Nurburgring - hard on brakes / tyres?
Discussion
francisb said:
ignoring heat dissipation from the disks
furthermore the pad is in contact for less time so you transfer less heat from the disk to the pads/fluid.
I'm not sure you should be ignoring heat dissipation. This will be one of the main differences between these two braking methods. The shorter braking distance will induce more heat and the disc/pads will have to dissipate heat at a faster rate. But in turn they will reach a higher temperature due to the higher braking forces involved.
A longer braking distance will create comparatively lower temperatures and lower rates of heat dissipation.
As a factor of the above, higher temps involved create faster rates of heat transfer. Even if there is shorter time involved on a shorter braking distance and therefore less time to allow the heat to transfer through to the discs/pads/fluid etc, the higher rate of heat transfer due to the higher temps involved would mean heat gets transferred more effectively.
It may be a case of swings and roundabouts on this topic.
I'm not saying I'm an expert in this.... its only my own take on the subject. Its good to hear the other side of the argument.
sorry... didn't mean to make you angry !! ;-)
its my fault.... when I say more heat I mean higher temperatures (I'm not all that good in typing down what I'm trying to say)... I didn't mean overall heat produced... as each car under the same deceleration will produce the same amount of heat as per the conservation of energy as you point out.
its my fault.... when I say more heat I mean higher temperatures (I'm not all that good in typing down what I'm trying to say)... I didn't mean overall heat produced... as each car under the same deceleration will produce the same amount of heat as per the conservation of energy as you point out.
francisb said:
The shorter braking distance will induce more heat.
ok the last i have to say on the subject.
no it won't. the heat "induced" is simply the difference between the kinetic energy of the car before and after braking. look up 'conservation of energy'
Mr B is right here. The total amount of heat generated will be similar, however, the rate of change of heat will be different. The subsequent rate of transfer of this heat to other components in a *shorter* space of time normally results in the other braking components not suffering from the effects ofheat transfer, i.e 'heat soak', as badly as the gradual application of heat.
Well, thanks for the feedback guys.
I doubt that I will be going particularly fast, but have decided to get a new set of front pads beforehand anyway and already changed the fluid.
BTW on the off-topic discussion about braking, perhaps it also depends how much heat the pad material can handle before glazing.
I doubt that I will be going particularly fast, but have decided to get a new set of front pads beforehand anyway and already changed the fluid.
BTW on the off-topic discussion about braking, perhaps it also depends how much heat the pad material can handle before glazing.
Ignoring all the physics stuff, in my experience, the 'ring is relatively kind on tyres, but less so on pads.
It's a much more flowing circuit than the usual fast/slow of some tracks. Besides, maybe when you've done 100+ laps and know the circuit, then you can consider braking at the last moment!
My advice is to err on the side of caution and brake a tad early - keeps your pants clean for the weekend
It's a much more flowing circuit than the usual fast/slow of some tracks. Besides, maybe when you've done 100+ laps and know the circuit, then you can consider braking at the last moment!
My advice is to err on the side of caution and brake a tad early - keeps your pants clean for the weekend
I get about 80 laps on a set of front tyres and around 120 to a set of rears. Pads I would say last around 50 laps for fronts and double that for rears. Thats on a 860KG front wheel drive car though.
Yes the ring is pretty bumpy in sections. Not really bumpy like an off road track but it isn't 100% smooth either.
My advice would be ALWAYS take a set of get me home brake pads with you....
Gary
Yes the ring is pretty bumpy in sections. Not really bumpy like an off road track but it isn't 100% smooth either.
My advice would be ALWAYS take a set of get me home brake pads with you....
Gary
atomicrex said:
Also take it easy after gallows corner, once under the gantry there is no need to see how fast the car will get to the cones! Its an ideal time to let the car cool down.
I also sometimes take it easy on the long run up the hill from Bergwerk. My E30 (320i standard) wouldn't break 85mph up the hill, screaming in 4th! So unless I was on a relatively traffic free and hence flowing lap, I would indicate right, stick to 70 in 5th and put my boot down again on the downhill section after the right hand kink (Before the tight right hander before Karussel, not sure of the bend anmes). Ideal opportunity to let the car cool! No point screwing your car is it needs to get you home
back on brake wear: for me it comes down to how the properties of the brake pad change at different temperatures
as has been said, total 'heat' generated is the same in both methods (low force long decel. or hard force short decel.) if the drop in speed is that same... however, applying this logic directly to pad wear assumes that the pads exhibit a liner relationship between pad wear and operating temperature (as a result of caliper force). The pads will operate at different temps in both methods, and therefore we need to consider how the properties of the pad material are effected
If the pad wear was directly proportional to the temp (linear relationship) then I would expect pad wear to be the same in both methods as there would be a direct link between heat (not temp) and wear, but perhaps the pad properties are not like this, making it non-linear
just my view for what it's worth
Martin
as has been said, total 'heat' generated is the same in both methods (low force long decel. or hard force short decel.) if the drop in speed is that same... however, applying this logic directly to pad wear assumes that the pads exhibit a liner relationship between pad wear and operating temperature (as a result of caliper force). The pads will operate at different temps in both methods, and therefore we need to consider how the properties of the pad material are effected
If the pad wear was directly proportional to the temp (linear relationship) then I would expect pad wear to be the same in both methods as there would be a direct link between heat (not temp) and wear, but perhaps the pad properties are not like this, making it non-linear
just my view for what it's worth
Martin
extra factors to consider are engine braking, resistances from the passing air, bearings etc.
Over a longer braking period these benefit deceleration (as in they have more time to act) and will reduce wear and tear on materials.
But as you say, without knowing how the pad/disc materials wear at different temperatures I don't think that a definative answer can be given as to which method is better to any particular degree.
>> Edited by AJI on Saturday 22 April 11:36
Over a longer braking period these benefit deceleration (as in they have more time to act) and will reduce wear and tear on materials.
But as you say, without knowing how the pad/disc materials wear at different temperatures I don't think that a definative answer can be given as to which method is better to any particular degree.
>> Edited by AJI on Saturday 22 April 11:36
AJI said:
But as you say, without knowing how the pad/disc materials wear at different temperatures I don't think that a definative answer can be given as to which method is better.
more hand waving...
are we trying to go faster here or trying to conserve brake pads?
its obvious which method does which
this topic started as a simple question as to whether the 'ring is good on brake wear... and then went into how different braking methods affect pad/dics wear, which is a very good development on the original question IMO.
Francis - yeah it is obvious that late braking is going to give quicker lap times... and that by having longer braking zones is going to conserve pads/discs.
Francis - yeah it is obvious that late braking is going to give quicker lap times... and that by having longer braking zones is going to conserve pads/discs.
Ok... I respect everyones comments and it looks like I'm well in the minority when it comes to trying to put my point of view across. (which I'm not the best at I admit) ;-)
What if then, you had a massive braking zone and only slightly pressed the brakes so that there was minimum contact and 99% of the braking was acheived by resistances via engine braking, wheel bearings, drag etc.
Brake temps wouldn't get very high due to pad-to-air cooling and also disc-to-air cooling. (Ignore brake fluid .... if you put in a fluid which didn't have any moisture and you had hose lines which were in-affected by pressures involved in either of these situations - so 'boiling' your brakes was not an issue).
This is surely not going to cause as much brake wear as a last second stamp on the pedal to rub off all the speed at the very end is it?
If you didn't use brakes at all you'd eventually come to a stop anyways, resulting in zero brake wear. You'd end up with a braking zone purely from engine and other resistant factors.
So if you're going from zero brake wear from a long braking zone to 'a value of' brake wear to a shorter braking zone then this surely must mean that brake wear increases with the shorter braking zone.
I've no idea what a graph of this would look like because I don't have any data on how pads/discs wear at different temp magnitudes. If somebody comes back with data stating that pad and dics wear at a much higher rate with low temps then my theory is flawed, but until then I still stick by my line of thinking. (or until somebody explains in decent level of laymen term thinking otherwise).
What if then, you had a massive braking zone and only slightly pressed the brakes so that there was minimum contact and 99% of the braking was acheived by resistances via engine braking, wheel bearings, drag etc.
Brake temps wouldn't get very high due to pad-to-air cooling and also disc-to-air cooling. (Ignore brake fluid .... if you put in a fluid which didn't have any moisture and you had hose lines which were in-affected by pressures involved in either of these situations - so 'boiling' your brakes was not an issue).
This is surely not going to cause as much brake wear as a last second stamp on the pedal to rub off all the speed at the very end is it?
If you didn't use brakes at all you'd eventually come to a stop anyways, resulting in zero brake wear. You'd end up with a braking zone purely from engine and other resistant factors.
So if you're going from zero brake wear from a long braking zone to 'a value of' brake wear to a shorter braking zone then this surely must mean that brake wear increases with the shorter braking zone.
I've no idea what a graph of this would look like because I don't have any data on how pads/discs wear at different temp magnitudes. If somebody comes back with data stating that pad and dics wear at a much higher rate with low temps then my theory is flawed, but until then I still stick by my line of thinking. (or until somebody explains in decent level of laymen term thinking otherwise).
I'd say that for normal drivers in normal cars the 'ring isn't too bad on rubber and pads, and unlike a few uk tracks, the 'ring has many sections where the brakes have a good rest.
The 'ring is harder on engines, I would say, than UK tracks 'cos of the amount of time you're at high revs/speed.
Incidentally, many will have seen that 'In-Car 956' vid. After Le Mans, the 'Ring and Spa, doesn't Brands Hatch look mickey mouse? It looks like Dinger is having to do about 5 laps just to get the brakes warm. No sooner does he get into top gear than he's back out of it again.
That vid really put many tracks into perspective, for me.
The 'ring is harder on engines, I would say, than UK tracks 'cos of the amount of time you're at high revs/speed.
Incidentally, many will have seen that 'In-Car 956' vid. After Le Mans, the 'Ring and Spa, doesn't Brands Hatch look mickey mouse? It looks like Dinger is having to do about 5 laps just to get the brakes warm. No sooner does he get into top gear than he's back out of it again.
That vid really put many tracks into perspective, for me.
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