the tyres on my 2004 outlander are just about done, so i'll be needing 4 new tyres within the next month or so.

Stock tyre size (on stock alloys) are 215 /60 /16.

My question is that if I change to a bigger tyre eg 225 /60 /16 or 225 /65 /16 will this effect the accuracy of the speedometer (which is already in accurate - indicated 70mph is 63mph on GPS)

I would like a bigger tyre for comfort and a more aggressive "chunky" look, probably with 1" spacers (similar to this post ;) http://www.mitsubishi-forums.com/t35511-br...-outlander.htm)


thanks!

I can help you only with little tool to see what will be the difference between regular APPROVED tyre size and new alternative tyre.

http://www.e-pneu.cz/rozmery_pneu.php

In fisrt row you enter original size. In 2nd row you put the intended alternative size. Last 2 columns show the absolute and relative difference in wheel CIRCUMFERENCE. Some people say that diff up to 2% is negligible...

The speedometer accuracy will be affected of course, because the sensor is reading RPM at the gearbox and recalculating it based on original tyre size to MPH / KMH. So if now you get 70 MPH when driving 63 MPH measured with GPS, wearing tyres with bit larger diameter will correct it at least at higher speeds. Becasue the inaccuracy is not linear through whoile speed scale.

Be carefull and think about available space within fenders which will be needed for bigger tyres, watch the lower handling performance due to the higher tyre profile (the tyre may pull off if cornering hard) and because larger tyre makes the car higher, expect even more sensible rolling in corners. Wheel spacers may reduce some of these issues.

My Outlander is a 2004 XLS and it rides on 225/60-R16. My speedometer is only off by 1.15%.

First number (225) is Tire belt width in mm.
Second number (60) is tire wall height in percentage of tire belt width; in this case 135mm.
third number (16) is rim size in inches (406mm).

So if I were to install a 215/60-R16 at a reading of 60 mph I would actually be rolling at 57mph which is about 5% less. 215 divide by 225 = 95.56 (4.4%)
If I were to install 225/65-R16 at a reading of 60 I would be rolling 63 mph which is 5% more.
Now if I go one further a 215/65-R16 is close to same ratio as 225/60-R16 at .3% bigger, so at a reading of 60 you would be rolling 60.2 mph.

When I calculated my Outlander calibration I found out that it was calibrated for 225/55-R17 tires which is the tire that came on the 2005 XLS. So somebody jumped the gun at the factory.

Hope this helps you and others.

I have one inch spacers on my Outlander and the 225/60/16 almost rubs front inner fender at back when wheel is turned out. 235/60 if they exist might rub.

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