How Air Disc Brakes are Different from S-Cam Brakes
Gain a deeper understanding of the safety components of disc brakes and how they square up against S-cam brakes in the trucking industry.
Episode 274: Ready to unlock the mysteries surrounding air disc brakes? Buckle up, as we take an exciting journey with Mike Konrad, the President of Bremskerl CV, who will shed light on the ins and outs of air disc brakes in the commercial vehicle scene.
We talk shop about the trends in air disc brake adoption and the vocations driving these trends headlong. Gain a deeper understanding of the safety components of these disc brakes and how they square up against S-cam brakes. We also dig into the causes of premature rotor and caliper failure and share tips on how to avoid these costly issues.
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Transcript of Episode
Jamie Irvine:
You are listening to The Heavy Duty Parts Report. I’m your host, Jamie Irvine, and this is the place where we have conversations that empower heavy-duty people. August 20th – 26th. 2023 is Brake Week. Not that long ago we did an entire episode dedicated to s-cam foundation brakes. Today we’re going to talk about air disc brakes. And to do so, my guest is an expert in air disc brakes. I’m really excited to have Mike Konrad, President of Bremskerl on the show today. Mike, welcome to The Heavy Duty Parts Report. So glad to have you here.
Mike Konrad:
Thanks, Jamie. Looking forward to it.
Jamie Irvine:
So we were introduced by a mutual colleague in the industry. That’s what I love about this industry. It’s filled with great people and you’re usually only one degree of separation. So maybe let’s start off our conversation today to give people just an idea of where are we at with air disc brake in 2023 in the commercial vehicle space.
Mike Konrad:
Certainly, and I think you had a previous episode, if I’m not mistaken, with Steven Roberts from BBB had a lot of the facts on the head in terms of adoption rates, things of that nature, but we’re certainly seeing a pickup on air disc brake by a lot of national fleets and then it’s rolling over into second generation as well. Really is dependent on the type of fleet at the end of the day, a lot more vocational fleets, specking disc, and then more and more line haul over the road operators as well.
Jamie Irvine:
When I was selling parts, pretty much it was buses and that was it. And now what we’re seeing is we’re seeing a lot more tractors and trailers with air disc brakes. So when you talk about vocation, what are some of the vocations that are really driving adoption of air disc brake?
Mike Konrad:
Yeah, I would say the two biggest ones that we see are ready mix and refuse.
Jamie Irvine:
Okay, and what makes those particular vocations get more out of an air disc brake than an sca? What performance enhancements were they looking for?
Mike Konrad:
Yeah, I’d say certainly from the customers that we do business with out there, a lot of them are safety oriented. They all run heavy, so they want to be able to stop. A lot of these guys stop frequently and safety was a big priority for them. And I’d say secondly, what we’re seeing a lot of is the ease of change in brake pads over changing traditional drum brake lining shoes.
Jamie Irvine:
Yeah, I mean there was over 24 parts in the dual pin design for s-cam, and that’s not including the brake kit that has hardware and two shoes. So it’s a lot of moving parts. Disc is certainly a lot easier. One of the things we talked about in our episode on s-cam, we actually brought back a original interview that we did all the way back in 2019 with former president of Marathon Brake.
He’s now since retired, and he was talking with s-cam breaks about the realities of fade and how that performance characteristic is now, what’s the main difference between an s-cam brake and how it fades under extreme temperature and brake application versus an air disc brake?
Mike Konrad:
Yeah, disc brake. I mean, inherently the design, you don’t have the same type of fade characteristics as you would with a drum brake. That being said, you could still have some fade characteristics dependent on the materials that a person’s using in the application. But just like your passenger car, when they went from drum brake to disc brake, the fade issues pretty much went away.
Jamie Irvine:
So if safety’s an issue, like you said, with ready mix or with refuse, especially refuse, you’re driving in people’s neighborhoods all the time, obviously there’s that safety component. Let’s talk about total cost of operation. So you already alluded to the fact that maintenance costs are driven up by the number of parts that you have to replace and the associated labor. What other ways do air disc brake lower the total cost of operation for fleets?
Mike Konrad:
The difference in cost between a disc brake system and an s-cam brake system from a replacement standpoint, if all you’re doing is changing brake pads, it’s great, but if you have to start digging in and you have to start changing rotors, you have to start changing calipers, then the cost scenario is not really good.
At the end of the day, you don’t want to have to change disc rotors. You don’t want to have to change the calipers. And so there’s some preventative maintenance that you want to do. You want to be smart in terms of what you do with picking out brake pad selection as well.
Jamie Irvine:
Okay. So when I was selling parts, one of the things I remember with calipers, there was an issue with core return. And I remember, if I remember correctly, you had to have an actual genuine product. It had to be in the original box. It was really a big deal and who still has the box from the core, but apparently that that’s what was required. So when it comes to the availability of aftermarket options, what’s been the trend with that? I mean, I assume your company’s heavily involved in that.
Mike Konrad:
Yeah, pads, there’s lots of options. Rotors, you have two flavors. You have mid in America and you have Chinese, you’ve got some other country of origin options as well. And then calipers, calipers are a little challenging. You’ve got OE, you’ve got some OE Reman, and then you’ve got some aftermarket reman as well that’s out there. Cores are a really big challenge, especially for some of the less popular calibers.
Jamie Irvine:
So when it comes to the different things that would lead to premature failure of rotors and calipers, you mentioned that preventative maintenance is needed. Walk me through that in more detail. So how does a fleet avoid those additional costs and how do they make it so that they just have to change pads and it is a cost improvement for them?
Mike Konrad:
And when you’re talking about, I’ll take the brake pad and the rotor combination for a moment. When you’re talking about brake pads, you want to have something that’s going to be friendly on the rotor while still being safe. And those exist. One of the biggest things is I think a lot of technician training too.
I can’t tell you how many times we’ve seen in the field where somebody’s put a pad in backwards or they let the pad get down to the underlay, or whether that’s a mesh or nrs fingers or something of that nature where it gets into the rotor that rotor’s trash, throw it away. You don’t have a lot of fleets out there turning rotors at this point in time.
Calipers on the other hand, are a little different story. The biggest failure point that we’ve seen on calipers is really on the slide pin boots. If the technician is looking for tears, if they have a good preventative maintenance cycle, they’ll catch these things. But if they don’t catch these things, that’s when you start getting an ingress of dirt or water and you could start seizing up those slide pins and when that happens, your caliper’s done.
Jamie Irvine:
So that visual inspection is key to being able to identify those things early, fix them so that we don’t have the damage done, and then you have to replace the whole caliper. Is that right?
Mike Konrad:
Correct. Yeah. And training’s real important because most of these technicians that are out there are familiar with s-cam breaks. More and more fleets are getting discs, so they’re becoming more familiar with it, but there’s still a learning curve.
Jamie Irvine:
So friction material selection is always a big part of s-cam brakes when it comes to the disc brakes. How important is it to match like friction to vocation?
Mike Konrad:
Super important. You won’t necessarily want to use the same friction material for a line haul application that’s frequently just going down the highway as you would for a refuse application that might do a thousand stops a day. You have different requirements. Refuse doesn’t want any noise. They have a higher duty cycle. They’re going to see higher wheel end temperatures and higher brake temperatures, especially at the interface versus going down the highway. They don’t necessarily need something that can handle that repetitive braking cycle.
Jamie Irvine:
Okay, that makes sense. We’re going to take a quick break to hear from our sponsor. We’ll be right back.
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Jamie Irvine:
We’re back from our break. Before the break, we were talking about air disc brakes. We’re talking about how they are being adopted more and more in the commercial vehicle space here in North America, and we’re also talking about some of the key trends when it comes to preventative maintenance and making sure that they actually lead to lower total cost of operation for a fleet. Mike, let’s talk a little bit about your company specifically. So maybe you could just give us a little bit of history first and then we’ll talk about some specific products. I’ve got a bunch of questions for you.
Mike Konrad:
Sure. Yeah. The current company, Bremskerl CV was born out of the Bremskerl Group. So Bremskerl from a history standpoint makes friction material for a high speed trains, makes friction material for van clutch applications, golf carts, elevators and commercial vehicles, you name it.
The only thing we never entailed into was the automotive market, passenger car, Bremskerl CV, as it stands today, is a spinoff of Bremskerl North America. We separated the businesses so that Bremskerl CV could focus on the commercial vehicle market because we saw an opportunity to really take a narrow focus and expand our offerings in that marketplace to help our end user customers.
Jamie Irvine:
That’s fantastic. So where are you located? Do you have multiple locations or do you cover the whole North America from one central place?
Mike Konrad:
Yes. Yeah, we’re based in Bartlett, Illinois, right outside of Chicago. We’re responsible for everything in North America, Canada, US, Mexico.
Jamie Irvine:
Okay, fantastic. Okay. So when it comes to the products that you sell, just give us an overview of the product lineup just so I make sure I haven’t missed anything.
Mike Konrad:
Yeah, absolutely. So our bread and butter is air disc brake pads. We also are venturing into some other brake related components. We’ve been developing a rotor line, we have a caliper line, and we’re slowly rolling out a foundation drum brake line as well.
Jamie Irvine:
Okay, perfect. So everything brakes. So, okay, let’s talk friction material. So I didn’t sell a lot of air disc brake in my career. It was mostly s-cam and there was always that classic we’ve got good, better, best. Does that exist with air disc brakes as well and is that even real?
Mike Konrad:
Sure it exists. I mean, it’s a marketing term all the way. If you know me in the market, I do not like the terminology at all. You know, could go out there with the value, the good, better, best. It’s all salesman speak at the end of the day. So just like in drum brake linings with disc brakes, there are formulations specific to certain applications, and one of those formulations might just be a existing base material that somebody modified, and that’s how friction material manufacturers, how we all come up with things.
We might have one really good material. We don’t usually go and start from scratch. We take an existing material and we tweak it based on experience, whether that’s in the lab or more importantly out in the field to see how something behaves in an application. And you may have to go back two times, you may have to go back a couple hundred times before you get it right.
Jamie Irvine:
Right. Now, one of the things I remember learning about friction material for s-cam brakes was that really the only way to lower the acquisition cost, the purchase price was to take something out of the material, all things being equal, the labor and all of that, the shipping that was pretty standard across the board regardless of who you were buying from. So if you wanted to get cheaper brakes, you had to take it out of something out of the raw materials. Does that cross over to air disc brake?
Mike Konrad:
Sure. Yeah. I mean, if from a manufacturing standpoint it’s the same like s-cam brakes, some people have a better manufacturing process than others and have been able to save money there and make it more cost effective to produce. But raw materials is definitely a very large portion of brake pads or drum brake linings. I mean, look, you have a steel or a cast iron backing plate, metals a commodity. Then you have lots of different raw ingredients that might go into a brake pad. Those are all commodities as well.
Some of them are 10 cents or 20 cents a pound, some of them cost $25 a pound. So it really just depends on what you put into the mixture and which percentage you put into the mixture that makes up that whole. But yeah, to answer your question, to reduce a upfront cost, all other things being equal, you’d have to take something out or put a lower cost material in there and take one of the more expensive materials out.
Jamie Irvine:
And as soon as you do that, to me, that translates into lower performance or increased wear. When it comes to brakes, they all have to meet the standard of stopping distances. But the question is for how long before they need to be changed. Is that correct?
Mike Konrad:
Correct. I mean the aftermarket, the only true requirement is an FMVS121 test. RSD as it stands today, there’s no requirement for the aftermarket. It’s a OE only specification. Now that doesn’t mean a supplier in the aftermarket can’t go and do the same type of stop distance tests. They certainly can. Many don’t.
Jamie Irvine:
Right many don’t. That’s the scary part. Is the friction material on an air disc brake system basically the exact same friction material on an s-cam just reformulated in a different shape and size. What’s the differences?
Mike Konrad:
You have a disc brake versus a drum brake application. One is inherently different in design than the other, without getting into specifics of what goes in the materials. You do have carryovers in terms of the types of raw materials that go into them. But philosophy wise, a disc brake and a drum brake are different. And so when we develop materials, what we develop for drum brake material is a different development path than what we developed for a disc brake material.
Jamie Irvine:
So I know that in breaks, one of the big goals and how you can get better performance really is how quickly can the friction material dissipate the heat, that that’s a big part of it. What are the differences in actual performance characteristics between the two systems when it comes to things like heat and it comes to stopping and all of that? Let’s just give me a little more there. I want to learn because I don’t know as much about air disk as I do about s-cam.
Mike Konrad:
Yeah, so I would say, and you touched on a lot of ’em, so I’d say there’s two really big fallacies in the marketplace. The first is heat dissipation. Friction material for all intensive purposes as an insulator, you have, if you look at a brake pad, you have almost an inch of material. You have steel backing plate.
The heat at the interface between the pad and the rotor is going to find its way out faster through that gray iron rotor than it is through that brake pad. You can put things in a brake pad or in a drum brake lining that could help from a heat transfer standpoint. But generally speaking, the heat is transferring through that drum or through that disc. And so when you talk about disc brakes, that’s what the vent is for. Now you’ve seen disc brakes with solid disc and you’ve seen disc brakes with vents.
Most stuff that’s out there in the commercial vehicle market has vent. And the intention of the vent is it draws air in and through centrifugal force is effectively throwing the heat out. And that’s why you need the speed of the vehicle to draw that air in when you’re going down the highway. So when we’re talking about a vocational application, start stop application, we have a thousand stops, maybe they’re going 10 miles an hour, they don’t get the same type of airflow into that wheel end.
And so consequently they have higher wheel end temps. Heat is the enemy of all brakes. And then I’d say the other thing that the second fallacy where you hear all the time is, well, if I want the pad to live or I want the rotor to live, one’s got to give, I’ve got to give something up. In a lot of cases that’s true, but you can get to a point in which a friction material manufacturer has been able to develop a material that will give you both, can extend that rotor life and can also extend that pad life at the same time.
And there’s two real basic philosophies on making friction material. One is abrasive where the pad is wearing the rotor and one is called adherent. Basically it’s putting down what we call a film transfer layer. And that film transfer layer, think of it as a protectant and the pad is running on that interface.
And so when you switch from one brake pad to another brake pad and you put it on an existing rotor, you have to give that brake pad time to seed into that rotor. You have to give it time to kind of condition that rotor. And there is a point in time where that rotor is too far gone and that’s not going to happen.
Jamie Irvine:
Yeah, that makes sense. So what makes a rotor warp? We’ve all had that experience. You get into an older vehicle maybe, and you hit those brakes and you get, oh man, there’s a lot of shake. What’s going on there? What has happened? Is it just that the rotor perhaps is a poor or low quality steel, or is there something else going on there?
Mike Konrad:
Yeah, I mean it could be that, it could be heat. So there’s different factors that contribute to it. You don’t see a lot of warping in commercial vehicle rotors per se. More what you’re going to see in rotor effects is you’re going to start seeing heat checks that are going to potentially turn into cracks. And when you start talking about roadside violations that CSA can actually see, they can see cracks and they can see top edges of brake pads, for instance. They no longer have the ability to really see the whole entire brake pad surface or anything of that nature. Disc brake pads are a little harder to inspect.
Jamie Irvine:
But hey, Brake Week is coming up August 20th – 26th. And those are the things they’re going to look for if you’re running air disc brakes. Correct?
Mike Konrad:
Correct.
Jamie Irvine:
Yeah. Anything visual. Well, that’s really great. So I’m, when you walk into a fleet and let’s say you’re helping one of your customers to sell that fleet, what are the two or three things that you’re going to look for right away to help decide what application or what product you’re going to recommend so that it matches product application?
Mike Konrad:
Sure. Yeah. We want to understand how their fleet operates first and foremost, what they do with their vehicles. We want to understand a baseline, the existing brake pad and rotor combination that they had, what kind of life are they getting? And I say combination for a reason.
If you were using OE pad, OE rotor and you got say 400,000 miles of life on that pad, and then you kept the OE pad and you went to an aftermarket rotor, the life may not be the same. And so when you start playing around with different materials, whether you’re talking frankly anything but brakes, you don’t want to change pad and rotor at the same time.
And so when we’ll go into a fleet and we’ll talk with the fleet, even though we offer all these products, we won’t say yes, change pad and rotor at the same time. We’ll say, let’s take one variable first. Let’s prove it. Let’s show you what happens, and then we’ll talk about the other component. Because if you were to put both components on right out of the gate, then potentially if something didn’t work as well as you wanted life-wise, you don’t know what contributed to it.
Jamie Irvine:
Right, too many variables.
Mike Konrad:
Correct. Yeah. So the other things we’re looking for is what’s the baseline? What do they do with their fleet? What kind of issues have they experienced? And that’s a hard question to ask, especially with air disc because they don’t have a lot of experience. The biggest thing we run into is when fleets have switched over from s-cam to disc. A lot of the manufacturers pushed up discs and said, oh, you’re going to get this great life on tractor or this great life on trailer, and they haven’t seen anywhere near that.
And you also have one other factor that’s contributing to all this is all the copper free materials. A lot of the OE materials, not all of them, a lot of them are still have some level of copper. Most of the materials in the aftermarket that we run across are copper free. You know, really only have two states that are pushing the copper free mandate at the moment, but potentially it expands across the United States.
We offer copper and copper free because copper is a really good material from a high temperature application standpoint. It really helps with life. I will tell you that. And so we have to look at each fleet on a case by case basis. They all operate differently, whether they’re running their vehicles just an eight hour day or they’re running slip seat, for instance, and continually running their vehicles 24 hours a day. So they all have different issues.
Jamie Irvine:
My name is Jamie Irvine, and you’ve been listening to The Heavy Duty Parts Report. We’ve had a chance to talk about air disc brakes today in depth, and I just want to thank you so much for sharing all of this information, Mike, really appreciate it. If people want to learn more about your company, what’s your website?
Mike Konrad:
Sure, yeah, they can go to bremskerlcv.com, and it’s B R E M S K E R L C V. com.
Jamie Irvine:
Nice easy one to spell. We’ll make sure that the links are in the show notes so that you can just do a one click and go check them out. Mike, again, thank you so much for taking some time to talk to us about Air disc brake. I really appreciate you coming on the show.
Mike Konrad:
Thanks for having me on.
