speedo calibration

I am about to calibrate the speedo(VDO).AS stated in the CAV manual I am going to use the rolled wheel circumference method.Then I have to work out the number of pulses the speedo will receive in 1Kilometre.Have any of you guys used this method and if so how accurate is the speedo?.
 
Worked fine, but the number I used was different than the manual in my car, #56. I was able to get the correct code from Bob Lacy. My car also has VDO, Smith is completely different.
 

Ian Clark

Supporter
Here's the link to Caerbont, the Smiths manufacturer website Speedo Install Pages . You'll have some math to do and make sure the speed sensor (proximtiy sensor) is within 5mm of the CV retaining bolts and 10mm away from anything else. Otherwise, should work fine:)

Cheers
 
I have had a problem with the CAV speedo calabration. Using the CAV system with my VDO speedo, it reads fast. I am using a 295-50-15 tire. What number should work with this combo?

Vic
 

Ian Clark

Supporter
Hi Victor,

How optomistic is it? We had one read in klm/hr the mph speed. So 100mph indicated was actually 100kph or 63mph. This was at values calculated by the book. What it took was multiplying the number of pulses per mile number you calculated by the optimistic value and then setting your dip switch. I think your number is too high. For example if the speedo is 20% high then reduce your number by 20% and reset the dip switch. Should work...

Cheers
 
Hi! Victor, I too am running 295/50 r15 rears. I measured the rolled circumference of the rear tyre
to be 2.062 metres. I then worked the number of pulses in 1 Km which came to 2910. This is the figure entered into the VDO. I have not tested the speedo as yet. What pulse number did you use?
 
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