OK After reading most of the tire size/choices I have made a decision on new affordable shoes for Moe... my last decision is on the size... the manufacture plus size recommendation is 215/40/17 but most of the posts here suggest 215/45/17. So, question which tire will give me the best gas mileage or am I better off keeping the stock size 205/45/17? I wanted a fatter tire for looks more than for anything else.. I'm going to get Yokohama Avid H4S

Moe has the white S-lights

 

Better gas mileage will be with slightly higher tire pressures than usual.

Using tires that are less wide makes more sense as do tires that weigh less.

215/40-17 are for performance and handling with stiffer sidewalls. They can cost more and weigh less. 205/45-17 is a little better at mpg. You can´t really go much narrower with a 17¨ wheel on a MINI. To get a narrow tire you´d need a narrow rim like 15x6 or 16x6.5. Stock 15¨rims are 15x5.5 and will take a 185/65-15 tire which is less good for handling but good for mpg.

 

narrower tires reduce your rolling resistance which improves the mileage.

A larger overall diameter would probably help as well with the way the mini is geared. Although the car will say the mileage is worse because it assumes everything based retaining stock diameter (so smaller will say its better). Both of those sizes wont be too far off the stock sizing, the 45 profile being a bit over and the 40 a bit under.

 

I saw this the other day. http://www.discounttiredirect.com/di...foTireMath.jsp

That seems like one of the better explained calculators I have seen before. It should help out anyone that doesn't want to try and do their own calculations.

 

Thanks everyone!