why do bigger brakes make you stop faster?

[mikeveal]

Hol said:

Wow!!

All those people who have been wasting money on Carbon Brakes for their supercars and big brake kits for race and track cars.



Who knew, they were all lying to hide the fact that the OEM brakes fitted to all cars were actually much better

Lost on me I'm afraid.
Are you choosing to ignore what I actually said for comic effect, or after seven pages of explanation do you genuinely still not understand?

[kambites]

julian64 said:

However if single sentence sound-bites are your thing the best answer for you is that:- The brakes need to be matched to the size and stickiness of the tyre, the weight of the vehicle, and the amount of 'feel' you desire through the braking system.

That's not a very catchy sound-byte is it?

[julian64]

kambites said:

julian64 said:

However if single sentence sound-bites are your thing the best answer for you is that:- The brakes need to be matched to the size and stickiness of the tyre, the weight of the vehicle, and the amount of 'feel' you desire through the braking system.

That's not a very catchy sound-byte is it?

True. I did keep it to one sentence though

[Renovation]

Debaser said:

Renovation said:

Debaser said:

Renovation said:

Correctly upgraded bigger brakes do make cars stop faster

Nah, don't think so.

That'll be why Touring cars have such tiny brakes.

In fact now you mention it I remember Sierra Cosworth owners upgrading their brakes to those off a 1.6 - it saved loads of weight too.

A car on standard brakes can stop from 130km/h in, say, 58 metres with ABS active from when the pedal is pressed until the car is stationary. The limiting factor is grip between tyres and road surface.

Please explain how bigger brakes will stop this car any faster.



By the way, sarcasm doesn't have the desired effect when you're wrong.

You can't get your ABS active at 130mph - that is a speed I regularly hit in my modified car - all my cars are modified including wheels, tyres and suspension.

If you do multiple stops your performance will get less and less - I've had several sets of standard brake pads on fire after a spirited drive.

Just because you drive like a girl so your brakes are ok don't assume everyone else does.

Finally none of my cars have ABS as I like to drive not rely on technology which in the past has refused to apply the brakes on a few mm of snow and wet leaves.

[Hol]

mikeveal said:

Hol said:

Wow!!

All those people who have been wasting money on Carbon Brakes for their supercars and big brake kits for race and track cars.



Who knew, they were all lying to hide the fact that the OEM brakes fitted to all cars were actually much better

Lost on me I'm afraid.
Are you choosing to ignore what I actually said for comic effect, or after seven pages of explanation do you genuinely still not understand?

Oh, I understand alright.

I just think some of the 'opionions' are highly amusing, especially the ones that have completly ignored the original question, so that the posters can jump on some soap box to talk about something they havent actually experienced themselves.

Some of it is hilarious

[lostkiwi]

Renovation said:

Debaser said:

Renovation said:

Debaser said:

Renovation said:

Correctly upgraded bigger brakes do make cars stop faster

Nah, don't think so.

That'll be why Touring cars have such tiny brakes.

In fact now you mention it I remember Sierra Cosworth owners upgrading their brakes to those off a 1.6 - it saved loads of weight too.

A car on standard brakes can stop from 130km/h in, say, 58 metres with ABS active from when the pedal is pressed until the car is stationary. The limiting factor is grip between tyres and road surface.

Please explain how bigger brakes will stop this car any faster.



By the way, sarcasm doesn't have the desired effect when you're wrong.

You can't get your ABS active at 130mph - that is a speed I regularly hit in my modified car - all my cars are modified including wheels, tyres and suspension.

If you do multiple stops your performance will get less and less - I've had several sets of standard brake pads on fire after a spirited drive.

Just because you drive like a girl so your brakes are ok don't assume everyone else does.

Finally none of my cars have ABS as I like to drive not rely on technology which in the past has refused to apply the brakes on a few mm of snow and wet leaves.

The original question wasn't "why do bigger brakes allow you to stop faster on repeated stops?" It was "why do bigger brakes make you stop faster?" for which the straight forward answer is they don't. Yes they will allow you to have consistent repeated stopping distances but they won't enable you to stop in a shorter distance at the first push unless the car was already underbraked.
And yes they will give better 'feel' potentially but thats also dependent on a large number of other factors such as hydraulic ratios (cross sectional area of master cylinder vs calipers), pad material, disc material, disc treatment (cryogenic treatment? Drilled? Grooved?) etc.

[Hol]

julian64 said:

Hol said:

Wow!!

All those people who have been wasting money on Carbon Brakes for their supercars and big brake kits for race and track cars.



Who knew, they were all lying to hide the fact that the OEM brakes fitted to all cars were actually much better

You are just choosing to ignore everything that's been said on this thread to make a sound-bite.

There isn't a single person on this thread that has said there is no reason for bigger brakes.

However if single sentence sound-bites are your thing the best answer for you is that:- The brakes need to be matched to the size and stickiness of the tyre, the weight of the vehicle, and the amount of 'feel' you desire through the braking system.

Seeing massive brakes on skinny rims is just fashion, and pretty daft.

As the post above, I read some of the comments with comical curiousity. Some of them were better than others though.

Having read the question in the original post and also having fitted bigger/uprated brakes to a number of my production vehicles over the years (with and without ABS), you will no doubt be interested to hear that I can clearly and positively make my own conclusions based on that experience rather than blidly accept the opinions of those people who haven't.


If PH has taught us anything, its that certain people will always have an defensive opinion on something they havent actually tried and tested themselves. SP&L is a prime example.

Edited by Hol on Tuesday 17th November 14:02

[Debaser]

Renovation said:

Debaser said:

Renovation said:

Debaser said:

Renovation said:

Correctly upgraded bigger brakes do make cars stop faster

Nah, don't think so.

That'll be why Touring cars have such tiny brakes.

In fact now you mention it I remember Sierra Cosworth owners upgrading their brakes to those off a 1.6 - it saved loads of weight too.

A car on standard brakes can stop from 130km/h in, say, 58 metres with ABS active from when the pedal is pressed until the car is stationary. The limiting factor is grip between tyres and road surface.

Please explain how bigger brakes will stop this car any faster.



By the way, sarcasm doesn't have the desired effect when you're wrong.

You can't get your ABS active at 130mph - that is a speed I regularly hit in my modified car - all my cars are modified including wheels, tyres and suspension.

If you do multiple stops your performance will get less and less - I've had several sets of standard brake pads on fire after a spirited drive.

Just because you drive like a girl so your brakes are ok don't assume everyone else does.

Finally none of my cars have ABS as I like to drive not rely on technology which in the past has refused to apply the brakes on a few mm of snow and wet leaves.

Why doesn't ABS work at 130mph?


You're trying to confuse the issue by claiming I drive like a girl, and talking about brake fade. I'll try and make the question I asked as simple as possible. Please try and answer it.

A car can brake at the limit of grip from any speed you choose. How do bigger brakes stop this car any faster?

Renovation said:

If you do multiple stops your performance will get less and less - I've had several sets of standard brake pads on fire after a spirited drive.

Just because you drive like a girl so your brakes are ok don't assume everyone else does.

Wow. I wish I could drive like you.

[Debaser]

doogz said:

Debaser said:

A car can brake at the limit of grip from any speed you choose. How do bigger brakes stop this car any faster?

See, this is the point that’s really worthy of investigation here.

At 150mph, with some downforce/ground effect, will a sports car’s brakes be able to overcome the immense rotational inertia of the rotating assembly, by providing enough clamping force, therefore enough torque to lock the wheels at that speed?

I’ve driven that fast before. Can’t say it occurred to me to stamp on the middle pedal as hard as I possibly could to see if the above statement could be true though.

Give it a go. You won't have a problem triggering ABS, assuming your brakes aren't hot enough to fade.

[stevesingo]

Debaser said:

Give it a go. You won't have a problem triggering ABS, assuming your brakes aren't hot enough to fade.

You think?

[Kawasicki]

stevesingo said:

Debaser said:

Give it a go. You won't have a problem triggering ABS, assuming your brakes aren't hot enough to fade.

You think?

That's what I was thinking.

[stevesingo]

I think as speed increases the energy stored in all the rotating components, (principally the wheels, brake discs, hubs, drive shafts, gearbox and even the engine if you don't declutch) increases to such a point that before the brakes can begin to slow the cars linear mass, they need to overcome the energy stored in the rotating mass.

Imagine the driven wheels being jacked up from the floor and you take the drivetrain up to an indicated 150mph and then jump on the brakes. Would it stop instantly? In a second? In several seconds?

[Galveston]

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

[Kawasicki]

xRIEx said:

Galveston said:

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

Now think about what happens in the dry on tarmac when the inertia of a 1.5 tonne car tries to carry on going forwards, with that 1.5 tonnes being carried through 4 high-friction contact patches.

Now think about what happens on a conveyor belt, with the inertial mass at 1200 kgm, but the speed of the belt reverses instantly. It tries to, but fails to spin.

Interesting.

[Garybee]

Kawasicki said:

xRIEx said:

Galveston said:

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

Now think about what happens in the dry on tarmac when the inertia of a 1.5 tonne car tries to carry on going forwards, with that 1.5 tonnes being carried through 4 high-friction contact patches.

Now think about what happens on a conveyor belt, with the inertial mass at 1200 kgm, but the speed of the belt reverses instantly. It tries to, but fails to spin.

Interesting.

Now think what happens with a large, high mass vehicle, driven in a low gravity environment such as the moon.

[Debaser]

Garybee said:

Kawasicki said:

xRIEx said:

Galveston said:

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

Now think about what happens in the dry on tarmac when the inertia of a 1.5 tonne car tries to carry on going forwards, with that 1.5 tonnes being carried through 4 high-friction contact patches.

Now think about what happens on a conveyor belt, with the inertial mass at 1200 kgm, but the speed of the belt reverses instantly. It tries to, but fails to spin.

Interesting.

Now think what happens with a large, high mass vehicle, driven in a low gravity environment such as the moon.

Now think about what happens driving around the rings of Saturn. I'm not so sure ABS would work.

[Kawasicki]

Debaser said:

Garybee said:

Kawasicki said:

xRIEx said:

Galveston said:

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

Now think about what happens in the dry on tarmac when the inertia of a 1.5 tonne car tries to carry on going forwards, with that 1.5 tonnes being carried through 4 high-friction contact patches.

Now think about what happens on a conveyor belt, with the inertial mass at 1200 kgm, but the speed of the belt reverses instantly. It tries to, but fails to spin.

Interesting.

Now think what happens with a large, high mass vehicle, driven in a low gravity environment such as the moon.

Now think about what happens driving around the rings of Saturn. I'm not so sure ABS would work.

The rings look solid, but I've heard that they're mainly dust.

[Debaser]

I'm still waiting for Renovation to explain why ABS doesn't work at 130mph, and how bigger brakes make a car stop faster.

And tell me some more amazing stories about how fast he can drive.

[996TT02]

Kawasicki said:

Debaser said:

Garybee said:

Kawasicki said:

xRIEx said:

Galveston said:

The wheels stop turning more-or-less instantly, even from high speeds. Think what happens on ice or when aquaplaning.

Now think about what happens in the dry on tarmac when the inertia of a 1.5 tonne car tries to carry on going forwards, with that 1.5 tonnes being carried through 4 high-friction contact patches.

Now think about what happens on a conveyor belt, with the inertial mass at 1200 kgm, but the speed of the belt reverses instantly. It tries to, but fails to spin.

Interesting.

Now think what happens with a large, high mass vehicle, driven in a low gravity environment such as the moon.

Now think about what happens driving around the rings of Saturn. I'm not so sure ABS would work.

The rings look solid, but I've heard that they're mainly dust.

You'd have to upgrade your filters instead.

[Kawasicki]

996TT02 said:

You'd have to upgrade your filters instead.

Should I fit a filter that's bigger than I need, smaller than I need, or the appropriate size for my needs? It's the last one isn't it. It just seems so obvious now that I put pen to paper.