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Cormac In The Sepang Pits: The Sepang Test In All Its Technical Glory, With Explanations

By David Emmett |

 
Is this a Ducati GP24 or a Ducati GP25? At the moment, the answer to that question is "yes".

 
Yamaha frames and swingarms that haven't yet been anodized usually means that they are new, though not necessary prototypes. This looks like a new swingarm design for Jack Miller to test

 
The biggest problem in motorcycle design is packaging. There is a lot of stuff to pack into a small space. 
Here is the Aprilia RS-GP without the front bottom fairing fitted. You can see the two large exhaust headers, with a balance pipe just ahead of the fairing 
The bottom radiator is the oil cooler. You can see the pipes running too and from the cooler, and what looks like an oil filter. The fact that there is duct tape on the oil cooler is a sign of how unseasonably cool it was at Sepang

 
Yamaha's side fairing looks largely unchanged from last year. But as the manufacturers get a better and better handle on aerodynamics, changes made are increasingly subtle

 
That doesn't always hold true of course. Here is the new aero on the Honda HRC Castrol bike, complete with large tail section. 
It's hard to see because it's black carbon, but if you zoom in you will see very large downwash duct, and middle wings which are very swept back rather than more vertical. 
At the rear is the large tail section, which some observers believe contains a mass damper. We do know that HRC have also been experimenting with weight distribution, placing heavy components in the tail. 
Whether these elements will be raced is still open to question. By the last day, all of the Honda riders had gone back to what looked like the Barcelona 2024 aero and tail.

 
Speaking of mass dampers, here's the massive box on the back of the KTM RC16. "It's a toastie maker" one paddock wit quipped. 
In all likelihood, this too is a mass damper. Judging by Friday afternoon, this has a better chance of being raced, as it was still present on some bikes.

 
For the first time, Yamaha have also started using a pitot tube to measure aerodynamic wind speed. This protrudes a good deal further forward and away from the fairing than the items used by Ducati and Aprilia

 
The rear end of the Aprilia RS-GP. Changes to carbon fiber swingarms are much harder to spot than on aluminum items, as you can radically change the dynamics of CF by changing the layers and direction of the layers. 
Aprilia were also experimenting with exhausts, and especially with end cans. 
Just above the exhaust, ahead of the mounting bracket and where the welds are, you can see a small pipe leading forward. This is probably connected to the crankcase, and serves to help suck air out of there to reduce parasitic losses

 
Fastest bike on the grid: The Duati Desmosedici GP24

 
Spot the difference with the factory Ducati Desmosedicie GP24/5

 
The Yamaha M1 outside the Prima Pramac garage. A new frame, but not a prototype (the frame stamp said 2025, not 2025 test). Ignore the fat idiot in the background

 
The difference between being a satellite rider and a factory rider is the number of people listening when you speak.

 
Nothing says testing quite like black carbon fairings and duct tape. The duct tape is holding a couple of horizontal blades channeling air back. Note also the much larger tail fins on the Aprilia RS-GP.

 
This too is testing: pushing hard enough for it to hurt. Jack Miller pushes his Yamaha M1 out of a gravel trap, with the help of a marshal, the true heroes of racing.

 
KTM are continuing with the shark-tooth rear winglets to reduce turbulence and create downforce on the rear wheel.

 
Fabio Quartararo discusses with his crew whether to go with a barrel cuff or a French cuff on his line of formal evening wear. Or possibly an electronics setting.

 
Another look at the large box on the tail section of the KTM RC16. Also visible, the new, long exhausts on the KTM, completely with EXUP-style back torque valve.

 
The mess of hydraulic cylinders, lines, cables and valves may weight a ton, and be a nightmare for the mechanics to have to deal with, but the speed gains are so significant it is all worth it. 
Having all this gubbins in the front of the fairing may also be the explanation for the Ducati having such a bulky tail. There may be a mass damper in the 'salad box', but they need the weight back there to counterbalance the mass of pistons in the front.

 
By contrast, the KTM nose is more traditional. Datalogger, electronics, and Dorna's telemetry unit. KTM's 3D printed connector blocks remain one of the most elegant solutions on the grid. A joy to see how well it all fits together.

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PhotoPage
CormacGP
MotoGP
Sepang, Malaysia
Aprilia
Ducati
Honda
KTM
Yamaha

This is truly fine photographic and journalistic work. As they say, a picture tells a thousand stories and clever captions make them even more enjoyable. You and David complement each other perfectly.

Many thanks Cormac and Dave for the great pics and technical insights!

In the last photo above, of the KTM's steering head area, you can see some aluminum cylinders that seem to be extensions of the forks. Dean Adams over at Superbike Planet also called these out in this photo:

KTM fork-tops

He theorizes they are accumulator canisters that give the fork tubes additional active volume/travel to absorb bumps when the shocks are already compressed (maybe when the front ride height device is engaged). He points out that (once again) this has been in use in MX for some time.

Any other theories?

Fabio Quartararo's bike looks like it has two tyre valves on the back wheel. In the photo with Kropotkin in his shorts. What is that about. 

Any intel ? Dirt bike technology that. 

The bikes have had two valves since the tire pressure rules were introduced. One has the pressure sensor favored by the manufacturer, the other has the official tyre pressure sensor. The teams also "wash" the air in the tyre by blowing dessicated air in one valve and out the other.

The Yamaha exhaust and adjacent swingarm are pure art. The KTM exhaust? Well hopefully it works but otherwise it literally looks like plumbing. And the KTM tailfin on the swingarm takes me back to when I was a toddler and cars with tails like that roamed American roads and frightened young children. 

Gawd, you can’t help but marvel at the minds of engineers let completely off the leash. Much of it is pure function over form but every now then there is a lil’ something that is just an exquisite combination of both. 
I know, praise all gods, the ride height malarkey is disappearing soon-ish but the requirement to make this stuff hydraulic has been an expensive exercise in futility. The initial premise seemed to be the imposition of engineering difficulty: what sane manufacturer would choose to throw vast sums of money down a development cul de sac? The answer was obviously the reverse: what sane manufacturer who wanted to win would NOT go down that dead end? 
So my mind does crocodile rolls that we’re still dealing with hydraulics, when any practical real world application would use levels of magnitude cheaper electronics/actuators. It would save everyone a fortune. 
I mean, it’s not like we’ll EVER see ride height devices as a dynamic component in the real world: no manufacturer is going to give that sort of control to any Tom, Dick or wannabe Fabio with enough money to purchase a Superbike. We’ve already seen the issues with the best riders on the planet struggling to engage/disengage them appropriately, now imagine the issues of Joe/Joanne Citizen and a bike that’s done 10,000/20,000km on salt encrusted Winter roads. 
The lawyers would be salivating like Sylvester ogling Tweetie Bird. 
I hate the stuff, but once the technological cat was outta the bag, they should have at least acknowledged the situation and allowed a cheaper electronic option. 
 

 

Yes they do, but they are only used (AFAIK) to lower the bike when coming to a stop, to make it easier for the rider to get both feet firmly on the ground. Great for shorter riders. Once moving, the bike comes back up and stays there until the next stop. So not a dynamic function when moving, or performance related in any way.

The key word I used is “dynamic”. 
It’s one thing pottering along a dirt track at sub-30mph and the ride height device (or rider) screws up…it’s a very different thing piling into a corner at 150mph.  
The “ride height” aspect, associated with simply climbing astride a “too tall” adventure bike, is in a  completely different universe to a 240hp superbike (potentially) equipped to improve corner exit/entry at massive speeds…. which also happens to completely screw up the bike dynamics if engaged/disengaged inappropriately. 
Bearing in mind there is no competency required beyond being able to sign a cheque. 
The “potential for misadventure” is far too high to ever be entrusted to the general public.

Just my gumby opinion, I’m happy to be corrected if folks think I’m wrong.

BMW, Ducati, KTM have all had some kind of autoleveling suspension system for a while. This is basically an electromotor which adjusts preload. It does that infrequently (basically when you start riding, then if the rear suspension sensor (yes, my GS has one, very trick) detects that the shock has compressed). 

That has now morphed into adaptive ride-height on (from memory) the Harley-Davidson Pan American (and hats off to H-D for building that bike) and now also the BMW R1300GS. Revzilla did a good explanation on how the H-D system work in this video (it's very clever actually).

Thanks man, nice to lead something even if it’s only talking bullshit.

Nah, the motogp rules are a weird mix of the practical, to the obtuse, to the downright weird. 

I mean, I can (and do) run 7075-T6 axles in my track bikes (alloy, 1/3 weight but equivalent strength to mild steel) but they’re illegal in motogp, cheap dual clutch gearboxes are illegal forcing teams into unobtainium seamless gearbox alternatives, a windscreen longer than 300mm is verboten etc etc. But the whole “zero electronic controls”, seems like Dorna are stuck in 1995 not 2025: electronic controls are now faaaar cheaper than any alternative, so why maintain the mantra?
This is why I struggle with people calling Motogp a “prototype” series: there are some incredible things happening (search Dave’s friends, the Oxley Bom Motogp Podcast dissecting “Squiggly Lines”). 
There is just too much antiquation, too many hsngovers from the past, to ever call MotoGP a free for all…and isn’t thst what a true prototype series should be?

….and with that drunken diatribe the Reverend Rantalot has left the building.

While I can open the photos in a new tab, they aren't the usual high-res ones. I know this is usually related to subscription issues, but I can access all the subscriber content and the Sepang Test riding style comparison article gives me the full-fat pictures, so I'm just curious if this article doesn't have those.

On the picture of the Yamaha test rider with the pitot tube: at the swingarm, behind the axle nut and above the paddock stand bracket, what is that relatively large silver thing? It has two large bosses sticking out of it, it's got a bracket to capture it behind the axle nut, and it looks very out of place. Another measurement device I assume?

 

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Comments

This is truly fine photographic and journalistic work. As they say, a picture tells a thousand stories and clever captions make them even more enjoyable. You and David complement each other perfectly.

Many thanks Cormac and Dave for the great pics and technical insights!

In the last photo above, of the KTM's steering head area, you can see some aluminum cylinders that seem to be extensions of the forks. Dean Adams over at Superbike Planet also called these out in this photo:

KTM fork-tops

He theorizes they are accumulator canisters that give the fork tubes additional active volume/travel to absorb bumps when the shocks are already compressed (maybe when the front ride height device is engaged). He points out that (once again) this has been in use in MX for some time.

Any other theories?

Fabio Quartararo's bike looks like it has two tyre valves on the back wheel. In the photo with Kropotkin in his shorts. What is that about. 

Any intel ? Dirt bike technology that. 

The bikes have had two valves since the tire pressure rules were introduced. One has the pressure sensor favored by the manufacturer, the other has the official tyre pressure sensor. The teams also "wash" the air in the tyre by blowing dessicated air in one valve and out the other.

The Yamaha exhaust and adjacent swingarm are pure art. The KTM exhaust? Well hopefully it works but otherwise it literally looks like plumbing. And the KTM tailfin on the swingarm takes me back to when I was a toddler and cars with tails like that roamed American roads and frightened young children. 

Gawd, you can’t help but marvel at the minds of engineers let completely off the leash. Much of it is pure function over form but every now then there is a lil’ something that is just an exquisite combination of both. 
I know, praise all gods, the ride height malarkey is disappearing soon-ish but the requirement to make this stuff hydraulic has been an expensive exercise in futility. The initial premise seemed to be the imposition of engineering difficulty: what sane manufacturer would choose to throw vast sums of money down a development cul de sac? The answer was obviously the reverse: what sane manufacturer who wanted to win would NOT go down that dead end? 
So my mind does crocodile rolls that we’re still dealing with hydraulics, when any practical real world application would use levels of magnitude cheaper electronics/actuators. It would save everyone a fortune. 
I mean, it’s not like we’ll EVER see ride height devices as a dynamic component in the real world: no manufacturer is going to give that sort of control to any Tom, Dick or wannabe Fabio with enough money to purchase a Superbike. We’ve already seen the issues with the best riders on the planet struggling to engage/disengage them appropriately, now imagine the issues of Joe/Joanne Citizen and a bike that’s done 10,000/20,000km on salt encrusted Winter roads. 
The lawyers would be salivating like Sylvester ogling Tweetie Bird. 
I hate the stuff, but once the technological cat was outta the bag, they should have at least acknowledged the situation and allowed a cheaper electronic option. 
 

 

Yes they do, but they are only used (AFAIK) to lower the bike when coming to a stop, to make it easier for the rider to get both feet firmly on the ground. Great for shorter riders. Once moving, the bike comes back up and stays there until the next stop. So not a dynamic function when moving, or performance related in any way.

The key word I used is “dynamic”. 
It’s one thing pottering along a dirt track at sub-30mph and the ride height device (or rider) screws up…it’s a very different thing piling into a corner at 150mph.  
The “ride height” aspect, associated with simply climbing astride a “too tall” adventure bike, is in a  completely different universe to a 240hp superbike (potentially) equipped to improve corner exit/entry at massive speeds…. which also happens to completely screw up the bike dynamics if engaged/disengaged inappropriately. 
Bearing in mind there is no competency required beyond being able to sign a cheque. 
The “potential for misadventure” is far too high to ever be entrusted to the general public.

Just my gumby opinion, I’m happy to be corrected if folks think I’m wrong.

BMW, Ducati, KTM have all had some kind of autoleveling suspension system for a while. This is basically an electromotor which adjusts preload. It does that infrequently (basically when you start riding, then if the rear suspension sensor (yes, my GS has one, very trick) detects that the shock has compressed). 

That has now morphed into adaptive ride-height on (from memory) the Harley-Davidson Pan American (and hats off to H-D for building that bike) and now also the BMW R1300GS. Revzilla did a good explanation on how the H-D system work in this video (it's very clever actually).

Thanks man, nice to lead something even if it’s only talking bullshit.

Nah, the motogp rules are a weird mix of the practical, to the obtuse, to the downright weird. 

I mean, I can (and do) run 7075-T6 axles in my track bikes (alloy, 1/3 weight but equivalent strength to mild steel) but they’re illegal in motogp, cheap dual clutch gearboxes are illegal forcing teams into unobtainium seamless gearbox alternatives, a windscreen longer than 300mm is verboten etc etc. But the whole “zero electronic controls”, seems like Dorna are stuck in 1995 not 2025: electronic controls are now faaaar cheaper than any alternative, so why maintain the mantra?
This is why I struggle with people calling Motogp a “prototype” series: there are some incredible things happening (search Dave’s friends, the Oxley Bom Motogp Podcast dissecting “Squiggly Lines”). 
There is just too much antiquation, too many hsngovers from the past, to ever call MotoGP a free for all…and isn’t thst what a true prototype series should be?

….and with that drunken diatribe the Reverend Rantalot has left the building.

While I can open the photos in a new tab, they aren't the usual high-res ones. I know this is usually related to subscription issues, but I can access all the subscriber content and the Sepang Test riding style comparison article gives me the full-fat pictures, so I'm just curious if this article doesn't have those.

On the picture of the Yamaha test rider with the pitot tube: at the swingarm, behind the axle nut and above the paddock stand bracket, what is that relatively large silver thing? It has two large bosses sticking out of it, it's got a bracket to capture it behind the axle nut, and it looks very out of place. Another measurement device I assume?