changing from 205/70/15 to 225/70/15

[Taz202]

I have a 1994 Dodge Intrepid. The tires on it are 205's. I was given a new set of 225's. I am wondering if they will fit and what sort of affect it will have on the cars handling, fuel economy etc.

[Nereth]

Tyres will have a greater diameter.

Your speedo will read slower than you are actually going.

They may be free now, but the speeding tickets will fix that

on a more serious note... CG will be slightly higher from afforementioned increase in diameter, which will come with all of its backage, more squat/dive/roll forces. Physically higher chassis will probably lead to slightly less favourable aerodynamics.

The greater diameter will also be like permanently being in a slightly higher gear (4.2% higher, assuming negligble sidewall deflection, which is a pretty hefty assumption).

As for changes in terms of the actual grip of the tyres - the tyre compound and tread design will probably have more impact than the width and height will have. I wouldn't think of it as a major change unless you are changing to a tyre with different 'priorities'. I.e. changing from an off road tyre to a summer performance/street slick tyre.

[MagicRat]

Excellent post^^

IMO install the new ones and just be aware of the new feel they may have. Don't try and adventurous moves until you explore the feel and performance of the new set.

Also be aware of any possible tire rubbing (on the chassis/body/control arms). As soon as they are installed visually check them, especially the front tires when the steering is turned to the extreme left or right.

Finally listen for any rubbing when the suspension fully compresses over speed bumps etc.

[KiwiBacon]

Regarding the speedo.
Most standard cars I've checked with a GPS were reading about 5% slow (indicates 100km/h, actual is 95km/h) so a 4% increase shouldn't be a problem there.

Check it with a GPS if you're unsure.

[J-Ri]

Take a look at the front struts with the tires that are on it now too. I remember the tires being about 1/4" from the bottom spring plate on the strut.