Question about 20's...
 

For those of you w/20's w/regular tires, how's the ride compared to oem 18's w/run flats assuming both aren't dropped? I'm trying to debate between 19's or 20's. My main concern is the ride harshness considering my gf's driving it mainly. Basically I just want to know if it's much stiffer then oem. Any help would be appreciated & yes I know it'll need to be lowered (waiting for the new Tein CS just like everyone else). Thx! :)

It is surprisingly better without the runflats even going up 2 inches in wheel size. I have 20's and it is lowered with just springs and it is pretty smooth. I plan on getting the Tein CS one day but I am doing just fine now.

Go for it!

Hot dayum!...That was a quick response. :D Thx for the info! What springs & wheels do you have? Pics? Were you w/in alignment specs? Thx again!

yup, my 20s with the low profiles ride a lot better than the stupid stock 18s with runflats. the ride was sooo harsh it wasn't even funny. now with 20s my ride is actually sooo comfortable!

One more thing. The ride with 20s are fine but only with the right tire. I had some 20s with Bridgestone Potenzas and the car was nervous over almost any surface. In fact, when I was waiting for my new wheels, I drove around on stocks and they (the stock wheels with run flats) felt better.
Dan

excellent point there dan, tire brand and model make huge difference. the so3 is nothing but noise and stiff. i have the michelin pilot sport a/s and i am very happy. had pzero nero as well and it's also very nice

I've never had the stocks or run flats but I just wanted to throw in that tire size matters big time. I went from 245/35/20s to the correct diameter fronts in 235/30/20s and the ride stiffness went up ten fold. Same brand tire... No side wall = unforgiving ...... =(

same brand, but is it same model tire as well? that's pretty surprising. i wonder if the 235 is a bit stretch on your wheel so the sidewall becomes stiffer

Were you guys w/in oem alignment specs still? If yes, then how many fingers (finger gap) can you guys stick in the wheel well front/rear? Thx!

Yeah they were both the same tire just different sizes. The reason the ride went bad is because I have less sidewall now. I went down a profile size on my tire.... 35 to 30 series. I lost an inch in diameter on already small sidewalls...

wow thats a really small tire! That sizing is honestly for cars like the 3series BMW and Cclass MB to be able to run 20" with less issues. Quite honestly on a bigger heavier car like the SC430 i would prefer to see 245/30 at the least. Some of your issues may be due to the fact that your tire is not the right size for your car, FYI

But the sizing is correct for a +2 size. I did want 245/30s but they were harder to get and the load rating was only one point higher... My front tire diameter is now correct and the smaller tire has cured all of my problems other than the ride harshness.

I'm kinda surprised when people recommend 20s for this car and run 245/35 and 275/30 tires. The extra inch in diameter raises the car another 1/2" off the ground, hurts performance and may cause rubbing problems on the front. I wish I could swing a good set of 19s right now... =(

of course out of spec. for lexus, i think once you lower the car for 1.5in or more, alignment is maxed out. but as long as you get a good shop that knows how to play with camber and toe, you should be ok

wait, now i read, 235/30, no wonder the ride is bad. that's rubber band.

i don't mind the overspec tires i have on my car. i would rather have more cushion so i haev more ride comfort

I think you misunderstood me...I meant for those of you that's lowered (after, not before the alignment), were you still w/in oem specs? :)

In addition to what hipendicul said, your speedo won't be accurate as well if you get oversized spec tires.