A flat spot is when part of your tire gets worn down into a flat-looking patch. It usually happens when you brake so hard that the tire stops spinning and starts sliding.
Flat spots can make the tire grip and brake less smoothly, because the tire surface isn’t even anymore. That can also mean you’ll wear the tire out sooner, so it costs more to replace.
Locked-up brakes mean the brakes are applied so strongly that a wheel stops turning. When that happens, the tire skids instead of rolling, which can damage it.
ABS is a safety system that helps stop your wheels from locking up when you brake hard. It keeps the tires rolling so you can steer instead of sliding.
In track driving, “trial and error” describes learning the right brake pressure and technique through repeated attempts. The segment ties this to avoiding flat spots by dialing in braking force before you ruin tires.
A flat spot is when a tire gets dragged while locked up, making part of the tread go flat. It can make the car shake and feel worse to drive until the tire is dealt with.
The “most loaded tire” is the tire that’s carrying the most weight. The more weight a tire has, the more it tends to be the one that grips or locks first.
They’re talking about a track that mostly turns to the right. Turning right shifts weight to certain tires, so those tires are more likely to be the ones that get overloaded and lock.
They mean the hardest braking part of the track. That’s when the tires are under the most stress and are most likely to lock up. If a tire is damaged, it shows up most during this phase.
They’re calling out the left front tire as the one that gets hit hardest. During hard braking and turning, the front tires do a lot of the work, especially the outside one. If that tire is damaged, the car can feel worse right away.
They’re talking about which tire position gets the least work during that part of the track. If you can’t replace a damaged tire, you try to put it where it won’t matter as much. That helps the car stay more stable and predictable.
They’re talking about moving the damaged tire to a different spot on the car. The goal is to put it where it will be less important. It’s a practical fix for race weekends when you can’t replace everything.
Front wheel drive means the front wheels do the steering and the pushing. Because of how the car behaves, certain tires—especially on the opposite side—may get less load in a turn. That’s why the speaker thinks a damaged tire might be survivable in a specific corner.
Flat spotting means your tire got stuck in one spot while it was still rolling or under braking, so part of the tread gets flattened. It can make the car shake and feel worse to drive until it’s fixed.
“Blowing motors up” means the engine fails badly, sometimes from running too hot or being tuned wrong. It’s a serious problem that can destroy the engine.
A lathe is a machine that can cut and shape material very precisely. Some people have used it on tires to change the tire’s shape, but it’s not a normal way to repair a flat-spotted tire.
Brake pads are made from different friction materials. Some work better when they’re hot, and some work better when they’re cooler—so matching them to the car helps braking feel consistent.
Carbotech XP10s are a type of track brake pad. They’re used on the front in a setup where the front and rear pads are intentionally different to balance braking.
Carbotech XP8s are another track brake pad type. In the example, they use XP8s on the rear so the braking balance is more even than if the front and rear pads were identical.
Chad Morehead is a person the hosts trust for racing brake advice. They say he tests and races a lot, so his recommendations are based on what works on track.
Morehead Speedworks is Chad Morehead’s operation. The hosts are saying it’s a good place to get racing brake parts and advice because they’re actively involved in testing.
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From the great halls of their house, there are assembled three who hope to one day be
the world's greatest driving heroes.
Created from the cosmic legends of the universe comes our team captain, The Vision, Bill Fisher,
their soon-to-be wonder woman, Vicky Fisher, our captain marvel and head-flight trainee,
Jennifer Scribchuk, and our Batman, the master of tools, gadgets and all things mechanical,
our mild-mannered soon-to-be billionaire, Alan Danvers.
Their mission, to fight injustice, share what is right and wrong, to get you out of your
house and come out racing with them, and serve all mankind.
They are the Garage Heroes in Training Team.
Dominating with Dawson.
Dominating with Dawson, Dominating with Dawson, I need me some Dawson!
Dawson, Ben, it's so good to see you again.
Good to see you guys too, I needed some Dawson, so it's nice to be back doing this kind of
Dawson and not buying normal boring ass Dawson stuff, so welcome back, welcome back me.
I was gonna say you should be pretty much full on your Dawson 24-7, but you know…
You would think so, but this is not always the right kind of Dawson.
Oh, there we are, I guess.
So, Mr. Dawson, we have often complained about this, we have often talked about this,
but it has come to my attention that some people don't understand what we're talking about,
and since we are the one-on-one podcast of racing and we often cover jargon,
I thought we'd get into the topic that we talked about and get a little more granular,
perhaps even more deeper. The topic that we have is flat spots, specifically flat spots on tires,
as a generic, how do they get there, what are they, what to do about them, what to not do about them,
how they mess you up both performance-wise and price-wise, things like that.
So, well, you know, as the premier motorsports podcast, not just in the nation but probably in
the world, this is something we should talk about, don't you think?
I believe we owe it to them.
You know, as the premier voice on this topic, I think it's important that we weigh in here,
what do you think?
It's the least we could do, and we have to make sure they get their money's worth.
And I really must say, everybody will do it at least once.
Yes, I agree. I think we're beholden to the community and let them know how we feel about
flat spots. You know, I think it's our duty. It's going to be my honor. I'm excited. Here we go.
Flat spotting a tire.
We're not talking anti, save the tatas. We're not talking anything like that. We're talking
tires. Yes. So, the flat spotting a tire happens when you have locked up your brakes and that
tire stops spinning. When your brakes are on, when your brakes are in the fully on position or
braking hard, your tires should still be rotating. You're not trying to lock the tires up. You're
trying to have them rotate, but you want the rotation to slow quickly. Does that make sense?
We want to quickly slow the rotation.
But not stop.
Right. But if you stop that wheel with too much brake pressure, all of a sudden the wheel,
instead of quickly decreasing its rotation, it's just going to slide along, which doesn't
really slow you down and it destroys the tire. So, what happens when you lock up that wheel
and make it stop instead of slowly rolling to a stop is that you just slide the tire along and
the tire stays in one position. It keeps sliding in that one spot and that spot is held down to
track by the non-rotating tire ends up being your flat spot. You just ground a bunch of like a
square patch of rubber off in one spot on a round tire. So, now you've ended up with a flat spot,
which you may even notice by hearing that corner go, or you may just feel it by just next time
you go try to use your brakes in a normal way. They'll lock up even easier because once you've
made that flat spot, even when the tire is trying to slowly decrease its rotation under
normal braking, it's more likely to catch that flat spot onto the flat ground and lock up even
quicker. So, you've flat spotted the tire. That's what happens. The tire has a flat place in it.
When you take the tire off to look at it, you can usually roll it along the ground. Once you've made
a full rotation of the tire, you're like, there's my flat spot. They're varying degrees of flat spot
off the way from grinding your wheel entirely down to the rim to just a little hop, skipping a jump.
Does that make sense? Yep. You can see chords if you do it really good.
And the fragrance that comes off a tire that's been flat spotted to everybody around you that
we love the fragrance. We love it. It's not pretty.
It is not. So, that is what they do. And you got a little bit into how they affect your performance.
What about ways to avoid it?
Well, that's the premier voice in this sport. I think the best way to avoid it is to race or
try a car that has ABS. Yes. Boom. There you go. That's your easiest way to avoid it because the car
with ABS or anti-lock braking system is going to keep that tire from locking up. It's going to
think kind of mechanically and then electronically patent your pedal to slow it down rather than
letting you just hold the same amount of pressure down. So, it's going to interrupt your brake pedal
pressure to make you not lock your tire up. So, that's the best way. The other way is just kind
of trial and error like, oops, was that too much brake pressure? Yes, it was. And now I've ruined
the tire. That's my experience. And we've done that with going from one brake pad to another
on-car. We put ST43s on the Miata for the first time. Everybody was standing that thing on the nose
and we trashed a whole set of fronts like everybody trying to get used to the
ST43s in the Miata. But the payoff was, of course, we got it. We were a lot better on the brakes.
So, sometimes it's a part of the learning process to over exceed your braking grip and lock the
tires up. But sometimes right across the lawn of locking the tires up is a gain in speed.
And one thing, I've had the same issue when I was teaching somebody else how to drive a stick.
You got to realize that the brake is not a unidirectional operation. You don't just go down
and then back up. You can come off the brake a little bit. If you lock the tires, come off the
brake just a little bit, just a tiny bit. And the same thing with the clutch, the car starts to stall.
Don't keep coming off the clutch. You can push the clutch back down just a little bit and not
stall your car. But it's a field thing and the thing that makes it complicated is you're trying
to do things as quick as you can, as fast as you can to get around the track as quick as you can.
But to add to the level of complexity, if the car is loaded unevenly front to back side to side,
you can actually lock one tire, not just two tires, not by the axle, but a corner.
That's harder to deal with. But the key is practice. You got to get used to it and you're
going to go through some tires. It's always good to have extra sets. So now that I've flat spotted
the tire, can the Premier Motorsports podcast in the universe tell me what to do with that tire?
Is there any way to still extract any value out of the tire with the flat spot?
Well, I mean, one of my favorite lemon's penalties is to give them a tire and have them
sand it to where it's smooth. I want the tire to be uniform and come back when they're done.
Oh, man. That's diabolical. I was thinking more along the lines.
Oh, that's that's that what you're looking for. I was thinking more along the lines of
you flat spotted the tire. Say you're at a track where most of the turns are right turns.
Who knows what our most loaded tire is going into a fast turn at the right turn track is.
What's the tire that's most loaded up?
Which tires most loaded up on a right hand predominantly turning track?
I'll give you four choices. Front left, front right. Okay, hold on. Let me let me think because I
don't I don't really think about the physics of it. Turning right. Where's the pressure?
Where's the force? It's on the outside left. Well, yes, front or back.
If I'm going into a turn, the track mostly turns to the right.
If you're going to be, where's most of your force?
I would have front or the back. It's in the front. There you go.
Yep. Front left nailed it. So to say you've gone through in the turn one of this track,
and that's the biggest breaking moment of the whole track. You just roasted that left front
tire trying to give it that right hand turn. You come in, you come in. Let's just say for us
that this has happened to you in the test day before Lemon's race, and then your Lemon's race
is Saturday. So you did this on a Friday test day, like crap, the other day we flat spotted the tire.
We're pulling all our tires off. We only came to the track with I set a tire. So we got, we got,
we could go home because we flat spotted the tire or we could figure out what we're going to do.
What we're going to do is we'll take that tire that got roasted and try to figure out
what's the least loaded corner at this track. So if the left front is the most, I know she's alive.
She's alive. Oh, it's the back right. Yeah. And the only reason why I say that is because I followed
many of little cars and especially that are front end, front wheel drive and their back,
their back right wheel is usually not touching the ground. Exactly. So, so check this out,
that wheel, that wheel that's not touching the ground very often can probably be okay with
the flat spotted tire on it because it's not doing the most amount of braking. It's not doing the
lion's share of the turning or anything like that, like it was when it's flat spotted. So
if I'm in that spot where I don't have another tire to sub in for a flat spotted tire, I have
certainly more than 10 times in my life taking that flat spotted tire and moving the least loaded
corner of the car and worked everything back around. So the most optimal tire now is at the
left front and then the spot that was the most crucial and everything else, the other two just
kind of sold out to the other two spots and use it for the best. But if you flat spotted a tire,
it's not necessarily a right off. And I mean, I'm not trying to nick them when dying, but I mean,
this stuff's expensive. I mean, sometimes the difference between a tire or a set of tires and
not a set of tires, maybe the difference between us getting to the track or not getting to the track.
So I wanted to make sure to include sort of the, what do you do with this tire now that it seems
like it's irrevocably f***ed up? It's probably not. You just put it in the easiest spot in the car
and you probably will be fine and you probably will forget about it until the tire is rolling out.
We forgot to cover one of the most important things about flat spotting your tires.
Yes. And that is if you were out of track and you flat spot your tires.
And it is a Saturday evening going into the potluck and the three-petal mafia happens to be there.
You'll likely be wearing some type of marital aid on your forehead for the entire evening.
And there's nothing you can do about it. So don't flat spot your tires. Highly recommend.
Good to know. Good to know. Or else don't go to events where most people are going to be.
You go to an event where race cars, race bars are going to be and they'll slap
them like a pink dildo on every window of your race vehicle and all your tow vehicles,
even if you didn't do anything weird. They don't need a flat spot as an excuse.
Exactly. All right. So how do they have so many dildos? I've never understood that.
The dildo budget for a race bar must be astronomically higher than their tire budget.
What about your dyno budget? You know those guys go to the dyno all the time? Really? Yeah.
That's why they kept blowing motors up for the first few years that you knew that you and I both
knew them pretty much. You know what comes to mind? Because they would go take it to the dyno.
They would build this thing and go take it and have some guy put like an autocross tune on it.
It's like, why don't we blow up? So we love race bar. We're not picking on you. But you know,
who's your race bar? You know what came to mind when you said they go to the dyno all the time?
The first sentence that went through my mind was, if they're doing that, they should be way better
than they are. The thing I think about taking a race bar vehicle to the dyno is much more along
the lines of like, lipstick on a pig, something like that. Yeah. Yeah. There's that. How many
cars have you done on the dyno that have a literally working bar in the back? You know?
But the times I've driven their cars after having that treatment and before like blowing up,
motor felt great. Yeah, I'm sure it does. Made to do 60-second pulls, not the 21.
Great feeling, motor. That's really good. That's like the old joke. Like, when does the motor have
the most power right before it blows up? That's absolutely the truth is my experience. It makes
all loosey-goosey, ready to rock. Oh, yep. So Ben, just to make sure, because I'm anticipating
a listener question, so we're trying to answer them even before they listen. Well, proactive.
Can you fix a flat-spotted tire once you've done it? Can you drive? Can you flat-spot it all the
way around and get it nice and circular? No, I don't think, I mean, there are some laid processes
you can do to a race tire. Like when I was racing cars for a system, people were using
lathes to cut down a lot of material off the tire to make it a less rotating mass.
But you know, in the instance of trying to use a lathe to fix a big defect like a flat-spot,
I wouldn't try that. But nothing by driving? Nothing by driving. I wouldn't imagine I would
try to take a flat-spot to a lathe or anything to try to fix it. Pretty much got what she got.
The best thing to do is to learn and not lock your brakes up. I forgot also, one of the ways that
back in the day when we had our Miata that had no ABS, it was kind of a stripper model. I don't
mean stripper like people would take their clothes off. It was kind of a model that didn't have any
extras. You mean the ballet? It didn't have cruise control. It didn't have ABS to have anything. So
that was the Miata. Yeah, there was also a little bit lighter than the car that would
have had all the stuff in there. So we were happy to have that car, but also it was really easy to
lock up the brakes in that pretty lightweight Miata. So one of the ways I learned and tell
if I've been locking up the brakes in a car is you can glance out the mirrors and you see tons
of white smoke come off the back of your vehicle. Yeah, that's not a good one. Oh, I'm locking the
tires. I mean, I just start pumping these brakes a little bit and get out of the fact that I'm
locking the tires up. So I'll always be watching your mirrors anyway, but it feels like I'm sliding
and not floating out. Let me glance out the mirror and see if there's a huge little white smoke coming
off of your locked up tire. Yeah, maybe one thing we could add though. You talked about a little bit,
but I'm not sure everybody's aware. If you're having an issue with front to back or back to front,
lockups, you may want to look at two different brake pads on the diffactals to get a better
balance unless you have a brake bias or fancy spansy schmancy stuff. But that's an easy knob
because we drive, well, until we run out, we have a stock of ST43s, but they're apparently
going away. But we use a different pad on the back to balance out the braking performance
front to back on our Civic. And we do it on almost the same thing on our Miata. We have two
who are always doing it there. That's pretty common. Yeah, that's a good point, Bill. It's
pretty common to try to balance out your braking compounds, your brake pad compounds.
Also, like you said, especially if you don't have a biasing knob that you can adjust the bias
directly with, sometimes you can adjust the bias by running pads that are happier at different
temperatures or something like that. Or different grips. Different. Yeah, different positions.
Yep. That's true. So we've definitely done the same thing. The old deal tricking me out is
used to be everybody used to run carbotech brakes. And you would run carbotech XP10s on
the front and XP8s on the back, just a little bit less friction in the back.
I like our version of that with the ST43s when we had our E30 was to run.
ST43s up front. And just because the pricing was messed up on the E30 rears, those tiny little
pucks that E30s had on the rear were more than the fronts in the ST43. But for some reason,
in the same, you know, the same manufacturer makes Porterfield and in Raybestis, the Porterfield
R4Es were less. And it just turns out, so we got those and turned out they wore exactly evenly
with the fronts because of the different friction. And we would literally get like 40 to 50 race
hours out of the set of both of those front and rear and they wear exactly even the cars really
balanced. So that there's a lot of value in trying to find compounds that work well for your vehicle.
Yep. And while we're here, we need to have a moment of silence. The ST40.
Pour it out. Oh, yeah. It's the ST43s. Anybody like Stoptec? That's gone now too, right?
Yep. Stoptec is gone. Raybestis. Yep. Porterfield.
I think. No, Porterfield and Raybestis, I thought were the same company. I guess maybe.
I think they're still there. I got to call Wendy, if that's true.
Porterfield is also a great break. So if Raybestis is going on Porterfield,
might be a good direction to turn in. Yeah. We're going to have to make,
we might have to have Wendy have a repeat, you know, even a short episode. Like what?
You know, and I got to say, if you're out in the weeds and not after this change with Raybestis
disappears and you're not sure what's working out real great, you know, a person who you can
turn to and ask and he will probably answer you, even if you don't buy stuff from him.
But it's also a guy who's constantly out there testing and racing is Chad Morehead.
Yep. So if you're dicking around like, oh, shit, what path is going to get next?
Ask Chad Morehead. Morehead Speedworks. That dude knows everything.
I would recommend you buy stuff from him, too. He's great to do business with.
You need racing stuff like brake fluid or anything. But that dude is also,
he's at the race in WRO all the time and like, you know, just constantly
tested and he's got, he's got clients who have them out there doing this stuff,
just kind of nonstop. So he's a great resource. That's who I would ask if I was like, oh crap,
what pad's good these days? Probably just ask, ask Chad Morehead. Awesome dude. Nice guy. Yep.
Yep. Well, hopefully, hopefully things will change, but the news at this point is not looking
good. But we'll see. Nope. Okay. There's always going to be good brakes out there. I mean, even
if it's not your latest favorite flavor, something will be out there and stop your car because
people want to do this quickly and well. So they're not doing it. Somebody else will come out and do
it. Indeed. The correct answer is not at advanced though. Yep. All right. Thank you, Ben. Thank
you. That was great. Good luck everybody with your flat spots and your feet on the brakes.
Thank you. Bye. I got, I got a dead spot. I can, I can edit that. That's fine. Thank you.
About this episode
Brake lockup and tire “flat spots” take center stage, with the hosts breaking down how sliding tires grind a square patch into a round tread, then make future lockups easier. They cover what to do (and not do) once it happens, including rotating the tire to the least-loaded corner instead of writing it off, and why ABS is the easiest prevention. Real-world stories include learning with different brake pads, spotting lockup via mirror smoke, and balancing front/rear braking compounds. The discussion also detours into pad availability and who to ask for current recommendations.
A link to the episode is: https://tinyurl.com/753FlatSpots
We hope you enjoy this episode!
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