Am i going to need a speedo corrector?

[muggo05]

hey guys just purchased some VZ Monaro/ VZ SSZ Mags for my VS which i haven't fitted yet.

now at the moment i have 225/50 R16 wheels on there, and the new wheels take 235/45 R18 rubber.

What is this going to do to my speedo? am i going to need a speedo corrector of some sort?

if so, where do i get one? tyre place?

complete lost on this subject, any help would be appreciated.

thanks

[ephect]

u need to bookmark this site!!! Tire size calculator

this will tell you the difference in ratio new and old tyre size. u should go 245/40/18 to give u the closest match. but what was the original tyre size 205/65/15?? u always must go the original tyre size to compare to your new set of rims & tyres

i know i have been looking at 18s recently

[muggo05]

wow thats freaking awesome! thanks mate.

yeah i'm guessing it came with the 205/65 R15, but i bought the car with the 16" SV5000/family wheels on it, which the guy before me had it from new, and i think had them put on when he bought the car so not sure whether or not the speedo was corrected for them or didnt need to be.

anyway thanks for that mate i will have a look at it.

[ephect]

its one of the better tools out there on the net

do a comparison from standard 205/65 15 to ur 16's, then go 15 to 18s and to check 16 to 18, just so you know how much its out by.

just to give u an idea, with my 16s i was 2-3kms under the what my speedo was saying at 80-100kms, now with my 17s, im dead spot on with my speedo, i always check it with GPS.

[muggo05]

yeah i checked it against the 15's and with the 18's the speedo will be 3% too fast which is good. will double check against GPS though.

Thanks for your help mate

[ephect]

glad i could be of some help let us know how u go, oh and dont forget the pics

[muggo05]

yeah mate definitely will. should be within the next few days