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Kombi Speedo Adjustment
grouch - August 27th, 2003 at 05:07 PM

Does anyone know if there is a way to adjust the speedo reading ie. my speedo reads approximately 10kph slower than it should at 60kph.

kombikim - August 27th, 2003 at 05:59 PM

speedo calibration is done by an instrument maker - costs heaps, better to start at the other end & work back, 1 what size tyres do you have, 2 is the gearbox diff correct for the vehicle & it's speedo ? large diameter tyres will make speedo read slow

vw54 - August 27th, 2003 at 06:01 PM

Best off removing it from the car and getting a Instrument fitter to Overhaul it and or calibrate it for you on the test bed.

We havea couple of places here in Sydney that can do it but i suspect that you have similar shops in Brisbane

kombikim - August 27th, 2003 at 11:08 PM

sorry made severe mistake - drive for kombi speedos is front wheel ei small diameter tyre will make speedo say you are going faster than you are , large diameter tyre will make speedo say you are going slower than what you are the speedos are & geared & calibrated anticipating a certain size tyre & rolling diameter the odometer is driven by a fixed gear & its accuracy therefore does not vary with wear or age
The needle indicating speed , however is driven indirectly by what i suppose you could call a combination of magnets a spring & centrifugical force & that setup can be subject to inaccuracy when the instrument is so old so - if you sit on exactly 60kmh for exactly 1 minute the odometer should register exactly 1 kilometre & if it does you are wasting a hell of a lot of money to get it cleaned and calibrated, you either have the wrong speedo or wrong diameter tyre

1303Steve - August 27th, 2003 at 11:33 PM

Hi

I have an aftermarket speedo in my car, I had a ratio box made for it by Speedscreen in Newtown. Have you checked the odometer on one of the freeway sign posts?


VDO now make all their speedos electronic, and they are easily user adjusted.

1302Steve

Purple Martin - August 28th, 2003 at 08:29 AM

Quote:
Originally posted by kombikim
if you sit on exactly 60kmh for exactly 1 minute the odometer should register exactly 1 kilometre & if it does......

......you know that your tyres are exactly the right size because the odometer is driven by a fixed gear. If the odometer is right but the speedo is wrong, the problem must be in the magnets/spring.

kombikim - August 28th, 2003 at 08:56 AM

yep that is it
Steve's electric speedo sounds great,

hate to think how much it would cost
a digital speed alert kit from Jaycar might also be a viable option

grouch - August 28th, 2003 at 07:16 PM

Thanks guys, I believe I have stock rims and tyres. I might do a test run with another car to check the speedo at different speeds.
Might be easier to just mark a spot on the speedo lens at the correct speeds.
:)