Hot brakes and sparks

  • Thread starter Thread starter AleksandarSRB
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I've tried holding back on this one, but I can't any longer.

A number of people have reference deformed or warped rotor, hate to break it to you guys but this is a total myth. Simply does not happen at all, the reason why you get brake judder is not because rotor have warped, but because the pad deposits are uneven on the rotor surface.

Info - http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml


Regards

Scaff
 
ooh, i wish you had said that a few months ago i had a awesome pic of a volvo brake disc which was visibly warped at 5.deg because of a faulty pad carrier causing offset heat build up.
 
Aloha62_2
ooh, i wish you had said that a few months ago i had a awesome pic of a volvo brake disc which was visibly warped at 5.deg because of a faulty pad carrier causing offset heat build up.
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Did I really need to add in a caveat regarding correct fitting of the braking components?

You don't believe me that with correctly fitted components rotors don't warp, then take a look at the person who wrote the article I linked to, and consider its not just me you are disagreeing with.


By the way please ensure you follow the AUP when posting, that does include the use of capital letters at the start of sentences, for nouns and single 'I's.


Thanks

Scaff
 
Scaff, you have an amazing ability to win arguments end a discussion with a single post. :lol:

EDIT: Happy Griffith? ;)
 
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Argument? Not really. :)

Anyway, surely the "correctly fitting brake components" caveat extends to "correctly engineered brake components"?

I actually wasn't aware that "warped disk" refers exclusively to a retro-actively diagnosed cause for brake judder. In my mind, thermal warping can occur in any plane, in any direction, depending on loads and thermal stresses (directional) - in fact, figure 2 in your reference is precisely the sort of thing I was imagining. Then there's figure 3 - would that not induce judder? I'm not saying it's wrong, just confused as to why a distinction is asserted between "warping" (the false diagnosis), "collapsed" inter-vane sections and uneven pad-material deposits. If it's to do with the combination of directions that the pads are forced during application, then it makes sense. In that case, "warping" would perhaps (have been assumed to) be in the axial direction, resulting in a wave-like shape to the outer edge? That's something I've seen too many times on mountain bike brakes. :grumpy:
Interestingly, it just causes problems with drag (when not applied) and does not really cause problems when braking proper (fixed or floating caliper).

At least I've learned that when I said "warping" I actually (as seems to be more widely accepted) meant "distortion". Could it not be that many before me have also "confused" these same terms?

The other thing is that this is veering off-topic ever so slightly... :dopey:

EDIT: I think I was wrong about the oxide colour of steels being caused by alloying agents (e.g. Chromium), since ordinary steels will do the same. Instead, it's probably due to the thickness of the oxide (Magnetite) film - thicker films formed by higher temperatures and / or longer tempering times. See "Thin Film Interference". This should still hold for Titanium alloys, which are often coloured by oxidative electrolysis for "aesthetic effect" - here, the voltage and electrolysis time are analagous to temperature and time in ordinary temper colouration, leading to a variation in oxide film thickness.
 
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Griffith500
Argument? Not really. :)

Anyway, surely the "correctly fitting brake components" caveat extends to "correctly engineered brake components"?
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It certainly could, however the point remains that thermally induced warping is still one of the things least likely to occur to a brake rotor, its more likely to crack or collapse in the area between the vanes before warping.


Griffith500
I actually wasn't aware that "warped disk" refers exclusively to a retro-actively diagnosed cause for brake judder.
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It of course doesn't, but if I had a fiver for every time I have heard brake judder be instantly diagnosed as being caused by a warped disc I would be a very rich man (with well over a decade in the motor industry its something I have heard a lot).


Griffith500
In my mind, thermal warping can occur in any plane, in any direction, depending on loads and thermal stresses (directional) - in fact, figure 2 in your reference is precisely the sort of thing I was imagining. Then there's figure 3 - would that not induce judder? I'm not saying it's wrong, just confused as to why a distinction is asserted between "warping" (the false diagnosis), "collapsed" inter-vane sections and uneven pad-material deposits. If it's to do with the combination of directions that the pads are forced during application, then it makes sense. In that case, "warping" would perhaps (have been assumed to) be in the axial direction, resulting in a wave-like shape to the outer edge? That's something I've seen too many times on mountain bike brakes. :grumpy:
Interestingly, it just causes problems with drag (when not applied) and does not really cause problems when braking proper (fixed or floating caliper).
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Figure 2 references a crack near the centre of the rotor and the subsequent failure of the rotor, as with the other two issues these are not 'warping; in the normally accepted definition of the word.

Mountain bike rotor as commonly made from Stainless Steel, which of course does not act in the same manner as Cast Iron (used exclusively for metal car rotors) when it comes to these kinds of stress'. Which could well explain the difference you have found.



Griffith500
At least I've learned that when I said "warping" I actually (as seems to be more widely accepted) meant "distortion". Could it not be that many before me have also "confused" these same terms?
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That's a large part of it, the term warping has (in this case) entered common usage, despite actually being an inaccurate description of the actual situation.

I guess things like that just annoy me quite a bit.
 
Realistic sparks and backfires would be a nice little addition to the game. Hearing the engine pop as the car backfires and seeing a little flame come out of the exhaust would be awesome.
 
Scaff
A number of people have reference deformed or warped rotor, hate to break it to you guys but this is a total myth. Simply does not happen at all, the reason why you get brake judder is not because rotor have warped, but because the pad deposits are uneven on the rotor surface.
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Rubbish. A few months after passing my test, I had a car that stopped just fine, nothing wrong with the brakes at all in that regard. My late father (a fully qualified mechanic of over 40 years experience) had fitted new brake pads a few months earlier, and there was no judder at all. One day, I was driving along a dual carriageway going to my cousins, where the slip road off is insanely short and has a really tight turn. In my inexperience I misjudged my speed and had to ram the braks as hard as I could while trying not to skid and coax the thing around the corner. Immediately after that my brakes were juddery and not as responsive.

I got home the next day and my dad took a look - his immediate diagnosis was two visibly warped disks at the front. The next week it needed an MOT, and without mentioning anything to the garage about the brakes beforehand, they failed it due to having two warped disks at the front. Exactly why it happened is irrelevant, because the fact is, the disks were not warped when I set off, but were warped when I got home.

It may be much less likely to happen these days, maybe if at all, but to say it simply does not happen at all is just a bit naive.
 
TokyoDrift
Rubbish. A few months after passing my test, I had a car that stopped just fine, nothing wrong with the brakes at all in that regard. My late father (a fully qualified mechanic of over 40 years experience) had fitted new brake pads a few months earlier, and there was no judder at all. One day, I was driving along a dual carriageway going to my cousins, where the slip road off is insanely short and has a really tight turn. In my inexperience I misjudged my speed and had to ram the braks as hard as I could while trying not to skid and coax the thing around the corner. Immediately after that my brakes were juddery and not as responsive.

I got home the next day and my dad took a look - his immediate diagnosis was two visibly warped disks at the front. The next week it needed an MOT, and without mentioning anything to the garage about the brakes beforehand, they failed it due to having two warped disks at the front. Exactly why it happened is irrelevant, because the fact is, the disks were not warped when I set off, but were warped when I got home.

It may be much less likely to happen these days, maybe if at all, but to say it simply does not happen at all is just a bit naive.
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Are you actually claiming here that from a single braking incident you managed to warp two rotors?

If so I'm not the naive one here at all.

Now actually go back and read the piece I linked to (written by a man with over 40 years in the racing business). What is far more likely to have happened is that you're single braking incident, particularly if you left the brakes jammed on, left a nice healthy build-up of brake pad material on the rotor. Which will cause quite unpleasant judder.

As the piece (and my own experience) explain, this is very commonly miss-diagnosed as warped brakes. That alone does not make them warped.

Its also interesting that you claim that the car failed its MOT due to warped rotors, funny that as the condition of the brakes are NOT checked (past obvious leaks in the system and corrosion to the brake lines), rather the efficiency of the braking system is.

Source - http://www.motinfo.gov.uk/htdocs/m4s03001001.htm

Even if the brakes judder its not an automatic failure, that would only occur should they fail to provide the required stopping efficiency, at most judder alone would get you an advisory note on the test.



Scaff
 
Scaff
...

Figure 2 references a crack near the centre of the rotor and the subsequent failure of the rotor, as with the other two issues these are not 'warping; in the normally accepted definition of the word.

Mountain bike rotor as commonly made from Stainless Steel, which of course does not act in the same manner as Cast Iron (used exclusively for metal car rotors) when it comes to these kinds of stress'. Which could well explain the difference you have found.
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Bah, I thought I checked the figure numbers, but probably got it wrong - I was watching the game at the time! :dopey:

Anyway, I meant the figure showing the "coning" of the disk, and then the figure showing the collapsed vanes.

I'd forgotten about the stainless steel thing. That would indeed better explain it, thanks! 👍
However, the most usual cause of mountain bike brake disk "warping" is in fact mechanical, not thermal - by which I mean, caused by the bike landing on things... (at least in my experience! :lol:)

Scaff
That's a large part of it, the term warping has (in this case) entered common usage, despite actually being an inaccurate description of the actual situation.

I guess things like that just annoy me quite a bit.
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I understand totally. People sometimes forget just how important terminology can be. That's the major problem I have going to the doctors' - they often refuse to explain things in a way that somebody without a medical dictionary shoved up their arse can actually understand!! And don't get me started on research / science vs. engineering... :D
 
Griffith500
However, the most usual cause of mountain bike brake disk "warping" is in fact mechanical, not thermal - by which I mean, caused by the bike landing on things... (at least in my experience! :lol:)
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I can vouch for that! :dopey: Besides, you have more important things to worry about than warped rotors if you actually manage to thermally warp your bike's brakes.
 
After TGS it's confirmed that we will have hot brakes... So I think that is great visual effect, especially in night races! :)
 
AleksandarSRB
After TGS it's confirmed that we will have hot brakes... So I think that is great visual effect, especially in night races! :)
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Hopefully this will also effect braking capability in a long race, the brakes will wear after constant usage and become less efficient, i hope this is all implemented correctly! :D
 
Hot brakes and the exhaust explosions are both confirmed in the night race video. At 1:25-30 the exhaust flashes as they shift down for the first chicane, it look incredible.

http://www.gamersyde.com/stream_gran_turismo_5_tgs_le_mans_replay-17195_en.html

Brake wear will be a great addition and will really change strategies. It wont just be about caining it around getting the fastest lap possible, we'll have to manage our pace.
 
Matti_Dude
Realistic sparks and backfires would be a nice little addition to the game. Hearing the engine pop as the car backfires and seeing a little flame come out of the exhaust would be awesome.
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👍
I agree! I have seen and heard this in games that are 5 years old!
 
SgtWhitten
Brake wear will be a great addition and will really change strategies. It wont just be about caining it around getting the fastest lap possible, we'll have to manage our pace.
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It MAY be a great edition, glowing brakes is not a confirmation of brake wear,
after all the brakes would glow red hot in GT4 but it didnt confirm brake wear, it was just a nice effect, and although we know mechanical damage is in, we still do not know how detailed it will be.
 

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