Research
Michigan blind-tested police brake pads. One set got fifty feet worse.
In 2010 the Michigan State Police asked twenty-eight manufacturers for their severe-duty police pads, culled the ones that failed the federal standard in a laboratory, and then took the survivors to a proving ground without being told whose was whose.
If you own one of these cars, the brake pads are a decision you make yourself. There is no police fleet buying them for you, and the boxes all say much the same thing: severe duty, police, pursuit, extreme service.
Michigan ran the test that tells you what those words are worth, and almost nobody knows the report exists. It is not part of the annual vehicle evaluation — it is a separate 2010 study by the same Precision Driving Unit, and the findings are considerably blunter than anything in the year books.
How they did it
The solicitation went to twenty-eight manufacturers offering severe-duty friction material for police vehicles, plus an open notice on the industry’s own iFriction site. Nobody was excluded for being small or unfamiliar.
Stage 1 was a laboratory. Matched sets of every submitted material went to Greening Testing Laboratories in Detroit and onto dual dynamometers, tested against Federal Motor Vehicle Safety Standard 135 — the braking standard every new car sold in America must meet.
And here is the first finding, stated flatly in the report and easy to miss: not all of the submitted aftermarket pads could meet the minimum requirements of FMVSS 135, and were removed from the pool before they got anywhere near a vehicle.
Products marketed for police use, failing the minimum standard that applies to an ordinary family car.
Only the top three per platform went forward. Stage 2 was blind — the make, model and manufacturer of each candidate were withheld from the test team until every run was finished.
Then they were tested on a 2009 Crown Victoria Police Interceptor, a 2009 Charger 5.7, a 2009 Impala 9C1 and a 2010 Tahoe PPV: twenty measured 60-to-0 ABS stops in two phases of ten with a cool-down between, six stops from 125 mph on the high-speed oval at Chelsea with a 4.5-mile cooling lap after each, and then 32 timed laps at Grattan.
The set that fell apart
One candidate failed in a way the numbers make impossible to argue with. On the Crown Victoria, here are the ten stops of the first 60-to-0 series, in order, for the FDP MaxStop Plus material — and, beside it, the factory pad on the same car.
| Stop | FDP MaxStop Plus | Factory pad |
|---|---|---|
| 1 | 148.44 | 147.22 |
| 3 | 156.72 | 145.77 |
| 5 | 173.86 | 143.20 |
| 7 | 189.19 | 142.54 |
| 8 | 198.23 | 143.01 |
| 10 | 193.68 | 147.15 |
It starts level with the factory pad and ends fifty feet longer. The factory material does not move at all across the same ten stops — it finishes where it started. The aftermarket set simply gives up, progressively, stop after stop, exactly as the brakes get hot.
From 125 mph it is worse. Its six stops averaged 635.63 feet against 586.90 for the factory pad on the same car, and the last stop of the six took 674.59 feet. Its standard deviation was 24.99, where every other candidate in the test sat between 3 and 15 — meaning it was not merely long, it was unpredictable.
Its average deceleration came out at 0.822 G. Every other material tested, on every platform, managed between 0.859 and 0.936.
And one that was suspended mid-test
On the Impala, the Fras-Le Extreme Service-Police material cleared the laboratory stage and then did not finish the road course. Testing was suspended after 16 of the 32 laps at Grattan because of high pad wear at the front brake.
It was also the longest-stopping material on that platform from 125 mph, at 608.35 feet.
What the wear numbers show
Stopping distance is only half of it. The report also measured how much pad each material consumed during the test sequence, and the results are not uniform in the direction you would expect.
| Platform | Material | Wear result |
|---|---|---|
| Charger 5.7 | Affinia (AC Delco) | consumed ~60% of front pad thickness, against ~30% for factory |
| Crown Victoria | Rayloc (NAPA Ultra Premium) | less wear than the factory pad |
| Crown Victoria | Affinia (AC Delco) | comparable at the front, significantly less at the rear |
| Crown Victoria | Factory | best overall front/rear balance of the four |
| Impala 9C1 | Fras-Le | test suspended at 16 laps — front pad wear |
| Tahoe PPV | Affinia (AC Delco) | higher front wear, significantly lower rear wear than factory |
The Rayloc result matters because it cuts against the easy conclusion. This is not a story about aftermarket bad, factory good. One aftermarket material outlasted the factory pad on the Crown Victoria while stopping within a few feet of it.
What the factory pads reliably had was balance. Several aftermarket materials wore heavily at one axle and lightly at the other, and the report is careful about why: front-to-rear wear imbalance reflects the vehicle’s brake force distribution and the thermal balance of that particular car-and-material combination. A pad that is excellent on one platform is not necessarily excellent on another.
Four brands, one pad
The most immediately useful page in the report is the one listing part numbers, because it quietly demolishes a shopping decision.
The Affinia-BPI material tested as AC Delco is listed there as also being marketed as Raybestos, NAPA and CarQuest — four brand names, four part numbers, and edge codes from the same family. It is one friction material in four boxes.
If you have been choosing between those four, you have not been choosing between anything.
Which is exactly what an edge code is for. It is stamped on the side of every pad sold in America and identifies the manufacturer and the specific friction formulation, regardless of whose name is on the box. The report lists them for every material it tested — and it is the one number worth checking before you buy.
The thinness of the market
One last finding, and it explains a great deal about why prices are what they are.
On the Charger, the Affinia material was the only aftermarket product that qualified for vehicle testing at all. On the Tahoe, the same — one qualifier. Only the Crown Victoria and the Impala had three each.
Out of twenty-eight manufacturers invited, two of the four most common police platforms in America produced a single aftermarket material good enough to be worth putting on a car.
What to do with this
Check the edge code, not the brand. It is stamped on the pad and it tells you who actually made the friction material. Four brands can be one product; two boxes from the same brand can be different formulations.
Judge a pad by its tenth stop, not its first. Everything in this test stopped acceptably once. The differences appear under repetition and heat, which is the same lesson the archive keeps producing — it is what separated the 2005 Tahoes, and it is why Michigan’s own procedure runs twenty stops instead of one.
And treat the wear figures as a warning, not a lifespan. The report says plainly that these numbers come from a deliberately punishing sequence and do not represent normal use. A pad that gave up sixty percent of its thickness here is not one that lasts a year on the road.
This test has never been repeated, and the vehicles in it are now the collector cars. That makes a fifteen-year-old government report the best independent information available on what to bolt to them.