The most important query throughout and after the Indy 500 concerned the spate of locked brakes, crashes, and dashing violations on pit lane.
“Not one of the issues you noticed have been the drivers’ fault,” one group member stated. “These have been created by their groups.” One other stated, “I don’t really feel dangerous for people who had issues. They introduced it on themselves.”
There doesn’t appear to be a single definitive reply as to why these drivers had points, however there’s a rising perception throughout the paddock that some groups might need been pushing the envelope with regard to how they set their braking techniques up for the race.
Years in the past, groups devised their very own techniques to maintain the brake pads away from the brake discs on superspeedways like Indianapolis. For the reason that brakes are hardly ever used all through every stint, and drivers can both raise off the throttle and let aerodynamic downforce and drag gradual the vehicles, or downshift, there’s worth in decreasing even the slightest quantity of friction attributable to the pads and discs making undesired contact till they’re actually wanted. Any contact, even for a nanosecond, would create friction, and with brake friction, you lose velocity, and with semi-regular friction, you’ve a gradual automotive.
The generic time period again then was “pullback springs,” they usually did simply because the title suggests: The springs pulled the brake pads away from the discs. And to get the brakes to perform, drivers would want to use some added muscle to overpower the springs and create sufficient clamping power so the brake caliper pistons would slam the pads into the discs.
Right now, with the spec brake package deal provided by PFC, groups have a built-in possibility to make use of. The times of groups making their very own pullback mechanisms are lengthy gone.
So with the PFC pad retraction package, springs have been changed with 4 little levers per caliper – two on either side – that maintain the pads a pre-set distance away from the disc. Like the previous pullback springs, it takes some power to overpower the levers and push the pads up towards the discs.
However we now have an necessary distinction with how the spring-like levers might be arrange. In case you have ever walked by means of a door that was both spring-loaded on the hinges, or perhaps walked by means of a revolving door that required some additional grunt to maneuver till you bought to the opposite facet, it’s an analogous precept right here when it comes to how arduous or simple groups make it to push by means of the retraction levers.
Groups, by means of their selection of brake grasp cylinder sizing, and the hole they set between the pads and discs, depart every driver a novel problem in getting their race day superspeedway brakes to clamp and gradual the automotive. That is all primarily based on predetermined choices earlier than the inexperienced flag waves, not a showcase of how some drivers are higher than others at utilizing the brakes.
That is why there’s a concept in some corners of the paddock that some groups selected to make use of a qualifying pad retraction setup within the race as an try to achieve a tiny benefit by eliminating any likelihood of on-track friction.
It’s regular for groups to make use of the little levers within the race. However there’s a big distinction between setting the retraction levers to carry the pads again a minimal quantity – perhaps 10 or 20 thousandths of an inch away from the disc – and setting the hole at double or triple that distance like they’d for qualifying. With just one automotive on monitor for qualifying and loads of time to slowly and safely pump up the brakes earlier than returning to pit lane, the large speed-giving hole shouldn’t be a problem.
But when some groups have been to try to use that greater hole within the race, their drivers could not have sufficient time or success to get the brakes to work whereas firing into pit lane when coming off Flip 4 at 220mph and had only some seconds to construct stress. That’s the place some points might come up.
And if the pads are comparatively distant from the discs, and there are robust spring-like levers pushing the pads up towards the brake caliper pistons, these drivers must pump up the brakes to try to get the brake fluid to maneuver and fill a void within the line behind the pistons. Consider a twig bottle that has no fluid close to the spout; there’s liquid within the bottle, however it takes a couple of squeezes of the set off to get that fluid up the hose and out the nozzle. Similar right here: there’s brake fluid within the line, however it’s not sitting and ready on the prepared to maneuver the pistons and push the pads because the little retractor levers are holding every thing nicely clear from the discs.
In order that’s the place the a number of pumps come into play – to get the fluid again out the place it belongs, creating stress on the pistons that smash the pads into the discs. That’s why, with a wider retraction hole, drivers appear to be they’re attempting to stomp out a fireplace with how they’re compelled to work the brake pedal to construct stress.
And right here’s the rub. It’s simple to think about pumping a brake pedal being an exponential factor; the place with each pump, extra stress will get constructed up till the brakes lastly seize. However relying on grasp cylinder sizing, and the way a lot fluid must be moved out to the pistons at the beginning of the method, there’s no assure that every pump will construct satisfactory stress. If plenty of fluid is moved in the course of the first 80-percent of journey on the brake pedal, there’s solely 20-percent left to try to overpower these levers and erase the large hole to the discs. And when you’ve solely received the final 20-percent of pedal journey to gradual the automotive, how would you achieve this in a clear and managed method? That is most likely what we noticed within the race.
When driving a highway automotive, the conventional braking course of entails pushing on the brake pedal, receiving nearly on the spot stress, and having the complete vary of journey to construct extra stress and modulate the power till you gradual the automotive or come to a cease. They key right here is when you’ve stress – on the prime of the pedal journey – and the way a lot journey you’ve left to use that power in a managed method. In that situation, on the road, or in an IndyCar on the Indy 500, most are in a position to brake usually and with out locking up the tires.
As among the drivers presumably skilled on Sunday, there was no instant pedal resistance attributable to a giant retractor hole. And when the brakes did lastly begin to work, the pedal was so near the ground, there wasn’t sufficient pedal journey left to correctly modulate the power.
However once more, there is no such thing as a single concept right here that explains each downside. There was plenty of randomness: Stefan Wilson’s automotive was the primary to have issues as he had a ton of rear braking power and never a lot up entrance; we all know this as a result of his rear wheels locked and speared him into the pit wall. This occurred on his first pit cease.
After the crash, on the NBC broadcast, he talked about pumping the brakes repeatedly, all to no avail, and at last, on the final determined pump, they labored, however not in unison on all 4 corners, and the automotive turned itself into the wall. His teammate Ryan Hunter-Reay had the precise reverse occur, as his fronts locked, the rears didn’t seem to do a lot, and he flew by means of pit lane, practically hitting Simona De Silvestro’s automotive. Rushing penalty; race ruined with a prime 5 all however assured.
Hunter-Reay accomplished 4 pit stops with out a problem, and on the fifth and final, he mirrored Wilson’s first, however as a result of it was his entrance brakes that locked, it didn’t flip the automotive into the wall. After which we now have Will Energy and De Silvestro’s brake-related loops, and Scott McLaughlin having an analogous expertise to Hunter-Reay in crusing previous the beginning of the slow-down stripe. Rushing penalty for the Kiwi, and his possibilities of a robust end misplaced.
What number of drivers received fortunate and saved from including themselves to the record? It might be optimistic to assume these are the one 5. Am I saying the groups that had brake issues have been doing one thing incorrect or dangerous? No, however don’t be shocked if IndyCar entails itself in future speedway races and units a most brake pad retraction hole.