Thursday, February 21, 2008

MotoGP versus World Superbike

With the World Superbike series about to start, the debates about WSBK versus MotoGP will kick off again. Both types of bike look broadly similar, and both contain the same list of manufacturers, so what's the diff?

MotoGP is considered the pinnacle of motorsport, with all of the bikes being racing prototypes. You can't buy a MotoGP bike for love nor money. They contain the latest cutting edge technology, and by definition bear very little resemblance to a road bike. MotoGP bikes are designed directly by the manufacturer. Smaller teams may lease bikes from a factory.

WSBK on the other hand, is a production-based series, that is to say the bikes start off as road bikes identical to those in showrooms across the world. They are stripped down, tuned up and fitted with various racing components, but if you had the time and the money you could buy a bike and upgrade it to World Superbike specifications. The emphasis in WSBK is on close racing, and lots of it. Ducati run a factory team, while most of the top teams are semi-factory (usually run by a national bike importer with help from the factory) and there are also independent privateers.

MotoGP bikes have a prototype chassis designed especially for racing. This means it is extremely stiff and highly configurable. Teams can make dozens of tiny changes to the suspension geometry to tune the setup precisely to the rider's needs.

WSBK bikes have the same chassis as the road-going version of the bike. Some extra pieces may be added to help strength and stiffness, but nothing structural can be removed. This means that the chassis is less stiff than a MotoGP bike, and less configurable.

MotoGP engines are specially designed prototype units, having a maximum capacity of 800cc. The major parts of the engine must not be based on any road-going engine. Although the number of cylinders is not restricted, all teams currently use 4-cylinder engines in either V4 (Ducati, Honda, Suzuki) or Inline 4 (Yamaha, Kawasaki) configurations. Suzuki, Kawasaki, Yamaha and Honda either use pneumatic valve springs or are using steel springs while they develop a pneumatic system. Ducati use desmodromic valves (the valves are actively pushed open and pushed shut, rather than being actively pushed open and allowed to spring shut). MotoGP engines are said to produce at least 220bhp at the crank.

World Superbike engines are highly tuned and modified versions of road-going engines. There are strict rules as to which parts may or may not be changed. All WSBK engines use steel valve springs, except for Ducati who use a desmodromic system. The Japanese bikes use Inline-4 cylinder engines with a maximum capacity of 1000cc, with the best producing an estimated 220bhp (equal to a MotoGP machine). Ducati run V-twin engines with a capacity of 1200cc. Initially in 2008, Ducati will have to run 50mm air inlet restrictors to limit power to around 200bhp. This is an attempt to compensate for Ducati's capacity advantage, and the restrictor size may be varied during the year to keep performance on a par with 4-cylinder machines.

MotoGP machines use a pair of 320mm diameter carbon brake discs at the front. These are extremely light, which reduces unsprung mass, improving handling over bumps and reducing the gyroscopic effect (which makes a motorcycle try to carry on in a straight line and resist turning). Carbon brakes also have very high stopping force, but only once they have come up to working temperature. The rear brakes are small and made of steel as most riders just use gentle rear braking to stabilize the bike. Nicky Hayden uses a larger rear brake due to his riding style, but it is still far smaller than the front disc.

WSBK machines use a pair of 320mm steel front brake discs. These are heavier and less effective than carbon discs, meaning the stopping distances are longer than MotoGP bikes and handling is compromised. Carbon brakes are banned in WSBK as they are extremely expensive. Rear brakes are made of steel.

MotoGP rules allow minimum bike weights based on the number of cylinders in the bike's engine, but as all bikes run 4-cylinder engines there is a de facto limit of 148kg. (The limit would vary from 133kg for 2-cylinder bikes to 168kg for 6-cylinder bikes if they existed.)

WSBK rules also have different maximum weight limits depending on the number of cylinders. 4-cylinder bikes must weigh at least 162kg, while 2-cylinder bikes (namely Ducatis) must weigh at least 168kg. However, the 2-cylinder weight limit may be varied during the year to equalize performance with 4-cylinder bikes, meaning Ducati may be asked to reduce the weight as low as 162kg or increase it as high as 171kg as required.

MotoGP bikes use prototype tyres from either Michelin or Bridgestone. This means that top teams get tyres specifically made to suit their bikes and riders. However, smaller teams may be forced to use tyres designed for somebody else, which increases the gap between the "haves" and "have nots". The number of tyres that can be used during a race meeting is restricted.

WSBK has a control tyre rule, meaning that all teams use identical Pirelli tyres, with only a choice of a few rubber compounds, e.g. soft, medium and hard. Small teams have access to exactly the same tyres as big teams. This does not stop conspiracy theories claiming that big teams receive special tyres, but these rumours are deeply dubious. Like MotoGP, there is a restriction on the number of tyres that can be used.

MotoGP has a qualifying hour, during which teams may use special super-sticky qualifying tyres which give great performance but only last for one flying lap of the track. Usually riders use race tyres for most of the qualifying period, as they only have 2 or 3 qualifying tyres to use for a fast lap to try and secure pole position. MotoGP bikes line up on the grid with 3 bikes per row.

WSBK uses the Superpole system. The top 16 riders from pre-qualifying practise come onto the track one at a time, in reverse order, to perform one flying lap that will count for their grid position. In wet conditions, Superpole is cancelled and replaced with a conventional qualifying session. Special qualifying tyres are used. There are 4 bikes per row on the grid. If a rider fails to finish his Superpole lap, he will line up on the grid at the end of the next row, meaning that if he was 3rd in pre-qualifying he is guaranteed at least 8th place on the grid. Everybody after 16th place lines up in their position from pre-qualifying.

MotoGP has one race per race meeting, lasting around 45 minutes. If it rains during a race, riders may come into the pits and jump onto their spare bike, so long as it is fitted with a different type of tyre (i.e. riders must switch from slick to rain tyres or vice versa).

WSBK has two races per race meeting, each lasting around 30 minutes. The riders line up in the same grid spot for both races.

MotoGP is a full-on, no expense spared prototype category. It attracts the best riders in the world, and is often seen as self-absorbed and highly pressurized. The bikes are small and light, the engines are high-tech and powerful, as are the brakes. Unfortunately, the current regulations made for dull racing last season, with MotoGP snobs wailing about any attempt to improve the spectacle.

WSBK uses highly-modified road bikes, with the rules leading to very similar performance from many bikes and therefore close racing. Many of the riders are either young MotoGP wannabes or burned out ex-MotoGP riders. The bikes are heavier and lower tech than MotoGP prototypes. The one tyre rule is now reckoned to have been a masterstroke, though it was criticized when first introduced. Superpole qualifying and two races per meeting are used as ways to improve the spectacle for fans. WSBK is generally considered to have a more friendly atmosphere than the high-pressure world of MotoGP, and usually provides more entertainment despite being less prestigious.


Anonymous said...

For an armchair fan, this is a fantastic insight to the parameters of each division, of the sport.

Jimmy said...

Thanks. :-)

Anonymous said...

Thanks for an interesting read!

Exactly what I was looking for!

If you were adding to it at any stage, I would also be interested in finding out which pays best - do motogp riders earn more than the wsb riders?


Jimmy said...

Nobody's sure of the exact figures because the details of people's contracts are kept secret, but the general view is that MotoGP riders earn a fair bit more than WSBK riders, and probably get a fair bit more money from personal sponsors too.

Anonymous said...

Thanks for this - have been pondering the difference :)