Contour Enthusiasts Group Archives Forums Modifications Wheels & Tires Just got 17" wheels, but got ? on performance...

I jumped my Stique from 205-60-15 to 225-45-17 and it seems like my car has lost some power on the top end...here's what I mean:

I take the same hill to work and I used to be able to hold 80mph easily up this incline without downshifting. Now, the car can only hold around 73mph and to get to 80 or more, it has to downshift. I'm wondering if my speedo is inaccurate or something, or if my car has indeed lost some edge due to the bigger diameter.



------------------
Peace: Moe - My Ride

=== 98 Mistyque LS (black) ===

• Side Markers
• Modded Headlights
• SVT Bumper - rear
• SVT Exhaust - no resonator
• Suspension Kit
• TH Fix
• KKM True Rev
• 17" Superior Tuners // GoodYear's 225-45-17

------------------

Your speedo would be low I would guess around 5mph at normal highway speeds because the 225/45/17's are about an inch and a half bigger in overal circumfurince (sp?) so expect a little drop off. Also depending on the weight of the new rims you could notice a little difference in performance. I could feel the differance when I took my 17" Spiders off and put on the stock rims again it just seemed faster. After I took the car for a spin I weighted the two rims and tires and found there was a 6 lb difference, 49 for the spiders and A520's and 43 for the stock EO and damn near bald GSC's

How's the clearance for your 225s, moeskii?

T.

This is the difference according to those wheel sizes (ideal, the rusults would be different if the tires are compressed more, or different tread depths)

old speed 80 mph (128.72 kph)
new speed 79.08 mph (127.24 kph)
difference -0.92 mph (-1.48 kph)

Yeah I would have to say that makes sense as far as overall diameter being taller and I'm sure they weigh more than stockers.

Timid:
I had to roll the fender lip as it was grinding with any minor bump. I did a half-*ss job on the fender roll, and will have to spend more time on it. Right now it doesn't rub except under extreme bumps with people in the car. Also my car is 1.8" lower in the fron and 1.7" lower in the rear. I knew the fender would have to be rolled, but I had to have the 225's because they look tight!



------------------
Peace: Moe - My Ride

=== 98 Mistyque LS (black) ===

• Side Markers
• Modded Headlights
• SVT Bumper - rear
• SVT Exhaust - no resonator
• Suspension Kit
• TH Fix
• KKM True Rev
• 17" Superior Tuners // GoodYear's 225-45-17

------------------