Speedo Recalibration - From 17 inch to 18 inch

[ac6122109 Lurker Find all posts View Profile Close ac6122109]

Hi All,
I was wondering if anyone could give me some advice with this one?
I currently have the latest Altitude model that originally come fitted with the 17 inch rims which are a 265 x 65 x 17.
The rims I bought are an 18 inch wheel that comes off the Kakadu and VX models which run a 265 x 60 x 18.
Do I need to recalibrate the speedo in the car as the difference seems to be only very minor but I'm just not sure what instruments will be thrown out of calibration with this upgrade or whether I will notice the difference?

[BobTheMonkey Member Find all posts View Profile Close BobTheMonkey]

How do you recalibrate the speedo? I went the other way I had 18s on my VX and had 17s put on by the dealership. I know the speedo is out but I hardly ever look at my speedo as I use a dash mount GPS.

[Guest Close Guest]

No you won't need to recalibrate the speedo as both diameter of the tyre is pretty much the same. It's not the diameter of the rim that affects the speedo but the diameter of the tyre.

[BobTheMonkey Member Find all posts View Profile Close BobTheMonkey]

265/65R17 - Overall Diameter: 30.56 in 776.22 mm

265/60R18 - Overall Diameter: 30.51 in 774.95 mm

Diameter Difference: 0.17%

Anyway how do you recalibrate you speedo? the difference between 17s and 18s with factory stock size is mm's but what if you went up a size in tyre?

[Guest Close Guest]

Modern cars have speedos which under read. So upsizing a tyre usually brings the speedo to being spot on. There are yellow boxes that can recalibrate the speedo.
https://www.google.com/search?q=yellow+box+speedo

[ac6122109 Lurker Find all posts View Profile Close ac6122109]

That makes sense. Thanks for the update.

[ac6122109 Lurker Find all posts View Profile Close ac6122109]

I'm not sure how you would recalibrate the speedo but I know it can be done?
The difference of 0.17% is very minimal and I'm sure that the current speedo's have a % inaccuracy anyway.
Thanks again for working this out.

[BobTheMonkey Member Find all posts View Profile Close BobTheMonkey]

if your able to change your speedo by +/- 50% i would speculate that you could then reduce the amount of miles your odometer has done as well...

http://www.yellr.com/yb_home.htm

seems legit

[butane8 Avid PP Poster! Find all posts View Profile Close butane8]

speedo calibration

if you blokes look at the 120 as a platform from which the 150 came from the , answers are there!

there is a yellow box mod currently being used by our member in the 120 section which may assist in what your after,



good luck with the research, cheers butane