This year’s Rolex 24 hour race at Daytona International Speedway was a record breaker. But the biggest talking point was the astonishing number of tyre failures which forced the race favourites to retire…
The Daytona 24 hours was run at a record pace, and it took everyone by surprise. The 36 year old distance record was broken by more than 100 miles, and with just four caution periods, totalling 20 laps, the whole rhythm was like nothing we have seen at Daytona for years.
Daytona is the start of the IMSA WeatherTech Sportscarseries, one of the three great titles to be won in North American endurance racing alongside the Sebring 12 hours in March, and the Petit Le Mans in October. IMSA has its work cut out to balance the performance of the cars before its headline event, as the FIA has its work cut out to establish true performance before its headline event, Le Mans.
Practice and qualifying, therefore, is relatively unimportant. With history demonstrating that caution periods, 21 in 2017, would dictate the strategy more than anything else and with the threat of rain, few paid much attention to the times.
The cars are these days set up for that final run to the flag, a two-hour sprint following the final caution period where you want your car to be as fast is it can be. You set the car up aggressively, knowing that when the sprint is needed you have the car under you to challenge, and before that, hide as much as you can.
It was therefore something of a surprise in qualifying to see the Cadillacs were significantly faster than in 2017, Renger van der Zande setting a 1m36.083 compared to a 1m36.903 12 months ago. So, the pace was in the cars, but the fastest race lap was a 1m36.269 in 2017…and a 1m37.475 in 2018, more than a second slower.
And, then came one of the main talking points of the race; the number of right rear tyre failures. Continental had the same slick tyre that it has brought for the last five years, and says that it never experienced problems like these, and nor did it have any indication from the test that this may be an issue. They figured that the teams had gone aggressive on set up, brought on by the increased competition from Joest and Penske.
Aggressive toe, camber and pressure settings were selected by some teams to generate the heat early, and give performance. According to Continental, one team admitted to them that they had packed out the dampers leaving the tyre sidewall as the only form of suspension. Three teams were warned that they would not receive any more tyres until they changed their set up to bring them into line with Continental’s recommended limits, but one said that they had their failures after raising the tyre pressures to Continental’s prescribed limits.
‘Last year we had lots of tyres that were used even in the rain, and I think because the teams didn’t have any issues last year, they decided that’s not something they had to protect against,’ surmised Kevin Fandozzi, Continental Tyre Product Manager, IMSA. ‘They decided that their biggest risk was not being competitive and then at the end of the stint they may lose a tyre, and they won’t change to make us look good.’
The few caution periods meant that the race was run fast, and if the teams were running a qualifying set up, that could be a reason for the failures. The problem is that at least one of the teams that experienced failures says that it was running within the prescribed limits yet suffered four failures.
Wayne Taylor Racing was also running within the limits, admitted the tyre manufacturer, but had some other issue that caused the tyres to fail. They had seven go, four with van der Zande at the wheel. Two other Cadillacs finished first and second. What was different about the WTR entry?
For each of the teams, the failures came at the end of either a second or a third stint on the tyres. Was it temperature related, speed related, tyre related or set up related, or a combination of the three? Whichever it was, Continental will no doubt be evaluating the data as a matter of urgency, but anyway is introducing a new slick tyre at Sebring, one that it says can take a much more aggressive set up and which will separate the teams that know what they are doing with those who do not. For the teams counting the cost of an expensive weekend, that’s a scant consolation.