smelling rubber - videos heel-brake stops on rec skates

[Ken Roberts]

I made a couple of short video clips of heel-brake stops and put them on this
heel-brake videos page

The first video shows a heel-brake stop being used from pushing strongly at a higher speed. The second shows a heel-brake stop on a pretty steep downhill. The skates are Rollerblade Aero 9.



The technique shown is for most normal “recreational” skates -- it does not work with speedskate boots or for some “fitness” skates without a high stiff cuff. It’s pretty much like the heel-brake stopping technique shown in some other instructional videos -- but applied quicker and stronger for more demanding situations.

Thoughts:

• Effective quick stopping makes a loud squeal noise.
• Most of my weight is not over the heel-brake pad -- rather it’s way behind the heel-brake, which is also good for stability in a quick stop.
• When I finished the stop on the steep downhill, I could smell the rubber.

My belief is that a skilled skater on most “recreational” skates made by leading manufacturers like Rollerblade and K2 -- who knows and uses this (non-obvious and not-often-used) heel-braking technique -- can stop as quickly as most people on a bicycle (but not as quick as a car).

Ken

[Davey_Speedstar]

A good point , and well made.

Can you stop on one foot?

[okskate]

Originally Posted by Ken Roberts

The skates are Rollerblade Aero 9.

My belief is that a skilled skater on most “recreational” skates made by leading manufacturers like Rollerblade and K2 -- who knows and uses this (non-obvious and not-often-used) heel-braking technique -- can stop as quickly as most people on a bicycle (but not as quick as a car).

Ken

Cool post - extremely nice videos - well done!

I had the Aero 9, too. The braking technique you are demonstrating is exactly how I stopped rapidly every time from a very fast speed. I agree regarding its effectiveness, but it took me a year or two of skating to burn rubber like that.

Recently, I was skating on a Radical 90, but could not apply the brake as easily - did not have as much leverage due to the lower cuff and extended frame size. I did not achieve the same stopping power. However, I did not use a strap. That probably would've made a difference.

[gatorback]

Thanks for posting the videos! I think these will very much help people who are trying to improve their brake performance.

Originally Posted by Ken Roberts

Thoughts:

• Effective quick stopping makes a loud squeal noise.
• Most of my weight is not over the heel-brake pad -- rather it’s way behind the heel-brake, which is also good for stability in a quick stop.
• When I finished the stop on the steep downhill, I could smell the rubber.

The loud squeal is more of an indication of how solid the brake system is made. I skated a bit with Abby yesterday and his brake was quite loud. Mostly I think this was due to vibration in the bolt on unit. My brake is much quieter and rarely makes squealing noises. The loud squeal noise with most systems is mostly from the vibration of brake pad and bolt on unit. A brake system with more solid construction will squeal much less.

Getting your weight over and behind the brake pad is key with any system. A good measure of this is if you can lift your non brake leg from the ground it shows that you have the control and are keeping your weight on the brake pad and centered with respect to the braking forces. In strong braking the non brake leg is doing very little. Lifting non brake leg off the ground is an advanced move and more of a show of balance/control vs. additional braking power but it can be a useful skill to work on.

As advice for anyone trying to improve their braking performance, I would say work on balance and control of the brake foot. If you can skate on one leg (i.e. rolling along like a flamingo) it will help a lot. When you feel you can coast easily on one foot with good balance you will be much more able to perform and effective stop using the a brake (one footed brake is still more advanced but one footed coasting is the first step).

[sk8scott]

Originally Posted by gatorback

The loud squeal is more of an indication of how solid the brake system is made. I skated a bit with Abby yesterday and his brake was quite loud. Mostly I think this was due to vibration in the bolt on unit. My brake is much quieter and rarely makes squealing noises. The loud squeal noise with most systems is mostly from the vibration of brake pad and bolt on unit. A brake system with more solid construction will squeal much less.

A loose brake will vibrate and add a high-pitched buzzing/grinding sound to the braking noise. Frame length and material may contribute, too, with lighter and longer frames vibrating more on rough pavement while braking. However, even a solidly-attached brake on sturdy high-cuff skates will squeal fairly loudly in certain situations, e.g. a hard stop on a steep hill.

Ken's videos are excellent. I'm sure a lot of newbie (and not-so-new) skaters can benefit from watching, as the lateral camera angle gives a great look at how to position the body for heel-braking.

One thing I'd add is that shifting the hips and torso forward a nudge can help to really drive the brake into the pavement on steeper slopes.

----Scott

P.S. Yes, a good downhill stop will definitely reek of burnt rubber!

[Ken Roberts]

Originally Posted by gatorback

Getting your weight over and behind the brake pad is key with any system.

Thanks for the idea of getting my weight more forward toward the brake pad -- something I can play with.

Originally Posted by gatorback

A good measure of this is if you can lift your non brake leg from the ground it shows that you have the control and are keeping your weight on the brake pad and centered with respect to the braking forces.

This is very interesting -- my immediate reaction is that it’s tricker than that.

(For one thing, the “advanced move” of lifting the non-braking foot off the ground does not work for speedskates with a heel-brake but no leash -- see reason further below.)

I’m thinking there’s a choice between two possible “good measures” or “advanced moves” for strong braking:

(1) to lift your non-braking foot off the ground - (so that the skater’s body is balanced over the braking skate’s rear wheel and the brake pad).

(2) to lift all the wheels (including rear wheel) of the braking skate off the ground - (so that the skater’s body is balanced over the brake pad and the non-braking foot).

(3) to lift all the wheels of the braking skate and the non-braking skate off the ground - (so the skater is balanced only on a single point of ground contact: the brake pad).

I think the advantage of approach (2) is that it offers a much wider base for balance, so it feels more secure, perhaps easier to learn, easier to use in a emergency by someone who doesn’t practice it all the time. An advantage of approach (1) is that it’s sort of self-regulating (if the stopping force suddenly increases, it tends to transfer weight from the brake pad to the braking skate's rear wheel, thus decreasing stopping force). A problem with approach (1) is that lifting the non-braking foot off the ground does not help much if most of the skater’s weight ends up on the braking skate’s rear wheel instead of on the braking pad (which is typically what happens if you try it with speedskates with heel-brake and no leash).

I suspect approach (1) tends to go better with using a leash, and I’m pretty sure approach (2) goes better with high-stiff-back boots.

The problem with the method shown in those videos for high-stiff-back boots is that you need to sit back in order to drive the back of the lower leg against the back of the boot -- which tends to put more weight on the non-braking skate, and less on the brake pad. I'm thinking the solution is to play with leaning the shoulders forward.

But not too far forward, otherwise you fall forward onto your face. If the skater’s center-of-mass were literally directly over the brake pad, then with significant successful braking force, they’re on their face.

The constraint of "not pitching forward onto face" implies roughly that the skater’s center of mass must be at least as far behind the rear wheel of braking skate horizontally as the coefficient of friction multiplied by the distance of the skater’s center of mass above the ground vertically.

Which raises the question of whether it’s possible with the high-stiff-back boot method, to lean my shoulders forward far enough to reach the maximum permitted by the constraint. I just don’t know the answer. Something to play with.

I feel pretty sure that with a leash it is possible to reach that maximum -- in which case the maximum possible braking force with a leash might be greater than with high-stiff-back boot with no leash. But that assumes that the leash user is (a) capable of removing all (or most) of the weight from the rear wheel of the braking skate; (b) practices lots to be able to take it that close to the maximum without falling forward in a real quick-braking situation; (c) practices lots to be able to grab the leash in an unexpected quick-braking situation as quickly as I can initiate dropping my butt for the high-stiff-boot back method.

More to play with.

Ken

[Davey_Speedstar]

On a slightly more serious note (from me), the most effective use of the heel brake that many people miss is to ensure that weight is distributed evenly across the pad.

It is easy to see if you are not doing this as the brake wears unevenly and more one side.

[Ken Roberts]

Originally Posted by gatorback

Getting your weight over and behind the brake pad is key with any system.

Yes I just got out and tried ducking my shoulders way forward, and I could feel that it made me stop quicker. When I went back to my old way (shown in the video) of keeping my shoulders more over my hips, it took longer to stop.

Now I have to shoot the videos again to show the better technique -- and hopefully the quicker stopping. (and I'll have to play with getting my arms forward also, like the Asha Kirkby video at the bottom of this LondonSkaters page)

Lifting non brake leg off the ground is an advanced move and more of a show of balance/control vs. additional braking power but it can be a useful skill to work on.

Yes I tried that exercise, it was interesting and helped me feel more control -- but like you said, didn't actually seem to increase braking power as much.

I also tried "approach 2" for increasing braking power: transferring more weight off the rear wheel of the braking skate onto the brake pad itself, with the goal of getting the rear wheel off the ground. I don't know if I actually did get the rear wheel up, but trying to do that sure felt like it increased my braking power.

So I was dropping my hips more down and backward and at the same time dropping my shoulders more down and forward. Two different ways to increase braking power performed at the same -- seemed to work.

The loud squeal is more of an indication of how solid the brake system is made.

Yes today I tried with my Salomon TR Mag Elites and the heel-brake was quieter and less "squeal" than my Rollerblade Aero 9.

Ken

[Ken Roberts]

I put three more video clips of stopping following the new ideas for technique suggested by Gatorback: getting my weight more over the brake, and with my rear foot up off the ground. They're linked from the same page:
www.roberts-1.com/t/808/hb
I think the new videos are showing a "better" position for quick stopping, so they're a better aid for learning.

Though the basic method has already been demonstrated in other people's videos on the web -- I'm just showing it at higher speed and on a steep hill.

Stopping with one foot off the ground came fairly easily to me on flat or gentle terrain, and I found out that I could get me rear foot up during stopping even if my arms were not as far forward as possible. Which shows that this "recreational" skate method of pressing the lower leg against the inside back of the boot cuff does allow getting my weight fully off the rear skate wheels and transferred toward the brake pad.

But while braking on the steep downhill, I found that I couldn't hold my rear foot off the ground -- I think I was unconsciously too afraid.

Strange observation: To me it doesn't look like the new method with shoulders and arms more forward in the latest videos actually stops me obviously noticeably quicker than my more erect stance in the previous videos (lower on the page) from a week earlier.

Here's a couple of attempts to explain that:
(a) Maybe there's just some limit on how quickly my rubber brake pad can stop me from higher speeds -- and my previous method already got me pretty close to the limit. (i.e. maybe real heel-brakes don't exactly follow the simple linear model of friction in these bigger longer stops, perhaps due to greater heating of the pad.)
(b) Oscillation: If the braking force increases unexpectely during stopping with my weight more forward, then my weight goes further forward, more onto the rear wheel of the front skate and less on the brake pad. So then braking force decreases, and my weight gets thrown back more on the brake pad. Which increases braking force again. I think I actually see this happening in the new video on steep downhill (which is on a paved surface with coarser stones). But there might still be a significant oscillation effect in other situations -- just not so perceptible in video.

One more thing: In all the videos it looks to me like the braking force decreases toward the end of my stop -- seems like it's quicker braking from fast to slow, than from slow to stopped. I'm guessing this is from heating of the brake pad.

Ken

[gatorback]

I use speed skates and the leash so I don't really have experience with high cuff rec skates. To me a big factor in the total amount of pressure applied to the brake pad is the force and stability of the skater. When using the leash I can get pressure on the pad since I have a vastly enhanced level of control and stability. I can do a one footed stop without the leash on speed skates but since the control without the leash is so limited I can't apply nearly the same level of pressure to the pad. Without a high level of control the natural thing in a one footed stop is to cheat a bit and put weight on the rear wheel. Using the leash makes it possible to apply force such that the more force you apply the quicker you stop and if you apply too much brake force your weight pitches forward to auto regulate the braking power.

Pad design and heat is also a big factor in brake pad performance. When I use the fire pad the pyrotechnic flint reduces the power of the brake system. Pad compound is also a big factor. I use a special pad with 87a black rubber. Other brands that use softer rubbers or even worse urethane rubbers do not produce the same level of friction. A smaller pad tends to radiate heat quicker and an aluminum brake frame can help pull some of the heat out of the system but at high speeds it is one of the biggest problems. In hindsight I wish I had included a system of vents through my pad design to provide better air cooling (I might do this in my version 2 pads). Pad wear can also be such that at very high speeds and quick stops it is possible to wear a lot of the pad away at a rapid rate. The key to a good pad system is to balance a number of factors and provide a shape, pad size, and compound that works for the majority of situations.

The old Roller Blade brand 742 pad were very good and in terms of absolute braking performance they had all the features one would like. The problem is that when skates changed to bigger wheels the old pad shape and angle was no longer correct. I am not sure if RB or others have redesigned pads based on the bigger wheels.

[sk8scott]

Originally Posted by gatorback

Pad wear can also be such that at very high speeds and quick stops it is possible to wear a lot of the pad away at a rapid rate. The key to a good pad system is to balance a number of factors and provide a shape, pad size, and compound that works for the majority of situations.

This is definitely true. I have toasted an entire brake pad in a weekend of hill skating. While I have not taken as in-depth a look at brake pad material, it seems that K2 pads wear a bit more quickly than Rollerblade pads on each brand's higher-end fitness skates.

Also, I would avoid the light grey "indoor" brake pads like the plague if one plans to do any sort of hill skating. A few years ago, I wore one down to almost nothing over the course of less than 2 hours.

----Scott

[haruspex]

Originally Posted by gatorback

Pad design and heat is also a big factor in brake pad performance. When I use the fire pad the pyrotechnic flint reduces the power of the brake system. Pad compound is also a big factor. I use a special pad with 87a black rubber. Other brands that use softer rubbers or even worse urethane rubbers do not produce the same level of friction. A smaller pad tends to radiate heat quicker and an aluminum brake frame can help pull some of the heat out of the system but at high speeds it is one of the biggest problems. In hindsight I wish I had included a system of vents through my pad design to provide better air cooling (I might do this in my version 2 pads). Pad wear can also be such that at very high speeds and quick stops it is possible to wear a lot of the pad away at a rapid rate. The key to a good pad system is to balance a number of factors and provide a shape, pad size, and compound that works for the majority of situations.

I am seriously looking forward to your improvements on break design, especially for speed skate systems. I would also like to see alternate designs for skating in general other than a heel break system. Has there been much insight as to disk breaks or internal mechanisms?

[Ken Roberts]

Originally Posted by gatorback

Pad compound is also a big factor. I use a special pad with 87a black rubber. Other brands that use softer rubbers or even worse urethane rubbers do not produce the same level of friction. A smaller pad tends to radiate heat quicker and an aluminum brake frame can help pull some of the heat out of the system but at high speeds it is one of the biggest problems.

Thanks for the insight about pad compounds and designs and the problem with heat. Seems like the rubber brakes on my bicycle resist "fading" on long steep hills better than the ones on my skates. Like recently I went down over 1200 vertical feet at an average steepness over 12%, including curvy sections at 16% or more -- on my road bike -- and it occurred to me that I would not want to try that on skates (though I have skated down the much longer Alpe d'Huez hill).

I don't think I can brake on skates as strongly as I myself can brake on a bicycle at high speeds or down long steep hills -- mainly because of the heat/fading problem. This doesn't contradict my claim that I can stop on my skates as quickly as most bicycle riders, because I get way way more practice stopping in demanding situations than most cyclists.

Originally Posted by gatorback

Using the leash makes it possible to apply force such that the more force you apply the quicker you stop and if you apply too much brake force your weight pitches forward to auto regulate the braking power.

Yes and I think the same thing happens with heel-braking with a high-back cuff. Keep in mind that the steep downhill which shows visible oscillation was on pretty coarse-stone pavement. I suppose I could do a video of stopping with my (much-appreciated) Gatorleash on that same slope and so if it works differently or similar.

Most video demonstrations of heel-braking (and non-heel-brake stopping) are done on very smooth asphalt (or indoor parking-garage concrete or wooden floors). My point on that steep-hill video was that a normal recreational-skate heel-brake with a normal recreational-skate boot cuff works pretty well in a very demanding real-world situation.

Ken