ClioSport.net

Register a free account today to become a member!
Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

  • When you purchase through links on our site, we may earn an affiliate commission. Read more here.

Clio big brake conversions?



  182/RS2/ Turbo/Mk1
Oh I know but what I'm saying is 280mm with good pads would be fine IMO, its a Clio not an escos or sierra remember. 300mm for show 280mm if that is all that can be done.

Ive had decent quality 280mm disks with ds2500 and with pagid blues, they just cant cope mate, on a long session the heat is getting into the disks quicker than it gets out again and that means they end up warping.
The difference between an escort cosworth and a clio with 300bhp is that the escort is heavier so requires more braking from the same speed which is why you are thinking they require bigger disks I assume?
But the thing is that if you put the same 300bhp into both of them, then the clio is going far faster than the escort, so although its lighter it needs to be stopped from a higher speed, which means that its essentially roughly the same amount of energy that needs to be got rid of either way.
In fact if anything for reasons that get a little more complicated such as the escort can technically carry more energy around the bend, and has far higher wind resistance, if anything I would say that the clio probably has to lose marginally more energy if anything, not less like you are thinking.
 
  Cup In bits
Lol at that answer, nothing to do with power. Try your 300mm setup and you'll realise it is overkill for a one ton car. Cossy = heavy car. Clio = light car, four pots don't put as much heat into the disk for a start as you have to brake lighter for the same effect, hence I think 280mm with four pots will be fine. Irrelevant if its 20mph faster at a braking point like your saying etc etc then you brake earlier as its carrying more speed, simple no?!?
 
  182/RS2/ Turbo/Mk1
Lol at that answer, nothing to do with power.

WTF?
Nothing to do with power?

Its a REALLY simple process mate, the engine puts energy into the car on the straights, the brakes need to then take it back out at the end of the straight before the corners, I cannot understand how you cant grasp something that basic, the more energy you put in on the main part of the straight with the engine the more you have to take out again at the end. Literally joule for joule, its a straight transaction.
Then once the energy has been taken out of the process as heat into the disk, it then has to lose that heat before it can absorb more, or it gets too hot and warps the disk. (exactly what mine does on 280mm, the brakes actually work very well but in one day on track will warp and I dont want to have to buy a new set of disks every time I go on track)

Try your 300mm setup and you'll realise it is overkill for a one ton car.
Ive driven lighter cars on bigger brake setups, and its been correctly matched to the job, 305mm disks on a 400bhp 900kg Astra turbo that I mapped for example. When he tried with 288mm disks beforehand they were nowhere coping and would warp in a single session, when you are putting 400bhp of energy into a car for 30-50% of the lap and only have 10% of the lap to take it out again, it quickly results in the temperature of the disks getting too high.

Cossy = heavy car. Clio = light car, four pots don't put as much heat into the disk for a start as you have to brake lighter for the same effect
FLOL!

You really dont even understand physics to a GCSE level do you? The energy of the car has to be converted into heat for the car to slow down, the same amount of heat needs to be generated in friction wether its a 4 pot or a single pot thats doing the clamping. Where do you think the extra energy from the cars momentum goes on a 4 pot?
Sure the calipers being larger and ally will dissipate the share going into the pads a little more quickly which helps with things like not boiling brake fluid but that doesnt significantly change the amount of heat that the disks have to absorb.



hence I think 280mm with four pots will be fine.
Well based on the way you think about things (ie without the most basic of understanding of the laws of physics, such as "energy cannot be created or destroyed merely transformed from one form to another" then I can understand why you would think that.

Irrelevant if its 20mph faster at a braking point like your saying etc etc then you brake earlier as its carrying more speed, simple no?!?
Yes if your brakes arent big enough to convert the kinetic energy into heat energy fast enough to still slow the car down in the same amount of distance then you need to brake sooner to still get down to the same speed, but what that means is that they are now working flat out for longer, which means they raise the temperatures of the disks by more, thats EXACTLY the problem that I have on 280mm disks on my turbo, Im on the brakes so hard for so long that the 280mm disks just cannot act as a big enough reservoir for that amount of energy, so their temperature elevates beyond the point that the material can cope with.


Basic newtonian kinetic energy

Ek = 0.5 * M * V * V

So if you have a car of mass 1000kg and it is going to enter a corner at 80mph (35.8 metres per second) then you need to enter that corner with a total energy of:

0.5 * 1000 * 35.8 * 35.8 = 640820 Joules = 0.641 MJ


Now if we are doing 90mph (40.2 metres per second) before we brake for that bend than we have:
0.5 * 1000 * 40.2 * 40.2 = 808020 = 0.808 MJ

And if we are doing 110mph (49.2 metres per second) then we have:


0.5 * 1000 * 49.2 * 49.2 = 1210320 = 1.21 MJ


So at 90mph approach to an 80mph bend we need to convert .808 - 0.641 = 0.167 MegaJoules of kinetic energy into heat
And at 110mph we need to convert 1.21 - 0.641 = 0.569 MegaJoules of energy


So in fact we can see that in our (heavily over simplified I must confess, ignored drivers weights and rounded to only 3SF etc) example of camp corner at combe comparing my car and my mrs car we find that I need to put 3.4 times more energy into the brakes than she does as heat.


Just to show you what I mean about the weight effecting energy carried and speed attained etc:


A 1400kg escort with 300bhp I know from personal experience will be doing approx 100mph (44.7 m/s) on the approach to the same corner
0.5 * 1400 * 44.7 * 44..7 = 1398663 = 1.40 MJ of energy

It will also take the bend at approx 80mph, so can carry:

0.5 * 1400 * 35.8 * 35.8 = 877100 Joules = 0.877 MJ

So the escort needs to lose 1.40 - 0.877 = 0.523 MJ


So as you can see in that example the braking requirements of the escort and the clio are in fact almost identical, and if anything its in fact the clio that needs very marginally more if anything, although we are talking such a minor difference that its best not to be considered too signfiicant due to the inherently rushed nature of my calculations having minor rounding errors and some assumptions rather than exact real world data etc.



Hope that helps you understand brakes a little mate :)
 
WTF?
Nothing to do with power?

Its a REALLY simple process mate, the engine puts energy into the car on the straights, the brakes need to then take it back out at the end of the straight before the corners, I cannot understand how you cant grasp something that basic, the more energy you put in on the main part of the straight with the engine the more you have to take out again at the end. Literally joule for joule, its a straight transaction.
Then once the energy has been taken out of the process as heat into the disk, it then has to lose that heat before it can absorb more, or it gets too hot and warps the disk. (exactly what mine does on 280mm, the brakes actually work very well but in one day on track will warp and I dont want to have to buy a new set of disks every time I go on track)


Ive driven lighter cars on bigger brake setups, and its been correctly matched to the job, 305mm disks on a 400bhp 900kg Astra turbo that I mapped for example. When he tried with 288mm disks beforehand they were nowhere coping and would warp in a single session, when you are putting 400bhp of energy into a car for 30-50% of the lap and only have 10% of the lap to take it out again, it quickly results in the temperature of the disks getting too high.


FLOL!

You really dont even understand physics to a GCSE level do you? The energy of the car has to be converted into heat for the car to slow down, the same amount of heat needs to be generated in friction wether its a 4 pot or a single pot thats doing the clamping. Where do you think the extra energy from the cars momentum goes on a 4 pot?
Sure the calipers being larger and ally will dissipate the share going into the pads a little more quickly which helps with things like not boiling brake fluid but that doesnt significantly change the amount of heat that the disks have to absorb.




Well based on the way you think about things (ie without the most basic of understanding of the laws of physics, such as "energy cannot be created or destroyed merely transformed from one form to another" then I can understand why you would think that.


Yes if your brakes arent big enough to convert the kinetic energy into heat energy fast enough to still slow the car down in the same amount of distance then you need to brake sooner to still get down to the same speed, but what that means is that they are now working flat out for longer, which means they raise the temperatures of the disks by more, thats EXACTLY the problem that I have on 280mm disks on my turbo, Im on the brakes so hard for so long that the 280mm disks just cannot act as a big enough reservoir for that amount of energy, so their temperature elevates beyond the point that the material can cope with.


Basic newtonian kinetic energy

Ek = 0.5 * M * V * V

So if you have a car of mass 1000kg and it is going to enter a corner at 80mph (35.8 metres per second) then you need to enter that corner with a total energy of:

0.5 * 1000 * 35.8 * 35.8 = 640820 Joules = 0.641 MJ


Now if we are doing 90mph (40.2 metres per second) before we brake for that bend than we have:
0.5 * 1000 * 40.2 * 40.2 = 808020 = 0.808 MJ

And if we are doing 110mph (49.2 metres per second) then we have:


0.5 * 1000 * 49.2 * 49.2 = 1210320 = 1.21 MJ


So at 90mph approach to an 80mph bend we need to convert .808 - 0.641 = 0.167 MegaJoules of kinetic energy into heat
And at 110mph we need to convert 1.21 - 0.641 = 0.569 MegaJoules of energy


So in fact we can see that in our (heavily over simplified I must confess, ignored drivers weights and rounded to only 3SF etc) example of camp corner at combe comparing my car and my mrs car we find that I need to put 3.4 times more energy into the brakes than she does as heat.


Just to show you what I mean about the weight effecting energy carried and speed attained etc:


A 1400kg escort with 300bhp I know from personal experience will be doing approx 100mph (44.7 m/s) on the approach to the same corner
0.5 * 1400 * 44.7 * 44..7 = 1398663 = 1.40 MJ of energy

It will also take the bend at approx 80mph, so can carry:

0.5 * 1400 * 35.8 * 35.8 = 877100 Joules = 0.877 MJ

So the escort needs to lose 1.40 - 0.877 = 0.523 MJ


So as you can see in that example the braking requirements of the escort and the clio are in fact almost identical, and if anything its in fact the clio that needs very marginally more if anything, although we are talking such a minor difference that its best not to be considered too signfiicant due to the inherently rushed nature of my calculations having minor rounding errors and some assumptions rather than exact real world data etc.



Hope that helps you understand brakes a little mate :)

I learn more from that post then in all my science lessons at school lol. Didn't know the science of braking was so in depth I just thought the more power the bigger the brakes regardless of car size
 
  182/RS2/ Turbo/Mk1
PS

Ive got an RS2 cup to map today for a mate of mine so wont have free time till probably this evening, but when I get a chance then for those who actually want to learn properly about brakes properly I will weigh a 280mm disk and a 300mm disk, and then based on a specific heat capacity of 0.49 for carbon steel I will work out for you the actual difference in temperature that the two disks will go through for the figures given above to show you even more about why bigger disks are so essential on higher power cars.
 
  Cup In bits
Lol at the answer again, no need to go so in depth. I understand that energy doesn't disappear but is transformed into other energy, noise, heat etc and Newton's first law of every force has an equal and opposing force da da da da DA.

The Escort v Clio example.

2 cars entering the corner at the same speed irrelevant of horsepower like I said previously before you assumed I didn't know basic physics. The Clio has less braking to do (as in it creates less joules of energy due to the lower mass that needs stopping, less energy transfer in Jargon) than the Escort.

As far as difference between calipers the 4pots will have to transfer the same energy as the standard calipers but will do it over a shorter time creating less heat in the process and dispersing it better also (your words) your problem is heat not performance so 4 pots on 280mm disks will out perform standard calipers and disperse the heat better due to less heat being created.

No need for mathematical equations, your not splitting an atom your choosing brakes to fit to your car.
 
Last edited:
  182/RS2/ Turbo/Mk1
I learn more from that post then in all my science lessons at school lol. Didn't know the science of braking was so in depth

Its a lot easier to learn when its a subject that interests you :)

TBH that is just scratching the surface of the whole science of brakes mate, I could explain far deeper with a lot more time, and then someone with a PHD in such things could then go ten times further than I can.

I just thought the more power the bigger the brakes regardless of car size
That is the golden rule for a trackday car. The more power you have, the bigger the brakes you require.

Its not a direct relationship so if you double the power of your car, then you need to go for brakes that can absorb significantly more heat or you will warp them but its not a case of being exactly double the heat capacity needed, as wind resistance on a big straight will absorb more of the power hence leaving less for the brakes to do etc, and there are of course exceptions for light but horrifically poor from an aerodynamics point of view cars (porkies westfiend being a great example) as it means that the extra power doesnt yield anything like the extra speed you would expect.


For a road car (essentially infinite space to get upto speed in means that its a very different equation and power is more or less removed from it) its more about weight though, and people often get the two confused. So start thinking weight is all that matters on track when deciding the size of brakes too, but thats of course far from being the case.
 
Last edited:
  182/RS2/ Turbo/Mk1
Lol at the answer again, no need to go so in depth. I understand that energy doesn't disappear but is transformed into other energy, noise, heat. Newtons law of every gorse has an e

Well clearly you DONT understand mate, or you wouldnt be saying that a 300bhp escos needs bigger brakes on a trackday than a 300bhp clio just because its heavier.
Power is far more of an indicator of brake size suitability for a trackday car than weight is, as weight will effect the speed achieved on a short straight so much in the first place, so if the cars are the same power the lighter one will be moving faster which negates the weight difference when it comes to braking.
 
  Cup In bits
PS I never said anything about a Clio with 300bhp versus an escort with 300bhp which is your argument. I am speaking about weight and simply that, two cars irrelevant of power the Clio has less work to do in braking.
 
  182/RS2/ Turbo/Mk1
PS I never said anything about a Clio with 300bhp versus an escort with 300bhp which is your argument. I am speaking about weight and simply that, two cars irrelevant of power the Clio has less work to do in braking.

That statement simply makes no sense at all, as demonstrated power is the key factor so trying to spec brakes while ignoring power is never going to work on weight alone. You may as well try and spec based on the colour of the car. Flol
 
  182/RS2/ Turbo/Mk1
The formula renaults have tiny brakes compared to their f4r Clio counterparts?

Main reason for that is the amount of extra energy they carry through the bends. If you carry more energy through the bends you need to dissipate less before hand.
Plus aerodynamics of course, any car with downforce aids uses a lot of power just to make those work, so that power can be removed from the equation.

also the rear wheels do a lot more of the braking than on a road car of course. So this lessens the requirements on the front too.

Then they are better materials and replaced more often as well of course.

Basically its a drastically different application. But those are factors that don't come into play as much when comparing say an escort and a Clio.
 
Last edited:
  Cup In bits
The formula renaults have tiny brakes compared to their f4r Clio counterparts?

Exactly they weigh less, go faster and hold higher cornering speeds but still do with smaller brakes.

But chip will argue that 3.1444444444 to the power of ten will leave joules (that's Jims sister) with a sore big toe due to the higher pedal exertion applied. Childish, yes but no need to beso pedantic.

That statement simply makes no sense at all, as demonstrated power is the key factor so trying to spec brakes while ignoring power is never going to work on weight alone. You may as well try and spec based on the colour of the car. Flol

Makes perfect sense, that was my initial statement and you started bringing even powered cars with different weights and lower corner entry speeds into things. Explain how a standard Clio doesn't have to do less braking than a standard escort given that they both enter the same braking zone at 100mph and have to achieve the same speed by the same apex of the same corner and have the same co effiecient of drag but the only differing thing is weight?
 
  182/RS2/ Turbo/Mk1
Exactly they weigh less, go faster and hold higher cornering speeds but still do with smaller brakes.

But chip will argue that 3.1444444444 to the power of ten will leave joules (that's Jims sister) with a sore big toe due to the higher pedal exertion applied. Childish, yes but no need to beso pedantic.

No as per my reply above yours, I will reply saying that because they hold so much higher cornering speeds it means that they need to dissipate less heat, and also factors like the rear doing more because of the aero keeping the weight on it, and the more even weight distribution keeping more weight on the rear effect it too, as does losing more power to aero.


Makes perfect sense, that was my initial statement and you started bringing even powered cars with different weights and lower corner entry speeds into things. Explain how a standard Clio doesn't have to do less braking than a standard escort given that they both enter the same braking zone at 100mph and have to achieve the same speed by the same apex of the same corner and have the same co effiecient of drag but the only differing thing is weight?
A standard clio and a standard escort both entering a braking zone at 100mph, would mean that one of two things was true:
The escort has more power, and hence needs bigger brakes.
We are talking about a motorway not a race track, in which case I said for a road car weight is more of an issue than power as unlike a trackday car power doesnt greatly effect speeds achieved as you dont hold your car flat out on the road between bends like you do on a trackday.


Just for the record though, an escort cosworth has 278mm front brakes, and a 172 has 280mm front brakes by the way. If you are talking about the standard cars. Both on floating 1 pot calipers, so actually the clio does have very slightly better brakes as standard.


Thing is though, I dont understand why you are talking about standard cars in an attempt to tell me why my clio doesnt need 300mm brakes, as you seem to have missed the part where my car has nearly double the standard power and more than double the standard torque, and this DOES effect what brakes it needs no matter how you try and ignore it because you want to talk about something completely different apparently.

I just cant see why you are using my thread to discuss the standard brakes on standard road cars, surely if that is what you want to talk about you should do so in a thread about that, not one about trackday brakes for much higher than standard power cars?
 
  182/RS2/ Turbo/Mk1
So maybe you should focus on higher cornering speeds and aero, you might not need 300mm discs then ;)

Ive focussed on higher cornering speeds already to a limited extent.
But my car is a road a car, and as such I dont want to cover it in horrendous wings etc, so I have limited my changes to cornering just to improving the suspension, diff and tyres, and even with tyres I am limited to what trackday organisers will allow on track, on saturday for example im at come and hence not allowed to run full slicks even if I had a set which I dont.
you are correct though (as Ive already mentioned with my previous posts in this thread) that if I did manage to add enough wings and splitters etc to allow to me to take bends 20mph or whatever faster it would indeed reduce dramatically the requirement for bigger brakes if you were talking about on an empty track, but given that my hobby is trackdays it wouldnt greatly effect my corner speeds as much as it might look on paper that it might if I did have big wings and slick tyres etc, as I tend to find that the majority of corners that I enter my cornering speed is limited by other track users, as you arent allowed to overtake mid bend and im generally already quicker through the bends than a lot of the cars im typically on track with anyway.
 
  Cup In bits
I tried to help with pictures and information to fit 197/225 brembos under a 15" oz f1 originally and then passed on information from actual experience of how my brakes were more than sufficient with standard pads and yours would suffice with a better pad on my setup.

You then went off on a tangent when I suggested it was a Clio you were specing and not a Escos or Sierra like you referenced in this thread and you usually reference in most threads. You started saying Escorts need different brakes because power not because weight as its a track car and not a road car and just generally over complicating a simple situation.

I said 280mm 4pots would suffice as simple as that you disagreed and threw maths at it.
 
  182/RS2/ Turbo/Mk1
I tried to help with pictures and information to fit 197/225 brembos under a 15" oz f1 originally and then passed on information from actual experience of how my brakes were more than sufficient with standard pads and yours would suffice with a better pad on my setup.

How much experience of my car on a track do you actually have to draw that conclusion from out of interest mate? (or something very similar to it at least)
You seem to think that your own car is somehow a good gauge of what mine needs, if I was driving around at never anymore than half throttle that might be the case, but the moment I use anymore than that your just becomes irrelevant as its so low powered.


You then went off on a tangent when I suggested it was a Clio you were specing and not a Escos or Sierra like you referenced in this thread and you usually reference in most threads. You started saying Escorts need different brakes because power not because weight as its a track car and not a road car and just generally over complicating a simple situation.

I said 280mm 4pots would suffice as simple as that you disagreed and threw maths at it.

Threads like this probably arent for you if you think that actually considering the amount of energy involved is "over complicating" deciding on brakes, as that is the thing they need to do, collect and then dissipate energy.
The problem I am having is that 280mm disks get too hot and warp, changing calipers wont effect that at all, they will still get just as hot.

The only way to use a 280mm disk for really my application would be to swap to a wider one so that it can contain more energy for the same rise in temperature, so for example going from the standard 24mm to a 28mm 280mm instead would do the trick as well, this what something else I considered but Im keen to keep the ongoing costs low and the 300mm disks I have used are very cheap as they are just scenic ones drilled and grooved.

There are also some other advantages to 300mm in that they have a larger surface area to dissipate heat from, even when compared to a wider 280mm of the same weight.
 
  Cup In bits
You have an answer for everything, can you not just admit you took my original comments out of context and be done with it.

Using logic with how much excess of braking I have in my car and adding that to a better friction material I would say its more than enough to suit your car.

You originally said you were looking for a setup to go under 15" oz f1's, i gave you my info then you said that you were looking for a setup for your missus car as you seem to have figured out a solution for yours on 300mm disks albeit not a very good one with huge spacers and no clearance. So the reference to my car is more than useful for your brief, overkill Infact on a track car and all on 280mm disks.
 
  182/RS2/ Turbo/Mk1
You have an answer for everything

I certianly have a lot of ansers when it comes to basic maths and basic phyiscs mate yes, I could easily teach GCSE physcs tomorrow I would imagine, so any question you ask that is at that level I can give you a really detailed answer for yes.

Using logic with how much excess of braking I have in my car and adding that to a better friction material I would say its more than enough to suit your car.

I felt that too when my car was around the 260bhp mark, and it did just about cope then, but with the extra power now, not to mention all the extra torque spread I im going so much faster now that it simply isnt good enough anymore, I know this because I have tried it, and a set of disks dont last a day, its not an old lipped and worn out set I warped at bedford, it was a nearly new set.
And I cant afford to add a set of 280mm disks to the cost of every trackday I do.



You originally said you were looking for a setup to go under 15" oz f1's, i gave you my info then you said that you were looking for a setup for your missus car as you seem to have figured out a solution for yours on 300mm disks albeit not a very good one with huge spacers and no clearance. So the reference to my car is more than useful for your brief, overkill Infact on a track car and all on 280mm disks.
For my mrs car I think that the 4 pots and 280 would be fine, in fact standard calipers are good enough, but I'd like the later braking points a 4 pot can offer me by putting the same amount of energy into the disks at a faster rate mainly due to a larger pad area.

The big spacers work well on track mate and even on the road dont effect the road manners like they would on say a corsa, I went and did some road miles and a very tight trackday with them on first before I even started making the brakes just to make sure it wouldnt have adverse effects on the handling like I thought it might but Tony had already proved they can work well as he runs a similar setup on his race car.
 
  182/RS2/ Turbo/Mk1
No question he's a clever cookie, I don't doubt him that for one minute but why....every time there's a simple answer does there have to be a long winded mathematical equation that has little to no importance.

Because your simple answer saying another 20mph is irrelevant was wrong, and the only way I could demonstrate it was wrong was to give the details of why.
Otherwise it would have just been several pages of you saying the extra speed made no difference and me keep replying yes it does, but by educating you about WHY it makes a difference, that should now not be a mistake you ever need to make again, and not just you of course, but anyone else reading this thread who might also think similar.
 
Some very interesting replies there Chip. I for one would be extremely interested in your findings if you were to go into more detail between 280mm and 300mm discs!
 
  S4 Avant
My only issue here is the idea that a larger disk will somehow manage heat better.

All a larger disk will do is take longer to cool down between braking. A disk with a larger surface area relative to its volume would work better, be it 300mm, 280mm or 4,000mm.
 
  182/RS2/ Turbo/Mk1
My only issue here is the idea that a larger disk will somehow manage heat better.

When talking about the 2 readily available cheap brake disks for the clio, which is the 172 280mm * 24mm disk and the scenic 300mm * 24mm disk, I dont quite understand what you think the issue is with saying the bigger one will manage heat better?

The reasons it will manage the heat better are:
1) It has a larger volume/weight and hence can absorb a greater amount of energy before its temperature gets too high.
2) It has a larger surface area and hence is in contact with more cool air at any point in time, and hence it can lose that heat to the environment around it quicker.

All a larger disk will do is take longer to cool down between braking.
Can you please explain that statement, or more to the point why you think its correct, as I am struggling to picture in what way you think that having a larger disk will mean it takes longer to cool down the same amount of energy?

A disk with a larger surface area relative to its volume would work better, be it 300mm, 280mm or 4,000mm.
How do you suggest we increase the surface area relative to its volume?
There are a few ways that spring to mind that I can think of:
Vented versus non vented. But NO ONE in this thread IMHO is even considering a non vented disks
Drilling or grooves, the difference is pretty minor, but it is there
Larger diameter and thinner means bigger surface area for the same amount of weight, so even if the weight was the same between say a 300mm/24mm disk and a 280mm/26mm disk the 300mm would be better at losing heat due to the increased surface area.
 
  182/RS2/ Turbo/Mk1
Forgot to mention.

On the subject of clearance, my mate who is a brakes prototype engineer who works on a lot of WRC cars etc had a look at the car last night with a caliper and wheel fitted, said that the clearance I had when running the extra 3mm spacer shims would definately not be a problem as he has run closer on applications himself.
 
  S4 Avant
If the 300mm disk and the 280mm disk are the same width then that's fine.

the 300mm disk would provide better cooling than the 280mm disk. You mentioned previously that a thicker 280mm would be better than a thinner one, since it could store more heat, but that's just not the case. If anything you'd lose breaking ability because it wouldn't cool down as quickly.

increasing surface area to volume is easy, thinner disks or drilled. But with drilled disks we get into the whole "cracking argument".
 
  182/RS2/ Turbo/Mk1
If the 300mm disk and the 280mm disk are the same width then that's fine.

the 300mm disk would provide better cooling than the 280mm disk. You mentioned previously that a thicker 280mm would be better than a thinner one, since it could store more heat, but that's just not the case. If anything you'd lose breaking ability because it wouldn't cool down as quickly.

Well generally speaking a thicker disk will have a wider venter area in the middle, so as a result it does still dissipate heat a little better than a thinner one as a result of the wider vented section it does still have a larger surface area, but its not as good as going to a bigger diameter disk.
Ie a 28mm 280mm is better than a 24mm 280mm is, but not as good as a 24mm 300mm is.

increasing surface area to volume is easy, thinner disks or drilled. But with drilled disks we get into the whole "cracking argument".
The problem with thinner disks as a way of increasing the volume of surface area to weight, is that you are improving the ratio by dropping the weight not by increasing the surface area, and for an application like mine where at the end of the main straight at bedford where im going from 150mph to probably 90mph or so (depending on conditions and how naughty a line I take through the chicane) that is a LOT of energy that has to be absorbed before there is a chance for the disk to dissipate much, while the disks DO lose a small amount of heat during braking, they lose far more after the braking has stopped as its such a small percentage of the time you are actually braking, so you need to think about how much energy just one big application of the brakes is putting in when deciding on the minimum weight that you can cope with.
 
  Clio 182 FF
LOL at this thread. Basically if you've got a lot of speed to lose, or a lot of weight to slow down, you want bigger brakes. For physics reasons, bigger = better.

Oh and LOL at the Combe analogies, it's great fun up there being last of late brakers and ****ing off all the Cossy/Evo/Scooby lot. 140something up Avon Rise is what we do, but that's in something that weighs under half a Clio :p.
 
  182/RS2/ Turbo/Mk1
Get ali bells and seperate discs for even better disapation.

Far better for weight that way around as well, especially if you have a big wheel to put them under, what I would really like is a 340mm rotor with an ally bell, that would be same weight as the 300mm disks (which is about enough weight) but massively better at losing the heat.
Sadly I would need a motorsport 17" rim to get it under though!
 
  AB182, Audi A5 3.0
seems pretty obvious to me that more power = higher speed for your mass into the corner, thus more stopping power is required to slow the mass to the same speed and time as a lower powered but same spec mass. Clio turbo = small mass, high speed = needs big brakes to slow down in the same time.
 
Last edited:


Top