The secret of undercut and offset
Posted on May 2, 2014
By James Allen
The recent 2014 FORMULA 1 UBS CHINESE GRAND PRIX underlined the importance of race strategy in getting a good result. It also highlighted a couple of tactics which teams use to get their drivers ahead of a rival if he is struggling to overtake him on the track.
The secret of an undercut is to harness the performance advantage of a new set of tyres over old ones; up to two seconds per lap.
An undercut is where Driver A leads Driver B, but Driver B turns into the pits before Driver A and changes to new tyres. As Driver A is ahead, he’s unaware that this move is coming until it’s too late to react and he has passed the pit lane entry.
On fresh tyres, Driver B then drives a very fast “Out” lap from the pits. Driver A will react to the stop and pit on the next lap, but his “In” lap time will have been set on old tyres, so will be slower. As he emerges from the pit lane after his stop, Driver B is often narrowly ahead of him into the first corner.
This is an undercut and it is up to the Race Strategists to spot an opportunity and go for it.
We saw a classic undercut in the recent 2014 FORMULA 1 UBS CHINESE GRAND PRIX, where Mercedes got Nico Rosberg ahead of Daniel Ricciardo by undercutting him at the first stop.
Another aspect of trying the undercut, if you have better tyre wear than your rival, is that it can force your rival into stopping earlier than he would ideally like, so making his next stints longer. This could make him run out of tyre performance at the end of the stint.
The opposite of an undercut, the offset can work very well if you have a fast car out of position down the field. The idea is to run longer than the car you are racing, accepting that you will not gain track position at that point and will lose some time initially, but you will gain later by having fresher tyres at the end of the race for an attack.
Later in that same race in Shanghai, Rosberg passed Ferrari’s Fernando Alonso with an offset.
Ferrari suspected that Rosberg was going to try to undercut Alonso, who was ahead on the road, so the team brought the Spaniard into the pits, but Rosberg continued. The German built a four-lap offset and then had much newer tyres to pass the Ferrari in the final stint.
This also pushed Alonso into a 23 lap final stint, which was longer than ideal.
The undercut and the offset; two commonly used tactics to look out for when you next watch a Formula 1 Grand Prix.