My "unwarpable" discs were Godspeed........!

Chris

Scary, Ive bought loads from him & never had a problem, Were they def warped or was it possibly pad deposit build up which appears a common problem.

I assume you discused it with Ian.

Scary, Ive bought loads from him & never had a problem, Were they def warped or was it possibly pad deposit build up which appears a common problem.

A mechanic took a look at them and showed us the cracks around the drill holes which had led to them warping. He said this is common on drilled discs and he'd recommend just going grooved on any performance disc. We spoke to Ian and he did suggest pad deposits on the disc (stupid EBC Green Stuff's that he supplied!) but said that we'd have to bring them to his workshop in Wales for him to look at, which would mean we'd have to stay up there for a day or two with the car off the road.

In the end it would have been cheaper to just buy and fit new discs, but as it happened, we ended up selling the car

Chris

IIRC the disks in the factory are cast then drilled/faced off BEFORE heat treatment, so you would need to normalise the disk then heat treat the disk again, I did a set when i was an apprentice just to see if i could and it did work, but i only used the disks for a few hundred miles.

I cant recall the heating/cooling process for the heat treatment, but i could rake out my old notes if you really wanted them

Pretty much agree with the "forget cross-drilling" lobby. Aside from cracking issues, drilled discs are lighter than solid faces the same size, which must have an adverse effect on temperature build-up. Also, as others, the basis of both drilling and grooving is to reduce gas build-up under the pads, and grooves cover the whole pad area, not just a fraction of it.

some grooves dont cover the whole area actually

i dont think anybody will ever use thier brakes hard enough to take advantage of having grooves or 'oles.....

i think a lot of the hype attached to 'fancy' discs is purely for cosmetic reasons

i dont think anybody will ever use thier brakes hard enough to take advantage of having grooves or 'oles.....

i think a lot of the hype attached to 'fancy' discs is purely for cosmetic reasons

On a personal note I would beg to disagree

On a personal note I would beg to disagree

maniac??

:sofahide:

maniac??

:sofahide:

What would you be insinuating, I just use the full potential of the vehicle whenever suitable tarmac can be found :)

i dont think anybody will ever use thier brakes hard enough to take advantage of having grooves or 'oles.....

2 things there:-

1) Some Briskodans do track days in their road cars, and sufficient "hot laps" in a standard road car will fade the standard brakes on just about anything.

2) Some of the rest of us do things like descending passes at "fast road" pace, and even without full fade, you're aware of barking distances increasing towards the bottom.

2 things there:-

1) Some Briskodans do track days in their road cars, and sufficient "hot laps" in a standard road car will fade the standard brakes on just about anything.

2) Some of the rest of us do things like descending passes at "fast road" pace, and even without full fade, you're aware of barking distances increasing towards the bottom.

you're using the wrong brake fluid then. i'm sorry but grooved discs and 'black widow' pads or whatever they are called:rolleyes: are just gimmickey rubbish, and if you ever were to go on the track you'd be better off using sintered metal based pads because they have a higher coeffiecient of friction at high temperatures.

if you find your brakes are fading it's normally because the fluid is boiling and the best thing to do is err.... go slower

you're using the wrong brake fluid then. i'm sorry but grooved discs and 'black widow' pads or whatever they are called:rolleyes: are just gimmickey rubbish, and if you ever were to go on the track you'd be better off using sintered metal based pads because they have a higher coeffiecient of friction at high temperatures.

if you find your brakes are fading it's normally because the fluid is boiling and the best thing to do is err.... go slower

Tom.. I do appreciate that you have a modicum of mechanical knowledge but there are often times when your confidence in what you're saying is often a little misplaced and could potentially lead someone way off track.

Brake fade is not due solely to fluid issues.

When pads get hot their surface gives off vapour.

This vapour can get trapped between the pad and disc, causing "brake fade".

Grooved/drilled discs prevent this from happening.

Who told me about this? The boss of the Lotus Elise design team (though I expect he knows less about it than you so he's probably wrong )

Someone p!ss in your Coffee this morning Phil?

Sounds like a lot of hot air to me or should that be vapour.

...you're aware of barking distances increasing towards the bottom.

is there a scientific reason why a dogs voice travels further as altitude decreases :confused:

is there a scientific reason why a dogs voice travels further as altitude decreases :confused:

Would expect it to be the other way round as the air is "thinner" the higher the altitude?

Chris

Would expect it to be the other way round as the air is "thinner" the higher the altitude?

Chris

Its exactly the opposite Chris.

They say "in space, no one can hear you scream" - because the sound has nothing to pass through.

Sound cant pass through a vacuum (double glazing )

Thinner air = less ability for sound to travel.

Depends if the dogs got grooved discs I guess

Its exactly the opposite Chris.

They say "in space, no one can hear you scream" - because the sound has nothing to pass through.

Sound cant pass through a vacuum (double glazing )

Thinner air = less ability for sound to travel.

yep, that makes perfect sense now in a sorta similar (but equally OT) vein...why does cat **** stink so bad :thumbdwn:

Its exactly the opposite Chris.

They say "in space, no one can hear you scream" - because the sound has nothing to pass through.

Sound cant pass through a vacuum (double glazing )

Thinner air = less ability for sound to travel.

But surely with denser air, it requires more energy to make a sound travel because of the molecules banging into each other dissipating the energy quicker. As the air thins, each molecule can travel further (for the same energy). I agree in a vacuum you can't hear anything because there's no molecules .... but when the air thins there are :P

For comparison, try shouting on a clear summers night (when the air is dry and less dense) or in the rain. Which sounds travels further

Chris

But surely with denser air, it requires more energy to make a sound travel because of the molecules banging into each other dissipating the energy quicker. As the air thins, each molecule can travel further (for the same energy). I agree in a vacuum you can't hear anything because there's no molecules .... but when the air thins there are :P

For comparison, try shouting on a clear summers night (when the air is dry and less dense) or in the rain. Which sounds travels further

Chris

now i'm just confused... you both make such compelling arguements :confused:

now i'm just confused... you both make such compelling arguements :confused:

I'm probably wrong - I usually am :rofl:

Chris

When pads get hot their surface gives off vapour.

This vapour can get trapped between the pad and disc, causing "brake fade".

Grooved/drilled discs prevent this from happening.

Who told me about this? The boss of the Lotus Elise design team (though I expect he knows less about it than you so he's probably wrong )

yes i agree that pads do give off vapour and groovy discs will dissipate this, but a lotus elise is a fast car and may benefit from grooved discs, however for any road application plain disc should be adequate for anything you throw at them.

can anybody here actually prove that grooved discs reduce their braking distance??

can anybody here actually prove that grooved discs reduce their braking distance??

Not so much prove the distance but the ability to break later and harder for longer is certainly evident

yes but are you comparing like for like??

are you comparing a brand new set of groovies against a set of part worm oe discs??