Scoop: This Is What Ducati's Holeshot Device Looks Like

The eyes of the MotoGP world have been on Ducati over the past few months, as they have rolled out new and surprising (not to mention controversial) engineering ideas on the Desmosedici GP19. At the Jerez test, there was an aerodynamic seat, and a brake torque arm connected to the rear chassis, and more.

But up until four manufacturers protested Ducati's use of an aerodynamic spoiler attached to the swingarm during the first race of the season at Qatar, all the talk had been of Ducati's so-called holeshot device. It first came to public attention when Ducati riders were spotted stopping at the exit of pit lane at Sepang, and twisting a lever on the top plate of the triple clamp (shown below) before practicing their starts.


Key for engaging the holeshot device

With fans and media alerted to its existence, TV cameras started keeping an eagle eye on the Ducatis, focusing closely every time they made a practice start. Each time we saw one, we learned a little more. That the lever took some effort to engage. That the riders were compressing the suspension when they stopped, to make it easier to twist the lever. And that the rear of the bike was significantly lower when the holeshot device was engaged.

Public knowledge of the holeshot device also confirmed earlier rumors which had been doing the rounds of the paddock. As more information leaked out, we could start to piece together a history of the part's development, and how it worked. And now, I have come into possession of a photograph of the holeshot device.

Naturally enough, I turned to friend and technical guru Peter Bom for advice and explanation. Former world championship winning crew chief, Peter has a keen intelligence and an excellent understanding of what a racing motorcycle can do, and should do. He explained to me what he thought the holeshot device was, and how it worked. The information below is based on his analysis of what he can see in the photo.

But first, some history. The holeshot device made its first appearance at the Motegi round last year, where Jack Miller used it on his Pramac Ducati. Miller used it for the rest of the season – with the exception of Phillip Island, where the braking for Turn 1 is not severe enough to disengage the mechanism after the start – and in 2019, it has now appeared on all of the Ducati GP19s, at the very least.

The device functions as follows: before the start of the race (or before a practice start), the rider uses their weight to compress the suspension, then twists the lever to engage the mechanism. The mechanism then locks the rear suspension in a lower position for the duration of the start. When the rider arrives at the first corner, and brakes hard before entering the turn. That hard braking causes the rear to lift, which in turn triggers the unlocking mechanism, which frees the device and returns the rear suspension to its normal operation.

It is something of a surprise that Ducati's holeshot device locks the rear suspension down, rather than lifting it up. Holeshot devices are common in motocross, but there, they lock the front forks down, rather than up. The idea there is to keep the front lower to help prevent wheelies, making it easier to control the bike off the line.

But Ducati's device appears to do the opposite, lowering the rear, rather than the front. Much to the surprise of Peter Bom, who had expected a holeshot device to focus on reducing wheelie.

That the device lowers the rear suggests to Bom that it serves a slightly different function, and that Ducati is not looking to reduce wheelie, but rather to increase rear grip. By lowering the rear of the bike, they place more weight on the rear tire, creating more mechanical grip. The fact that the Ducati is longer and lower than most other MotoGP bikes (also the reason the bike still suffers from understeer) may explain why Ducati is searching for rear grip, rather than trying to reduce wheelies.

So what exactly is this device? The photograph (shown below, for subscribers only) which came into my possession shows that the device is what looks like a miniature shock absorber which sits in the place where the suspension link would normally. The adjustable link (see the bottom of the page) is replaced by either a hydraulic or mechanical cylinder assembly, which joins the bottom of the suspension linkage to the swingarm. It looks like a hydraulic or mechanical actuator.

To see the photo of the holeshot device, you need to be a subscriber. You can find out more about subscribing to MotoMatters.com here.

Two things are visible in the photo. First, the piston / plunger. This is clearly an actuator, the mechanism which helps to change the length of the suspension linkage before the start, lowering the rear of the bike. The second, on the right, is a spring, which presumably operates the return mechanism.

When the rider turns the lever on the triple clamp, that must move the pushrod inside the cylinder to shorten the linkage and lower the rear. That, in turn, must put the spring under tension, which releases the mechanism under hard braking.

While the device is clearly the fruit of some highly innovative thinking. It also raises some questions. The link plays a vital role in managing the suspension ride height, and is subject to significant forces. After the holeshot device has been released after braking for the first corner, the system has to return to the position it was set up for, and remain there. It should not shift, changing the ride height which the team have settled on during practice. This means that Ducati have to be certain that the device will lock solid again after it has been released.

The addition of this actuator to the suspension linkage opens up some intriguing possibilities. In theory, it would be possible to adjust ride height during the race. However, as electronic adjustment of the ride height is explicitly banned, it could only be adjusted manually, or via mechanical/hydraulic adjusters.

Will other manufacturers follow suit? As Peter Bom points out, this device lowers the rear, rather than raising it, adding grip rather than reducing wheelie. For most other manufacturers, controlling wheelie at the start would be much more important, meaning their device would have to do the opposite to Ducati's holeshot device. That would make releasing the rear under braking much more complicated, as it would already be extended before the rider started braking. Discerning when to release the mechanism would be much more difficult.

Here is what a standard suspension link looks like, courtesy of Tom Morsellino of Offbikes:

This is the sort of article which our MotoMatters.com subscribers have access to. You can find out more about subscribing to MotoMatters.com here. You can find all of our exclusive subscriber content here, and see what you have been missing out on.

year: 
2019
Total votes: 19
Total votes: 9

Back to top

Comments

It almost looks like the plunger limits the movement range of the linkage not replaces part of it. My guess would be the lever on the triple clamps locks the plunger in place, then when the front end dives under brakes, another (unseen) doohickey at the front end unlatches the triple clamp lever, and the spring returns the plunger out of the way so the linkage regains its full range of motion... maybe?

Total votes: 4

I think you are spot-on with the plunger limiting the movement of the linkage, keeping it in a position of partly compressed rear suspension. Smart thinking. That seems like a much easier thing to make, too, with less complications!

Also, the plunger going back is probably triggered somehow by front end dive, I agree. That the plunger would return because of the rear lifting seems unlogical (although desirable). It could be done, but then it would have to be because of the pushing force on the plunger exceeding a certain limit, by the weight of the rear no longer taking a part of the compressing force on the rear spring. In that case however, there would be no need for a small return spring that apparently is there. A more reliable way of deactivating would seem to me a form of taking the load off the plunger, so it can extend a little bit and thereby get unlocked, like with many ratchet systems. But this is just guesswork on my part.

Total votes: 5

This kind of reminds me of the Canyon Spectral mtb.  They've been running a small air shock in the linkage for the past few years which changes the geometry and travel of the bike.  The device is activated via a thumb lever on the handlebar.  Ducati's set up seems like an even more complex iteration of that basic idea.  

Total votes: 43

Wow, this popped to mind as I was reading this too!  The system is called the Shapeshifter on the Strive rather than Spectral.  Ducati's seems to be a reverse of this as you load the rear (after clicking a lever) to release the system on a mountain bike.

Total votes: 1

Interesting, thanks!
Always ran x-country mtb bikes on single track, able to pick through technical sections. Then, when downhilling in earnest, envied the long raked geometry as I skittered like a Honda. Had no idea this existed. Cool!

Past tense of "beat everyone to T1?"
HOLESHAT
:)

Total votes: 2

I think this analysis is fundamentally wrong. Lowering the rear does indeed decrease wheelies, although this may seem counter-intuitive to some. It's simple: by lowering the rear, you lower the centre of gravity, thus reducing the wheelie tendency. It basically does the same as the motocross version, which also lowers the centre of gravity. Raising the rear may look like you put the nose down, but of course it does not. By raising the rear, you raise the centre of gravity, especially since you lift the rider up as well. Higher bike, higher rider position, more wheelie. That's why they make drag racing bikes so low. Have you ever seen a drag bike with a high rear?

Total votes: 18

You add an interesting comparison though. Indeed does an anti-dive system result in less possible deceleration because of the higher centre of gravity. I had never thought of that. Just never liked the BMW's with Telelever and (to a slightly lesser degree) Duolever because of their braking characteristics, next to the general lack of feel.

Total votes: 1

Its not a surprise that it locks the back in a lower position, its about getting the centre of gravity as low as possible. Wheelie tendancy comes from the torque or moment that a launch causes - there is only the thrust force and the lenght of lever (height of the CoG) to play with - you either lower the thrust (nobody wants to do that) or lower the CoG. Drag bikes will aim to have their sumps barely off the ground. The same principle is what killed off anti-dive systems, keeping the forks extended lowers the point at which the rear wheel will start to lift. Bikes are a big old ball of compromises.......

 

Total votes: 7

Such a device would be awesome on their road bikes.  First to the head of the queue at Starbucks or into the kitty litter, as the case may be. 😁

Total votes: 3