Re: Speedometer Accuracy

["Pete and Nat Lavengood" <laveng@xxxxxxxx>]

BMW Designs the speedos to read high. The intent is for the speedo to always 
read high even with the largest possible tire mounted on the front rim. They 
will not recalibrate as it is supposed to be this way. Inexpensive and 
accurate solution is to get a bicycle speedo using a magnetic pick-up 
mounted on the brake disc. This unit is calibrated to to the tire on your 
bike. ie mark a spot on the tire and the pavement, roll ten times and 
measure the distance between spots and divide by 10. This is an accurate 
circumference of the loaded tire and is entered into the bicycle speedo to 
calibrate it to your bike.
From: "Gregory Appling" <gappling@xxxxxxxxxxxxxx>
To: <oilheads@xxxxxxxxx>
Sent: Wednesday, June 01, 2005 10:32 AM
Subject: Speedometer Accuracy


> The bike in question: 2002 R1150r
>
> Does anyone know how accurate the speedometers for the R1150r's are? I'm 
> currently trying to figure out if my speedometer is way off or if my GPS 
> units is just so cheap that it's not even close.
>
> Yesterday while running down the highway my speedometer read 92mph, my GPS 
> read 81.7mph and my girlfriends SUV (following closely) was somewhere 
> around 85mph.
>
> Just wondering if this is normal or time to take it in to be checked 
> (still under warranty).
>
> Thanks for any help.
>
> gregory
>
>
>
> 2002 R1150r
> 1975 R90/6
> ABC# 8111
> BMWMOA # 117910
> San Francisco, CA

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