calibration

Has anyone ever got a speedometer calibration? I know they typically run high on bimmers but i wanted to know an exact result...does it depend on the model or is it unique to how well car is maintained etc?

It has nothing to do with maintenance with exception to keeping your tires at the correct pressure.

I believe the speedo can be calibrated by recoding the instrument cluster.

OP, use or borrow a GPS device to get an accurate speed. Your speedometer isn't "inaccurate", it was made (by law!) to read the way it does. Even if you do recalibrate it so it matches your GPS, a tire profile change, or a change in tire pressure will will make it inaccurate again.

there is an app for the Iphone, I used it to check my speedometer on my boat, its pretty close, like 1 MPH off, how close did you want to get. I believe the tolerance is + or - 5% so at 50. legally if you are anywhere between 48 and 52 its considered correct

Euro law specifies that a speedo may not under-read and may over-read by a maximum of 10%. For BMWs, it varies from car to car - my 5 Bimmers have ranged from 1 to 5% high.

And any speedo error has nothing to do with the odometer.

Tom

Reason I ask is because i was caught by a gendarmes "enjoying my BMW" - I've been advised by a lawyer to get a speed calibration done but i've always thought they read high and i dont want to spend $60 for result thats not goign to help my case.

It doesn't matter if your speedo said you were doing 30 in a 50. Then you'll get a faulty equipment ticket at best. Keep it under the limit and you've got no worries.

waze checks ur speed with the gps, free app for iphone and android

also I rather it read high so in my mind it feels like im going 80 in a 75 so not bad =p

Originally Posted by 8355adam

Reason I ask is because i was caught by a gendarmes "enjoying my BMW" - I've been advised by a lawyer to get a speed calibration done but i've always thought they read high and i dont want to spend $60 for result thats not goign to help my case.

its not going to help you, the speedometer reads high, meaning that the displayed speed was even higher than the speed you were clocked at....
so if you got clocked at 80 in a 65, the speedometer was likely reading 85 or more.

thats what i figured it would likely be. I wont waste my money on it then.

ps... orient i wish it was only 80 on a 65

Originally Posted by 8355adam

ps... orient i wish it was only 80 on a 65

You might consider either changing your driving habits or moving to a state where radar detectors are legal - but even that is no guarantee...

Tom

I'll just say one thing.

A Track Day is WAAAAAAY more fun than speeding on public roads. And cheaper. And much faster.

Okay, three things.

I am not sure how accurate the mile markers on Arizona freeways are; I set the cruise to get my car speed, and use the stopwatch in I-drive to obtain how many seconds it takes me to go 1 mile, and do the quick math to see my speed via mile marker method. Both cars are typically 2 to 3.5 miles/hr faster comparing the car speed with the mile marker speed.

Just give me your keys.

ha...well its my first traffic stop ticket. 85/55 which is too fast ofcourse but when trucks are doing 70-75 it makes you think which one stops quicker at such speeds. That ofcourse is not my defence but i just felt like saying that to the cop.