My van's on oversize tyres as they are 215R14's instead of what I think was 185R14's originally so I'd have thought that would help reduce overreading a fair bit but it is as follows when compaired to a GPS device on a 12.8mile trip...
Trip meter 8% over - is this normal? would have thought it could be but only with normal size tyres (maybe my van was built with 205R14's then?).
GPS speed 30, indicated speed 40
GPS speed 50, indicated speed 64
GPS 57, speedo 72.
It seems to be overreading between 25-35% which is really quite anoying! Does go a long way to explaining why the tailback behind the van is considerably bigger than my old landy despite me suposubly driving faster in the van (55-60 is actully about 45 it turns out). I thought the higher driving position was making it feal a bit slower
.I'm sure my clock is knackered (week needle spring probubly) so I guess the real question is wether the odo accuracy is about what I should expect from these vans as that would mean the speedo drive is alright, just need to change the clock? The needle wobbles a bit around 20 (indicated) but apart from that its pritty steady so that all seems fine.
Its a Syncro so the speedo drive is different to a RWD van but that shouldn't effect the reading it was designed to give on standard tyres so anyones views will be helpful.
I think my dads old 87 Caravelle was near 10% overreading on speed, don't know about trip. His current T5 is under 5% speed and an impressive 0% inacuracy on the trip counter! Maybe there is something good about fully electronic dashbords/vehicles? (no theres not, he had to jumpstart it off the syncro last week as the batt went flat, theres so many wires in it we wouldn't have a clue where to start fault finding!)
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Glen
