KevinGS

I have a 2001 Lexus GS430. And I am seriously considering 20 inch rims because many of the rims that I like are either 18s or 20s (19s are rare), and I just like the look of the 20s a bit more than the 18s on the GS.

HOWEVER, I understand that 18s and 19s wont change the diameter of the wheel setup, but when you cross over into 20s, it does. The diameter increases, which effects the speedometer and slows the car down even more so than the 19s.

This makes me lean towards 19s now, even though it's hard to find 19s that I like.

I imagine the actual sidewall isn't different by much when comparing 19s and 20s, as both are razor thin. 18s give you quite a bit more sidewall, which is a big advantage for that size, in terms of ride comfort and road noise.

I guess I am willing to sacrifice comfort and some road noise, but I don't want the extra negative effects of the "dubs" which will affect my speedometer, and will actually slow the car down even more with such a large radius wheel.

Any feedback would be appreciated.

KevinGS

...double post OOPS!

NT2SHBBY

my $.02:


you gotta pay to play. If you want big rims, you deal with rubberbands for tires


the speedo will be offset on anything that doesn't match stock wheel/tire diameter-I wouldn't be too concerned with ~2mph either way.

for me personally-it's all about ride comfort and potholes here in NYC-to ride on 20's with 35-30 series rubber is crazy. People do it and I don't get it. I find 17's riding rough enough here.

400DGRZ

iTrader: (2)

What are some of the wheels/designs you like that you can't find in 19"?

johnnyt

Go with the 20's. You can get light weight wheels too if you worried about the weight of the rim and slowing of the car. Also you should think about lowering it with the 20's to make it look clean and not have any fender gap. Your speedometer probably will be off 2-4 miles an hour so it won't cause you to get any extra tickets. Most everyone I know that has a gs has 20's on it not 19's. Plus since 19 are rare, 20's usually are about the same price.

Technics

What are your goals for this car? It sounds like your concerned about performance but want decent ride quality. An 18" wheel would probably yield the best mix of both of those factors. IMO, some styles of wheels can look small in that size, I would personally go with at least a 19" wheel on a GS.

rominl

iTrader: (4)

normal 20s and 19s, they have the same amount of sidewall, so they will ride the same. and yes, 20s are out of spec, so you will rub a little bit when you are doing full crank turns depending on offset, etc...

sometimes people with 19s they have the "fat" setup where the overall diameter become like the 20s for better ride quality, and the sidewall size is just like that of the 18s.

it really depends on what what you want, and also what tires you get. for example, i have 20s, but the tires i got are so soft, and together with my tein cs and daizen (haha i know that's what you want), i am totally cool.

there is a fitment faq at the top of this forum you can read for more info

KevinGS

Does "rolling the fender" eliminate all rubbing with 19s and 20s? Or will you still get some on full crank turns?

Also, when you say overall diameter is the same, are you saying that when you have 18s, 19s and 20s, the overall diameter size of the rim and tire combo are each different??? I was told differently. I was told that the overall diameter stays the same no matter if you are using a 16", 18" or 20" or anything in between. I was told that you just lose sidewall and gain rim each time you go up in size, and that you aren't changing the overall diameter.

Is this not true? HELP! LOL

Neo

iTrader: (3)

The goal is to keep the ourside diameter the same. Sometimes, it can be off just a little but that's OK. With 20s, though, to get the same OD, you'd need 30 (and 25 series if staggered) tires. The sidewall will be even thinner plus these sizes are not as widely available. The result is that 20s ride on 35 (and 30 series if staggered) tires, which are the same series as 19s. The standard sizes for 18s and 19s will be very close, if not dead on, compared to OEM. It is only the 20s that will be out ouf spec.

rominl was also talking about a "fat" setup for 19s. This setup is not the norm so that is why it is out of spec.

KevinGS

Gotcha! Thanx.

So basically, what you are saying is...if you get 20s and get a 35 series tire, you shouldnt have to roll the fenders if the offset is correct.

If the 20's are staggered in the back, then you go to a 30 series tire, but still won't have to tuck the fenders if the offset is correct.

You mentioned that the standard 18s and 19s would be real close to OEM, but the 20s would be "out of spec". Out of spec how?...if the offset is correct and the right series is selected?

And if everything is correct (offset, series, no increase in tire/wheel diameter compared to OEM), doesn't this mean that any speedometer fluctuations will be negligible?

The rims I am interested in are a staggered 20x8.5/20x9.5 setup...and have a 35mm offset rear and 32mm offset front, which sounds like it should still stay within the GS430s range. Even when I lower the car, like an inch or so, I am hoping I won't have to 'roll the fender'.

Neo

iTrader: (3)

The problem with 20s is that the 35/30 combo is NOT the right series. It is just more people use these sizes for real world driving and availability.

You are partially right that depending on the offset, you will not have to modify your fenders. It seems, though, that many have the problem with the full turn. I try to avoid it but have had to a few times and I did not get rubbing. But, I think people have problems more when going into inclines like driveways. Here the springs are compressed and the wheel is closer to other components, and therefore cause rubbing. I have not tried this last scenario so I probably have this issue too. From what I can tell, this has more to do with the increased diameter. 99% of the time, you won't be in this situation though. The amount of drop will also affect rubbing problems.

Your front offset is actually on the aggressive side. rominl has that setup. He can give you more direct data on that. Your rear offset should be OK although it is right on the border of needing fender modification. You should be OK though with only an inch drop.

KevinGS

Thanks, Neo.

I don't need much drop over my 20's...JUST enough to sit over my rims. Nothing too dramatic.

So hopefully, with the proper offset, my 20's will fit with little problems with turning. We'll see.

rominl

iTrader: (4)

well, if you get 20s, not drop a lot, and right offset, yes you won't rub the top of the wheel well, but you are still going to rub the front and back of the wheel well when you do full hard turns, coz' the overall diameter is big. that's just something you haev to live with

regarding diameters, in case i confused you. yes, if you get 18 or 19s, the goal is to keep the overall diameter. taht's why it's 245/35/19 and 275/30/19, 245/40/18 and 245/35/18. with 20s, the spec size would be 245/30/20 and 275/25/20. however the sidewall is so thin, you risk bending the wheels easy, plus the tires are hard to find like neo said. so most people including me get the 245/35/20 and 275/30/20. overall diameter is about 6% over spec i remember? to me that's ok.

some people, instead of 245/35/19 and 275/30/19, they get 245/40/19 and 275/35/19. the overall diameter is that of the 20s, so it's still ok (rub a litlte bit) but the sidewall is just like that of the 18s and more comfortable

KevinGS

Is this possible for the 20" setup, Rom? I would love to have a little more sidewall, honestly. Can you still lower the car about an inch with the taller 19" setup?

I assume if you try to get the larger wheel setup with 20s, it's gonna rub alot, which means you GOTTA tuck the fenders.

Actually, I'd rather get 20s or even 19s with the increased sidewall and tuck the fenders if need be.

Thanks for this info, I'll check into it.

Neo

iTrader: (3)

I would recommend against the 20" "fatter" setup. Technically, the 35/30 combo is already the "fat" setup for 20s since you have 1" more outside diameter than stock. I think you will be asking for trouble trying for even more sidewall on 20s. You will rub a whole lot while turning. I don't think you will even need to go full lock before hitting something. Aesthetically, I think the extra inch (for 20s and fat 19s) is a good size for the GS. More would make it look too big.

The taller 19" has the same diameter as 20s so all the same info on lowering 20s apply.