flat spot tires
Race Car
Joined: Nov 2005
Posts: 3,915
Likes: 14
From: Calgary...Under my car... :)
Shaving them can help, it depends on how badly flat spotted they are. If you use the car on the track unfortunatly they will always "stop" on the flatspot area and keep locking up... If the flatspot was caused by locking the wheels and they generated alot of heat, the rubber changes (just like heat cycles in tires, they can only go through so many).
I have always just replaced them, find someone to shave them (should be cheap) as the starting point, if it works great otherwise get your self some replacements.
I have always just replaced them, find someone to shave them (should be cheap) as the starting point, if it works great otherwise get your self some replacements.
Thread Starter
Three Wheelin'
Joined: Dec 2006
Posts: 1,607
Likes: 2
From: Portland, OR
Never heard of shaving....
Have you guys ever heard of rotors being so rusting from a car standing to the point of where it feels as if the rotors are warped when driving the car?
or could this really be a tire problem?
Have you guys ever heard of rotors being so rusting from a car standing to the point of where it feels as if the rotors are warped when driving the car?
or could this really be a tire problem?
Race Car
Joined: Nov 2005
Posts: 3,915
Likes: 14
From: Calgary...Under my car... :)
Steve W would be able to give you a name of someone there in OR where you could get them done. Shaving is done regularily by track junkies to reduce tread block movement and the subsequent temperature issues.
Just because the rotors are rusted doesn't always mean they are warped. I would have the runout of the rotors checked, I assume you have driven it enough now that there is no more rust? If it is only surface rust drving is ok ish, if there is a ton of rust I would have them re-surfaced.
For a car like yours that has sat for while it is prudent to pull everything off and check them, it could be rotors or the tires. Do you have access to a wheel balancer? If so spin up the wheels and have a look, could also be bent wheels. This really is a process of elimination. For locals to do the work I would see Steve W, I haven't had work done by him, however when I had some issues he was very helpful and spent quite a while on the phone with me..
Just because the rotors are rusted doesn't always mean they are warped. I would have the runout of the rotors checked, I assume you have driven it enough now that there is no more rust? If it is only surface rust drving is ok ish, if there is a ton of rust I would have them re-surfaced.
For a car like yours that has sat for while it is prudent to pull everything off and check them, it could be rotors or the tires. Do you have access to a wheel balancer? If so spin up the wheels and have a look, could also be bent wheels. This really is a process of elimination. For locals to do the work I would see Steve W, I haven't had work done by him, however when I had some issues he was very helpful and spent quite a while on the phone with me..
Thread Starter
Three Wheelin'
Joined: Dec 2006
Posts: 1,607
Likes: 2
From: Portland, OR
Thanks for the advice.
I have drivin it for about 7-9 miles and the rust isent gone.
I lifted the front end and spun the tire by hand and saw that there is a flat spot, Doesent seem like much of a spot but probably enough to be part of the problem.
Im almost certin the rotors are not bent, there is NO way someone would drive the car with the way it is when you try to stop.
I think it is pretty simple but I will see. I think it is the flat spot plus the Rust that is left that is making this possible. I will drive it more and do some hard braking and see if it helps.
I have drivin it for about 7-9 miles and the rust isent gone.
I lifted the front end and spun the tire by hand and saw that there is a flat spot, Doesent seem like much of a spot but probably enough to be part of the problem.
Im almost certin the rotors are not bent, there is NO way someone would drive the car with the way it is when you try to stop.
I think it is pretty simple but I will see. I think it is the flat spot plus the Rust that is left that is making this possible. I will drive it more and do some hard braking and see if it helps.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
It seems like we are discussing two separate things here: rusty rotors (they do not warp) and flat spotted tires,...
I need a LOT more detailed information here to be able to offer anything constructive beyond what I've already written,...
I need a LOT more detailed information here to be able to offer anything constructive beyond what I've already written,...
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Rennlist Member
Joined: May 2002
Posts: 23,303
Likes: 511
From: Baltimore, MD
Most tire shops that I've spoken with won't even think of shaving a used tire, lest road grit damage the cutting blades. Also, at least with MPSC's, Hoosier R6's and BFG R1's (all R compound track tires), I have never had an issue with permanent flat spotting.
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Thread Starter
Three Wheelin'
Joined: Dec 2006
Posts: 1,607
Likes: 2
From: Portland, OR
It "feels" like warped rotors when you step on the brakes, However I dont think thats what it is. and I was asking if you have ever heard or seen anything like that happen from rusty rotors (I mean get the feeling of warped rotors) not getting warped rotors from rust.
Rennlist Member
Joined: May 2002
Posts: 23,303
Likes: 511
From: Baltimore, MD
I dont think you guys understood my first post.
It "feels" like warped rotors when you step on the brakes, However I dont think thats what it is. and I was asking if you have ever heard or seen anything like that happen from rusty rotors (I mean get the feeling of warped rotors) not getting warped rotors from rust.
It "feels" like warped rotors when you step on the brakes, However I dont think thats what it is. and I was asking if you have ever heard or seen anything like that happen from rusty rotors (I mean get the feeling of warped rotors) not getting warped rotors from rust.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
In conclusion, I'd ask (assuming that you have a vibration):
1) Did you actually flat-spot your tires (which is visible by inspection while rotating the wheels)??
2) Did you check the axial runout of your brake rotors to see if they are damaged?
Vibrations can be caused by a multitude of tire problems as well as some brake-related issues and worn front suspension bushings. Some detective work may be in order to find the source of the problem.
1) Did you actually flat-spot your tires (which is visible by inspection while rotating the wheels)??
2) Did you check the axial runout of your brake rotors to see if they are damaged?
Vibrations can be caused by a multitude of tire problems as well as some brake-related issues and worn front suspension bushings. Some detective work may be in order to find the source of the problem.
Thread Starter
Three Wheelin'
Joined: Dec 2006
Posts: 1,607
Likes: 2
From: Portland, OR
1. Yes I lifted the car and did see a flat spot when spinning the wheels by hand.
2. Axial runout? not sure what that is sorry.
Also Vibration only comes when I brake. The faster I go the worse it is. Would flat spot tires cause pushback (or vibration) on the brake pedal?
2. Axial runout? not sure what that is sorry.
Also Vibration only comes when I brake. The faster I go the worse it is. Would flat spot tires cause pushback (or vibration) on the brake pedal?
Racer
Joined: Nov 2007
Posts: 399
Likes: 2
From: Seattle, WA
You basically mount dial gauge to where the caliper goes and measure the height to the rotor surface as the rotor is turned.
What I am guessing is that you have a bit of pad deposition, and a few good panic stops from 85mph down to 20mph will clean the rotors up and that should be that.
If your tires sat for a long time (talking 10s of months or so) then they can develop a flat-spot. This is different than the "I flat spotted my tires because I forgot my car doesn't have ABS".
To eliminate that, just swap tires with a friend and buy him a beer.
What I am guessing is that you have a bit of pad deposition, and a few good panic stops from 85mph down to 20mph will clean the rotors up and that should be that.
If your tires sat for a long time (talking 10s of months or so) then they can develop a flat-spot. This is different than the "I flat spotted my tires because I forgot my car doesn't have ABS".
To eliminate that, just swap tires with a friend and buy him a beer.