driving on a different size tire

[kaanage]

Radius doesnt matter its The DIAMETER that does as it does a different number of revs per kilometer and will there fore make the diff work a very slight bit harder

Diameter = 2 x radius. I suspect your meant circumference which is the length around the perimeter of the tyre but this = 2 x pi x radius (or pi * diameter), so the difference in radius is directly proportional to the difference in circumference.

[ericcs]

Diameter = 2 x radius. I suspect your meant circumference which is the length around the perimeter of the tyre but this = 2 x pi x radius (or pi * diameter), so the difference in radius is directly proportional to the difference in circumference.

the diameter difference is only 3mm, and the circumference 8.5mm as per online conversion chart

195/65/15 v 225/40/18

[dylan8]

the diameter difference is only 3mm, and the circumference 8.5mm as per online conversion chart

195/65/15 v 225/40/18

youll be fine.
iv seen 4 different size tyres come off a 4mo bora once.
if you did it for long enough there would be odd wear on either the 225/40 or the 195/65

[Guest001]

Diameter = 2 x radius. I suspect your meant circumference which is the length around the perimeter of the tyre but this = 2 x pi x radius (or pi * diameter), so the difference in radius is directly proportional to the difference in circumference.

One alters the other. If your radius is 1.5mm larger your diameter will be 3mm larger and your circumference will also increase and therefore will do less turns per kilometer. Normally most people refer to the Diameter when talking tyre sizes. Thats all I was meaning.

In the OP's case it wont make enough difference to matter. Lots of people use an old worn tyre for a spare and have no hesitation using it, if needed the day after putting new tyres on the vehicle. It could therefore have a difference in diameter of up to 12 mm.
Havent heard of any diffs going bang.

[ericcs]

it's only going to be driven to work and back till 18"er get it's crack welded. 18" + 40 series tires + pothole = bent/cracked rim/$120 repair

[Guest001]

it's only going to be driven to work and back till 18"er get it's crack welded. 18" + 40 series tires + pothole = bent/cracked rim/$120 repair

If its a MAG rim I would recommend a read of this

Alloy Wheel Repairs

Dont know about here but it is illegal in NZ to get mags repaired in anyway at all No rolling or anything for safety reasons

[ericcs]

If its a MAG rim I would recommend a read of this

Alloy Wheel Repairs

Dont know about here but it is illegal in NZ to get mags repaired in anyway at all No rolling or anything for safety reasons

it's a legit business i found on the internet down at springwood. there were alloy wheels everywhere, plenty that had been welded waiting to be machined and rolled, so i can only imagine it's legal here