Does adding 18 inch wheels require suspension tune?

[cohibabluntz]

In the 2006 model year, Mustang GT also will have two new 18-inch wheel and tire combinations – the largest tires ever fitted to a production V-8 Mustang since the 2000 SVT Cobra R model – and unique suspension tuning calibrated to the larger treads. Mustang GT customers will be able to choose from four wheel- and -tire combinations.

I had 18 inch wheels added on at the dealer, is there a procedure I missed out on at the factory?

 

[VegasGT]

In the 2006 model year, Mustang GT also will have two new 18-inch wheel and tire combinations – the largest tires ever fitted to a production V-8 Mustang since the 2000 SVT Cobra R model – and unique suspension tuning calibrated to the larger treads. Mustang GT customers will be able to choose from four wheel- and -tire combinations.

I had 18 inch wheels added on at the dealer, is there a procedure I missed out on at the factory?

No

 

[cohibabluntz]

Good to know, Thank You.

 

[cohibabluntz]

Good to know, Thank you.

 

[LuS1fer]

The suspension rate may be changed to take into account the extra weight of the 18" wheels but I can't see Ford spending too much moneyy doing that. Possibly might change the springs but again, seems to be overkill.

 

[cohibabluntz]

Based on the paragraph above, I wasnt sure if when the car comes with the 18 inch option from the factory, if they set the car up differently, to account for the change in wheel size. While trying to reach a deal, the salesman offered to upgrade the 18 in.wheels, from another car on the lot.

 

[KemahGT]

One way to find out for sure is to look up Ford part numbers for springs, shocks, and sway bars. If the part numbers are different based on wheel size that would answer your question.

 

[anthony05gt]

They do come with a slightly different tuned suspension. I think it's the shocks, I don't remember. I've been on aftermarket 18's for almost 2 years and have no problems, rides great.

 

[royb]

In the 2006 model year, Mustang GT also will have two new 18-inch wheel and tire combinations – the largest tires ever fitted to a production V-8 Mustang since the 2000 SVT Cobra R model – and unique suspension tuning calibrated to the larger treads. Mustang GT customers will be able to choose from four wheel- and -tire combinations.

I had 18 inch wheels added on at the dealer, is there a procedure I missed out on at the factory?

If your car came stock with 17 an d you moved to 18 then you will need to change the Tire_rev_per_mile in your tune so your milage is correct.

 

[cowtown]

A ford engineer on another forum that shall not be named said slightly different dampning rates on the shocks and a little larger sway bars were put in on cars with factory 18's. I'm sure it's not necessary but it's probably to keep the road feel similar between the two.

 

[65up2d8]

If your car came stock with 17 an d you moved to 18 then you will need to change the Tire_rev_per_mile in your tune so your milage is correct.

This is only true if the overall diameter of the tires and wheels is different than with the 17's.

 

[KemahGT]

This is only true if the overall diameter of the tires and wheels is different than with the 17's.

Reminds me of the time that I got pulled over for speeding by a Texas DPS Trooper. While writing the ticket he said, "Boy, you know when you put wider tires on that car it messes up the speedometer calibration." I started to reply but figured there probably wasn't much use in replying to such a profound statement. I was already getting a ticket for speeding and didn't feel like getting tasered on the side of the road.

 

[cohibabluntz]

So should I have the shocks adjusted? Bigger sway bar added? If the car is set up for 17's, do the 18's just make the ride a little rougher?

 

[cowtown]

All depends on your wheels and tires really. But really I don't think it's necessary. Ford wants to keep a certain minimum ride quality and making those adjustments obviously helps that.

I wouldn't worry about the shocks but better sway bars and other items like strut and A pillar bars are certainly worth the upgrades for handling.