Speedo WAY off!

[sector6]

Hi guys, Hope someone might have some insight into this problem...
My car, 89' 325is all original motor/tranny/rear end/ stock wheels and stock tire size.
Problem: Speedo is reading 12mph faster than I am actually traveling. I calibrated it with my buddies GPS. When I'm going 50mph, the speedo reads roughly 62mph???

This is a major kick in the dick as the cops around here are BALL BUSTERS!! If everything is original spec how can it be so far out of wack? Only a matter of time before I get popped by the PO-PO!!

Not sure what to do on this one...
Any ideas?

Thanks!!

[CarsSuck]

Well GPS isn't the most accurate method of checking your speedometer.


What is your actual tire size? A lot of shops will put 195/60/14s on cars and thats incorrect. 195/65/14 is. 205/60/14 is slightly undersized, but only a little.

[nando]

You said stock tire size, but early E30s actually have a smaller diameter tire. so what size are you running?

changing the transmission and diff wouldn't make a difference either since all BMW speedos use the same toothed wheel sensor.

[sector6]

Thanks for the replys...
Without running out to check, I'm pretty sure they are 195/60/14. I'll double check after I get out of work.

Edit: would running 195/60's vs 65's really make it read that far off though?

[CAOSyAMOR]

based on what you said, you should be travelling slower than the posted speed limit if referencing your speedo. U worried about getting pulled over for driving too slow?

[sector6]

based on what you said, you should be travelling slower than the posted speed limit if referencing your spedo. Worried about getting pulled over for driving too slow?

no, it's not that I'm worried about going too slow. I can't trust what speedo says. I try and do what "seems like" (say 45mph) but I just never know for sure. Just waiting for one of these dick eaters to fuck with me. :D

EDIT: Diggin' your e30 M3, very nice looking!

[nando]

it's a 3.2% difference in size. Not quite the full 12% you are seeing but it's a good chunk of it.

[sector6]

what are the odds my wheel sensor took a shit?

[Stevie30]

Try this link: http://www.r3vlimited.com/board/show...te+speedometer

[sector6]

Try this link: http://www.r3vlimited.com/board/show...te+speedometer

thanks! Don't know how I missed that post :oops:
...this opens up a whole ton of stuff I was hoping not to have to get into!!...lol
I'll read through it and hopefully come up with a solution.

Why can't it ever be simple, haha!

Thanks for the reply's everyone, and for trying to help me out! 8)

[sector6]

Try this link: http://www.r3vlimited.com/board/show...te+speedometer

After reading that, I'm still at where I was. Thanks though!
It had more to do with the odometer than the speedo.
I'm just going to buy a speedometer sensor from BAV (Part # : 62 16 8 355 008 ) and start there. I don't need to get into dickin' with the cluster at this point as the speedo seems to function just fine.:D

I'll let ya know how it works out.
Thanks!

[BTP325ic]

WTF who needs a speedo.

[sector6]

WTF who needs a speedo.

The ball bags in Blue, that's who
I could give a shit personally.

[Red88]

Mine's 9 mph off at 30 mph. My car might only have 12,000 miles on it.

[mattdk318i]

same here, Almost all of the E30's ive owned have been at least 5mph off, And on the slow side.....The first one to be right on the money is my 332i....Simply because im using the E36 electronics