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Braking distance concern by Consumer Reports

Does any current M3 owners feel that the cars braking capabilities are any less capable vs. any other car that you drive?

Tesla shares hit by Consumer Reports criticism

From Consumer Reports...
Tesla's stopping distance of 152 feet when braking at 60 mph was far worse than any contemporary car tested by the magazine and about seven feet longer than the stopping distance of a Ford F-150 full-sized pickup.

Responding, a Tesla spokesperson said: "Tesla's own testing has found braking distances with an average of 133 feet when conducting the 60-0 mph stops using the 18" Michelin all season tire and as low as 126 feet with all tires currently available.
 

bdy0627

Active Member
May 19, 2015
3,505
12,193
Appleton, WI
Does any current M3 owners feel that the cars braking capabilities are any less capable vs. any other car that you drive?

Tesla shares hit by Consumer Reports criticism

From Consumer Reports...
Tesla's stopping distance of 152 feet when braking at 60 mph was far worse than any contemporary car tested by the magazine and about seven feet longer than the stopping distance of a Ford F-150 full-sized pickup.

Responding, a Tesla spokesperson said: "Tesla's own testing has found braking distances with an average of 133 feet when conducting the 60-0 mph stops using the 18" Michelin all season tire and as low as 126 feet with all tires currently available.
I don't have one but can't imagine Tesla would have known about this and still released the car with such poor braking performance. This will get fixed very quickly I'm sure.
 

N5329K

Active Member
Aug 12, 2009
1,863
3,764
California
Comparing stopping distances recorded by any one tester with those from another tester will always show differences. Kind of like running a compression check. Two testers on the same engine will show different results.
What counts is consistency of method. If CR always does it the same way and found an issue, chances are pretty good there's a real live issue someplace. But putting their numbers against Tesla's proves almost nothing, except that the tests were probably different.
Robin
 
Interesting that the car can stop adequately the first time, but future attempts even on a second test car still had the much longer stopping distance requirements. I am curious if the Anti-lock/traction control capabilities are too relaxed preventing the car from stopping in shorter distances or if it is related to poor brake pad quality (brakes glazing over), smaller than required rotor size or weak braking system and calipers??? I am also curious if the Performance M3 will have larger rotors and braking system???
 
Does any current M3 owners feel that the cars braking capabilities are any less capable vs. any other car that you drive?

Tesla shares hit by Consumer Reports criticism

From Consumer Reports...
Tesla's stopping distance of 152 feet when braking at 60 mph was far worse than any contemporary car tested by the magazine and about seven feet longer than the stopping distance of a Ford F-150 full-sized pickup.

Responding, a Tesla spokesperson said: "Tesla's own testing has found braking distances with an average of 133 feet when conducting the 60-0 mph stops using the 18" Michelin all season tire and as low as 126 feet with all tires currently available.


I refuse to buy this car because its stopping distance is too close to a standard pickup!... said no car buyer EVER.
 

mongo

Well-Known Member
May 3, 2017
14,496
48,916
Michigan
Interesting that the car can stop adequately the first time, but future attempts even on a second test car still had the much longer stopping distance requirements. I am curious if the Anti-lock/traction control capabilities are too relaxed preventing the car from stopping in shorter distances or if it is related to poor brake pad quality (brakes glazing over), smaller than required rotor size or weak braking system and calipers??? I am also curious if the Performance M3 will have larger rotors and braking system???

CR says their standard cool down is about one mile.
Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat.

The 3 has aero covers based on the site pic...
 
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With such a fast car, it seems braking should be the most important since the electric drive can accelerate so fast. I would say that braking is more important then acceleration to me since again this is a safety issue and many people give this the highest priority. My suggestion is to check what brake pad your using and see if a different brake pad could improve the situation. Many brake pads are designed for long wear, and, just like tires designed for long wear, they lack in adhesion because the materials are harder and less gripping.

This may be why your production has not scaled quickly. Scaling production up slowly is allowing Tesla to address some important issues before production is scaled up exponentially.

Just my 2 cents.
 
This needs to be looked into. There is no reason a car that small should have that poor a breaking distance. From CR's own reporting here is the quote on a Model S P85 which is a MUCH larger and heavier vehicle.

Braking
No track testing is done before the vehicle hits 2,000 miles, and we perform a brake seating procedure the day before we take measurements. The test procedure is done on special areas of our test track that are monitored for consistent friction and involves over a dozen stops, with cool-down laps in between to ensure accurate results. We begin measurement as soon as the driver hits the pedal, and the distances are adjusted for temperature. The P85D stopping distances were very short, like a high-performance sports car at 118 feet in the dry and 129 feet in the wet with the optional 21-inch wheel and tire package.
 
I agree that this may be an issue. I strongly suggest that Tesla carefully look into this and initially try looking at the brake pads which could be an easy fix. People usually don't notice bad breaking until it is too late. And now that consumer reports has identified this as a potential issue, take it as a blessing that this was identified early and if it is clearly a problem and addressed now it will definitely save lives.
Evan
 
Maybe they tried the worst case scenario, with a fully charged battery and no regen.
Regen doesn't help braking distance. Every modern car has brakes powerful enough to lock the wheels at speeds way more than 60mph. Regen is limited to .15G acceleration right? Stopping from 60mph in ~130 feet is ~1G of acceleration.
 

mongo

Well-Known Member
May 3, 2017
14,496
48,916
Michigan
Regen doesn't help braking distance. Every modern car has brakes powerful enough to lock the wheels at speeds way more than 60mph. Regen is limited to .15G acceleration right? Stopping from 60mph in ~130 feet is ~1G of acceleration.
Regen would help with brake fade by offloading some (albeit a small amount, 1/7 in your example) of the braking force.
 
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