Although it was resurfaced only two years ago the Rio de Janeiro circuit doesn’t have a reputation for offering the traction one would hope for while racing a 180 horsepower two-wheeled 500. In fact a combination of many bumps, low grip levels and camberless medium to high-speed corners make this a challenging circuit to stay on, let alone race on.

Since there’s only one extremely hard braking corner, most of the technical team’s attention during practice will be focused on manoeuvrability and drive. Last season Yamaha learnt a valuable lesson in this key area of setup. With its initial effort aimed at keeping the bike manageable on the medium to high-speed changes in direction, Yamaha firmed up the machine to prevent the rear end from squatting. Working within the range of a higher rate rear spring the goal was achieved, but with a less than ideal side effect. Sure, the geometry of the YZR500 ensued that the agility of the bike wasn’t compromised, but the stability was. The 500 became easily agitated, making it difficult for the riders to keep a fast flowing rhythm through these fast and crucial points on the track. With the firmer spring working the rear tyre harder it would easily break traction before biting back again – causing it to become unpredictable and unforgiving.

Throughout the 2001 season Yamaha has adapted to the challenge. Again the key issue is agility; this time achieved by preventing the rear from squatting under power with a softer spring rate but with more preload to hold the shock high in its stroke. Combined with less rebound damping – to allow the shock to return to its static length before the next series of bumps – feel will be improved and therefore control under power, without sacrificing the positive handling traits initially sought after.

Again the front end will follow the same basic theme to ensure an overall neutral balance, and with minimal hard braking areas it will allow more effort to be directed to improving feedback from this area too.

As Rio is an acceleration circuit the power characteristics will be concentrated towards the midrange and top end, while offering a good consistent delivery rather than a progressive curve. The latter can make it difficult to drive off the side of the tyre effectively without the rear breaking traction as the revs rise.

With track temperatures usually high, tyres will be chosen to last, and the 16.5inch is the most likely option, although, with the high-speed changes in direction, some might opt for the 17.0’s easier handling qualities.