Tire height is the key issue with VDC, not the width of the tire. The VDC doesn't care if the car tires are 3 inches wide or 30 inches as long as the outside diameter remains close to OEM so the computer senses what has been programmed into it for stock tires at any given speed.

 

I'm having my rear tires changed today by the dealer to match the original tires up front. That means there will be 225/50/17 all around. The original rear tire was a 235/50/17. The total difference in the total diameter (height) comes to .4" shorter. That is less than 1/2 inch. I'm sure that shouldn't mess up my VDC. I believe the speedo will register 1mph different. When it reads 61MPH I should be going 60MPH.

 

My car's an '04 so it has the 18" OEM rim's... not the 19's like you have. I'm not sure what's a good size to go to for the 19" rims, but I'm very happy with my nonstaggered setup.

Since you have 19" rims, you'd have to go onto one of those tire diameter calculator websites and try to find what wider front tires would have a similar front to rear tire size ratio to your OEM setup.

 

As long as you keep that gf of yours happy in anyway then that IS350 is pretty much yours. FYI you know what I meant, you don't get to ride the car but you get to ride something else.

 

Got my car back from dealer with all non staggered tires on my 04 Coupe with 17s. The rear tires don't look any different from the back and the ride and handling for me are the same. I'm now using 225/50/17s all aound and unless you look at the size up close you cannot see the difference. The ride is the same as well. I'm not an aggressive driver so that might be something to consider as well. FYI.......The VDC is unaffected.

 

You should be pissed if the dealer put those tires on at their own expense(not sure if maybe you just bought the car and part of the purchase agreement was for them to put on new tires). If so... they shortchanged you and gave you a tire size that is cheaper than what you're supposed to have... plus it will have less grip in the rear for hard acceleration/cornering.

 

The Avon 550 A/S that I placed on the rears were at one time from the front of my car. I never paid for them as they were compt by the dealer as were 3 other sets of tires. I had taken them off the fronts due to exceessive noise from the feathering. Now that they are on the back, the noise is much less noticeable and does not roar on deceleration since the weight on braking is off of the rears. Yes, if I had to pay for the tires I would be unhappy, however since ownership of my car I have never paid for one tire! However this will all end on the next set of tires which won't be for awhile as I only drive 6-7K a year. Bottom line is I don't accelerate hard and the non staggered setup works fine for me. If my rear rims were the exact same size width as the fronts I would even be rotating, but I won't since they are slightly wider.

 

All I know is that the sidewall is a lot higher on my 18s in the rear than the front. Doesn't seem like the VDC would like a sidewall that high up front. Off by 2.7%, (Diameter +.7") but I don't know what percent it would take to put it outta wack. Anyone know?

 

I was off by 1.5% without any affect on the VDC.

 

So we know 1.5% will work, anyone take it further?

 

I've run 3.8% variance from stock on my 04 Sedan with no VDC problem.

Stock is 225/55/17. I ran 245/40/18s.

 

I just want to update my previous post. After 4 years of ownership I am now driving on a non staggered setup on my Coupe of 225/50/17's all around. I am not an overly aggressive driver but I do get on my car every now and then and like to go hard onto the on and off ramps. I truthfully cannot see any difference in handling. Although I am not planning on rotating my tires because my stock rims are not the same width, depending upon tire wear (especially the rear centers) I may choose to replace my future tires with the same size all around. If I find that the rear center treads do not wear as quickly as the staggered setup did, I will only get the non staggered setup from now on.

 

I'll be non-staggered in a bit, not really by choice, but I figure I'll give it a go with the set of wheels/tires I'm picking up used. Will be off 2.9%, .7 higher circumference. I'll let you guys know how it goes.