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      02-18-2020, 12:40 PM   #23
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I will be tracking my car this year and wondered if you guys could help with the following?

If running dedicated front track pads (for example; RS29’s) could you still run the rear OEM pads and be OK? (bearing in mind rear braking accounts for approx. 25% of your total braking force).Ankit Mishra
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      02-18-2020, 01:42 PM   #24
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Quote:
Originally Posted by credit69 View Post
I will be tracking my car this year and wondered if you guys could help with the following?

If running dedicated front track pads (for example; RS29's) could you still run the rear OEM pads and be OK? (bearing in mind rear braking accounts for approx. 25% of your total braking force).Ankit Mishra
I would at least put better street/light track pads but waiting to go trough your stock pads could be fine also. Mine just did not last very long with all the MDM mode dsc intervention
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      02-19-2020, 08:56 PM   #25
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Quote:
Originally Posted by detroitm2 View Post
I wouldn't run street pads on the track, even if they are just on the rear. The potential for them to quickly wear down and damage your rotors is still a possibility.

I personally run Ferodo DS1.11's in the front, and DS2500's in the rear on the track. This provides a pretty even brake feel and wear appears to be about the same.

As a bonus, you can run the DS2500's on the street as they aren't very noisy, and they are the same compound as the 1.11's, so theres no need to rebed the pads when you swap them out if you run the DS2500's on the street (all 4 corners).

The DS2500's however likely arent enough brake to run in the front for track day, hence the reason for the 1.11's.

Hope this helps!
Depends on your brakes, if you have the 2NH option on the Competition with the 6 pot caliper and 400MM rotors you shouldn't have too much problem with the stock pads.

I've heard the other brakes are indeed a very big shortcoming.
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      02-24-2020, 10:31 AM   #26
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Some input on the Ferodo DS compounds with regards to front/rear, and some overall notes on mixed mu pad setups.

Our recommendation on this chassis (and just about all chassis for which we develop brake systems) is to the run the same pad compound front and rear for superior performance and longevity. We design, run calculations, run simulations, conduct testing, etc. with the assumption of the same brake pad compound front and rear. Any deviation from that is going to impact brake bias. Any time you run a higher mu pad on one end of the car, you're shifting some amount of brake work to that end of the car. In the case of this thread, the DS1.11 is a higher mu pad than the DS2500, so you're shifting bias towards the front when you run 1.11 front/2500 rear.

The relevant question here is, "Is that bias difference enough to be problematic?"

We have quite a few customers across different platforms running the DS1.11 up front and DS2500 in the rear. As noted by others, this is mostly born out of the convenience of only having to swap one axle of pads. For the casual HPDE enthusiast, our experience tells us that leaving the DS2500 in the rear tends to NOT be problematic on BMW M cars. It's not ideal, but it doesn't create any major issues. Just keep in mind though, that when you're running DS1.11 front and DS2500 rear, you're shifting a little bit of brake bias to the front of the car. That is going to put more strain and wear and tear on the front brakes. Having the same pad compound at both ends of the car will use the brakes at both ends of the car most efficiently.

To some people, the convenience factor is worth the trade-off in performance and wear. Some things below to watch out for however:
  • If you are running a higher mu front pad and are seeing more pad wear on the front than you'd like, switch to the same compound front and rear.
  • If you are running a higher mu front pad and are not getting the life out of your front discs that you want, or are boiling brake fluid, swap to the same compound front and rear.
  • If you are trying to squeeze every tenth of a second out of your car, particularly on race tires, run the same compound front and rear.
  • If you are having any type of ABS funkiness or early ABS intervention up front, run the same pad compound front and rear.

In some cases we've actually had people tune their brakes in the opposite manner via a higher mu rear pad compound. For example, we had one Subaru STI time attack gent run a slightly higher mu pad in the rear to try and get the car to rotate more under trail-braking. However, that would be much more of a problem on a nose-heavy pig, excuse me platform, such as the STI than it would on a beautifully balanced M2.

Also of note, if you are running a more aggressive Ferodo compound like the new DS3.12 on the front, we definitely would NOT suggest running the DS2500 on the rear. Running the DS3.12 front and DS1.11 rear would likely be okay, as the difference in mu between those is not as great. The gap in mu between the DS3.12 and DS1.11 is considerable however, and more than we'd suggest running. That setup isn't going to give you the results you want.

Below is a mu graph from Ferodo that shows the relative difference in mu curves across their pad compounds. Don't worry about the specific mu numbers. Trying to compare mu values on this chart with numbers provided by other pad brands is no different than trying to compare horsepower numbers from a Dynojet vs. a Mustang Dyno. This graph is really only useful for comparing mu curves within the Ferodo pad lineup. You'll see that the DS1.11 and DS2500 have fairly similar shapes to their mu curves up to about 900 degrees F (500C). At that point, you'll see a steady drop-off in the DS2500's mu, whereas the DS1.11 declines more slowly. The hotter you get 'em, the greater the difference you'll see in the ability of the DS1.11 and DS2500 to generate friction. In other words, if you're running your brakes super hot on a tough braking track, the spread between how much friction the pads are generating at the front vs. the rear of the car is going to widen.



Hopefully the above is helpful and makes sense.
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      02-25-2020, 12:09 PM   #27
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Quote:
Originally Posted by jritt@essex View Post
Some input on the Ferodo DS compounds with regards to front/rear, and some overall notes on mixed mu pad setups.

Our recommendation on this chassis (and just about all chassis for which we develop brake systems) is to the run the same pad compound front and rear for superior performance and longevity. We design, run calculations, run simulations, conduct testing, etc. with the assumption of the same brake pad compound front and rear. Any deviation from that is going to impact brake bias. Any time you run a higher mu pad on one end of the car, you're shifting some amount of brake work to that end of the car. In the case of this thread, the DS1.11 is a higher mu pad than the DS2500, so you're shifting bias towards the front when you run 1.11 front/2500 rear.

The relevant question here is, "Is that bias difference enough to be problematic?"

We have quite a few customers across different platforms running the DS1.11 up front and DS2500 in the rear. As noted by others, this is mostly born out of the convenience of only having to swap one axle of pads. For the casual HPDE enthusiast, our experience tells us that leaving the DS2500 in the rear tends to NOT be problematic on BMW M cars. It's not ideal, but it doesn't create any major issues. Just keep in mind though, that when you're running DS1.11 front and DS2500 rear, you're shifting a little bit of brake bias to the front of the car. That is going to put more strain and wear and tear on the front brakes. Having the same pad compound at both ends of the car will use the brakes at both ends of the car most efficiently.

To some people, the convenience factor is worth the trade-off in performance and wear. Some things below to watch out for however:
  • If you are running a higher mu front pad and are seeing more pad wear on the front than you'd like, switch to the same compound front and rear.
  • If you are running a higher mu front pad and are not getting the life out of your front discs that you want, or are boiling brake fluid, swap to the same compound front and rear.
  • If you are trying to squeeze every tenth of a second out of your car, particularly on race tires, run the same compound front and rear.
  • If you are having any type of ABS funkiness or early ABS intervention up front, run the same pad compound front and rear.

In some cases we've actually had people tune their brakes in the opposite manner via a higher mu rear pad compound. For example, we had one Subaru STI time attack gent run a slightly higher mu pad in the rear to try and get the car to rotate more under trail-braking. However, that would be much more of a problem on a nose-heavy pig, excuse me platform, such as the STI than it would on a beautifully balanced M2.

Also of note, if you are running a more aggressive Ferodo compound like the new DS3.12 on the front, we definitely would NOT suggest running the DS2500 on the rear. Running the DS3.12 front and DS1.11 rear would likely be okay, as the difference in mu between those is not as great. The gap in mu between the DS3.12 and DS1.11 is considerable however, and more than we'd suggest running. That setup isn't going to give you the results you want.

Below is a mu graph from Ferodo that shows the relative difference in mu curves across their pad compounds. Don't worry about the specific mu numbers. Trying to compare mu values on this chart with numbers provided by other pad brands is no different than trying to compare horsepower numbers from a Dynojet vs. a Mustang Dyno. This graph is really only useful for comparing mu curves within the Ferodo pad lineup. You'll see that the DS1.11 and DS2500 have fairly similar shapes to their mu curves up to about 900 degrees F (500C). At that point, you'll see a steady drop-off in the DS2500's mu, whereas the DS1.11 declines more slowly. The hotter you get 'em, the greater the difference you'll see in the ability of the DS1.11 and DS2500 to generate friction. In other words, if you're running your brakes super hot on a tough braking track, the spread between how much friction the pads are generating at the front vs. the rear of the car is going to widen.



Hopefully the above is helpful and makes sense.
Great info, Jeff!
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      03-30-2020, 02:27 PM   #28
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Does anyone have a link to best practices when bedding brakes before a track day?
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      03-30-2020, 03:00 PM   #29
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Quote:
Originally Posted by m2cWW View Post
Does anyone have a link to best practices when bedding brakes before a track day?
I really like the videos on the Essex site:

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      03-30-2020, 03:04 PM   #30
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Quote:
Originally Posted by m2cWW View Post
Does anyone have a link to best practices when bedding brakes before a track day?
How this:

https://www.apcautotech.com/getmedia...e-8-2018_1.pdf

All I do is find a road with little to no traffic on it.

With the car going 55-65 MPH Left foot brake while keeping your right foot down on the gas. DO this with heavy brake pedal effort for 5 seconds at a time. Use the throttle to try to maintain steady speeds...Do this 3xs quickly then drive around and let them cool off. Repeat above a 2nd series of 5-7 sec applications.

If you do this correctly your pads and rotors will get stinking hot and they will be bedded.

I've been bedding pads like this for 30 years. Works awesome...
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      03-31-2020, 05:42 PM   #31
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Quote:
Originally Posted by PLF69 View Post
I really like the videos on the Essex site:

Awesome video man! Much appreciated!
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      03-31-2020, 05:44 PM   #32
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Quote:
Originally Posted by SEAT TIME RULES View Post
How this:

https://www.apcautotech.com/getmedia...e-8-2018_1.pdf

All I do is find a road with little to no traffic on it.

With the car going 55-65 MPH Left foot brake while keeping your right foot down on the gas. DO this with heavy brake pedal effort for 5 seconds at a time. Use the throttle to try to maintain steady speeds...Do this 3xs quickly then drive around and let them cool off. Repeat above a 2nd series of 5-7 sec applications.

If you do this correctly your pads and rotors will get stinking hot and they will be bedded.

I've been bedding pads like this for 30 years. Works awesome...

Link explained it super quickly, much appreciated man!
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      04-01-2020, 07:18 AM   #33
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Thanks gents. Here's another video on swapping between street and track pads. This one can save you some serious headaches:

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      04-01-2020, 10:57 AM   #34
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Any tips when you don't have time to do this and you kind of have to do it in the track ?
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