Hi guys and gals,

I was wondering if any of you that have switched to 235 or 245 either /40 or /45, have compared your gas mileage to the one you were getting with 225s.

I'm looking for a new set of tires, got 3.5/32 left on the back and 2/32 on the front, and I'm trying to weigh some of the pros and cons of 225,235 and 245; I'll be keeping the stock mags on. I've read that I can safely go to 245 on them.

One last thing, I know that there have been a lot of threads regarding what the best tires are etc. Here's my story, I do maybe 2000-3000 Km with the 8 in a year, I'm planning on taking it to the track this summer, maybe every w.e. or every other w.e. and I don't want to spend more than 130-140 $ on tires. I know that all those tires handle 240 km/h, but I want them to "safely" handle that speed. I don't care THAT much about tire noise. On tirerack, I've found the

Kumha Ecsta SPT; 235/45 for 117 $, 245/40 for 122 $
Dunlops Direzza DZ101; 235/40 for 125 $ and 245/40 for 131 $
Bridgestone Potenza S-03 Pole Position (there is a closeout on the 225/45, 134 $)
Avon Techn M500; 225/40 for 118 $ and 245/40 for 138 $

What would you guys suggest, if you keep in mind my needs and based on your experiences?

And the last thing, really now, what does XL mean besides a tire size say 235/40ZR18 XL?

Thanks a lot.

Cheers.

i just went from 225 to 245 kumho spt.. no change in gas mileage..

beers :beer:

i just went from 225 to 245 kumho spt.. no change in gas mileage..

beers :beer:
Me too. I went from 225 to 245 Kumho MX's and the gas mileage is the same.

someone should go up to 315 and see if there's a difference. I nominate jedi.

i would say you need to look at better tires for track tires

and if you only do 2-3000kms for an entire year what does gas mileage really mean to you? seriously.

someone should go up to 315 and see if there's a difference. I nominate jedi.
you buy 'em and I'll be the guinea pig. :D:

someone should go up to 315 and see if there's a difference. I nominate jedi.


i am sure that will decrease mileage by more than just a bit.

beers :beer:

XL means extra load.

One thing to keep in mind about gas mileage is that your odometer reading changes in lock step with your rolling circumference and so even with a smaller wheel and tire combination you'll get the same rpm per indicated mph. Therefore, if using the odometer to calculate mpg, you'll actually get a very slightly better mpg figure with smaller tires as the aerodynamic drag at any indicated mph is now slightly lower. Even though you've covered less real miles, the odometer doesn't know that. The only way to calculate mpg with new tires is through GPS figures.

Now that we've covered the gas mileage, which tires would you guys recommend from the ones I've listed, remember I don't want to go over 140 $ a tire, so I can't pick better tires from tirerack :Eyecrazy:

I also want to track the car with those tires.

Now that we've covered the gas mileage, which tires would you guys recommend from the ones I've listed, remember I don't want to go over 140 $ a tire, so I can't pick better tires from tirerack :Eyecrazy:

I also want to track the car with those tires.


Pay to play.

Tires are not the area to cheap out. they are your only safety feature that touches the ground. They are imperitive in acceleration, handling and braking.

Kumho MX's if you are on a budget.

Tire rack is not the only place that sells tires.

XL means extra load.

One thing to keep in mind about gas mileage is that your odometer reading changes in lock step with your rolling circumference and so even with a smaller wheel and tire combination you'll get the same rpm per indicated mph. Therefore, if using the odometer to calculate mpg, you'll actually get a very slightly better mpg figure with smaller tires as the aerodynamic drag at any indicated mph is now slightly lower. Even though you've covered less real miles, the odometer doesn't know that. The only way to calculate mpg with new tires is through GPS figures.

did that test. wass enabled.. off by less than .5%.

beers :beer: