The following is excerpted from an in-depth article by Marshall Pruett posted on Racer.com examining how braking issues, like locked brakes, occurred with unusual frequency.
INDIANAPOLIS — The biggest question during and after the Indy 500 involved the spate of locked brakes, crashes, and speeding violations on pit lane.
“None of the problems you saw were the drivers’ fault,” one team member said. “Those were created by their teams.” Another said, “I don’t feel bad for those that had problems. They brought it on themselves.”
There doesn’t seem to be a single definitive answer as to why those drivers had issues, but there’s a growing belief within the paddock that some teams might have been pushing the envelope with regard to how they set their braking systems up for the race.
Years ago, teams devised their own systems to keep the brake pads away from the brake discs on superspeedways like Indianapolis. Since the brakes are rarely used throughout each stint, and drivers can either lift off the throttle and let aerodynamic downforce and drag slow the cars, or downshift, there’s value in reducing even the slightest amount of friction caused by the pads and discs making undesired contact until they’re really needed. Any contact, even for a nanosecond, would create friction, and with brake friction, you lose speed, and with semi-regular friction, you have a slow car.
The generic term back then was “pullback springs,” and they did just as the name suggests: The springs pulled the brake pads away from the discs. And to get the brakes to function, drivers would need to apply some added muscle to overpower the springs and create enough clamping force so the brake caliper pistons would slam the pads into the discs.
Today, with the spec brake package supplied by PFC, teams have a built-in option to use. The days of teams making their own pullback mechanisms are long gone.
So with the PFC pad retraction kit, springs have been replaced with four little levers per caliper – two on each side – that hold the pads a pre-set distance away from the disc. Like the former pullback springs, it takes some force to overpower the levers and push the pads up against the discs.
But we have an important difference with how the spring-like levers can be set up. If you have ever walked through a door that was either spring-loaded at the hinges, or maybe walked through a revolving door that required some extra grunt to move until you got to the other side, it’s a similar principle here in terms of how hard or easy teams make it to push through the retraction levers.
The arrival of spec brakes has eliminated some of the DIY solutions seen in years past, but teams can make significant changes in brake setup. Joe Skibinski/IndyCar
Teams, through their choice of brake master cylinder sizing, and the gap they set between the pads and discs, leave each driver a unique challenge in getting their race day superspeedway brakes to clamp and slow the car. This is all based on predetermined decisions before the green flag waves, not a showcase of how some drivers are better than others at using the brakes.
How many drivers got lucky and kept from adding themselves to the list? It would be optimistic to think these are the only five. Am I saying the teams that had brake problems were doing something wrong or risky? No, but don’t be surprised if IndyCar involves itself in future speedway races and sets a maximum brake pad retraction gap.