Better acceleration by going from 255/45/18s to 255/35/18s? 2006 GXP

[GXPerforms]

So I love my Grand Prix GXP all except for the gear ratio suuucckckkksssssss! There is no reason I should be able to run all the way up to 108mph in second gear and I honestly wish the TCM was retuned so I could downshift into first at 45MPH since it runs all the way out to the 50-55ish MPH range anyway.

I know changing gear ratios is the proper way to fix my one and only real complaint about this car, however being that we have transaxles and I do not have the time nor money to invest in doing this I was interested in maybe going about this with a lower profile tire. Its time for me to replace my tires soon and I was interested in moving to a 255/35/18 instead of the stock 255/45/18. It looks like the effective gear ratio would be increased about 0.24 - so it would be like going from 3.29s to 3.53s if I did the math correctly. Is this a kind of change that would provide a somewhat noticeable increase in acceleration? I would also have less sidewall which would mean better cornering correct?

 

[spazzz]

Not the answer you are looking for but....Shouldn't you be worried about how it looks with rubber bands and wheel gaps
If that would? work coilovers would help the FWD drive race car look better
I understand it is hard to get a glimpse of a speeding bullet but easy to see a powerful locomotive.

 

[Fivefingerdeathpunch]

A downshift into 1st gear at 45 mph would prolly explode the input shaft.

 

[stealthee]

Fix acceleration by adding power.

 

[Scottydoggs]

so your just beating the crap out of your car it seems. that trannys not gonna last to long. they are made of glass as it is.

 

[91parkave]

You do have some things right..less rotational mass with 35 series tires however the smaller the diameter the more revs go up at a given rpm. Remember gxp has a overall 2.93 gear ratio. Handling would be nice but your car would look uber gay with all that gap without lowering the **** out it.you're also going to throw off the abs so you'll need a tuner to change your tire height in your pcm.