When and why did rubber start getting picked back up by the tires under yellow?
It gets mentioned on TV from time to time that the rubber gets picked back up under yellow. This is especially apparent at concrete tracks.
I don't remember this always being the case though. The first time I remember specifically noticing it was in 2010 at Dover.
I've added photos from 2024, 2010, and 2002 at Dover. They are all from late in the race, after and before a yellow. You can see the rubber gets picked up in '24 and '10 but not in '02. The track is just as dark in '02 under yellow as it is under green.
Does anyone know why this starting happening? Or at least why it's so much more noticeable than it was 20 some years ago?
It has always happened to some extent or another, and isn't unique to NASCAR. Tires wear, and the softer the tire is, the more it will wear. That rubber doesn't just vanish, it goes somewhere. It's just like a pencil eraser. It leaves little shreds of worn off rubber.
That worn off rubber is sticky, so it sticks to the track. At green flag speeds the forces on the tires are enough that it removes rubber instead of picking it up. At slower speeds the tires aren't under enough stress to wear the rubber off, so the shreds of rubber on the track get picked up by the hot, stick tires.
Go watch old races, and you'll see cars weaving back and forth under caution. This was partly to keep heat in the tires, but it was also to keep the tires clean for the restart. Maybe rubber pickup didn't get as much direct attention back in The Day, but it was always something that happened.
Yep. In Formula 1, the drivers swerve into the rubber marbles after the race is over to pick them up on their tires. Just trying to make sure they meet minimum weight in post-race inspection.
F1 drivers will also intentionally pick up rubber to help ensure they aren’t underweight after the race. That and maybe hiding how worn their tires are from other teams.
And a big reason why George got DQ’ed last year at Spa, they don’t run a full cool down lap around the whole track. It’s a very short one into the pits
That’s actually wild to learn. I’m just now trying to get into all kinds of racing. I watched a lot as a kid because of my grandpa and went to everything at IMS but I just watched cars go fast and that was it lol
Side note from that: still trying to learn why the point system is set up the way it is. Stages seem weird to me for racing but idk anything about anything lmao
Or even in NHRA. Watch the Top Fuel cars after they do their burnout (specifically to heat the tires) and they back up to the starting line, as they pull back forward crew members will be wiping all the loose “marbles” off that are stuck to the tire so that they have hot, sticky, clean tires for the launch.
Tires have gotten softer and softer as NASCAR tries to compensate for the gutless engine they're running right now. No surprise that tires are laying down (and therefore picking up) far more rubber now
Pretty much spot on. It's especially obvious if you watch a NASCAR short track race then go to a local short track that runs more traditional tire compounds. The way the track rubbers up is very different.
I've been watching for a long time and I know that they've always scrubbed their tires to clean off rubber before restarts. It never seemed like it pulled up as much rubber though back in the day
I don't know, but I remember going to Richmond 27 years ago and seeing chunks of rubber everywhere just outside the catch fence and it's something I haven't noticed for a long time. Maybe I'm not looking, or maybe the tires don't do it as much anymore, but it was certainly a problem when I was a kid.
If I had to guess - specific to Goodyear/NASCAR (and ARCA - General aka Hoosier tires) - Federal regulation eliminated some compounds/chemicals that Goodyear had used for years in their oval racing tires. I don't remember the exact year but getting these tires to lay rubber became MUCH harder after this change/EPA compliance to effect.
I think you may be on to something here. At least at Dover, there were a few years it seemed like no rubber was put down. Around 2010 is when it started laying more, but was picked back up more too
There's also temperature, surface age, grinding, track sweepers, etc. Lots of factors go into. Like at Darlington they used to talk about all the rubber clogging up the grills, and that was in the late 90's and early 00's
Part of the Indianapolis 2008 fiasco was the tire not rubbering the track properly, could that have contributed? When did the federal regulation change?
I'm well aware of the principal causes: a heavier and higher center of gravity Car of Tomorrow prone to body roll and therefore loading the right side to the max, Indy's diamond ground abrasive surface, and Goodyear's lax testing policies.
I definitely started noticing more around 2009/2010 after the Brickyard tire fiasco when Goodyear turned the tires into bricks that over rubbered tracks like Dover. I think that its been going on forever though, we just didn't really pay attention.
Yeah, it naturally happens since hot tires are more likely to pick up rubber from the track, and when the tires cool as the cars move more slowly under caution, those bits of rubber tend to stick. The Gen 7 has wider tires so they pick up more rubber.
I think it's when tire manufacturing got more eco friendly. They took some of the chemicals out that provided more oily bonding agent and went to a dryer bonding agent. Kind of like how shoes used to leave black marks when you skidded them and now they dont.
I think what you’re seeing is track sweeping. During cautions there are track sweepers that come on track. Their job is literally to sweep the track of debris and oil that can cause tire punctures and sudden wrecks. They’ve been doing it since at least 2001 though the sweepers have gotten steadily more advanced.
It's normal. But it is a little different than it used to be. I've wondered if it's tha same in other series, but the modern tires are more like a rubbery plastic, and the worn rubber on track balls up more. If you look at the sides of cars after the race,where they used to look almost like black spray paint on fenders, now it's peppered with balls of rubber
There's a whole spiel but the extreme tl;dr is that a lot of the fundamentals of how racing tires are made in the United States at least- not sure about anywhere else- changed in the late 2000s. There was a bit of a shitshow right after all that went into effect, I want to say in 2008? There was a big mess at Indy with tire failures and Goodyear compensated by working up some absolute bricks for safety's sake.
It's a bit more, hm, accessible for cars running over the deposited bits of tire than it was twenty-five years ago. Not as firmly planted on the racing surface and easier for your tires to pick up.
What it is exactly about the newer methods that cause that tendency, I don't know.
There's always been some, of course. Just more now.
Outside of that, tire temp- hell, track temp- how old your racing surface is, what your racing surface is, what exactly is the tire being run on the soft/hard scale- tires have been trending softer of late for several reasons, how effective are the track sweepers... you can end up with a lot of variance.
Softer tires of course are going to be better at picking it back up. So I guess we're at a point where we have tires that both put down looser rubber and pick it up better under caution now.
I remember as a kid I noticed this at Michigan in the 90's when we sat at the exit of 4. Always intrigued me seeing tire marks where the cars drove through the rubber under caution.
The tires are sliding and literally tearing themselves apart at speed, laying rubber down.
Under caution, they’re still hot, and they’re staying in a single spot a touch longer than they typically would. The hot rubber heats up the cooled-ish rubber and picks the rubber back up.
I always figured this was more of a thing on concrete surfaces. We see it a lot at Martinsville and Bristol for sure.
I've never been 100% certain on it-- I've always wondered if it works the same at asphalt tracks but it's harder to see? Or if it has something to do with the type of paving?
Always has in fact my youngest daughter would walk around Richmond and pick up all the rubber that was in the walkway going to our seats.We had tire rubber in one of the side pockets of our scanner bag for years.
It’s been a huge talking point that these new cars don’t wear tires. Goodyear has been working in making softer tires that wear but it’s been a trial by fire approach. But I think that’s why you don’t see as much rubber in these newer pics as opposed to the older pics with older gen cars
You are misinterpeting what you are seeing in the pictures. The darkness of the racing line is influnced by the tire compound, the weather, and the amount of laps run. It doesn't get noticably lighter under caution and gets darker as the race goes on.
Much of it also will get washed off when it rains. The darkening of the track is more noticable on concreate but happens on asphalt and even dirt.
When you hear the TV talk about rubber "being picked up" under caution they are talking about the bigger chunks, we call them marbles, that are on the track. At racing speed the air from the cars keep the bulk of the marbles out of the racing groove, and even if you pick one up they self clean in the next corner most of the time. Under caution if you run over the marbles the hot sticky tire will pick them up and they will cover the tire. Those marbles are not as hot as the tire and are not consistent so they don't hook up, this can cause wheel spin if you don't clean the tires well before a restart.
The cars absolutely do pick rubber back off the racing line. It absolutely does get noticeably lighter under caution.
These two images are from the end of the same race, less than 20 laps apart. One under green, one under yellow. The bottom image is 18 laps after the top image.
Is the bottom image just after they've taken tires? My thought would be that it's due to the heat in the tires. Colder tires are going to pick up the rubber that sits on the top layers of the track and that when it heats up, the rubber gets shed off and placed onto the track.
As to why it happens that way now and not back then? Could be a bunch of reasons - cars are more dependent on aero grip than mechanical grip, tire compound could be different, sealer application could be different, the track has smoothed out over the years, etc.
You are comparing a picture of the track under race conditions and the track after the blowers and sweepers have been out. I will say it again you are misunderstanding what is happening
I have seen cars pick up the rubber with my own eyes, in person. For years!
Dover 2019. Onboard Kyle Larson for the last lap. Watch the cool down after the checkers in 1&2. See all the lines in the groove from the slowing cars picking up the rubber?
Sorry dude but I have to agree with Complete. The rubber in the groove absolutely does get picked up. Marbles get flung to the outside. The blowers don't come out every yellow so your theory is moot. Harvick and Boyer even commented on it and it was shown on the TV screen.
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u/Mike__O 3d ago
It has always happened to some extent or another, and isn't unique to NASCAR. Tires wear, and the softer the tire is, the more it will wear. That rubber doesn't just vanish, it goes somewhere. It's just like a pencil eraser. It leaves little shreds of worn off rubber.
That worn off rubber is sticky, so it sticks to the track. At green flag speeds the forces on the tires are enough that it removes rubber instead of picking it up. At slower speeds the tires aren't under enough stress to wear the rubber off, so the shreds of rubber on the track get picked up by the hot, stick tires.
Go watch old races, and you'll see cars weaving back and forth under caution. This was partly to keep heat in the tires, but it was also to keep the tires clean for the restart. Maybe rubber pickup didn't get as much direct attention back in The Day, but it was always something that happened.