How to read your speedo correctly

[Ozzie]

just curious...

This is a dumb question but here I go...

Is there any difference in speed for say a car with bald tyres and a car with brand new tread. Both cars have 15"s standard?

Tread on most standard tyres is like 5mm.. Would it nock the speedo out by much if any at all?

 

[VrWagz1]

not by much,but yes it will, if your circumfrence becomes smaller then they will travel less distance with each revolution, so you will go slower than your speedo shows. But not by much at all.

 

[LightningVP]

in Victoria, last I heard it is 3 pts margin, and 10% when over 100. I got caught doing 75km/h in a 60 zone, and was processed as doing 72km/h, but it also depends on the cop some will ask you the same old "did you know you were speeding" and if you are a good lier you can work a warning out of them...not that i am telling people to, lying is wrong

 

[vnv8driver]

Im with vrwags, i recon it would be out, but not by a great deal.

lightning- im looking into it today (qld) but should be the same aus wide.

 

[Nevyn]

manufactures have never guaranteed that the speedos were 100% actuate....they are the ones who started the 10% by stating the speedos can be out by up to 10%, that way drivers can't sue them when they get a speeding ticket. With better and more actuate speed cameras & radar guns, at least here in Vic, the tolerance is now down from 10k's to 3k's over.

 

[Deutscher]

that's kind of gay. I always set my cruise control just slightly over the speed limit (mainly so I don't get abused for going too slow), but if you can get done for 3kms over, THATS GAY!

 

[kopper69]

I remember reading in the Wheels magazine (I think it was wheels) in late 2006 when the VE had just been released about the speed they were travelling when their instrument cluster said 100km/hr. I assumed the speed was measured on a radar and it said that all of the brand new VE's would only be doing 96km/hr when their speedo read 100km/hr. I have had my GPS in my car and found that my speedo is about 10% under. So when my speedo says 110 Im really only doing 100. The only change I have is 16" rims instead of the 15". When I first started driving I wondered why everyone was always sitting just over the speed limit, then found out that most people did sit right on the speed limit, it was just my speedo was out.

I have checked with the GPS in other cars, VT, VX, ford territory, ford G6E, toyota echo and found that they were almost exactly spot on in every one - as in the GPS matched exactly the speedo reading. Just my VR that has the inaccuracy. For those interested you can have your speedo calibrated too if you would like it fixed up. Dont just assume that your speedo is out though and sit above the speed limit - the excuse wont work on Mr Policeman.

 

[XeKToReX]

victoria is 3km/h when under 100km/h, 3% when over.. its on my fine here..

 

[Nevyn]

thats odd...my last speeding ticket was for exceeding 100km/h but under10km/h....nothing about 3%

 

[XeKToReX]

hmm.. yeah under 10 is the charge, my orig one said it but 2nd notice says alleged is 2km/h under detected