Speedometer correction factors

[Indy555]

Indeed!!
And based on a couple of comparisons I've done with gps, it seems you're right!
However, isn't all this also depending on wheels diameter?

Yes. You're right. But most wheel dimensions that fit the e21 are comparable in scope.
So it's correct to have always an eye on the factory fitted wheels for Your e21...

175/60R13 : 1.63m
185/60R13 : 1.67m
185/50R14 : 1.63m
195/45R15 : 1.68m

Just a few....

[petroscf]

My car initially, as a 316 used to wear 165/13 which means I guess a profile of 82? Or 80?

[Jeroen]

Stock size is, I believe, 185/70-13, diameter 589mm, or 165R13 (80% sidewall), 594mm in diameter

[petroscf]

found a lovely calculator for working out variants

http://johnmaherracing.com/calculators/ ... alculator/

As this is really lovely, shouldn't we add this to the "all kinds of useful calculators" thread, perhaps?

[Jeroen]

We had one in there but the link was now dead so I put this one in, thanks!

[petroscf]

[petroscf]

We had one in there but the link was now dead so I put this one in, thanks!

Today tried a couple of times to reach this link, it doesn't seem to work, hope it is only temporary

[petroscf]

Found this one instead, seems ok:

http://www.cargister.com/calculator-gear-ratio

[Jeroen]

Thanks I'll update the link once again haha

[petroscf]

The speed correction factor should be taken into account when calculating the distances shown on the odometer?