Hands up all who knows where your masseter muscle is? Given the intelligence of our readership, a forest of hands is now reaching for the sky.
For the minority who don't know - myself included until last week - it's the chewing muscle which acts to raise the jaw and clench the teeth. It derives its name from the Greek for chewing, and is associated with angry and aggressive states.
All very fine, but what, pray tell, has it got to do with tyres? Well, according to Toshihiko Suzuki, head of Yokohama's tyre technical division, it's the secret of success.
The Japanese tyre firm has been attaching minute sensors to the masseters of its test drivers to measure the muscle's reaction to things such as lane change, cornering and sudden braking. According to Suzuki, it's the key to your comfort and confidence in the tyre's grip.
Have Suzuki and his team spent too long inhaling noxious fumes at the tyre plant? No, they're just prepared to go to extraordinary lengths to differentiate their products and claim superiority over competitors.
Tyres are hard to brand, but several firms have succeeded. When it comes to your connection to the road, price is the general determinant at the lower end of the market, but image plays its part with more expensive marques and models. If you're spending €70,000 on a car with a sporty image, it starts to matter how it's shod. No different than wearing the right Nikes to the track, or Manolo Blahniks to the ball.
So, when you're in the rubber business, if you have the engineering ability to produce a tyre with the ability to keep 500 wild horses grounded, then you want to differentiate yourself from the rest of the crowd. That's why Bridgestone has its Potenza range, Dunlop has SP Sport and Pirelli its P Zeros. Now Yokohama has joined the fray in Europe with its Advan range.
Originally only available in Japan, the high performance tyre made its debut in Europe at the Paris Motor Show last September, but it really took to the track only in the past few weeks. Yokohama holds only two per cent of the European market, but hopes its entry into the premium segment proper will buy it some much-needed sales.
Already the Japanese brand has had some notable success here, becoming accepted as the standard fit - or original equipment (OE) as it is known in the trade - for the Bentley Continental GT and the Lotus Exige. Big scalps to capture in your first few months, but only the start in a market where hooking up with marques such as Porsche, Mercedes and BMW means a lucrative future.
There's also the burgeoning off-road market - or more appropriately the Sports Utility Vehicle (SUV) segment. These are vehicles which, for all their ability to go off-road, stick mainly to the tarmac.
Yokohama has already built up a credible reputation with its Geolander brand of off-road rubber, currently featuring on the Mercedes G-Class and the AMG version. While we got the chance to put these great big swathes of rubber to the test in the deserts of Dubai, few Irish owners are going to have to battle 60 degree sand dunes.
A more appropriate test is on the track. So we took a Porsche Cayenne Turbo clad in Advan ST - the range aimed for road-going SUVs - onto the Dubai autodrome, a twisty winding track with several chicanes and treacherous 180 degree turns.
The aim is to keep the car firmly attached to terra firma despite its height. Selling tyres to the SUV set is a brave move, given the Firestone debacle of some years back - it nearly crippled Ford, when blowouts were identified as the cause of several serious accidents. The dust has now settled and Yokohama wants a piece of the action.
The claim is the ST retains stability in SUVs up to 187mph (300km/h) - at this speed the tyres may be composed if the driver isn't.
We then completed 10 laps in both a Mercedes SL320 and a SL500. These had Advan Sport, Yokohama's new premium car tyre. In the scorching desert heat, it wasn't the tyres that gave way, but the Mercedes brakes. After a couple of hours of track work, two of the four cars had to be retired. Not the sort of thing you'd expect from a pair of cars each costing over €120,000 here.
Part of the course featured a wet test, but the water evaporated as quickly as it hit the track. With tyre temperatures only adding to that, it's really impossible to say what sort of wet weather grip either the ST or Sport versions offer. However, the tyres were tested on the Nürburgring and on German autobahns in order to identify correct tyres for European roads. Perhaps a quick trip to Ireland would be in order.
All we can say is that on the track our masseter muscles were set on grin.
