10-07-2020, 09:12 PM | #24 |
Second Lieutenant
252
Rep 236
Posts |
|
Appreciate
0
|
10-07-2020, 09:33 PM | #25 |
Major General
3127
Rep 6,728
Posts |
Tires rather than brakes are often the biggest factor in stopping distance. If you can lock them with your brakes, there's no difference between the actual brakes. How well they handle heat from repeated use could easily be different, as can the amount of pressure required to lock those brakes, but that also depends on the actual pads used. How much pedal travel and the feel can differ between calipers and pads, too.
|
Appreciate
0
|
10-08-2020, 02:16 PM | #26 | ||
Colonel
1077
Rep 2,415
Posts |
Quote:
I think we can conclude from this that they have really bad standard brakes on some US produced police cars that is for sure. The differences between the different brake pads are below 4% even at 125 mph to 0 testing. Doesn't look significant to me and there is no statistical analysis. The differences in the graph look bigger than they are because of the well chosen numbers on the y axis. |
||
Appreciate
1
GrussGott18113.00 |
10-08-2020, 02:25 PM | #27 |
Lieutenant
265
Rep 479
Posts |
The M sport package looks so much better than the x-line. I would recommend getting the M sport, just for the M sport look. The brakes are really not needed. I prefer the standard brakes as they are less dusty and just a tad bit smoother when cold. Yes, the feel is better with the M sport brakes but the standard brakes are very effective too, make less dust, and cost less to replace.
|
Appreciate
1
GrussGott18113.00 |
10-09-2020, 06:39 PM | #28 | |
Second Lieutenant
252
Rep 236
Posts |
Quote:
Those standard brakes may be bad, but if anyone thinks they can't lock the wheels I have a bridge I'd like to sell. |
|
Appreciate
0
|
10-09-2020, 07:22 PM | #29 |
Major General
3127
Rep 6,728
Posts |
The bigger thing on stopping distance is the tire compound. I do not know what tires BMW puts on the vehicles with M sport, but it may be a higher performance tire. The feel of the brake can easily change as can how much pressure it takes to lock the wheel up, but once the wheel is locked, it's all about friction between the tire and the road. To get a valid comparison, you need the same tires and the vehicles need to be the same weight. The 45e is quite a bit heavier than the other versions, and it will take longer to stop even if the tires are the same compared to one of the other versions.
|
Appreciate
1
GrussGott18113.00 |
10-09-2020, 09:36 PM | #30 | ||
Colonel
1077
Rep 2,415
Posts |
Quote:
There is only one outlier in CVP1 (FDP) that is really performing worse. Statics aside and just looking at the graph. The only higher quality car tested in the Dodge Charger and the OE pads have the same results as the after market pads. I think this article is better than the flyer you found first, good job. But they didn't formulate a hypothesis and conclusion nor significance. And this doesn't say anything about the stopping quality of the standard BMW brakes in a single emergency brake event compared to the M brakes when both are at normal working temperature. This is what we were discussing: do the m brakes reduce the stopping distance significantly compared to the standard brakes when not tracking the car. So at normal working temperatures and speeds. And like mentioned, other variables might be just as important. Type and quality of tires, reaction speed. Having the driving assistant pro for example will assist in applying maximal braking power if needed. |
||
Appreciate
1
GrussGott18113.00 |
10-09-2020, 11:39 PM | #31 |
Colonel
1698
Rep 2,609
Posts |
Also, not sure why there is constant discussion of locking tires for vehicles equipped with always-on ABS and certainly always on during normal daily driving that triggers emergency braking situations. What am I missing?
__________________
G05 X5 x40i (04/2019 mfg, Canada) on S18A-19-11-540
|
Appreciate
0
|
10-10-2020, 12:45 AM | #32 | |
Lieutenant General
18113
Rep 11,746
Posts
Drives: 2018 M4 Comp Indv
Join Date: Jun 2009
Location: Newport Beach
|
Quote:
For example, if your brakes aren't ever strong enough to lock the wheels then no ABS and trouble! Where big brakes come into play is during high heat situations when brake "fade" starts happening, i.e, the brakes lose their ability to turn kinetic energy into heat since the brakes are overheating. The ///M brakes are built to resist fade in heavy duty use scenarios, i.e., when the brakes are prone to overheating like for track use or riding the brakes down a 15,000 foot mountain while towing 5,000 lbs. In that scenario the ///M brakes would outperform the standards as the standard would start to fade faster and lose their ability to lock the wheel. An analogy might be a contest to see who can press the "N" key the fastest; let's say my index finger is twice as strong as yours ... it might seem like I would win, but since your index finger is already plenty strong enough to press the N key, my greater strength is meaningless in the single press scenario, ie., the difference between us will be insignificant. However if we had to rapidly press that key as many times as we could, your times would likely start slowing before mine, and eventually you'd fail to press the key before I would.
__________________
Last edited by GrussGott; 10-10-2020 at 01:31 AM.. |
|
Appreciate
1
X5 45e1077.00 |
10-10-2020, 01:45 AM | #33 | ||
Colonel
1077
Rep 2,415
Posts |
Quote:
If you have the money go for the m sport brakes. And then go to the other thread on the red and blue choice. Good they only have two color options. 😂 Some thoughts to add to the discussion. Larger / heavier wheels also increase the braking distance. And wider tires are better on dry roads but are more prone to aqua planing on wed roads. So for safety reasons in all situations don't go for the largest tires. The looks is another discussion. I think for safety reasons go for: Driving assistent pro to reduce reaction time it can regulate braking power when you react to late. Make sure your tires are in good condition Don't drink and drive Take a stop when you feel tired. Those two seconds reacting earlier might be more important. |
||
Appreciate
1
GrussGott18113.00 |
10-10-2020, 03:26 AM | #34 | |
Lieutenant General
18113
Rep 11,746
Posts
Drives: 2018 M4 Comp Indv
Join Date: Jun 2009
Location: Newport Beach
|
Quote:
FWIW I've had ///M brakes for the last decade on all of my BMWs, and have fried a few sets of brakes in my day ... with that, I have no hesitation getting the standard brakes that come with the x-line. If I wanted the m-sport package I'd for sure get the ///M brakes, but I don't and feel perfectly satisfied with the standards. |
|
Appreciate
1
X5 45e1077.00 |
10-10-2020, 07:27 AM | #35 | |
Second Lieutenant
252
Rep 236
Posts |
Quote:
|
|
Appreciate
0
|
10-10-2020, 08:09 AM | #36 | ||
Colonel
1077
Rep 2,415
Posts |
Quote:
Maybe my English is a part of the problem. Do you know anything about statistic and defining if differences are significant? If the differences between the different brake pads is not significant the test is inconclusive. Like I mention there is only one outlier in one of the tested cars. The other ones are quite similar. I don't know and don't see the statistic analysis with p lesser than 0,05. So scientifically this test is not correct either. Anyway if you like blue or red brakes buy the m sport brakes. And if you want more safety buy driving assistant pro and good tires. |
||
Appreciate
0
|
10-10-2020, 08:30 AM | #37 |
Colonel
1077
Rep 2,415
Posts |
My colleague has a 45e x line without m brakes. Maybe to finish this discussion we should do a test side by side and see who stops first. Unfortunately he has 19inch summers and me 20 inch. We both have 19 inch winter wheels.
Lots of 45e's here also others with 21 and 22 inch maybe we can even test if wheels size matters. |
Appreciate
0
|
10-10-2020, 03:40 PM | #39 | |
Second Lieutenant
252
Rep 236
Posts |
Quote:
|
|
Appreciate
0
|
10-10-2020, 03:49 PM | #40 | ||
Colonel
1077
Rep 2,415
Posts |
Quote:
|
||
Appreciate
0
|
10-10-2020, 04:20 PM | #41 |
Second Lieutenant
252
Rep 236
Posts |
Sorry, I don't have the desire to explain p-values to amateurs, especially when given amateurs have shown no interest in thinking. Yes, I realize that the above sentence makes it even less likely that you'll think, but alas I truly am really done with this thread. At the very least read a little about standard deviations and p-values, if you manage to understand the point I made, PM me.
|
Appreciate
0
|
10-10-2020, 04:22 PM | #42 | |
Second Lieutenant
252
Rep 236
Posts |
Quote:
|
|
Appreciate
0
|
10-10-2020, 05:11 PM | #43 | |
Second Lieutenant
129
Rep 243
Posts |
Quote:
And before you waste your time trying to figure out how many standard deviations you need in difference for two series to be significantly different from each other: It's the difference expressed as a multiple of standard errors(!), not standard deviations that determines the significance level of said difference. Anyway, you might be better of with Welch's t-test for this comparison. Good luck, let us know what you find |
|
10-10-2020, 05:38 PM | #44 | |
Second Lieutenant
252
Rep 236
Posts |
Quote:
> t.test(c(138.07, 138.29, 137.62, 138.14, 138.19, 139.01, 141.35, 140.29, 135.05, 138.58), c(144.88, 146.7, 147.73, 145.44, 145.16, 142.06, 140.51, 141.66, 141.52, 145.26)) Welch Two Sample t-test data: c(138.07, 138.29, 137.62, 138.14, 138.19, 139.01, 141.35, 140.29, 135.05, 138.58) and c(144.88, 146.7, 147.73, 145.44, 145.16, 142.06, 140.51, 141.66, 141.52, 145.26) t = -6.0057, df = 15.772, p-value = 1.947e-05 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: -7.623701 -3.642299 sample estimates: mean of x mean of y 138.459 144.092 |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|