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It’s no secret that synergy has helped KTM and Akrapovič grow from strength to strength across their over 20-year relationship working together to deliver the best products not just for KTM Factory Racing teams, but for every rider too. KTM Blog takes a closer look into the past, present and future of this solid partnership.

@Sebas Romero

Some quick facts: 130 world titles, 76 achieved with KTM, 9 Red Dot awards for design accrued over 28 years of operation. Founded by an ex-racer who used his passion for motorsport to develop market leading hardware in terms of both quality and performance and a name synonymous with the best. This can only be one company: Akrapovič.

To see how the great achievements celebrated in the top tiers of motorcycle racing filter down to the products available to the grass roots racer, KTM Blog talks with some of the brains behind the brawn of Akrapovič, Head of Racing R&D, Alojz “Slavko” Trstenjak.

Slavko Trstenjak @Akrapovič

Slavko has been working alongside Igor Akrapovič since the infancy of the market leading manufacturer, with his own responsibilities, experience and book of stories growing along with the company and its now 1200 plus strong team.

“I started working full-time for Akrapovič at the beginning of 1993, but I’d already been working with the company a few months before that. At the beginning I worked as a mechanic, as an engine builder, because at that time the company specialized in motorcycle tuning, and it was later that it specialized in exhaust systems. During the first years we were all multitasking, we were involved in several areas, which was necessary because there were very few of us at the company, less than ten. After that I focused on work with Igor Akrapovič on the dyno as a tester, looking for and defining new exhaust configurations. I did that for almost ten years. After that I took over leadership of the still relatively small R&D department – and in a few years it expanded to over 40 engineers in the department. Later I shifted to managing the Racing R&D department for developing racing exhausts for all kinds of motorcycles.”

Joel Smets (2003) @KTM

During this time the Slovenian company has celebrated a staggering number of victories across a wide array of disciplines, when asked Slavko proudly recalled some of his personal highlights:

“An unforgettable milestone for sure was our first world champion using an Akrapovič exhaust – Colin Edwards on a Honda in the WorldSBK series. This title was won after almost ten years of hard development work and visiting countless WorldSBK races and the German championship. Before this, there was an important achievement a year earlier, when we partnered with all the Japanese motorcycle manufacturers in WorldSBK. All the Japanese factory teams and Aprilia relied on our know-how and our achievements. Personally, as a big offroad enthusiast, I was very satisfied when I was also able to help the company start developing exhausts for Offroad motorcycles, and we saw our first successes with these pretty quickly, including the first world champion title on motocross with KTM and Joël Smets, and we also celebrated success in the Dakar Rally with a two-cylinder KTM.”

The special relationship between KTM and Akrapovič ensures the highest levels of quality and a seamless fit.

Thierry Van Den Bosch (2004) @KTM

“From the very beginning, cooperation between KTM and Akrapovič was based on exchanging information in the early phase of development while seeking the best solutions together. Over the years of cooperation, we had a big impact on the design trend of exhaust systems on production bikes manufactured by KTM, especially in the offroad segment. Our engineers are usually already involved in the early phase of designing the motorcycle itself and in preproduction bikes, where we usually prepare prototypes for KTM’s basic testing; these are essential for developing other components of the bike in the development phase. This work method especially applies to certain motorsport categories like MotoGP™, where developing the exhaust system takes place at the same time as developing the other components, and toward the end all the components are fused into a complete whole. These days all the parts can be developed in a 3D model, and then the 3D models are exchanged among the engineers. The work takes place simultaneously.”

There are some differences in the design process for production bikes compared to those intended for Red Bull KTM Factory Racing teams. This is mostly due to timing as new designs are developed in racing first, and then there are some other factors to consider. Slavko explained further for us:

“If we’re talking about bikes that are intended exclusively for racing, we usually develop their exhaust systems before our exhausts used for production motorcycles. When we’re talking about the general production bikes sold by KTM, the Racing R&D department doesn’t have anything to do with that; they’re developed separately, between KTM and Akrapovič’s R&D department. Here engineers already closely cooperate in the development phase and with the first prototypes, which determine the development guidelines based on the demands that define today’s development of exhaust systems, such as shapes and environmental requirements regarding emissions and noise restrictions.”

Fabrizio Meoni (2004) @KTM

“For racing exhausts, I can confirm that the shape is developed exclusively in our Racing R&D department, and we provide the guidelines. For exhaust systems installed on production bikes like the Adventure segment and all others, as far as the shape is concerned, KTM designers are also involved. We follow the principle “form follows function” and we work so that the exhaust systems are made to be used, for which we have lots of feedback and invaluable experience from close cooperation with the factory racing teams that use our exhaust systems.”

Although Slavko is not overseeing the work carried out for production bikes, this does not mean that the hard work of his team does not greatly influence the design of the product.

“We absolutely use the knowledge and experience from the Racing department for production bikes. Looking at offroad bikes, it’s an advantage to the end-users that they receive an exhaust system that’s virtually identical to the one the KTM factory teams are racing with – for example, what Cairoli, Herlings, Prado, and others are using. Most times there are minimal changes because of certain components required by layout, but regarding performance, weight, and other characteristics we try to retain the characteristics as much as possible from the racing environment to the production exhaust. With the exhaust systems for enduro and extreme enduro, it’s a nearly identical system”

Antonio Cairoli (2012) @KTM

Each racing environment demands different specifications in order to meet the needs of the rider, and ultimately win. Thanks to their broad team of engineers and scientists Akrapovič can control all factors of the design of the exhaust. Using an in-house metallurgical laboratory, they can even predetermine the titanium’s properties before being formed, ensuring the perfect finish. Slavko went on to explain some of the differences that can be seen between disciplines:

“The finish itself involves an added value that’s been present since the very beginnings of the Akrapovič company. With a lot of exhaust systems, we further increased their durability through the use of custom materials; for example, Rally is the only motorcycle series in which we use special 1.2 mm thick titanium, and not tubes with the usual 0.9 mm thickness. We know that Rally is a very long race where the exhaust has to survive the entire race for amateur racers – an unforgiving two-week torture test. This is why the choice of material and optimizing it is really important. In MotoGP™, for example, there’s a big emphasis on weight, but this isn’t the main reason we use 0.65 mm thick tubes. At the same time, we have to make sure that the material can withstand the high temperatures, stresses, and pressures that are created in the exhaust system, and so we dedicate great attention to the choice of material and constant checks. All of this already takes place in the very selection of the material supplier.”

“The Akrapovič brand is known for its race-proven products; it was born in races that we know demand performance, light weight, great sound, drivability, throttle response, and other characteristics. For a product to achieve this, you have to give it your all and pay attention to every detail, to every gram, to every mounting element.”



Brad Binder (2016) @FocusPollution

If you stop to ask any motorcyclist about what makes Akrapovič stand out, then quality and this precise attention to detail will come up. The vast majority will answer with the distinctive sound.

“Considering all the different categories of motorsport that exist today, it’s clear that we can’t ensure the characteristic Akrapovič sound for each and every one of them – but it’s true that we strive to make that sound a pleasure sound as much as possible. It’s impossible to compare the sounds of so many different championships – say, from enduro to MotoGP™. Oftentimes the configuration determines the sound produced by these instruments, but we make great efforts to tune them well, so they produce the very best sound for both the rider and the environment.”

After creating various designs, simulating models and manufacturing prototypes comes the real testing. Even in an age of advanced computer technologies and accurate simulations, Akrapovič follow an intense program of both dyno runs and real-world testing as ultimately the success of the product on track is directly related to riders’ preferences.

Pol Espargaro (2018) @Sebas Romero

“In the offroad segment we make use of testing on the motocross track near the company, and we also carry out a lot of testing on it with racers and teams. We also take part in factory team tests held at various locations, usually in Italy and Belgium, where they’re held in the winter. There we make the “final touch” and choose the configuration. The dyno is only a tool for making measurements and obtaining results, but the dyno itself doesn’t decide which configuration is the best. Here, as developers and engineers, we have to make a preselection, and we leave the final choice to the racing riders. Our philosophy is that the end user has to be satisfied. If the rider isn’t satisfied with the character of the power, with the responsiveness of the engine, then – regardless of the results that can be measured on the dyno – we haven’t achieved our goal. Conceptually, the development of an exhaust system begins on the drawing board or at the computer and with creating a prototype. This is followed by comparative testing on the dyno, and after that even more testing. These tests are often carried out by our test riders, and after them the factory racers do the final testing. In this way we can evaluate our feedback on the configurations, see if we’re working in the right direction, and whether the feedback result is relevant or not.”

“Each exhaust is unique, a development story in itself; we don’t have universal exhaust systems. Each exhaust is made for a very specific kind of motorcycle, developed to optimize its power, reduce its weight, and satisfy any type-approval requirements that apply to that kind of system.”

Nathan Watson (2019) @Future7Media

And there’s no resting on their laurels either! Constant development and product evolution go on year on year, with new products released as they maintain their position as the world’s premier exhaust manufacturer. This can be seen in the release of an all new look for the KTM ENDURO MY20 range.

“A new shape is a new beginning for the EXC family era. We’ve been working on the most stress-laden parts of the exhaust system, weak points, and research directions to improve the current exhaust and optimize it. This is why we moved to the “relief profile” of the exterior sleeve, which ensures greater durability, better scratch resistance, and more resilience to the impacts and damage that can be expected in enduro use every day. The development goal is to preserve the maximum volume in a limited space along with ensuring the lowest sound level friendly to the environment.”


To round things up we asked Slavko to summarize what he thinks is the number one benefit of an Akrapovič exhaust is to a KTM rider, regardless of their level of riding:

“The biggest benefit to end customers is that when they use our exhaust systems, they really get identical materials and solutions, and often also the identical exhaust system configuration that we create for factory bikes. End users buy what we produce for world champions, regardless of whether they’re racers or recreational riders. The end user gets a product that’s the result of working together with factory teams. This is really important to me.”

Images: KTM, Akrapovič

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