Estoril, venue for this weekend's Portuguese Grand Prix, is a technically challenging venue, due to a combination of its design and geography.
The 4182m circuit is situated 32km west of Lisbon on the western coast of Portugal, 7km from the beach resorts of Cascais. As beautiful as the costal area is Estoril is regularly hit by offshore winds which can result in a light film of dust forming on the track surface. Combined with its flat camber and irregular use, grip levels are always minimal for the first few days during the Portuguese MotoGP, until a clean racing line is formed.
As with Welkom (South Africa), this makes setting up a MotoGP bike very difficult. As the circuit naturally becomes cleaner and faster over the course of the GP weekend the ideal chassis set-up also changes. Although this is common with all circuits - the ideal chassis set-up being a work in progress - the effects are more noticeable here.
This is amplified by the fact that the actual layout of this venue lends itself to being inherently difficult on set-up. With its high-speed straight - topping 320kmh - combined with some seriously hard braking - especially into turn one, the most popular passing point. Add in a sequence of tight twists and turns, a few fast sweepers, the meanest chicane on the championship calendar, and the best race set-up is the result of a compromise.
The engine alone must cater for all extremes here. Predictability, due to the low grip levels, low to midrange power must satisfy the drive needed off the half dozen second gear corners as well as the everlasting high-speed right hander onto the main straight. Here the rider needs high amounts of grip, confidence and predictability to achieve the drive necessary in order to reduce the risk of being passed on the line at the chequered flag.
Chassis wise the first target is a balanced, neutral geometry; offering good turn-in characteristics while also catering for the big braking areas - such as turn one. The base setting will be similar to those used at Donington, only with slightly higher rate fork springs to deal with the extra weight transfer under deceleration. Meanwhile the rear spring will be softer to improve feedback under power, although it is a fine line, with the circuit reasonably narrow and the limited amount of grip off the racing line there is little room to run wide.
All this will be done while the technicians and riders focus on a set-up suited more on the latter part of the race, at which point the tyre grip levels will be fading - more so than at any other circuit. Again the low grip levels are a factor, as are the repetitive bumps in the track surface on the exits of the turns, which can unsettle a fast bike on old tyres easily.
Although Yamaha did reveal a new fairing for the YZR-M1 during recent tests, following the Czech Grand Prix, this was only a preliminary 'real-world' test for the new design and as a result all four Yamaha riders will continue with the 'standard cowlings until further wind tunnel test can be completed.