07-25-2019, 06:25 AM | #1 |
New Member
8
Rep 28
Posts |
Speedometer reading accuracy
Hi all,
I have a question for y'all: how accurate is your speed reading on your G30?? You see, I have a 2017 540i with the HUD and the digital cluster (can't remember the option... 6W something something) and have noticed a persistent 4 to 6 km/h error on my speed reading in both. I always show a slower speed than acutally travelling, which is driving me absolutely mad! The slower I go, the less the margin is but it's still almost always around 5 km/h (or around 3 mph). I know this through GPS and with radar (didn't get a ticket, just the warning ones around town ). What really gets me is when I told the dealership they answer "it's normal, BMW are like that to keep you from speeding". WHAT?! So first, that's stupid. Second, the cheap a** Hyundai Sonata I got for work shows me the EXACT speed I'm travelling, how is it BMW doesn't. And lastly, that's STUPID. I've had three 3 series before that and never noticed such a difference, except if I have the wrong wheel size... So, before I blow a gasket at them (first time buying from them, not impressed) is there truth to that? And if there is, is there any way to fix it?!? I can go in details on why I don't trust them anymore, but suffice to say they better give me one damn good price on a car to buy from them again. |
07-25-2019, 06:38 AM | #2 |
Private First Class
25
Rep 118
Posts |
afaik bmw speedo always shows 3 more (real speed is 3 less)
for europe thats 3 km less [the real speed] (this has always been the case in a bmw for me atleast) and for US 3 mph less (I suppose, i think I've read it somewhere) this is of course assuming you use the correct oem wheel + tire size Last edited by lnaukkar; 07-25-2019 at 10:19 AM.. Reason: more is less, less is more. |
Appreciate
0
|
07-25-2019, 07:11 AM | #3 |
Captain
471
Rep 888
Posts
Drives: 2019 M550i
Join Date: Aug 2018
Location: Tampa Bay
|
mine always reads 2 to 3 mph faster than what I'm actually going. All the speed reading signs on the side of the road read 35 when I'm going 37-38 and so does waze.
|
Appreciate
0
|
07-25-2019, 08:22 AM | #4 | |
Second Lieutenant
159
Rep 263
Posts |
Quote:
My understanding is that speedometers are calibrated to display a faster speed than actual to prevent you from speeding. If the indicated speed is lower than actual and you get pulled over for speeding, the car manufacturers could be liable because your speedometer indicated you were going slower than you actually were. |
|
Appreciate
0
|
07-25-2019, 09:33 AM | #5 |
Major General
4411
Rep 7,449
Posts |
Uhh...here we go again.
The accuracy of the speedometer (as discussed for DECADES across multiple forums)...is altered due to European regulations. It's easy to find by just googling it because it has been asked a million times. And no...it does not affect your odometer. Japanese & American made cars usually follow the 4% rule: The four percent rule European made cars follow a different formula: The European formula
__________________
2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)| 2014 F15 X5 50i MSport (Space Gray/Mocha)
Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral. |
Appreciate
1
clee1982797.50 |
07-25-2019, 10:12 AM | #6 | |
New Member
8
Rep 28
Posts |
Quote:
I did do a search on the forum, and nothing turned up. As for google, I must have simply missed it... too narrow a search I guess. Going on my asessment of other cars (hindsight Korean and American) I didn't think regulations could be an actual thing. Case closed. |
|
Appreciate
0
|
07-25-2019, 11:37 AM | #8 |
New Member
8
Rep 28
Posts |
|
Appreciate
0
|
07-25-2019, 12:19 PM | #9 |
Private First Class
119
Rep 156
Posts |
|
Appreciate
0
|
07-25-2019, 08:45 PM | #10 | |
Fight On!
109
Rep 325
Posts |
Quote:
A typical BMW, as the others painfully pointed out already, shows a faster speed (by about 5%) than actual. So, at a highway speed of 65mph (as shown by your speedometer), you are actually traveling at roughly 62mph. |
|
Appreciate
1
clee1982797.50 |
07-25-2019, 08:50 PM | #11 | |
Lieutenant Colonel
369
Rep 1,887
Posts
Drives: '20 M5C, '09 M3 DCT Coupe
Join Date: Apr 2008
Location: Eastern Oregon... They call 'em rigs here
|
Quote:
__________________
M5C 20% tint, Xpel full front, partial sides and rear. Spacers, 15mm front, 12mm rear. Turner Motorsport Oil Cooler Guard.
M3: Active Autowerke filter, Dinan underdrive pulley, Dinan full exhaust and software, 3.45 Differential, Springs, Brakes, Dinan/HRE wheels, 275/30-19 w/10mm spacer, 295/30-19 w/3mm spacer, painted front reflectors, 30% tint, Escort 8500i & Lidar Jammer, LUX H8 V5 halos, Euro rear foglights, 3M ClearBra. |
|
Appreciate
0
|
07-26-2019, 10:32 PM | #12 |
Major General
4439
Rep 5,329
Posts |
|
Appreciate
0
|
07-27-2019, 09:44 AM | #14 |
Major General
4439
Rep 5,329
Posts |
|
Appreciate
0
|
07-27-2019, 12:20 PM | #15 |
Private First Class
75
Rep 100
Posts |
When I've driven by those "Your Speed Is X mph" signs, my speedometer reads about 1.05X. That is, my speedo reports about 5% higher speed than actual speed (assuming the signs are accurate).
Some vectors: (Speedometer Reading, Actual Speed) (84, 80) (63, 60) (42, 40) (21, 20) |
Appreciate
0
|
07-28-2019, 05:34 PM | #16 |
Brigadier General
3086
Rep 4,210
Posts |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|