Downsizing From 18 To 17 Wheels?

[DBest]

I have a 2007 IS350 with 18" rims, live and drive in a city with rough roads and the ride quality is rattling me to bits. I'm considering dropping down to 17" rims to get a taller and more (hopefully) more supple tire. I'm willing to give up cornering performance for ride quality. How much of a difference would I notice by changing the wheels to 17" versus current 18" (excluding any differences in swapping out the tires to a different brand/model)?

Thanks.

[Rory]

i'm not sure you need any advice, just try 17's and that'll answer your questions, the difference will be quite noticable

[Igino Cazzola]

What damper do you have?

[tonyr5500]

i looked into doing this on my girlfriends dads gs300 due to the same issues,

after hours of looking on the web and not coming up with alot i called one of the big alloy wheel dealers,

the only thing they said that you had to make sure you do is keep the rolling road size of the wheel and tyre the same,

so for smaller wheels bigger profile tyres for bigger wheels lower profile tyres.

because if you dont you will have issues with cornering, mpg, breaking, and if you have an auto gearbox the ratios are set for the best performance with the size of wheels.

hope this helps.

[Enda IRL]

Cant see it makin that much of a difference? as Rory says just borrow a set and giv it a try...tho your spendin money to get smaller wheels :(