Wheels and distance

[mesobitchy]

got a question about wheels.

it isnt the usuel will these fit or whats the offset etc....

tho it is about size.


A few months back we took both the legnum and the galant up to colchester.
both cars filled up at the same time, both trip counters reset at the same time.
both cars did the same trip with out any extra detours.

so how come the legnum had more miles on the clock then the v6?


the v6 is running standard 15" alloys and the vr4 is on them monster 17s.

any idea as to why there was a differance in miles? (IIRC there was about 30miles different between the two cars)

[Nutter_John]

Whats the tyre sizes ?

30 miles difference is a lot

[mesobitchy]

195/60/15 for the v6 all round

255/40/17 for the vr4 at the back
235/45/17 for the vr4 at the front

[Louis]

You should really run the same size tyres all round, especially on a 4wd. But the main thing fro your speedo and odometer is the rolling circumference, go to a tyre website and you can do a comparison of different size tyres and it tells you what will keep your speedo etc correct.
If you have a GPS sat nav check the speedo on it against your spdeo.

[Louis]

Try this one

http://www.alloywheels.com/tyrecalc.asp

[Nutter_John]

You should not be running different tyre sizes , you are doing 10 revs per mile more on the rears of the vr4 than the front

Vr4 has a circumference of 79.6"
V6 has a circumference of 76.1"

I would assume that the speedo's are out of sync , if you drive the v6 at 70 mph what speed does the vr4 say your at ?

[Nick Mann]

Your wheels are approx 4 or 5 % different between the two cars. However, as the VR4 wheels are bigger, the V6 should be reading more miles. If both speedos were working the same way, then for a difference of 30 miles you would have to do a trip of 670 miles.

So I suspect a glitch on the VR4's speedo converter.

[mesobitchy]

that wont susprise me at all nick, as we suspect there is something up with it, and we dont think the miles its telling us is true!
iv noticed it when sat in traffic not going anywere and sat with the engine off but the key turned that every so offten it would add 0.1 of a mile on.
iv gotten to the stage that at night when i get home i sometimes take a note of what the miles are and check it in the morning, an sure enough its clicked over a few 0.1 of a miles.

could this be down to the conversion as well?

i know my v6 is roughly 5 to 6mph out when placed agenst the GPS
and on the vr4 it is spot on.

[chris g]

And get those tyres changed...

[bradc]

While the calculation will show that the 255/40's are quite a bit smaller than 235/45's some of the brands will actually be quite close in diameter in those sizes. Overall though 225/45 + 255/40 would be a better option as those sizes are virtually identical.