Can 545i sport use Tire size 255/40/18 for front?

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Dec 28, 2005 | 08:22 PM

#11

EBMCS03

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Joined: Oct 2004

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From: So Cal, USA

My Ride: 545iSMGSilver GrayAuburn Dakota LeatherLogic 7 Premium SoundSports Package

Quote:

Originally Posted by bmw545' post='216491' date='Dec 28 2005, 02:43 PM

Speed at 78 show 80 on odometer.
78*1.03 = 80.34 so 3% right?

I thought the odometer reading is usually the front. I might be wrong.

Oh you're using 80... mph... well you cant do that... cuz the faster you drive the larger the error will be. you have to use "a standard" of measurement... the diameter of the tire or percent difference at 65mph.

BUT you see... you're already getting that error BEFORE you changed to 255s I have that error too in all the BMWs already...

So technically speaking with respect of the new tires its less than 3% difference.

But back to the odometer reading... is it the front?? I have no idea...

Dec 28, 2005 | 09:45 PM

#12

bmw545

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From: Irvine, CA

My Ride: 2004 545i Silver Gray/Black Step Auto. Sports Package, Logic 7, Cold Weather Package, Parking Distance, and Rear Sun Shades 2002 330ci Titanium Silver/Gray Step Auto, Sports Package, Premium Package, Xenon, 18 inch wheels.

Ah.... I think you are right.

I think I should use circumference instead.
25.7 * 3.14 vs 2.6 * 3.14
It's only 1.1% difference. I feel lots of better now.

1.1% who cares. Even a cheap person like me.

Thanks