MotoMatters.com | Kropotkin Thinks

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Fans and media have been waiting for the 2027 MotoGP technical regulations with a mixture of hope and trepidation. Though the racing has been close the past couple of years, and even exciting, the unstoppable advance of aerodynamics paired with the sudden ubiquity of ride-height devices has changed the sport enormously.

On Monday, Dorna and the FIM announced the details of the new rules. It was, by and large, as expected: 850cc engines with a maximum of 75mm bore, with less fuel and fewer engines. To the delight of many - including many fans, MotoGP insiders, and no doubt also riders - ride-height devices and holeshot devices have been completely banned, and aerodynamics has been severely curtailed (for the moment, at least, but more of that later). For the full details, read the story posted earlier today, which lays out the exact changes so far.

The question on everyone's mind is, of course, what will the 2027 bikes look like, and how will they affect the racing? With the caveat that rule changes tend never to work out quite as intended - even as we speak, engineers in the various factories are scouring the rules to find what the rule makers have overlooked - we can try to guess at the effect the rules will have on the bikes, and the intentions of those who drew them up.

First, perhaps, a refresher on how the rules are made. Technical regulations are fixed (except for minor adjustments) for a period of five years at a time. Dorna agrees contracts with manufacturers in which they commit to supply bikes for five years, and having technical rules frozen helps the factories to manage costs. We are currently in the middle of the contract period which runs from 2022 through 2026.

The process as set out in the rules is that the promoter of the championship (Dorna), the governing body (the FIM), the teams (IRTA), and the manufacturers (the MSMA) negotiate a set of rules they are all happy with. Dorna puts forward proposals which it hopes will steer the championship in the direction which will help them promote it, and allow it to continue successfully. The MSMA discuss those proposals and put forward counter proposals to address those concerns, but also allow them to achieve their goals in terms of marketing, research & development, and training their engineering staff. And once the MSMA are unanimous about a set of rules and Dorna can accept them, they are put to the Grand Prix Commission (where Dorna sit with the MSMA, IRTA, and the FIM) for a vote.

The start of each five-year contract period is the only real opportunity for Dorna to steer the rules. At other times, the MSMA retains a veto over the technical rules, as long as they are unanimous. But at contract time, Dorna have much greater input into the rules. At the end, of course, both Dorna and the manufacturers want a set of rules they are all happy with. Dorna wants the factories to be racing in MotoGP for the status of the championship, and the factories want the championship to be challenging enough to be interesting without the cost of competing spiraling out of control.

All four parties involved agreed that the biggest challenge facing MotoGP at the moment is the ever-increasing speeds the bikes are reaching. It has been a topic of conversation among senior MotoGP officials almost since I entered the paddock full time fifteen years ago. Since then, the bikes have only gotten faster, culminating in Brad Binder hitting 366.1 km/h at Mugello last year. As speeds increase, the circuits need more runoff. And at current speeds, the tracks are running out of physical room to create more runoff, due either to geography (hills, slopes, and cliffs) and economics (the cost of purchasing extra land to make space for runoff).

That issue is what the set of rules agreed for 2027 are aimed at addressing. The objective is to lower top speeds. The simplest way of reducing top speeds is to limit the amount of power the engines make. And the quickest way to do that is to reduce capacity. Hence the drop from 1000cc to 850cc.

We have been here before, of course. In the early part of this century, after MotoGP switched from 500cc two stroke engines to 990cc four strokes, the same worry arose. The bikes were simply going too fast. So for the 2007 season, capacity was reduced to 800cc.

It is fair to say that the capacity reduction did very little to make the bikes slower. At the first race of the 800cc era, in Qatar, Casey Stoner broke the race lap record by eight tenths of a second, and Valentino Rossi broke the pole record by nearly seven tenths. In terms of top speed, Alex Barros was 3km/h slower on the Ducati GP7 (316.3 km/h) than Dani Pedrosa on the 990cc Honda RC211V (319.8 km/h) the previous year. And he was 1 km/h slower than Loris Capirossi on the Ducati GP6 (317.3 km/h). For comparison, in 2024, Jack Miller hit 360 km/h in the sprint race.

Reading the 2027 technical regulations, it is clear that the rule makers have learned the lesson of the 800cc era. Yes, MotoGP is reducing capacity again, but the way capacity is being reduced, and the other changes to the rules, are aimed at avoiding the blind pursuit of revs and horsepower, with power being managed with electronics.

In 2007, the only restriction on the engines was limiting engine size from 990cc to 800cc. What happened was that the manufacturers shortened the engine stroke and kept the bore pretty much the same, making the engines massively oversquare, with bores around 86mm. That allowed the engines to rev to dizzy heights, over 21,000 RPM in some instances. Honda and Yamaha were forced to ditch their steel valve springs for pneumatic valves as engine life dropped as low as 300km and valve springs had to be replaced at the end of each day.

For 2027, engine capacity has been reduced by reducing the bore, from 81mm to 75mm. That allows the engines to keep almost the same stroke: 48.5mm for the current generation of 1000cc MotoGP machines, where the 2027 850cc bikes will use a stroke of 48.1mm. The 850cc engines will rev to roughly the same level - between 18,000 and 19,500 RPM - that the 1000cc bikes do.

The reduction in bore size will have an impact on engine character, however. Smaller bore size means smaller valve sizes, and smaller valve sizes mean faster air flow through the valves, more swirl in the chamber, and better combustion. It will allow the engines to run less advance, meaning more of the combustion is converted into power, rather than lost by burning before the piston has reached TDC.

75mm bore engines will have better combustion efficiency, but that efficiency will be highest at lower revs. In effect, the 850cc engines will have more torque over a wider rev range than the larger engines.

Another change to the engines point in the same direction. For 2027, the number of possible gear ratios has been drastically reduced, from 24 to 16. Having 24 different gear ratios allows engineers to more precisely match the gearbox to a specific track. In effect, it makes it easier to keep the engine inside a narrower power band at each circuit.

Having only 16 different ratios to choose from means that you are a little bit further away from optimal in most circumstances. And the way to handle having the wrong gear ratio is to have more torque, and a wider spread of power. That gives you more leeway with your gearing, and means the rider is less likely to be caught with an engine just outside its power band.

As an illustration of how this changes, think of the different demands of the Sachsenring: tight, twisty, slow in most places with a low top speed; Mugello: fast, open, and flowing, where you are mostly in higher gears and a lot of throttle; and Spielberg: big, fast straights, with a lot of hairpins and tight corners, where you are going from low gear to high gear and high top speeds.

At the Sachsenring, you need a close ratio gearbox with a relatively short sixth gear and low final drive gearing. At Mugello, you need a gearbox with ratios slightly more spread out, and a very long top gear. At Spielberg, you need a wide ratio gearbox and long top gear to accommodate the tight hairpins and fast straights, and still be able to accelerate efficiently.

Reducing the number of possible gear ratios to choose the six allowed at each race becomes much more difficult with just 16 available. And you have to compensate for that with more torque.

The reduction in fuel capacity, from 22 liters to 20 liters in the main race and 12 to 11 liters in the sprint race, will play a role here. In 2007, fuel capacity was reduced as well, but the difference then was that each factory could use their own proprietary software. Manufacturers focused on saving fuel in braking and partial throttle to give them more top end horsepower. In 2027, factories will still be using the spec Magneti Marelli ECUs and software, which does not allow such fine control.

A greater focus on torque will also be needed to compensate for the loss of ride-height devices. These have had a huge impact on both acceleration out of corners and braking, by lowering the center of mass and reducing wheelie. They have effectively given the MotoGP engineers a lot of acceleration and drive out of corners for free, and allowed them to get more out of the tire without increasing consumption. They have increased the amount of usable thrust.

Having found that acceleration from geometry rather than engine, the manufacturers were able to change the nature of the engines to produce more horsepower. And that additional horsepower allowed them to run more aerodynamic downforce, which again helped with acceleration by reducing wheelie.

Without the ride-height devices, factory engineers will have to find different ways to get drive out of corners. And the easiest way to do that is by producing more usable torque, generating more thrust, from a more manageable engine. Engine character will play a bigger role in tire consumption again. And a bigger role in racing.

The removal of the ride-height devices will also affect bike design as well. When the rider operates the ride-height device, the rear of the bike drops, reducing the space between rear wheel and fuel tank (which is under the seat) and seat unit. Because of the way the device operates, the bike still has its full degree of suspension travel, so the seat and tank have to be designed such that if the rear suspension compresses, the rear wheel will not hit the tank or seat unit.

Without having to take ride-height devices into account, the seat unit can be lower and the fuel tank can be moved further back. It will once again be able to locate the fuel tank closer to the center of mass, without making uncomfortable compromises.

The steps to reduce aerodynamic surface are interesting, but how effective they are on reducing downforce and the focus on aerodynamics is open to question. Smaller bore engines will have less horsepower, and require less aerodynamics, and also make the cost of running more downforce higher (there is much less excess horsepower with which to overcome drag).

However, the aerodynamics genie is very much out of the bottle, and aerodynamics is now an integral part of MotoGP bike design. Having a narrower maximum width, less taper of the lower fairing, and allowing the nose to protrude less far forward will take away easy sources of downforce. But factory aero engineers will find other ways of generating usable downforce, and it is unlikely they will have much effect on the ground effect fairings and downwash ducts.

What we can expect is that the bikes will look as if they have less aero on them, when viewed from the perspective of 2024. But the aero they do have will be different, and will be doing slightly different things.

The goal of Dorna was to reduce aero for 2027, but not eliminate it entirely. Aerodynamics is what sets MotoGP apart from WorldSBK, and makes the bikes look special (whether that is special in the ugly sense or special in the magical sense is up to the eye of the beholder).

Will the 850cc MotoGP bikes in 2027 follow in the path of the 800cc bikes of two decades previously? Will corner speed be king and bikes be as fast as ever? We won't know for sure until they actually hit the track, of course, but it looks like the rules have been designed to try to focus on acceleration rather than corner speed, torque rather than power. The removal of ride-height devices will put more into the hands of the rider, and the removal of holeshot devices will make starts more difficult, and reduce the importance of qualifying on the front row.

Seen from the viewpoint of 12 hours after the rules were announced, there is reason for cautious optimism. But if there is one lesson we have learned from MotoGP over the years, it is that manufacturers find holes in the rules to exploit, and find avenues to explore that we have not yet imagined. Placing restrictions on engineers is one of the best ways of stimulating their creativity. I for one am eager to find out what creations they will come up with.

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