Hey chaps, i finally got hold of some VY ss rims in the 18x8 flavor having put them on my car im not sure if my speedo is giving an incorrect reading now, the original wheels/tyre config was 205x65x15 and the new config is 235x40x18, traveling along side my misses in her mazda 3, she reckons her speedo was reporting 80km/h where as mine said 71km/h ish, however yesterday went past one of those trailers that tell you your speed the other day in a 70 limit according to the radar i was doing 69, is it possible my girls brand new car has an awfully inaccurate speedo? or is it mine? when u stand my new wheels side by side the vy mags are a fraction taller, should i have the speedo calibrated by holden to make sure its not mine that is at fault?
yea you should 18" wheels have a larger diameter so you should get it changed..i think ne way...id get it checked out just incase
Just some info i've learned over time about car speedos. VX's speedo is noramlly about 5km higher than what ur actually doing... Going from the 15 to an 18 using the tyre data u gave ur speed will increase by 4km. So atm you speedo should be 1 km off... which would make sense with the speed trailer! Same deal is this the all cars as far an i know... its an inbuilt error so there is a margin of error so u can't sue them caus u got a speeding ticket in the case of being done 1km. Sumfin like that anyway! SO Your missus mazda would be showing 105 ish when she is traveling 100... But i guess if ur really worried about it you should get it checked out just in case... I tried this out with my car on the HUME where they got those over the road speed indicators... With 17's my speedo said 110 but their indicator said 106. When i put the 19's on it was on the dot... ANYWAY! that was abit of a rant... Oh yeah, $116 is rediculous! Considering all they gotta do it plug ur car upto a TECH2 n input all the ratios. Their all bastards! lol Good luck with it!
yeah real bastards hey, they spend the $8000 on the tool to do it, they supply the tech with the know how to work the tool, they calculate the correct PPK to program in... <my rant...lol>
I recon if they could ONLY use the too for reseting a Speedo than fair enough charging that much... But that thing takes care of everything from the speedo, fuel gauge, ECU systems, Error Detecting, etc... PLUS, they had to re-calibrate my car with the tech2 when the gauge was out. They said that it would cost 65 bux but in the end they only charged me 27... I dunno why thier charging 116 for a speedo recalibration? Plus its Holden, im sure they can adsorb a 8000 initial cost considering once they have used it on say 100 car's their in the green...
Beg / Borrow / ..... a GPS unit from someone, that will give you an accurate reading, and wee bit cheaper than going to holden. Check out http://www.miata.net/garage/tirecalc.html, very good calculator for tyre / wheel combinations.
