SVA Question

[Conker]

During a SVA does the speedo have to be recalibrated like HGV to ensure a correct reading?
I have a 3rd Gen Surf that had 15" wheels 235/70x15 put on it [ and still are ]for the SVA.
I am hopeing to put 16" wheels 265/70x16 on very soon, but will the speedo then be miles out ?
Got me a bit confused as I though it was just a case of putting a MPH speedo face on with no calibration.
If that is the case with no recalibration is my speedo wrong now due to the 15" wheels ? and will read correct with the 16" wheels ?
With these Bl**dy speed cameras every where I would like to now what is going on.

Cheers
Conker

[marky]

speedo wrong now due to the 15" wheels
16" are standard on 3rd gen so yes speedo out with 15". by the sound of condition of original tyres on your truck they were swapped after SVA

[Conker]

so will it read faster or slower with 15" wheels ?

[Jameswood345]

Faster as one rotation of 15inch wheels is quicker than one with 16inch wheels

James

[JimL]

waaaayyyy to confusing for my little brain to follow that

but I reckon the 16'rims with their 265tyres on will have you going faster than you think you are

[Koi]

waaaayyyy to confusing for my little brain to follow that

but I reckon the 16'rims with their 265tyres on will have you going faster than you think you are

Thats correct, rims don't really matter its the o/d of the tyre.

I went from 30 x 9.5 x 15 to 31 x 10 x 15 my speedo now reads about 3-4mph under what I am actually doing.

So the smaller the overall diameter the more revolutions so the speedo will read faster than you are actually going.
The larger diameter the less revolutions so reads slower than you are actually going.

I think Tony's on 33" runs about 10% out, ie speedo reads 70mph and hes really doing 77mph

[Guest]

Thats correct, rims don't really matter its the o/d of the tyre.

I went from 30 x 9.5 x 15 to 31 x 10 x 15 my speedo now reads about 3-4mph under what I am actually doing.

So the smaller the overall diameter the more revolutions so the speedo will read faster than you are actually going.
The larger diameter the less revolutions so reads slower than you are actually going.

I think Tony's on 33" runs about 10% out, ie speedo reads 70mph and hes really doing 77mph

And mine on the standard 2nd gen 265/70/15s runs about 10% under.

Cheers