Analyzing the KTM RC16 MotoGP Bike

Google+ Pinterest LinkedIn Tumblr

At the Red Bull Ring in Spielberg, at the Austrian round of MotoGP, KTM finally officially presented its MotoGP project, the KTM RC16. There had been months of testing, with press releases and photos issued.

There had been KTM’s participation in the private MotoGP test at the Red Bull Ring in July, alongside the rest of the MotoGP teams. But at the Austrian GP, the fans and media got their first chance to see the bike close up.

What are we to make of it? First, we should ask what we know about the bike.

On their corporate blog, KTM list some specs for the bike. There are few surprises: 1000cc V4 engine, using pneumatic valves, housed in a tubular steel trellis frame and an aluminum swing arm.

Suspension is by WP, while brakes are by Brembo, and exhaust by Akrapovic. Electronics are the spec MotoGP Magneti Marelli ECU.

Big Numbers

What is slightly more interesting are the numbers for maximum engine revs and horsepower. Like all official numbers on values such as torque, horsepower, and revs, they are not to be trusted, but these both seem highly inaccurate.

KTM claims the RC16 makes 250hp. It certainly makes that, and probably 10% more, given that most MotoGP engines are believed to make somewhere between 260 and 275 horsepower.

Reports from the track said that the KTM was not short of top speed, though test rider Mika Kallio told a group of reporters that he believed they were still down a little on the Ducati. “On the engine side, we are on the good level,” the Finnish test rider told us.

“There is still room to improve, at the moment the Ducati is still the fastest bike on the straight, so we are not there, but we are close to the other bikes.”

Those who saw the speeds through the speed traps reported KTM as being very fast indeed, though no one would be drawn into revealing actual speeds.

19,000 RPM?

Where does that horsepower come from? On the corporate blog, KTM report the maximum revs as being 19,000 RPM. If that number is accurate, it is insanely high: MotoGP adopted the engine bore limit of 81mm precisely to limit engine speeds, after the manufacturers rejected a mandatory rev limit.

Conventional engineering wisdom had it that reliable engines would not be able to rev much above 16,000 RPM, as engine speeds above that would place too much stress on pistons and conrods, causing them to fall apart. A mean piston speed (MPS) of 26 m/s was believed to be a fairly firm limit.

That has not turned out to be the case. The bikes were soon revving well up towards 17,000 RPM, and making further inroads into the laws of physics.

According to our research, the Ducatis can rev to 18,000 RPM, the Hondas to 17,750 RPM, the Yamahas to 17,250 RPM (with satellite bikes having engine limits set several hundred RPM below the max revs of the factory machines).

Ducati was already achieving an MPS of 29.1 m/s, a seemingly impossibly high number. If KTM really are revving to 19,000 RPM, that would be an MPS of 30.7 m/s, which is up in drag engine territory.

Dragsters have to cover around 1200 meters between engine rebuilds. MotoGP bikes have to hang together for close to 2000 kilometers.

How do KTM – or Ducati, Honda, and Yamaha, for that matter – achieve such engine speeds? MPS – mean piston speed – is a rough approximation, but it is not an accurate reflection of the stresses placed on the engine.

What matters is the amount of acceleration and deceleration which the piston and connecting rod undergo as they slow down for bottom and top dead center, then speed up again towards the middle of the stroke.

The weight of components such as pistons, wrist pins and conrods is a factor here, as force is acceleration times mass, and force is stress.

Clearly, the factories are working to find clever ways of reducing stress, which will include lighter weight components, paying close attention to mass distribution, the location of the wrist pin, and smoothing the transition between acceleration and deceleration as much as possible.

What they are doing is impossible to know, nor how they are doing it. But the lessons learned will at some point pass down into production vehicles, though we may have to wait a few years to find out.

A V4, For Sure

What we do know about the engine is layout of the engine. Though KTM Technical Director Sebastian Risse was cagey when asked directly what layout the engine used, he tacitly acknowledged it was a 90° V4.

When I put it to him that the aim of running the bike without a balance shaft had implications for engine design, he replied, “This is true, yes.” Not an admission as such, but as close as you might expect from a factory engineer.

The engine firing order is also not yet fixed. When asked whether the engine would have a big bang (cylinders firing together) or screamer (each cylinder firing separately) firing order, Risse answered that KTM had not yet made up their minds.

“We are still doing some investigations about this,” Risse said. “Especially now with the electronics, there’s not just the mechanical firing order, there’s more about it, and you can play a lot with it.”

What he is implying is that although two pistons may reach TDC at the same time, the charges in the cylinders can be ignited a degree or so apart. That can help smooth the power delivery, and reduce the load placed on the crankshaft.





Hard to Hide Chassis and Suspension

While we may never know details of the engine internals, there are a couple of things which KTM cannot hide. The two biggest differences between the KTM and the other bikes on the grid are the suspension and the chassis.

KTM will be the only bike on the grid to use WP suspension, rather than the Öhlins used by everyone else. And it is the only bike on the grid to choose a tubular steel frame over an aluminum beam frame.

Will this be a disadvantage for KTM over the rest of the field? After all, the other factories are all using the same suspension and chassis design for a reason, right?

And Ducati dropped the trellis frame, for a carbon fiber frameless design, and then swapped that for an aluminum beam frame, and now they are starting to become competitive.

In an informal conversation, a senior member of a rival factory was impressed by the way the bike looked during the test. “The bike doesn’t move at all in the corners,” they said. “It’s much more stable than we expected.”

The fact that the KTM RC16 was a second off the Yamahas, and 1.9 seconds off the fastest Ducati, proved it was already a competitive package. Mika Kallio was just five hundredths of a second behind Ducati test rider Michele Pirro.

Full Factory WP

Choosing WP over Öhlins is a logical choice for KTM. WP is a subsidiary of KTM, and the two have worked closely in every motorcycle racing discipline they have been involved in.

WP supply the factory KTM machines in Moto3, and will be the official name of KTM’s Moto2 project. They have gained a lot of experience in Moto2 – so much so that some teams using WP in Moto2 have started referring to the Ajo squad as the “WP factory Moto2 team” – which will be applicable in MotoGP.

Above all, KTM will have the full support of WP. “This will be a full factory effort,” one source close to KTM told me privately. The two factories are just a short cycle ride away in Mattighofen, Austria, so communication is extremely direct. Updates will be fast and frequent.

Will a Trellis Work?

Pol Espargaro, who will race for KTM in MotoGP next season, was more concerned about the trellis frame. “We need to check if the tubular chassis works,” he told us at Barcelona. “If the tubular chassis is not working we will struggle so much.

I prefer a slow bike that is good in the corners than a fast bike on the straight and impossible to manage. I think [the chassis] will be harder than we are used to do with Yamaha. It’s a different system.”

So far, the performance of the KTM RC16 has not given much cause for concern, though there are still areas that need work.

“We need to improve the rear grip somehow on the exit,” Mika Kallio told us at the launch. “We have a lot of power in the engine, but on the exit side, we can’t really use everything, all of the potential. So we need to find some way to do this. Everyone can see Ducati are really good on that side.”

But a lack of rear grip is not unique to the KTM. Both Maverick Viñales and Aleix Espargaro have complained of exactly the same thing, especially once temperatures rise.

The Honda suffers even worse problems, either spinning the rear wheel or wanting to wheelie out of corners. The Yamaha is much better, but still lacks grip compared to the Ducati.

The Ducati gets a lot of its advantage from its aerodynamics, however. The vast array of winglets make a big difference in keeping the front wheel down and providing drive to the rear wheel. Those winglets are banned from next year, so the difference between the KTM and the Ducati could be much smaller in 2017.

With KTM currently working hard on a bike without winglets, they may well get an advantage. Sources familiar with the situation report that Ducati have been testing without winglets for next year, and suffering real problems with wheelie. Part of their advantage will be gone.

The Problem Is Adapting

The tubular steel frame will pose a set of challenges for both Pol Espargaro and current and future teammate Bradley Smith when they switch to KTM.

Having spent all their lives racing an aluminum beam frame, they have an intimate understanding of how that frame feels and responds. A trellis frame, such as the KTM RC16 uses, responds differently.

I asked Mika Kallio if he could feel the difference with the tubular steel frame.

“Yes,” he responded. “Also for the rider, it was not easy to jump to this bike. It gives you a different feeling, this frame, and I needed to learn first how I felt with this bike, and then I needed to make a lot of laps to see exactly how to give the right comments on which way we need to go on the development. It has also been a big challenge for me, to learn the bike and this feeling that this frame gives.”

Would it take Espargaro and Smith some time to get to grips with the different frame?

“I believe it will take a few laps more to understand, but there’s no problem, anyway. We have been testing many different kind of frames, about the stiffness and that kind of thing, and there were some interesting things that we could find.”

Why Throw Away What You Know?

The reason for choosing a tubular steel frame over an aluminum beam frame was simple: KTM has a vast amount of knowledge and experience with this kind of frame, which they would be throwing away if they went with an aluminum chassis.

“KTM has a lot of history with this tubular frame,” Kallio said. “I think they know what they are doing, so I believe that there is something how we can be better than the competitors. Like we saw in the other races in the past, Ducati was using a same kind of tubular frame and they were fast. So I don’t see any problem why we can’t be OK with that.”

The fear of using a tubular steel frame was that the many different components and welds would make it difficult to produce two identical frames. Kallio told us he had never noticed that problem.

“I was impressed that all the bikes that I tested, I felt different, and then if there were two similar frames, I couldn’t feel the difference between the bikes.”

That is not to say that KTM did not consider an aluminum beam frame. “Already in past projects, like Moto3, of course we were considering it,” KTM Technical Director Sebastian Risse told me.

“There we also had the experience from 125 and 250. So it was a decision which was really well thought through. We even had some aluminum frames running, but in the end, it was a conscious decision. We know more about the steel frame, we didn’t find any disadvantages, we knew our strong points and can use them, and we know also what to work on to reach the similar level to aluminum.”

Winning by Being Different?

Can the KTM RC16 be a competitive package in MotoGP? Given the Austrian company’s approach and success in other areas, there is no reason they will not succeed in the premier class.

They have dominated almost every series they have entered, first in off-road disciplines, and now in road racing. As KTM continues to grow, they have the budget and the knowhow to build competitive motorcycles. They have the backing of Red Bull, and a healthy balance sheet to invest.

KTM wants to make a mark as the premier European sports motorcycle brand. Success in MotoGP has become a cornerstone of that objective. They have learned from previous failed projects, and from success in Moto3.

They are doing so while trying to retain their identity, sticking to steel tubular frames and WP suspension rather than just copying others. That, in itself, is to be applauded.




Photo: © 2016 Scott Jones / Photo.GP – All Rights Reserved

This article was originally published on MotoMatters, and is republished here on Asphalt & Rubber with permission by the author.