Drivers will be compelled to use both hard and soft tyres in each of this weekend’s three Supercars Championship races at Sydney Motorsport Park.

While the Armor All Sydney SuperNight is once again comprised of a trio of 125km races, it differs from the event which unfolded at Eastern Creek a fortnight earlier in so much that both dry weather compounds will be in play.

As was the case in last year’s mixed-compound events, it was to have been left up to the teams how to decide how to divide their tyre allocation across those races.

That would have probably led to divergent results through the weekend, but a rule change contained in the Further Supplementary Regulations now greatly lessens the scope for putting one’s eggs in one basket and sacrificing one or both other races.

Supplementary Regulation 5.3.4 has been varied to read as follows: “In each of the following races (Race 23, 24 and 25) both dry tyre compounds (H) and (S) must be used. Rule D17.1.10 applies.”*

Effectively, it encourages every driver to either start a race on softs and finish on hards or vice versa, throughout the event, assuming rain does not fall at certain times.

It also means that pit stops must necessarily be for four tyres, save for the unlikely event of not changing compound, given only a single compound may be used at any one time.

While the rule change takes away a significant level of strategic freedom, the tyre allocation will still make for a tightrope in qualifying.

That is because each driver starts the weekend with five new sets of soft tyres and three sets of new hards, but the two post-practice handback sets must be of the soft compound.

Therefore, a car only had three sets of each compound to get through three races and the corresponding qualifying sessions, of which Saturday’s is a three-part knockout affair.

Furthermore, unlike last year’s mixed-compound event at Sydney Motorsport Park, the knockout session culminates in a 10-car, 10-minute third part, rather than a Top 15 Shootout.

That raises the stakes for anyone who might try to ration their soft tyres in Saturday afternoon’s qualifying hit-out, with less margin for error in terms of getting out of Part 2.

Beyond qualifying, a Safety Car becomes a major factor, given the impact it would have on strategy.

Generally speaking, a late Safety Car should help the drivers who finish on softs, but it did not appear at all last weekend and those who start on softs will gain valuable track position at the expense of those who do not.

Practice 1 for this weekend’s ninth event of the season starts on Saturday at 13:55 local time/AEDT, with the first race of the weekend, the 23rd of 2021, from 19:45.

* ‘Rule D17.1.10’ is an addition to the Operations Manual for mixed-compound events which compels teams to notify race control as to whether their cars are starting on hard or soft tyres before the race gets underway.

Tyre allocation: Event 9, Sydney Motorsport Park

Handback: Event-marked 8S plus pre-marked 4S