BRAKES - Any experts here ?

Recently I replaced My front brake pads [as I was replacing the complete front end plus some ball joints tie rod ends ,torsion bar seals] and the old pads were worn down a bit,
Now the new pads seemed to work great, but they do NOT lock up the front wheels as the old ones did, even in the wet, it seems all the brakes are working great, even the rear ones.?

Yesterday I really hit the brakes hard at a stop sign to see if the fronts would lock up, or whether they are working better than before.
Well, the car stopped so suddenly the passenger seat flew forwards... lol.. the locking lever was up..
so, it seems they are working just as good as the locking front brakes... but the car is stopping rather then sliding with front locked up...

The rears were adjusted up a bit over a year ago, and then there was the problem with the REGO brake check..
too much braking at the rear wheels...??

Why has new pads made all this difference?

LEE

did u bed the new pads in ??

u may have glassed them now and will have to remove and scuff the surface of the pad

also good to replace the flex brake hoses at same time

Hi
Yes I bedded them in as per instructions on another box.. lol

all brake hoses were replaced new in 2005 along with rear cylinders etc..

LEE

maybe a different compound on the pads what brand where they ( i hope not CHINESE )

A good set of brakes do not lock up, the moment you lock the front brakes you have no control over the steering, you should be able to modulate the brakes just above there lock up point and then you still maintanece control of the car

Lee, ifg you have a better feeling pedal, with no lockup then sounds great dont change a thing... As long as the braking distance hasnt been increased. From what you have listed i am assuming the material is slightly different. Did you replace front pads in 2005?

the pads u have fitted to the front may be of a harder compound so slightly lower friction rating sounds like u have close to ideal weight transfer as in rear brakes coming on first transfering weight to front end and not locking cheers Rudi

Not wanting to Hijack Lees thread too much but while we're on the topic is there any better options other than stock pads for the twin Pin ATE/Varga style calipers that anyone knows of?

Bendix certainly dont list anything for the twin pin calipers other than standard DB15 pads.

EBC do a good range Greens or Reds depends on how hard ur pushing cheers Rudi

Cheers, will suss them out.

I occasionally get them a little warm and smelly with some spirited driving through the twistys but stock ones have always safely pulled up.

I do have cross drilled discs on the front and Fiat Spider discs with single pots on rear which I've been happy with but the front pads are starting to wear down abit.

might not have been just the new pads Lee, if your photo is a guide and you have changed the front shocks a the same time. Worn shocks can be a cause of premature brake lock up under heavy braking. Did you put new shocks on?

But yes, there are hard long-wearing pads and relatively soft fast-wearing pads, guess which ones grip best?

Also, I would prefer to have brakes that gave me the option to lock up the front, because then I would know what they are capable of, and I would use my own judgement how much force to use based on the conditions.

I have TRW twin pin pads in my ATE calipers and I reckon they work well. Brake place that has many years of experience and whose recommendations I trust sold them to me. No idea how long they last but I asked for pads with a high coeficient of friction and have been happy. Not expensive either. I have type 3 drums on the rear with linings similar to formula vee (or so I was told).
Cheers.........Wayne

I'm no brake expert Lee, but it does sound like they're less agressive on the front, and so letting the rear do more of the effort. Makes sense if you think of the reverse - if your rear brakes weren't working at all you'd ALWAYS lock the fronts and take more time & distance to stop, so no wheels locking has got to be closer to the ideal.

Joel - re your hijacking I've used EBC Greens several times previously on the front and loved 'em.

Pretty sure hellbugged has 'em on a car now too - be worth sussing his thoughts, as don't suspect he drives his car at all gently !!!

😀

I've been in the passengers seat, your suspicions are correct 😉

Any suppliers out there aside from RDA?

Ok Lee, it looks like your cal for an 'expert' hasnt got any responses. We are all just enthusiastic amateurs. With no consensus.

You need to search further afield than this website.

cheers.

I'm thinking it's the new steering parts and wheel align. Before the work, the wheels would go out of alignment (due to the worn steering components) and so would be easier to skid due the reduced traction.
Whatever the cause, your describing a tyre - road grip level, the pads may change the feel, but 'locking the fronts' is a tyre grip level which could be the weather, the bitumen, the suspension, the brake fluid, the disc rotors, the style of driving at time of test, the earths rotational spped compared to the local gravitational pull at your latitude .......etc etc etc......🤪...well....maybe🙅

vwo60 wrote:A good set of brakes do not lock up, the moment you lock the front brakes you have no control over the steering, you should be able to modulate the brakes just above there lock up point and then you still maintenance control of the car

I was just about to say the same thing, the better the brakes including the pad compound the faster you can stop and the less they are likely to lock up.

only shit brakes lock up is the rule, good ones don't. I am surprised how many people don't know this? they should, its just physics.

Also don't gradually slow down, slow down fast! used your brakes moderately to hard. pulsate the brakes too like abs does. your brake will continue to work better throughout the pad and rotor life, minimizes warping and also lasts longer.

Sounds counter intuitive? no its that guy physics again.

bigrudi wrote:EBC do a good range Greens or Reds depends on how hard ur pushing cheers Rudi

I got ferrodo green ones before they were apparently bought out by EBC. so I believe it should be the same pad. they are pretty good though not so when they are cold.


I am going to try out QFM A1RM 0-780oC pads and see how they go. I can easily fade my green ones out after a few min of my good mood driving moments.

Aussie Dubbin wrote:Lee, ifg you have a better feeling pedal, with no lockup then sounds great dont change a thing... As long as the braking distance hasnt been increased. From what you have listed i am assuming the material is slightly different. Did you replace front pads in 2005?

No I used the old pads, must have had a lot of material still on them..
as I had the new pads I fitted them instead of wearing the old ones right down, which is safer anyway..

LEE

Uber Kafer wrote:might not have been just the new pads Lee, if your photo is a guide and you have changed the front shocks a the same time. Worn shocks can be a cause of premature brake lock up under heavy braking. Did you put new shocks on?

But yes, there are hard long-wearing pads and relatively soft fast-wearing pads, guess which ones grip best?

Also, I would prefer to have brakes that gave me the option to lock up the front, because then I would know what they are capable of, and I would use my own judgement how much force to use based on the conditions.

Yes found the old shocks were still Ok, although a very soft monroe gas shocks..
on one of the side roads off the highway in Scone where I always like to take the corner at 50 kmh [usually with a semi trailer or B double on My tail] and then brake fairly hard, if the road is wet I used to lock up the front wheels and skid straight ahead towards the median strio, so naturally I would release the brakes and turn the steering wheel...
well, I have done this twice in the wet since and no locking up.. I've even tried to lock them up in the wet..
but it just stops..

just remembered that I have the front tyres at 18psi
I normally run about 20 PSI.. I wouldn't have thought a couple of psi would change things..

reason i swapped front ends was the RHS front wheel had a positive camber..

so, maybe all those things added up ???

LEE

vw54 wrote:maybe a different compound on the pads what brand where they ( i hope not CHINESE )

They were Bendix DB something..

I've had them for a few years...

LEE

PS: I like to leave the chinese parts to the chinese.. lol

theres a LOT consider here

vlad01 wrote:your brake will continue to work better throughout the pad and rotor life, minimizes warping and also lasts longer.

Sounds counter intuitive? no its that guy physics again.

I was under the assumption that brake warp was due to distortion from a 'hot spot' being at the caliper and rotor when you have stopped after braking. While the rest of the rotor vents and cools, the pads clamped to the rotor don't allow the heat to dissipate at the same rate.

So by riding them hard, you'll make the temperature difference even greater (as the hotter the whole rotor is (delta T)) the faster the rate of cooling down will be for the 'rest' of the rotor while the stinking hot spot in the caliper remains toastie.

The concept might work for a race car, but compared to a street car, race cars don't stop at intersections and induce 'hot spots'.

Personally I rev match and down shift far prior to the corner, use the gear-braking style (without using the clutch to brake) like a truck. Then apply the brake for the 40-50kmph left or so, say after takin an exit ramp of the pacific highway. And after driving various models, I have never had to change the front brake pads as there was still plenty of flesh left. Plus it sounds cool 🙂 Just be sure to get those rev's up otherwise the clutch is going to hate ya.

i found out early that the standard disc heats up quickly with some spirited driving and cannot get rid of the heat, then they fade badly, in my case going from hardly any brakes to wheel lock with no warning, a change of pads will help this but at the end of the day they will generate more heat in the brakes, the solid disc is a problem and they need to be replaced with vented rotors , i fabricated my set of brakes on the front using a 300MM vented rotor, no brake fade or wheel lock up now.

Joel wrote:I've been in the passengers seat, your suspicions are correct 😉

Any suppliers out there aside from RDA?

Hi Joel

I put some green EBCs in Davids bug for the supersprint, no complaints or bad smells.
I got them from,
Brabond Brakes (Penshurst) Pty Ltd
504 Forest Rd, Penshurst NSW 2222, Australia
(02) 9580 7562

I think they were about $100

Steve

Joel wrote:I've been in the passengers seat, your suspicions are correct 😉

Any suppliers out there aside from RDA?

Hi Joel

I put some green EBCs in Davids bug for the supersprint, no complaints or bad smells.
I got them from,
Brabond Brakes (Penshurst) Pty Ltd
504 Forest Rd, Penshurst NSW 2222, Australia
(02) 9580 7562

I think they were about $100

Steve

68AutoBug wrote:

vw54 wrote:maybe a different compound on the pads what brand where they ( i hope not CHINESE )

They were Bendix DB something..

I've had them for a few years...

LEE

PS: I like to leave the chinese parts to the chinese.. lol

I had bendix CT as well as a mate of mine. I tossed mine out in favor of the no longer in existence Ferrodo green pads. What a difference! My mate still has his bendix and his car has ABS, worst brakes ever! you cannot stop in his car with both feet on the brakes. Stopping hard on them with the bendix took hmm? maybe 150m or more traveling at 100km/h. they were just ok when cold but once warmed up were shockingly crap, about equivalent to trying to stop with the integrated mini drum type handbrake alone.

Don't know why but never had good luck with bendix, kinda like noalthane, everyone raves about them but are rubbish average at best.

Lee, the Chinese are smart, they keep all the good stuff they make in their country and sell all the junk to the rest of the world. They are excellent business people. White people are the ones that are stupid buying that crap 😂

The only 2 pads I would use are EBC or QFM

vwo60 wrote:i found out early that the standard disc heats up quickly with some spirited driving and cannot get rid of the heat, then they fade badly, in my case going from hardly any brakes to wheel lock with no warning, a change of pads will help this but at the end of the day they will generate more heat in the brakes, the solid disc is a problem and they need to be replaced with vented rotors , i fabricated my set of brakes on the front using a 300MM vented rotor, no brake fade or wheel lock up now.

Dude! I want those center cap decals 😵 I been looking for a set for ages but can't find any and ROH wont sell me any decals or center caps separately. 😬

bajachris88 wrote:

vlad01 wrote:your brake will continue to work better throughout the pad and rotor life, minimizes warping and also lasts longer.

Sounds counter intuitive? no its that guy physics again.

I was under the assumption that brake warp was due to distortion from a 'hot spot' being at the caliper and rotor when you have stopped after braking. While the rest of the rotor vents and cools, the pads clamped to the rotor don't allow the heat to dissipate at the same rate.

So by riding them hard, you'll make the temperature difference even greater (as the hotter the whole rotor is (delta T)) the faster the rate of cooling down will be for the 'rest' of the rotor while the stinking hot spot in the caliper remains toastie.

The concept might work for a race car, but compared to a street car, race cars don't stop at intersections and induce 'hot spots'.

Personally I rev match and down shift far prior to the corner, use the gear-braking style (without using the clutch to brake) like a truck. Then apply the brake for the 40-50kmph left or so, say after takin an exit ramp of the pacific highway. And after driving various models, I have never had to change the front brake pads as there was still plenty of flesh left. Plus it sounds cool 🙂 Just be sure to get those rev's up otherwise the clutch is going to hate ya.

I don't leave the brakes applied when I stop, I immediately pull up the handbrake.

I just jam down through the gears when slowing down quick, no time to even slip the clutch. Its all good, nothing a little rear compression lockup in the daily commute.

68AutoBug wrote:

Aussie Dubbin wrote:Lee, ifg you have a better feeling pedal, with no lockup then sounds great dont change a thing... As long as the braking distance hasnt been increased. From what you have listed i am assuming the material is slightly different. Did you replace front pads in 2005?

No I used the old pads, must have had a lot of material still on them..
as I had the new pads I fitted them instead of wearing the old ones right down, which is safer anyway..

LEE

Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around. Also good quality pads replaced at this interval can slightly true up a disc or drum, mainly because bugger all damage has been done yet. (did my apprenticeship on fleet maintenance).

Regards,

Matt.

Thanks Steve, I'll find out what they have

Matt Ryan wrote:Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around.

Regards,

Matt.

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Thank god atleast NSW has annual roadworthys, stops things like this being on the road

Matt Ryan wrote:

68AutoBug wrote:

Aussie Dubbin wrote:Lee, ifg you have a better feeling pedal, with no lockup then sounds great dont change a thing... As long as the braking distance hasnt been increased. From what you have listed i am assuming the material is slightly different. Did you replace front pads in 2005?

No I used the old pads, must have had a lot of material still on them..
as I had the new pads I fitted them instead of wearing the old ones right down, which is safer anyway..

LEE

Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around. Also good quality pads replaced at this interval can slightly true up a disc or drum, mainly because bugger all damage has been done yet. (did my apprenticeship on fleet maintenance).

Regards,

Matt.

some pads will out the rotors faster than the actual pads 😂

Joel wrote:

Matt Ryan wrote:Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around.

Regards,

Matt.

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Thank god atleast NSW has annual roadworthys, stops things like this being on the road

🤪🤪🤪🤪 😂🥲

Joel wrote:

Matt Ryan wrote:Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around.

Regards,

Matt.

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Thank god atleast NSW has annual roadworthys, stops things like this being on the road

I bet the customer said "it only started making a noise just recently"


Regards,

Matt.

At least they won't overheat anymore🤪

vlad01 wrote:only shit brakes lock up is the rule, good ones don't. I am surprised how many people don't know this? they should, its just physics.
.

I am interested to hear the physics clarified, how it relates to non ABS of course.
For example, you have brakes that are capable of pulling up a fully loaded vehicle from high speed in the absolutely shortest possible distance, which would mean braking to the limits of adhesion, awesome performance. Then on another occasion you do a panic stop at low speed with an empty car, naturally those awesome brakes are capable of locking up the wheels.

Does that make them 'shit brakes' ?

mmmmm 🙂

I'm with you Mr Kafer

I am with kafer on this one two. Without ABS good brakes should all reach lock up at about the same time. For safety the fronts should go first, so you don't loose the rear end. if you can't reach lock up, you still have more braking to go.

I will be trying to the QFM pads next time i change. They will put various compunds on your old backing plates for non standard cars/pads. Won't do shoes though for the drums.

Drew

Matt Ryan wrote:

Joel wrote:

Matt Ryan wrote:Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around.

Regards,

Matt.

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Thank god atleast NSW has annual roadworthys, stops things like this being on the road

I bet the customer said "it only started making a noise just recently"


Regards,

Matt.

Read in the paper recently about people complaining having to replace their front brake discs after 30,000klms...
their first 30,000klms..
Ford say they have fitted very abrasive pads... and that is normal....
FORD FOCUS cars... imported..

I never let brake pads get down near the metal... YIKES

LEE

That is why I don't like rear disc brakes.... lol

You just never know what is going on back there...
😂😂😂😂😂😂

Lee

Matt Ryan wrote:

Joel wrote:

Matt Ryan wrote:Rule of thumb is to replace pads or shoes when they are worn to half thickness or over. Then there is far less risk of scoring disk or drum by the time next service or brake check comes around.

Regards,

Matt.

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Thank god atleast NSW has annual roadworthys, stops things like this being on the road

I bet the customer said "it only started making a noise just recently"


Regards,

Matt.

But rear discs pull such awesome handbrake-ies 😂

bajachris88 wrote:But rear discs pull such awesome handbrake-ies 😂

not necessarily! most cars if not all these days use a mini drum brakes for the handbrake inside the hat of the disk. only old 80s to 90s had calipers with integrated handbrake.

vlad01 wrote:

bajachris88 wrote:But rear discs pull such awesome handbrake-ies 😂

not necessarily! most cars if not all these days use a mini drum brakes for the handbrake inside the hat of the disk. only old 80s to 90s had calipers with integrated handbrake.

Fraid not. My Bro's 04 Seat Ibiza has integral handbrake calipers as do the same age VW Bora's, Golfs, etc. They are far cheaper to manufacture than a seperate mini drum.

Joel wrote:Thanks Steve, I'll find out what they have

I really cringe when I see Mr or Mrs average non mechanical savvy driver in thier car going screeech screech screeech without a care in the world.

My brakes are making an annoying screech noise, meh I'll just turn the radio up more 🙄

Funny you say this Joel as the wife came home one day and said the brakes are making a weird noise. Low and behold no pad material left. 'oh it made the noise a few days ago but then went away so I didn't tell you. And now we need new rotors 🙄 She must have a bloody heavy foot cos they were under 5k old.

Anyway..............................🙄🙄

I used to see that alot at the garage.
With so many of todays cars being auto and modern brakes are big and vented these days, alot of drivers just sit on the brakes all the way down hills and wait till the last sec and brake heavily at traffic lights and intersections.

You see their front wheels and even the back on some cars look like they are matte black but it's just all the brake dust.

Joel wrote:I used to see that alot at the garage.
With so many of todays cars being auto and modern brakes are big and vented these days, alot of drivers just sit on the brakes all the way down hills and wait till the last sec and brake heavily at traffic lights and intersections.

You see their front wheels and even the back on some cars look like they are matte black but it's just all the brake dust.

Yes. I used to notice that a lot when in Sydney, watching the traffic... lol

ALL european cars front wheels were black.... really black compared to the rears...

BMWs seemed to be the worst...

but Now I even notice it on European cars in Scone...
can't tell with local cars as they are all covered in mud or dust.. lol

LEE

On the service record of One of Our Lancers it even had how thick the brake pads were....
now that's dedication... lol

We got a years worth of free service with the car.. lol

LEE

Uber Kafer wrote:

vlad01 wrote:only shit brakes lock up is the rule, good ones don't. I am surprised how many people don't know this? they should, its just physics.
.

I am interested to hear the physics clarified, how it relates to non ABS of course.
For example, you have brakes that are capable of pulling up a fully loaded vehicle from high speed in the absolutely shortest possible distance, which would mean braking to the limits of adhesion, awesome performance. Then on another occasion you do a panic stop at low speed with an empty car, naturally those awesome brakes are capable of locking up the wheels.

Does that make them 'shit brakes' ?

very hard to lock good brakes, but pretty easy in the wet though 😂

but I am saying is if the brakes lock easy with little control over it, is either something wrong, or they are too small, or they are drums. Thats what I mean by shit brakes. Most people are like "oh they lock easy they must be great!" 🙄

If the brakes are large, with correct piston sizing ratio to MC piston and high quality pads, locking the bakes become very difficult and only happens in the extreme cases typically at the last 0.5- 1m remaining to a dead stop, or gravel or wet road (normally eliminated if you have ABS)

it mostly comes down to relation ship between static and kinetic friction. Better and larger brakes have a greater % of kinetic friction while having reduced static friction which = greater stopping, greatly reduced locking.

btw are you making the assumption that I was referring to ABS? well I wasn't.

like I said simple physics 🤓

Joel wrote:I used to see that alot at the garage.
With so many of todays cars being auto and modern brakes are big and vented these days, alot of drivers just sit on the brakes all the way down hills and wait till the last sec and brake heavily at traffic lights and intersections.

You see their front wheels and even the back on some cars look like they are matte black but it's just all the brake dust.

I F**ken hate that! with their brake light on all the time you can't tell if they are stopping or their brake light switch has failed until they suddenly stop at the last sec and you nearly hit them. I bet 9/10 rear ender happen like this.

watch out for the inversed ford territorys. brakes light on when no brakes and they turn off when they brake 😬


seriously, they need to force people to use their brakes properly or put brake effort bar graph type brake light that show a % of pedal effort so people know how much the person in front is braking.

it mostly comes down to relation ship between static and kinetic friction. Better and larger brakes have a greater % of kinetic friction while having reduced static friction which = greater stopping, greatly reduced locking.
[/quote]

I'm aware that "static friction " term si being used, but makes me wonder how correct it is...my understanding is, there is no friction between two stationary objects....the friction factor steps in at the moment, when one of the objects becomes kinetic...this falls to the same category as "army intelligence"...

maybe you need to revise your physics, static friction just the friction that keep 2 surfaces from moving while force is being applied. Just because it isn't moving doesn't mean it hasn't got friction. Its like saying, if I kill you does the universe exist? of course it does! Just you are not conscious to experience it anymore.

Without static friction nothing in our sense of reality of the physical universe wouldn't exist.

Thanks, you REALLY enlightened me....

cb john wrote:Thanks, you REALLY enlightened me....

No help is he 😂

The usual 'textbook' terms is sliding friction and static friction, but alot do call sliding friction kinetic friction instead.

Friction requires a force to be present. without a force, there is no friction. Why? Because Friction = Net Force x Friction Coefficient. This coefficient represents how 'rough' or 'smooth' a surface is. Larger the coefficients value, the rougher the surface, larger the friction force.

Now! If we have a force present, we have Mass & an Acceleration. Why? Well, Force (F) = Mass x Acceleration. Newton's Law. Mass could be a car (kg), person, anything thats matter. Acceleration could be you putting your foot down in a car, or even gravity (because gravity tries to accelerate you 'downwards' to the ground).

Friction is a force that 'opposes' motion. if you want to 'accelerate' something one way, friction will push against you in the other direction.

So whats sliding friction and static friction?

Sliding friction: is the friction force (opposing force) present when two contacting surfaces 'slide' across each other. For example, when a car has hit the skids, the wheels lock up, and thus the car 'slides' across the road. The car will eventually come to a stop, because a 'sliding' friction force has opposed the cars motion and slowed you to a hault.

Static friction: Is again, the friction force (opposing force) present when two surfaces are simply in contact without any sliding. The car example complicates this phenomenon so lets use a different one. Simply put, your standing still, and take a step forward. You pushed on one foot to move your body forward when taking your step. The foot you pushed with, pushed on the ground, it does not slide across the ground. There is some force preventing your foot from sliding on the ground, this is your 'static' friction force. Without this 'static' friction force, you would be slipping over, there would be no 'grip' on the ground. Its called static friction as the surfaces (your shoe and the ground) are still and not moving or sliding across each other, although you yourself are actually moving forward.

From the car example, if you stop your car without locking up the wheels, the tyres do not slide. They provide a 'static' friction while rotating and NOT sliding across the surface. This friction force is a force opposing the direction of motion and thus your vehicle stops.

To make it complicated, sliding friction is present when your brake pads are sliding over the rotating brake disk as your wheels spin. If the wheels lock up, then the brake pads are providing static friction, as the friction force is holding the brake rotors still (hence static) and the surfaces are no longer sliding.

In general, the 'size' of the force for static friction, compared to sliding friction is greater regardless of the application. Hence why you can stop your car sooner if you do not lock up the wheels. This is why ABS was invented, such that your car can maintain static friction between the tyres and road surface and thus a 'stronger' opposing force can be present to stop the motion of the vehicle sooner.

Hope that helps.
Chris.

As the song says, "There's a fraction too much friction" going on. 😁

Lee simply wanted to know why his new pads were behaving differently.

HappyDaze wrote:As the song says, "There's a fraction too much friction" going on. 😁

Lee simply wanted to know why his new pads were behaving differently.

different compounds obviously.

cb john wrote:Thanks, you REALLY enlightened me....

I might as well be talking to a brick wall ey 🙄

bajachris88 wrote:

cb john wrote:Thanks, you REALLY enlightened me....

No help is he 😂

The usual 'textbook' terms is sliding friction and static friction, but alot do call sliding friction kinetic friction instead.

Friction requires a force to be present. without a force, there is no friction. Why? Because Friction = Net Force x Friction Coefficient. This coefficient represents how 'rough' or 'smooth' a surface is. Larger the coefficients value, the rougher the surface, larger the friction force.

Now! If we have a force present, we have Mass & an Acceleration. Why? Well, Force (F) = Mass x Acceleration. Newton's Law. Mass could be a car (kg), person, anything thats matter. Acceleration could be you putting your foot down in a car, or even gravity (because gravity tries to accelerate you 'downwards' to the ground).

Friction is a force that 'opposes' motion. if you want to 'accelerate' something one way, friction will push against you in the other direction.

So whats sliding friction and static friction?

Sliding friction: is the friction force (opposing force) present when two contacting surfaces 'slide' across each other. For example, when a car has hit the skids, the wheels lock up, and thus the car 'slides' across the road. The car will eventually come to a stop, because a 'sliding' friction force has opposed the cars motion and slowed you to a hault.

Static friction: Is again, the friction force (opposing force) present when two surfaces are simply in contact without any sliding. The car example complicates this phenomenon so lets use a different one. Simply put, your standing still, and take a step forward. You pushed on one foot to move your body forward when taking your step. The foot you pushed with, pushed on the ground, it does not slide across the ground. There is some force preventing your foot from sliding on the ground, this is your 'static' friction force. Without this 'static' friction force, you would be slipping over, there would be no 'grip' on the ground. Its called static friction as the surfaces (your shoe and the ground) are still and not moving or sliding across each other, although you yourself are actually moving forward.

From the car example, if you stop your car without locking up the wheels, the tyres do not slide. They provide a 'static' friction while rotating and NOT sliding across the surface. This friction force is a force opposing the direction of motion and thus your vehicle stops.

To make it complicated, sliding friction is present when your brake pads are sliding over the rotating brake disk as your wheels spin. If the wheels lock up, then the brake pads are providing static friction, as the friction force is holding the brake rotors still (hence static) and the surfaces are no longer sliding.In general, the 'size' of the force for static friction, compared to sliding friction is greater regardless of the application. Hence why you can stop your car sooner if you do not lock up the wheels. This is why ABS was invented, such that your car can maintain static friction between the tyres and road surface and thus a 'stronger' opposing force can be present to stop the motion of the vehicle sooner.

Hope that helps.
Chris.

Also I will add, by maintaining kinetic friction at the brakes rather than at the tires allows more heat to be generated in a shorter time frame whilst being absorbed from the conversion of kinetic energy to thermal energy without loosing too much overall friction in the system otherwise lost when rubber liquifies, then evaporates from the heat of sliding and reduces its friction coefficient thus decreasing the efficiency of the system.

in other words the pads and rotors are far better at converting movement into heat faster with minimal lost of efficiency in that system than what rubber sliding over a road would do.

just another point of view, food for thought? or too hard to understand

Also one very important point, you can steer if the brakes don't lock and still brake hard at the same time.

If you lock and try to steer, well you're ***ked unless you let go and continue pulsating the bakes so you can steer and stop at the same time, or like Chris mentioned ABS can help 🤓 I think? last time I seriously drove an ABS car it wouldn't stop 😂

Well done Chris. Remnded me of Maths 2 at high school

HappyDaze wrote:As the song says, "There's a fraction too much friction" going on. 😁

Lee simply wanted to know why his new pads were behaving differently.

Yes, as they are Not locking up as they were before and very easily..
One corner coming off the highway onto a wide side street , and having a truck doing 50kmh at least on Your tail
I usually go round the corner at 50 and then brake, but if the road is wet, the front would lock up and I would go straight ahead towards a median strip... so I would have to take My foot off the pedal and then steer left... lol

Well. I did the same thing a few days again in the rain, and the Left hand front was just starting to lock up but the RHS one didn';t and I steered around the corner...

So, really, I don't care how it all works, I was just wondering why two new front pads would make that difference..
Same tyres.. but new shock absorbers but old gas shocks still worked.. were a soft monroe gas shock.

I did fit another front end as one wheel was positive camber
also aligned the front wheels correctly..

anyway it brakes and steers etc all perfectly... excellent

it may have just been a lot of things all corrected---
toe in - camber - caster? - new shocks - NEW PADS ....??

LEE