Speedo Calibration

[syncro]

It cant be out by more than 10kmph which is the legal boundaries by which ur speedo can be incorrect by. That might have changed tho.

No it's 10%.

[peedman]

Hehehe my bad. I really wouldnt worry about it, you would think that if u were doing 61kmph in a 60 zone the coppers wouldnt pull you over.

[silverMK1]

im getting new tires put on my car and there 2cm smaller profile and the mechanic said my speedo would be out... sounds to me it wont be more than 10% so sould i get it checked out or dont worry about it

[rayray086]

Try playing around with this program:
http://members.optusnet.com.au/~sthchan/tiresizer.zip

It's similar to the link that golf3 posted.

Another tyre sizer program thingy can be found at http://www.1010tires.com/TireSizeCal...?action=submit

All three are very useful, and should give you an idea of what size tyres you should really be using to keep the same overall diameter (or something close enough to it).

[syncro]

Legally, replacement tyres should be no larger than 15mm more than any optional fitment.

A Dunlop 205/55x16 may not be the same diameter as a Toyo 205/55x16.

[wayz]

All good info!... however, this still doesn't account for my 80-100km loss per full tank of fuel.
According to a -3.2% differential with the new tyres - i should only be losing around about 25-35kms per tank..

hmm, well i've just refuelled again, we'll see how far this gets me

[syncro]

The tyres may have more rolling resistance.

[peedman]

Yeah I sorta agree. What tyre pressure you running? But 80-100kms is pretty high if its just bad tyres tho

[Eddy]

Hoyhoy.
For a start legal tolerances are now only 3%.
So if you want to find your true reading, you will have to ring around in Syd. Look in the yellow pages under speedometers. I done this on the Gold Coast & on the third Ph. call found a bloke who would check the speedo with a mobile GPS plotter which is accurate. Got it in writing, cost me $30.00.

[syncro]

Hoyhoy.
For a start legal tolerances are now only 3%.

I have never seen a speedo that is within 3%.

Read this thread;
http://forums.vwvortex.com/zerothread?id=2938451