How far off is your speedo?

[swimfreak]

Just curious about other peoples' experiences with the speedometer. I have rough numbers that I calculated my speedo to read 3-4% faster than actual speed.

My '00 Z3 ran about 8% fast. Wife's '08 Mini is about the same, maybe 7%.

Anybody have definitive numbers? Thanks.

[CarJunkie]

As soon as I get my car, I'll check with my garmin and let you know. Its always good to know.

[BMW86]

Mine is out a fair bit, about 8%

[LOVEM]

Mine Came With Navigon App. About 6 Percent Fast

[Oaktree]

65mph was equaling 100km/h on GPS

[ESC OFF]

Based on Garmin, speedo says 73 garmin says 70.

[T1T2GRE]

I thought all BMWs ran slightly over as a "safety measure". My old E30 ran slightly over.

[Dackelone]

Originally Posted by ESC OFF

Based on Garmin, speedo says 73 garmin says 70.

Are you sure? Normally all German cars indicate a faster speed than actual speed. Unless you have changed your tires or something.

[mPlasticDesign]

Originally Posted by Dackelone

Are you sure? Normally all German cars indicate a faster speed than actual speed. Unless you have changed your tires or something.

73(speedo) is higher than 70(actual).

[Dan Parker]

At 183 mph (gps) its reading about 165 on the speedo, I heard.

[MusclezMarinara]

Originally Posted by Dan Parker

At 183 mph (gps) its reading about 165 on the speedo, I heard.

[Dackelone]

Originally Posted by Dan Parker

At 183 mph (gps) its reading about 165 on the speedo, I heard.

Noop! Actually... the speedo will be pegged at 160 mph - while the car is really traveling faster. AND that is only IF you have removedthe top speed limiter via a tune.

Non M-sports are limited to 130mph while M-sport optioned cars are limited to 155mph. Both speeds on the speedo - not actutal speed. For instance on my 135i while teh speedo would read 155 mph the car was "only" going 140 mph in actual.

I had my instrument pannel coded with the digital M3 display. So while the speedo reads high the M3 digi one reads true vehicle speed. AND it will continue to work ABOVE 160mph (260 kph). I have seen 274 on my dgital speedo while the needle just stayed pegged at 160mph. But it is really hard to read it(!) while driving that fast. I know at 274 kph I was only going 6,100 rpms. I also know quite a few times that I have gone as fast as 6,300 rpms with my 6MT 135i (w/flash tune 380 PS and 510Nm of tq, with 225's/255's tires). I think 6,300 rpms is a real (true) speed of 280 kph or 174 mph.

I have also heard (on the 1er forum) that a tuned 135i will do about 290 kph. I think its possible. But you need one hell of a clear fast Autobahn for that. I have not found the right Autobahn - not yet.

Back before my flash tune... 155 mph(250 kph) max speed indicated on the speedo. True speed was 240 kph!


Post tune... speedo reading 165 kph, while M3 digital speedo reads 159 kph AND GPS reads also 159 kph(true) vehicle speed.





OP - to answer your original question... yes, the speedo reads high by about 5%.

[GaryS]

Originally Posted by Dackelone

I had my instrument pannel coded with the digital M3 display. So while the speedo reads high the M3 digi one reads true vehicle speed. AND it will continue to work ABOVE 160mph (260 kph).

Don't you have oversized tires? How does it know the true speed? I have an OBD2 reader on my steering column. It has a setup feature to correct MPH by +- 1% increments; but if I set it for zero correction, it shows the same MPH as the analog speedometer.

[Dackelone]

Originally Posted by GaryS

Don't you have oversized tires? How does it know the true speed? I have an OBD2 reader on my steering column. It has a setup feature to correct MPH by +- 1% increments; but if I set it for zero correction, it shows the same MPH as the analog speedometer.

Before I had stock rubber and the M3 digital speedo - and I checked it with my GPS. With OE rubber, my M3 speedo read EXACTLY what my GPS read. While the speedo would always read high by a few percent. +4% or +5%. ie: speedo reads 105 kph, M3 speedo reads 100 kph, PS reads 100kph.

When I switched to 225/255's (oversized)tires my M3 speedo would read about 0.5 to 1 kph BELLOW true vehicle speed(what my GPS) would read. For example that second picture... speedo reads 165 kph, M3 speedo reads 159, GPS reads 159 kph. What I found is that even with the 255's tires you really have to be going fast (over 250 kph) to see more than 1 kph difference. Under 250 kph it is about a 1/2 kph diff( M3 vs GPS speeds).