On Sat, 22 Feb 2003, at around 13:21:46 local time, Laura G.
<Laura.G@141.com> wrote:
>>Date: Sat, 22 Feb 2003 18:05:55 -0000
>>From: "William Davies" <bill@rarebits4classics.co.uk>
>>Subject: Re: Odometer readings on Spitfire 1500s
>>The usual weak link is the speedo unit itself. They were never
>>particularly accurate and as the internal magnets weaken with age they
>>only become less accurate. Unless you find something which has obviouly
>>been swapped, it's a fairly safe bet that your speedo is at fault,
>> Cheers, Bill
>
>Which is why I am reluctant to take my Spit on a rallye-too much math,
>trying to compensate for the inaccuracies in the speedo.
>
>On the other hand, there is a Smith's competition speedo available now that
>is quite accurate and easy to hook up. Runs off magnates like most other
>competition rallye speedos and bicycle speedos. The dial is very clearly
>marked so that you can easily identify the speeds. I believe it is an 80
>mph speedo, but in TDS rallyes, you don't usually go much over 50. I also
>believe that it is priced in the range of a new speedometer...so, if you
>really want to know, with accuracy how fast you're going, that might be an
>option.
But a really accurate speedo still won't tell me anything about what
speed I am actually doing, if the drive gear which is powering it has
the wrong number of teeth! I am convinced that, whatever the error in
the speedo, the cause of the error in the odometer (which is driven by
gears, and not by magnets) has to be at the gearbox.
Of course, the good news in all of this is that my mpg figures are
actually 9% higher than I thought... <g>
ATB
--
Mike
Ellie - 1963 White Herald 1200 Convertible GA125624 CV
Connie - 1968 Conifer Herald 1200 Saloon GA237511 DL
Carly - 1977 Inca Yellow Spitfire 1500 FH105671
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