Date: Mon, 3 Sep 2007 22:11:30 -0400
Reply-To: Wesley Pegden <wes@CS.UCHICAGO.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Wesley Pegden <wes@CS.UCHICAGO.EDU>
Subject: Re: MPG
In-Reply-To: <126001c7ee8c$847068e0$6401a8c0@TOSHIBALAP>
Content-Type: text/plain; charset=ISO-8859-1
I know it's the cable, I just haven't gotten around to doing it yet. I
don't see how it could affect the odometer reading though... I mean, the
end by the dash is going to go around as many times as the wheel,
right? It seems like it should signal the same distance, just "unevenly".
No?
Scott Daniel - Shazam wrote:
> A bouncy speedo needle makes me think of a binding/worn jumpy speedometer
> cable.
> It could affect the odometer too.
> I'd lube the cable at least.
> Vanagon speedo needles are very steady normally.
> Scott
> www.turbovans.com
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Wesley Pegden
> Sent: Monday, September 03, 2007 5:25 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: MPG
>
> Good info,
> I wasn't aware of the difference between speedometer error and odometer
> error... my speedo needle bounces too much for me to tell what it's real
> error is ;)
>
> In any case, it's the error on the odometer that matters for calculating
> mpg.
>
> -Wes
>
> Kim Brennan wrote:
>
>> You haven't even begun to touch on this topic with this little sentence.
>>
>> On Sep 3, 2007, at 6:43 PM, Wesley Pegden wrote:
>>
>>
>>> One thing to keep in mind is that many speedometers read a little fast.
>>> You should compare your trip odometer to highway mileage markers to see
>>> what factor it's off by to correct your numbers.
>>>
>> The US Standard is that speedometers read 3-5% below actual speed. But
>> odometers should be 1% or less from actual. But all that is moot once
>> you start going away from stock tires. And if you have gone with
>> larger wheels your figures can be all over the map.
>>
>> In my case. I have one syncro, where the SPEEDOMETER reads pretty much
>> 10% low with the tires on it (when it says you are at 50 mph, you are
>> actually at 55mph.) The ODOMETER, on the other paw is 7% off. When it
>> says you have traveled 200 miles you have actually traveled 214 miles.
>>
>> In another van, the numbers are different. And the tire sizes are
>> different. In that van the speedometer is 12% off, and the odometer is
>> 8% off.
>>
>> Just because you have calculated the margin of error for your ODOMETER
>> doesn't mean you have calculated the margin of error for your
>> SPEEDOMETER.
>>
>> My calculations of margin of error are based on GPS values for speed
>> and distance.
>>
>>
>
>
>
| 
