Originally posted by Troll Pete:
Originally posted by scottd60:
Originally posted by 1314:
I did. When I was trying to decide between a 225/45 or a 235/40, I wanted to be as close to stock in diameter as possible. That calculator showed that the stock diameter of a 215/50 16 is 24.46. The 225/45 is 24.97 and the 235/40 is 24.40. The 235's were closest and that's what I went with and haven't had a single problem.


That is exactly how it should be used/done...



Trust me, I've used those calculators in the past and like I said, they are informative, but not accurate.

Using that calculator, here are some examples.

Stock:
215/50-16 - 24.46

Most commonly used 18" tire:
225/40-18 - 25.08

Tire calculator:
225/35-18 - 24.20
No thank you. Not enough tire.

Tire calculator:
225/30-19 - 24.31
No chance on earth I'm putting that rubberband on 19" wheels. I had 225/35-19s and thought they weren't wide enough.

I've never understood the small minority of people who sacrifice wheel protection, appearance, ride comfort to keep their odometer as accurate as possible / "be as close to stock" diameter. Is 1.5mph at 60mph really that important?



That is just plain silly, you are saying the calculator is inaccurate...that is completely false. It tells you exactly what you ask for based on what you enter. These two examples you gave are pointless.

Quote:

Tire calculator:
225/35-18 - 24.20
No thank you. Not enough tire.
Tire calculator:
225/30-19 - 24.31


Why would anybody go down in tire diameter especialy when going up in wheel size neither of these are standard/common wheel/tire upgrades from a stock SVT 215/50-16 tire

Nobody driving a Contour in all reality should be running 19's unless it is for show...while I like the 18's on my car they are borderline on the big size and definitly not optimal for performance/handling on a Contour, I'd say it is a reasonable compromise for looks/handling. Generaly when autocrossing or putting a car on road course/track you would not go up 3 wheel sizes from stock for performance , +1 or +2 in wheel size with propper fitting tires would be about it in most cases. Also a 225mm tire is pushing it on a 7" rim, should really be 7.5-8" in most wheel/tire application charts. Impropper wheel width will also change handling and tire wear by creating a poor contact patch.

Your adviceis to add tire sidewall/increase the overall diameter of the tire to compensate for the need to use huge oversized wheels and not look like rubber bands That is only going for a look and not for optimum handling which is fine if thats what you want. But IMO that is really poor advice. If you don't like the sidewall/rubberband look then stick with a smaller wheel and use the propoer tire size for the car that best suits your need.

The goal should always be to try and maintain the the original tire diameter in most cases unless you have a 4x4, drag car or show car. You say 1.5 mph really isn't that important...yeah if you drive like an old lady. If you regularly speed then 1.5 mph can make the difference between a $275 ticket and a $500 ticket, 3 points and 5 points, suspended liecense or not...thust me I know. Been driving for 29 years and have had my share of tickets, suspensions, & driving class...not that I'm pround of it I just like to drive fast

Quote:

In addition, I'm not trying to knock people who do use the calculator, but until you've tried as many wheel and tire combinations as I have you're giving poor advice by telling people to use the calculator to determine tire size.



Not trying to knock you either troll but...
Not even close, you know I have a lot of cars currently in my stable (00 SVT, 89 TTA, 02 SuperCrew, 01 A4, 93 Civic, 94 TransSport, 87 S-10 V8 lowrider, 02 Sonata) and have had 8 others before that for a total of 16 cars over the last 29 years. Most have had different wheels and tire combinations several times over the years. The contour is on the 3rd set (16x6.6 E1's, 17x7 FSVT, 18x7 OZ's). I was running 50 series tires when most people didn't even know they existed back in 1979 on my 68 Firbird (255/50-R15 on 15x10" wheels). I autocrossed regularly for about 5 years at the time 13" light weight wheels were what most ran. I also have drag raced on and off ever since I was 16. I have gone through LOTS of tires and wheels...so not really much of a comparison if you ask me

You still the man, brother in BLUE


Scott 2000 Contour SVT #1464 Mustang Dyno: 171.6hp/145.3lb Dynojet Dyno: 171.1hp/148.9lb 1989 20th Anniversary Turbo T/A "Indy 500 Pace Car" #1376 of 1550 All Original, 46k with a few mods 2002 F150 SuperCrew