I've got 18'' gunmetal sc wheels on my cobalt na. Its programmed for 17'' wheels. My speedometer is off. Will the dealership fix this or will they give you hell?

 

i have the same issue

 

how much is it off by?

 

about how much of a difference would it cause

 

like 10 mph.. its an automatic and it seems like it holds 1st gear longer than it should.. I'd like to keep the wheels on

 

Go here....

http://www.supermotors.net/calculators/index.php

Use the one on the bottom

It will tell you exactly how much you are off by... Its only gonna be like 1% or 2% lol Not worth the hassle and cost of a re-calibration, and most likely, your dealer will not be able to do it, seeing as they need rollers and a calibrated machine themselves.

 

it feels like that to me as well mine is an auto

 

it should not be off by anything close to 10 mph by changing 1". how do u know it's off that much

 

Actually, I dont think I gave you the right site, lol...

Here you go

http://www.net-comber.com/tirecalc.html

 

its only off by a few mph

 

no the dealer cant. the LE5 model did not come with optional 18 inch wheels so they don't have that calibration. hptuners can re-program that though

 

This is the results i got... I swear its off by WAY WAY more than that ! Its crazy it will show i'm going 55 but i'm really going like 65. I"ve got speeding tickets to prove it.

 

thats also what i got it must be right

 

a speedign ticket is not proof lol... how do you know it's off by 10 mph. are you basing that off of anything other than a speeding ticket?

 

all it proves is that you were speeding that is even what the numbers show

 

Ok.. take the results.. Is that enough to Fu** up your transmission shift points? If you were me would you keep the 18's or just go back to the stock wheels?

 

I'm with d4. I remember looking it up cause I was gonna get SC wheels for my 2.4. 18's with 225/40 tires you're off by like 1 mph. 10 mph is HUGE. Something ain't right.

 

it's fine.... it's only a 4 speed auto so 1st gear is long. it's all in your head, because you think that your speedo is off, so now you're looking for "problems" that have happened because of it.

 

should i be ok with the 18s that wont wrek anything right

 

Yes 18's will be fine... our cars pretty much the same as SS/SC's in that regard... same brakes, only slightly different suspension. Hell, there's morons that put 20" on these cars.

 

cool and did you have any issues rubbing cause i have the plastic peice from my side skirts is bending out a bit and if i turn to fast i here it rube what should i do

 

How wide are your 18"? Stock is only 7" wide on the SC, like our stock wheels... if you have 8 or 8.5 inch wheels you might have rubbing.

 

they were off a 2006 SS/SC and Mine is a 06 SS/NA

i just wanted to know if i was to bend the side skirt peice in the wheel well back agaist where it should be how should i do it

if it helps i will post a pic tomorrow

 

i have 215 45 18's and it did the following below..
https://www.cobaltss.net/forums/suspension-67/i-found-my-rubbing-problem-159938/


I had to hack saw that piece of plastic off

i have 215 45 18's and it did the following below..
https://www.cobaltss.net/forums/showthread.php?t=159938


I had to hack saw that piece of plastic off