Is there any reason why I shouldn't do this? I looked at a tire calculator and it seems 245/40/18 is closest to the stock 225/45/18. BTW - 03 coupe, 6speed, 7 spoke wheel pattern.

 

your vdc might act up beyond that you will have a neutral feel to the steering

 

why would the vdc act up?

 

Your OEM tires are 225/45/18 in the front only, the rears should be 245/45/18. There is a stock height stagger that the VDC looks for and can cause some people problems if this stagger is changed. If you want 245's all around, I would go 245/40/18 in the front and 245/45/18 in the rear

 

i think that's what the OP was going for...

 

Thats why I provided a very thorough answer, his question was kind of ambiguous

 

I'm glad this topic brought up, i was going to ask that question.
I thought of changing front wheel speed vs. rear wheel might trip the VDC...

so is it a theory? or does it really matter?
what about all those folks who changed to diff wheels with different tire size??
like 245 front 275 rear on those 19's

 

the OP has 18's whereas you have 19's, so that would be going to a different ballpark since your wheel are an inch bigger and half an inch wider.. try a search and you'll find some threads within the parameters you're looking at, it's been discussed several times in this forum...

as far as the VDC is concerned, i'm not entirely sure it's going to be that big of a deal in the front cuz if i'm not mistaken, VDC only monitors the rears, but i could be wrong...

 

I have 19in stock rim 225 front 245 rear tires stock.I changed and got a set of snow tires for these and went with 225/40/19 for front and rear.3000 miles later still no problem.no lights or anything.I think as long as the tires are within spec there is no problem..

 

Thanks to everyone who responded. My car (used) actually has 225/45/18 all around. I always wondered why until today when I was looking on tirerack.com and noticed the tire he bought (kumho ecsta spt) doesn't come in 245/45/18.

Anyway I've never noticed my vdc "acting up" so it shouldn't if I went to 245/40/18 right? Does the speedo get its information from the front or rear wheels?

 

i DID have 245/40/18 as my rears at one point in time, and they sucked... i didn't get any issues with VDC but they looked wierd and the tires themselves sucked..

 

What tires were they? do you have any pictures? It doesn't seem like they would look that different.