume you will stay off your ass when you hit a bump and/or lose traction. Its the same way if you try to accellerate like a banshee on slick surfaces. Unless you anticipate the loss of traction from bumps or surface, it will upset your balance. If you are leaning hard and relying on the wheel to keep you from falling and it slips. Well, durr... the thing holding against you to keep you upright, just let go. Lean way back as a friend holds you up. I mean WAY back. Now have him just drop your ass. How could this be prevented? If your friend cant be reliable (as bumps and rocks on pavement arent), you must simply not lean back into him. Only brake hard on surfaces with proper tracton and no jumps. If you see bad spots coming, get ready to preemptively accomodate the change in lean. In a REAL e-stop, stopping IS the name of the game. If I fall off the back at a slow speed, i would call that a win. In an e-stop, I'd grab my wheel and yank by hand too. IF the alternative for a longer stop would be worse. Leaning beyond the back of the wheel AND wedging, along with pulling back by hand, is a full dedication last resort. The best practice is to simply not need stop any faster than traction allows, and don't utilize both the leverage AND the real lean, to maximum effort. For offroad, you dont get much an e-stop, as traction wont allow. You really need power pads for offroad, as the need to stay centered increases, because the terrain is unpredictable. Leveraging into pads and bending those knees while centered balance, is pretty standard MO for dirt. Long climbs without pads is miserable. So much muscle wasted on clenching the wheel. Muscles that should be used for leverage or balance management.

I e-brake hard as hell on my sherman on pavement. I sh*t stop and lean back into my pads(uppers only), wedged like a mofo. I'm wedged enough that I get overcurrent beeps. If i loose traction or hit bumps, I will hit my ass, as I've no time to upright my posture w/o anticipation. If I DO upright myself in time, my stopping distance will increase a LOT. I lean so far past easily recoverable during an emergency stop, that I have to remember to get back atop the wheel as I near 5-7mph. If i dont, I DO fall off the back, as once the speed decreases enough, its assistance in holding me up against my lean, diminishes. If i am worried about traction, I tend to wedge into the pads and use leverage more, while keeping my actual balance more centered. Its not the fastest stop I can make, but it does allow me a little more reaction time for bumps or slip. The harder you stop, the more the thrust line angle of traction changes.

Traction is the name of the game. Knees, suspension, anticipation, lean angle, tire pressure/type and speed are all parts of the equation. If a suspension is properly dialed in and its dampening AND rebound is on point for the conditions and rider weight, it will help. If a suspension gives false security or is imporperly setup, it will make things worse. No matter what you ride, too fast for conditions and lack of traction, will result in bad things.

Edited February 3, 2022 by ShanesPlanet

[conecones]

On 1/31/2022 at 10:54 PM, kolmog said:

So I figure I've got some of braking down pretty good... Get into a sitting position, focus weight on heels... But there is yet a big problem that would stop me from braking hard reliably, which is what happens if you hit a bump.

When you hit a bump while braking, at least on a non suspension wheel, the following happens:

1. The wheel is pushed up and leaves the surface
2. Your feet are pushed up and some of that upwards motion from the wheel is transferred upwards to your feet, but not underneath your center of gravity
3. Your body will rotate back slightly so when you come back down you will be lower than you were before the bump
4. The wheel will probably have lost a bit of speed to the bump also, so your feet will land further forward than where they were pre-bump.
5. Too far forward and you'll be rewarded with a very sore bum

Any solution to this? I figure there must be one, otherwise it would be impossible to brake hard riding trails...

 

 

If you've ever done mountain biking at a resort or local downhill trails, this might be a little easier to understand/visualize:

Your main focus for good braking should be traction. To get the best traction possible, you need to maintain as much weight over the wheel's contact patch as possible. This means you should avoid doing the crazy leaning that many road riders do. Leaning way back on a bumpy downhill trail causes the following:

1. You lose sight of the trail because your wheel is now blocking your vision downhill. 
2. You lose ability to properly absorb the bump with your legs.
3. You will cause the wheel to spin back/lose traction during the time you are in the air, between bumps.
4. Your ability to recover from slipping will be limited since you've committed all your body weight behind the wheel.

So how to brake then without the crazy lean? Drop the pads down to your feet and leverage the wheel by pushing up on the toes (against the pad) while pushing down on the heel. You can still lean backwards but focus on keeping your butt LOW, instead of far BACK as possible. Because your center of weight is still mostly over the wheel rather than way behind it, you will have better bump absorption ability and can recover from unexpected terrain changes much easier in this more neutral "attack position".

This applies going uphill as well. Instead of having your legs straight and arms outstretched in a superman lean like seen in most Youtube videos, you want to crouch down, crank your shins against the pads while pushing down with the toes. Your torso should still be mostly over the wheel.

By focusing on centering your weight, you can brake hard enough to skid on gravel while also being in control. Similarly you can lose traction while climbing steep hills and not instant-face plant. 

In mountain biking, the same idea translates into putting your weight forward when braking downhill, and putting your weight backward when pedaling uphill - this concept can seem counter-intuitive and this is why a lot of new riders get it backwards.

Edited February 3, 2022 by conecones

[Planemo]

8 hours ago, conecones said:

If you've ever done mountain biking at a resort or local downhill trails, this might be a little easier to understand/visualize:

With the caveat that in MTB, the contact patch doesn't move forward/aft at all in relation to gradient. On an EUC it does, by quite a lot as well.

8 hours ago, conecones said:

In mountain biking, the same idea translates into putting your weight forward when braking downhill

I would never go further forward than the centre of the bike on any downhill, simply to avoid any OTB situations. Plus, spreading the load between two tyres gives maximum braking efficiency and control.

8 hours ago, conecones said:

, and putting your weight backward when pedaling uphill 

Agreed, but only to a point. That point is where you risk looping the bike, quite easily done on an electric MTB where the ability to pedal up far more serious gradients than a non electric is entirely possible. As a result, I never go any further back than my regular seated position.

8 hours ago, conecones said:

this concept can seem counter-intuitive and this is why a lot of new riders get it backwards.

I don't think it's counter-intuitive. Physics dictates the limit at which you either go over the front or the back. Most riders do their utmost to avoid this, which usually means moving weight rearwards on descents and frontwards on ascents. I hear you re maximising weight movement as much as possible to maintain traction, but traction is less important than going OTB or looping out. 

[conecones]

3 hours ago, Planemo said:

With the caveat that in MTB, the contact patch doesn't move forward/aft at all in relation to gradient. On an EUC it does, by quite a lot as well.

I would never go further forward than the centre of the bike on any downhill, simply to avoid any OTB situations. Plus, spreading the load between two tyres gives maximum braking efficiency and control.

Agreed, but only to a point. That point is where you risk looping the bike, quite easily done on an electric MTB where the ability to pedal up far more serious gradients than a non electric is entirely possible. As a result, I never go any further back than my regular seated position.

I don't think it's counter-intuitive. Physics dictates the limit at which you either go over the front or the back. Most riders do their utmost to avoid this, which usually means moving weight rearwards on descents and frontwards on ascents. I hear you re maximising weight movement as much as possible to maintain traction, but traction is less important than going OTB or looping out. 

Yes you have two wheels on a bike so its not a perfect example but it is the closest activity to riding EUC down a bumpy trail. It's the same concept of maximizing traction by putting weight directly over the contact patch. More traction = more reliable, faster braking. As a general rule of thumb, on a bike going downhill, the front wheel is doing 75%+ of the braking work, and vice versa on a steep climb. You want your weight over the contact patch that is doing most of the work. Nobody wants to go OTB or spin out but the closer you are able to come to either condition, the better your traction and this is largely what separates new riders from experienced ones (how close can you stay just below that limit?).

It's counter-intuitive to some people because the instinct is to get scared on a downhill and hide behind your handlebars and never touch the front brake for fear of going OTB - end result is dragging your rear brake all the way down, like a beginner skier that just does the pizza brake. It does work, but only up to the point where you meet a properly steep section that if you lose traction on the rear wheel (or when the pizza doesn't slow you fast enough), that you are in some deep trouble . Explaining the physics behind it might help some people understand.

Maybe using a Muni could be a better comparison but the amount of people doing that is so rare it's probably not going to help. 

Edited February 3, 2022 by conecones

[supercurio]

Same, I think there's not really a perfect solution here.
However it's something that can be practiced, I remember doing so to test my pads setup on a bumpy bike lane which was bent by tree roots.

The conclusion was to sit in the invisible chair as usual, but also keep the knees ready to be mobile while breaking.
Sometimes when hard breaking we tend to lock joints and hold the pedals/pads/wheel tight. When doing that over bumps it'll give poor results.

Instead, you can start that way but as soon as the bump is there you can keep the knees flexible to flow with the bump. Depending on how deep they are you can even follow the bump and hole following with your legs like an active suspension would, to preserve maximum traction. And your upper body would remain unaffected, at constant height during the whole process.

Agree tho that even when doing that, you won't be able to break as hard, just like you would not on ice, snow or even gravel. So when you see the area of reduced grip you reduce the braking pressure accordingly.

[Planemo]

28 minutes ago, conecones said:

 You want your weight over the contact patch that is doing most of the work.

The issue I have with that is that I don't want to load up the front tyre in a downhill because it's also trying to cope with steering/lean angles. I would rather get some braking out of the rear as well and that means having some weight on the rear, not loading up the front as much as possible to get maximum braking in the hope that it won't wash out in a corner.

I'm not saying I hang off the back of the bike on a downhill, but neither do I strive to load the front. Mainly because a rear end washout is far more recoverable than a front one.

And your properly steep Vs a skier analogy doesn't really work because a skier isn't risking an OTB. If an MTB track is properly steep then I don't want to be anywhere near the front end of the bike, nor applying front brake for that matter because although the tyre itself maybe capable of grip, the physics of it doing so will cause an OTB. If I still don't have enough braking on the rear then so be it - I went in too fast. I will deal with it as best I can and maybe bail to the side if I have to get the bike down. Anything rather than going OTB.

I do hear you re the ideal point of getting as close as safely possible to the limits, as you say skill and experience, but I would have thought that would apply to anything. In any event much of this is largely irrelevant to EUCS because we don't have anything like the same ability to play around transferring weight fore/aft as we do on a bicycle, because doing it on an EUC changes the speed.

[TantasStarke]

On 1/31/2022 at 10:58 PM, kolmog said:

I've never fallen off a wheel hitting a bump while braking, but it does interrupt my braking, almost flew into traffic one time because of a pretty bad one. Was slowing down from ~35MPH, and I have a bad habit of braking late and braking hard (damn you all those racing games as a kid!) and I hit a bump in the pavement and it bounced me and the wheel up a bit, and I had to lean back to center to maintain balance. Doing so meant I was still barreling forward and had to slam real hard on the brakes. Crossed the line by a bit but never made it into the line of oncoming traffic thankfully

[TantasStarke]

14 hours ago, TantasStarke said:

I've never fallen off a wheel hitting a bump while braking, but it does interrupt my braking, almost flew into traffic one time because of a pretty bad one. Was slowing down from ~35MPH, and I have a bad habit of braking late and braking hard (damn you all those racing games as a kid!) and I hit a bump in the pavement and it bounced me and the wheel up a bit, and I had to lean back to center to maintain balance. Doing so meant I was still barreling forward and had to slam real hard on the brakes. Crossed the line by a bit but never made it into the line of oncoming traffic thankfully

Well ask and ye shall receive, it happened to me today. Was braking looking back at my riding friend and hit a bump, bounced off the back of the wheel and slid on my back. Was only wearing knee pads, elbow pads, wrist guards, and a helmet. My left elbow is fine, but the skin right next to it has some painful road rash. Reached up to around 25mph before braking, probably around 10-15 when I fell. Ouch