Pirelli brought a new rear tyre for the WorldSBK riders to use at Portimao, the W0735. It is a soft new development option featuring different structural solutions in comparison to the standard SC0 soft and the SC1.

All the riders liked the new W0735 so much that they did most of their practice and race preparation on it. Until it was taken from the allocation midway through Saturday.

At this race Pirelli had brought a truck that is normally only used in F1 races, with several pieces of analytical equipment to test tyres on site.

Overnight tests by Pirelli concluded that the performance of the tyre over full race distance would take it outside of a zone that the company was comfortable with, in teams of wear rates.

Matteo Giusti from Pirelli explained why the new tyre was withdrawn from the list of options so late in the weekend. “We analysed both tyres and looked at them from both of the opening day sessions. We noticed that with the 735 there is that the new one has a strange decrease in terms of performance, at least after some KMs, in comparison to the other option. So although we are pretty sure nothing will happen – because we are still inside the tyre safety zone – we have decided to withdraw the 735 for the race. Johnny Rea was on a 1’32.0 lap time this morning on the tyre. It was an experiment to bring the performance to the highest possible level; something completely different. After 17 laps it had decreased its performance by 50%. We do not know what would be the situation at 20 laps – maybe a 51% decrease in performance? The critical area is when you get to 80%. So, just as an extremely safe reason, it has been decided to withdraw it. Thanks to the mobile lab we have been able to discover this. From an external point of view you cannot see anything on the tyre.”

The loss of the tyre was something of a shock for the riders and teams who had to make allowances shortly before the race, leaving even winner Jonathan Rea saying he had a far from ideal set-up in the race.

Pirelli have given the OK for the 735 to be used in warm-up and for short runs but not for the second race on Sunday.