stock tire 215-45-18
rolling radius: 204.42 cm
Total Diameter:65.07 cm
Sidewall Height:9.68cm

225-40-18
200.18cm
63.72cm
9.00cm

225-45-18
207.25cm
65.97cm
10.13cm

235-45-18
210.08cm
66.87cm
10.58cm

 

I normally run 225/45/18's ~ they just seem to be a more common tire size ~ which I can find better deals on.
I feel they fill the wheel wells a little better than 225/40 ~ and the speedo difference is negligible at best ~ I'd be VERY surprised if GM did anything to re calibrate for 225/40 vs 215/45...

Currently running ContiWinterContacs @ 225/45/18
Summer Tires are ContiSportContacts (not the CSC2's) @ 225/45/18
Next set of winter tires will be 235/40 ~ and probably from here on in I'll be rolling on 235/40

 

Ya the 45s are a little cheaper than the 40s. This is a tough decision lol

 

How much cheaper.

as the resident mennonite i'd say go 40's unless its a noticeable savings.

 

Lol! Only $10 a tire. So nothing crazy.

 

that's $40 a set...

My current winters (used) were found about 45 minutes south of where I live for (get this) $100!!

My summers are OEM BMW tires - fromts for some M3's iirc ~ I think those tires which are at probably 80% tread life right now ~ costed me $280 less install for the set...

Finding deals can be fun.

IMHO, screw savings;
If you're worried about tires 'bottoming' out get the 40's ~ if you aren't, get the 45's since they will fill your wheel wells a bit better (and make the car look a smidge cooler at the same time

 

i got 245/45 in the back and 215/45 in the front. im going to swap them to get better traction. and i feel they drive just fine.

 

You have 245's on SC rims?

 

Ya I found a local selling a used set of KDW's but he wants too much for them. So new it is. It's hard to find good used tires.

 

yup

 

yup - it takes a TON of patience... and a little luck.

 

(spacers required for clearing calipers only)

 

Holy crap. Can't see that working overly well compared to being on a wider rim.

 

Here is a pic from a post made in 2006. I think this tire size looks good and fits the rim really well.


https://www.cobaltss.net/forums/whee...2s-pics-19354/

 

I ran both, 225/40 and 235/40 KDW's on LSJ stocks and the 235 looked way better and worked fine, my car was dropped on sportlines for the entire time on both sets and never rubbed.

 

on a stock ss/sc rim the perfect size is 225/40/18, 235's are too big and 215/45 series tire just looks ugly.

 

Different tires are different sizes and shapes, despite what the number is. Manufacturers are not held to a standard of measurement so some will be 'meatier' or more 'stretched'.



Just like va-jay-jays

 

^^this is a seldomly observed, but totally factual point.

 

Lol I have worked in the retail tire industry for a couple years, there is a huge difference in reality but until you see 1000 tires on the shelf next to each other it just doesn't look obvious. And nowadays with the stretched tire fad people are caring less and less so tire manufacturers are shrinking low profile tires. I've seen 275's that look like a stretch compared to the 265 before them that looked meaty as hell. My Z has a 245 on it now (stock size, stock rim) that looks totally stretched compared to the OEM tire, and they are both bridgestones, just different models.

 

This is exactly what I wanted to hear. I'm leaning towards 235's. My tvs needs it if I can do it haha.

 

You will be able to hook on them. I had a very heavily bolted+spray LSJ and they worked fine from a 40. You won't be hitting them with as much torque as I was anyway. Awesome tires, if you don't mind the noise.

 

Noise that bad? Just the research I've done everyone rants about how good they are. Also I love how the tread looks haha.

 

even more proof that the lnf guys wanna be LSJ's!