Speedo

[enzo]

i notice that my speedo is a lil off, is this normal? or is it something i should be concerned about?

if it is something i should be concerned about is there a place where i can get the speedo fixed or adjusted in melbourne?

[sonicii]

most Speedos normally read up to 10% fast..

[enzo]

what do you mean by that?

[sonicii]

When you are travelling at 100km/h, it is possible your speedo could read as much as 110km/h and still be classified as 'normal'. But most will generally only read about 5% fast. show 105km/h when travelling at 100km/h.

[enzo]

yeah that's what my speedo is doing, so like my speedo is sayin 100km/h but on my gps its saying i'm only going 90km/h

so that is normal?

[thinktea]

This is normal.

[..350GT8..]

Do u have aftermarket bigger wheels?? If so maybe ur rolling diameter is out and could cause your speedo to read wrong...

[sonicii]

If he had bigger wheels, the issue would be reversed.. (speedo would read 90km/h and GPS would show higher). Smaller wheels would cause the speedo to read fast..

[enzo]

well i do have an aftermarket rim's they are 17" and i got low profile tyres on them as well

[sonicii]

what tyre size? you can put different size rims on your car without upsetting your speedo, as long as you buy the right tyre size to keep the overall diameter correct.

[t5iv]

Exactly. If the car came with 2xx/55/R17 and you're now running 2xx/40/R17, it will throw your speedo out as the rolling diameter has changed.

[enzo]

it says that my tyre is 235/45/17 what does it mean?

[sonicii]

it means your tyre size is contributing to your speedo inaccuracy. not causing the full 10% error, but at least some.

You should be running a 50 profile for that size tyre/rim (235/50/17), to match the standard tyre diameter.

[enzo]

so if i put on the right tyre when my speedo reads 100 then my actual speed would be close to 100 rather than it reading 90 atm?

[scotty nm35]

It will still be out. My speedo displays 100k's when I am doing 90, but the Informeter I have displays the correct speed so the ecu isnt the issue, the speed error is inside the dash unit from the factory. You would have to go for a much larger tyre size to correct it.

[sonicii]

^^ as scotty said.. the tyres you have aren't 10% smaller than the correct size, so you aren't going to recover the 10km/h. For example, you might only be about 7km/h out instead of 10km/h at 100.

Mine reads about 2% fast, so when the speedo reads 100km/h, I am actually travelling at about 98km/h, but my wife's J31 maxima is worse.. it is about 6%. in each case the ECU reads correct, it is just the speedo unit that shows the wrong speed.