How Fan Drives Are Designed for Commercial Trucks
Learn about the role application engineering plays in the development of heavy-duty parts for commercial trucks, and how Horton adapts their fan drives.
Episode 136: Have you ever wondered how things get designed and spec’d on commercial trucks? There is something called application engineering and it is how heavy-duty parts get designed and manufactured for commercial trucks.
Our guest in this episode is Robert Cayton, the Application Engineer Manager at Horton.

Robert has been with Horton for over 10-years in various roles, so he is well versed in the role application engineering plays in the development of heavy-duty parts for commercial trucks.
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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 show where you get expert advice about heavy-duty parts that keeps trucks and trailers on the road longer while lowering cost-per-mile.
Technology is constantly evolving. And we have certainly seen a lot of changes with commercial trucks in the last few years, but have you ever wondered how things are designed and how those specifications are established to make a commercial truck operate the way it is, or to have a specific part added to that truck so that it can achieve certain different performance characteristics?
I’ve certainly thought about that, and I’m certainly happy to have my guest today, Robert Cayton with us, he’s the Application Engineer Manager at Horton. Now Rob leads a group of engineers who spec Horton products on heavy-duty truck applications. And he’s been with the company for over 10 years. He was part of the product development group and he’s various roles over the years. So he has been integral in developing the latest and greatest fan drive products that we’ve seen coming from Horton. So he’s got a lot of experience in this area and I’m very glad to have him on the show. Rob, welcome to The Heavy-Duty Parts Report. So glad to have you here.
Robert Cayton:
Yeah, thanks for having me Jamie.
Jamie Irvine:
So I’m not an engineer. The closest I got to that was when I worked at a remanufacturing facility and I was part of production. So when I think of engineering, I kind of think of it as one thing, but you’re talking about application engineering. That’s something different. Can you explain for us what that is?
Robert Cayton:
Yeah. So at Horton we make fans and fan drives and we have two groups. We have a product development group that kind of creates the latest and greatest product type. And then we have an application engineering department, which is really customer focused and the goal is applying the production Horton products on new vehicle applications.
Jamie Irvine:
Okay. So I’m envisioning in your manufacturing facility, you’ve got all these production lines, you’re making these products and the application engineering department says, okay, we’ve got these products, now where is an opportunity to use these products, maybe in an application that wasn’t originally part of the concept, but it’s a good fit for some reason. Do I have that right?
Robert Cayton:
Yeah for the most part. Really what we do is we take existing applications and put them into customer applications. What I mean by that is different truck types, different truck spec builds. You obviously have your heavy-duty trucks, your medium-duty trucks, you have your different engine options. All of those require a different fan and fan drive. And we make sure that the right Horton product is in the right application.
Jamie Irvine:
Okay I get it. So, you know, you might be buying a Kenworth, but one Kenworth is being sent to the oil fields of Texas or Alberta. And another Kenworth is over the road and it’s a completely different environment. So based on vocation, it has different needs.
Robert Cayton:
Yep, exactly. It has different cooling needs, obviously you have different engine types that you could pick from when buying your truck. You have your Cummins, you have your MX from Paccar. You have your A26 from Navistar and your Detroit Diesel from Daimler or Freightliner. All of those in a specific truck model will have a different fan and fan drive because the cooling needs are different, the fit is different. So we work with the engine manufacturers and the truck OEs to make sure the right fan is in the application that provides the sufficient cooling and gets the customer the best mileage and the best reliability.
Jamie Irvine:
So explain to me how that interaction between your company Horton and one of these OEs works. Like what are the mechanics behind the interactions between the two companies?
Robert Cayton:
Yeah. So the way it works at Horton is we have dedicated application engineers for each OE. So each Horton engineer works regularly with the same engineers from Freightliner, the same engineers from Paccar, same engineers from Navistar. They develop a pretty close relationship and work well together. And what happens is they come to Horton and they say, we have a new truck development project, or we want to upgrade an existing truck or even, Hey, we have a new customer that needs a new use or needs to add something to the truck. They come to us and say, Hey, we need a fan and we need a fan drive that meets certain specs. So we work on again, project that need to be completed in six months, we work on projects with the new prototype trucks, which are 2, 3, 4 years down the line. And we provide all of the fans and fan drives that they may need to meet their needs.
Jamie Irvine:
And the stakes are very high because we all know with work trucks, they have to make money. They have to be reliable. And so the stakes are high, both for the truck OE, because they don’t wanna put out something that doesn’t work. And then obviously for Horton’s reputation, you want to be part of the solution. So the stakes are high for your company as well because you wanna maintain a great relationship with all of these OEM manufacturers and engine manufacturers.
Robert Cayton:
Yeah, absolutely. I mean obviously reliability is absolutely key and to meet the reliability requirements from the OE, we’re very stringent at Horton. We make sure that, t’s are crossed, i’s are dotted. And one way we do that is we take this technical specifications and the requirements from the customer for given application, we spec the right fan. It could have nine blades, it could have 11, also could have different diameters. Then we make that up with the right clutch product. That could be a variable speed drive like an RCX or LCX from Horton. It could be a pneumatic drive like our DM Advantage or DM Advantage Two Speed.
We make sure that the right fan drive is in that application. And then all that initial work happens on the computer in CAD software. Once we have the model set up, then we start going through the validation with the OEs. And that could take two, three years for some projects we’re working on trucks that go into production in 2024, 2025 right now. To ensure the product is reliable we work very closely with the OEs to make sure that we have prototypes on design validation trucks, they call them, which is usually when they build the first three to five trucks. We make sure we have the right product on when they do quality validation builds, which somewhere in like the 40 to 50 truck build, they make sure that they can kind of build these in higher volumes, that they get more reliability date off the truck. And then we also help them when they go to production and officially release the design. And again, we’re working on right now, the 2024, 2025 truck models from Paccar and Navistar and Freightliner.
Jamie Irvine:
So this application engineering process is proved to be obviously very successful because you wouldn’t have that many layers and have it working so closely together if it wasn’t. What makes it so successful though for the end user, once they get the truck and it’s got the product on it that they need for the vocation they’re doing?
Robert Cayton:
Our customers obviously have customers and that’s the end user in that way, we try to get right close with the end user and figure out what problems they’re having, what needs they may have, what benefit from those needs that we can provide. And we bring that voice a lot of times to the OE engineers. And an example may be, there may be a truck in Canada and you know, obviously it gets pretty cold.
Jamie Irvine:
Totally it’s -30 Celsius today. I’m not sure what that is in Fahrenheit. I have to do the math on that real quick.
Robert Cayton:
Close to -30 Fahrenheit. So a truck radiator and fan is usually spec to climb out of the hill outta death valley. Obviously that’s too much cooling for someone who’s in the dead of winter in Alaska of Canada and their truck may overcool and they may have issues there. So we try to get on the ground and understand that those needs, and maybe there’s a better product and a better fan that they could use so that they don’t overcool knowing that they’re never gonna climb out of death valley in July. And we bring that voice to the customer. I mean also with serviceability, I think we’ve all worked on our own cars and been frustrated at why I have to take off four brackets to get to the part I want to replace. We try to make sure our products are easily serviceable because we know that at some point a mechanic’s gonna have to get in there and put on a reman or a repair kit.
Jamie Irvine:
That makes me think it was a GM product. I think it was a Pontiac in the ’90s that you actually had to unbolt the motor mount on one side, lift the engine to change the oil filter. That’s an example where application engineering has failed us all.
Robert Cayton:
Exactly, exactly. It was easy to make on the production line. And if that’s the only thing you’re incentivized to care about, you end up with that. So yeah, we try to bring a voice of our customer’s customer of the conversation. And I think we’ve found a lot of success in that. And also that makes the end user want to spec a Horton fan drive and fan over a competitor.
Jamie Irvine:
Gonna take a quick break. We’ll be right back. Don’t have a heavy-duty part number and need to look up a part? Go to parts.diesellaptops.com or download the app on Apple or Android to create your free account. Looking for high quality fuel injection for heavy-duty applications? Having one supplier for fuel injection allows you to better serve customers by providing them with a complete line, which increases your sales and profitability. Learn more at ambacinternational.com/aftermarket.
We’re back from our break. And before the break, we were talking about application engineering, the process, why it’s successful, how it works. Roby did a great job of explaining that to us. Now let’s focus on how fan drives specifically get designed. How do cooling targets and engine mounting affect the design and specs of a fan drive? Just before the break we were talking about in the past, there has been times when certain vehicles have been built in a way that makes it very difficult to maintain. So I’d like to hear more about that.
Robert Cayton:
Yeah. So the fan and the fan drive are kind of actually the last, I’d like to think of it as like, the component that connects the loop. So when new trucks are designed, obviously the body style changes, they do different things to try to improve aerodynamics which affect fuel efficiency. Then they start picking an engine. You know, there’s always the latest and greatest from Cummins and there’s always the latest and greatest from each of the OEs and their engines. Then that goes into a radiator choice. So if you have a real slim down hood and a real small radiator, that’s gonna drive your cooling needs way up, but essentially the fan and fan drive are selected last. So when you have your engine and you understand the radiator size, that then drives your fan selection, which then drives your fan drive selection. And so what that means for us is we gotta work quick because by the time everything things finally solidified, we finally know all of our specs and have to work quickly to make product so that they can meet their production deadlines.
It also means that we have to be agile because if anything changes upstream in the design, so to speak, we have to change our drive. If they move the engine a little bit, if they move the radiator a little bit, all of a sudden, if they do a DV test and the engine doesn’t hit the cooling targets, we have to do a fire drill and see what we can do to help the customer out and solve their problem. So it’s a fun job to do because we get to work closely with our customer and get to solve problems frequently. And I enjoy that. And I think the fellow application engineers get to enjoy that.
Jamie Irvine:
Is there some advantage in some ways to being the last in that long line, because I mean, it gives you a chance if you’re the first and then they’re coming back to you and saying, oh, well then we had this problem, this problem, and this problem, you’re constantly having to go back and redesign, at least with this, you’re looking at all of the metrics and able to come up with a solution, I guess in some ways there’s gotta be a bit of an advantage.
Robert Cayton:
Yeah. I, I think you’re right. You get a lot of points with the customer and you’re able to meet their needs and solve their problems at the end very quickly. You know, if an engineer somewhere along the way, maybe didn’t select the right radiator at the truck OEs. We can sort of cover that up for them a little bit. If you know, they’re not hitting their cooling targets, some CFD, some analysis didn’t quite prove to be correct, then we can help solve that problem and get the truck out into production. There is some advantage to that and we see a big advantage in being really close to our customers and giving them exactly what they need as quickly as they needed.
Jamie Irvine:
So back in the days when I was working at a remanufacturing facility very early in my career, I was familiar with Horton fan clutches, and now they’re all fan drives. It seems. And so has there been just incremental changes to the specs over the last few years? Or has the changes been quite dramatically? What’s been the trend in the last few years and where are we going over the next few years? I
Robert Cayton:
I should say, fan drive and fan clutch, maybe we could still, there’s still synonyms. You can use them interchangeably a little bit. What’s really coming down the pipeline engine temperatures are increasing. So if you can increase the engine temperature, the diesel engine runs more efficient. That’s obviously really important. And so higher engine temps mean greater cool demand sometimes. So we have to find the right drive, the right fan that meets those high cooling needs. And now variable speed drives are becoming more common. Horton has our LCX and RCX product lines, which you’ll see now on new Kenworth and Peterbilt. Those variable speed or viscus fan clutches or fan drives provide just a right amount of cooling for any given situation.
So theoretically the engine runs in the optimal temperature range more, you get better fuel efficiency. You run the fan at a slower speed, which also increases fuel efficiency. So we’re really seeing a little bit of, you know, next generation of technology coming into the industry and providing a benefit to the customers. Then down the line, I think electrification is coming and it’s a very popular buzzword and Horton is going to provide electric fans for those battery electric and fuel cell electric vehicles as well. So industry is changing, but essentially it’s still the same because we were given a cooling demand and some geometry, and we have to figure out how to cool engine cool the system in the best way possible.
Jamie Irvine:
And I was just thinking of the changes to exhaust requirements in 2027, right, where there’s a new target there for the reduction of NOx even further. So that’s gonna change specs. And as you said, alternate power sources and power trains are gonna come into play here so it’s a dynamic time for the industry. And I can see that Horton’s gonna have to make some adjustments as things change. In preparation for our conversation, I came across a term truck manufacturer ability. How does that impact the way you design your fan drives? Is that what we’ve been talking about the whole time in essence? Or is there more to it?
Robert Cayton:
Yeah. In essence. So when the OE engineers start putting together design and when manufacturing people look at it, they look at it from a perspective of how do I build this as cost efficient as I can with the highest level of quality on our production lines. And that may be kind of like we talked before with your moving engine mounts, it means that maybe serviceability or end user experience might not be completely factored in. And again, at Horton, we really try to get to our customers customer and figure out their complaints, their voice, and bring that into the conversation. I mean, we also then try to balance that with the OE manufacturability, we try to design a fan clutch in a way that it can easily be dropped in and assembled onto the engine quickly and efficiently. We try to reduce weight as much as possible for the assemblers, but then also for the, you know, it’s important to have the light of drive as possible on the truck.
Jamie Irvine:
Yeah. I can see how there’s so many different factors that have to be taken into consideration. And if you ignore one, like for example, on the aftermarket side, once this thing is manufactured and out into the market, it’s gotta be serviced. It’s gotta be repaired. There has to be the supply of parts and the ability to take it out and fix it if there’s a problem. So those factors can’t be ignored. Otherwise you’re gonna have some very unhappy fleets and vehicle owners and that’s no good long term for anybody.
Robert Cayton:
Yeah, exactly. There’s a total cost of ownership and designing a product that maybe will be a little bit cheaper upfront for the OE manufacturer. Maybe a little bit lower purchase price doesn’t necessarily correlate with lower total cost of ownership overall, if it takes 10 hours to a fan drive.
Jamie Irvine:
That is a subject we talk about here on The Heavy-Duty Parts Report all the time that purchase price is not the number you need to concern yourself with when you’re charged with fixing these things. So really at the end of the day, if you just want people to remember one thing about what we’ve been talking about today, what’s that one thing?
Robert Cayton:
It’s that at Horton, you’re our customer’s customer. Your voice is critical, and we want to hear it. There’s Horton sales reps across the country, across North America. If you have complaints, we elevate them and we try to get it into the conversation when we’re designing and implementing fan drives and fans.
Jamie Irvine:
Yes. And I do know that manufacturers reps also love to hear success stories, not just the complaints. You’ve been listening to The Heavy-Duty Parts Report. I’m your host, Jamie Irvine. And we’ve been speaking with Rob Cayton, the Application Engineer Manager at Horton. To learn more about Horton, visit Hortonww.com. Links are in the show notes. Rob, thank you so much for being on The Heavy-Duty Parts Report. I really appreciate it.
Robert Cayton:
Thank you for having me, Jamie. It is a pleasure.