Whats your guys views here???
I dont think suspension wise and ride wise that its gonna be much better with 19s as opposed to 20s. 17s vs 20s yes.....but I think once you get above 18 you are gonna get the same ride.

Second....are 20s gonna be a pain in the *** to fit, will I have to mod the body at all....will there be any rubbing??? I believe mjames did this....but he had to remove a plastic cover or something.....is the plastic cover missing noticeable or no?
Any rubbing with 19s?
Finally....would I run same size tires all around on 19s and 20s, or no? I want my speedometer to be on......as much as possible.
Thanks.

 

For what it's worth, the ride from 18" to 19" is noticablty harsher. I think it's because originally I was rolling on 235/40/18 and now I'm on skinnier 245/35/19 tires. Less cushion for the bumps. I'm guessing with 20" you'd have to go to a 30 aspect ratio which is even thinner (less tire to absorb vibrations.) Personnaly I think the 19" will look better than 20". As far as tire size, that depends on if you are running staggered or not. If not, then you will use the same tire size all around.

 

D+2 there was a post a while ago about the D+2 rule. You can safely go 2 inches larger than the stock dia. of the wheel -- the SC comes stock with 16, so you can safely go 18. If it was me, I'd get 18s. Depending on the road conditions where you live, you might run into trouble with 19 or 20s because of potholes or bumps. (Bending or cracking rims) But if you have a body kit on the car, your wheels might look minature with only 18s, so you might be better off with 19s or 20s.

but my .02 is go w/ 18s.

 

I have 18s and they look like they fit the car. I have seen 20s on an SC400 and they look out of place.

 

My take: 20s look the best, 19s are most practical, 18s look too small. I plan on 19s. Either which way you decide to go, your car will look a lot better with a one-inch lowering spring. If you want your springs to last though, you'll want to upgrade your shocks too. Never heard of the D+2 rule, the rule of thumb I know is to maintain the same diameter tire within 10% deviation, so the larger the wheel the thinner the tire must be. This is really more to effect the ABS brakes and instrument cluster (speedo, odo, mileage). One thing to consider though, tires for 19" wheels is proposterous as opposed to 18"s!

 

I've pondered the 19" versus 20" set-up as well: a lot of guys run 20s on their SC's and GS's, and here in Cali, you need to make a statement if you're going to 'coin-up' for new wheels.

I was all ready to go 20s on an SC4 until I did the math on the rolling diameter- they are 1" taller in diameter than the OE tires. This will do 2 things:
1) raise the car up 1/2"
2) change the gearing of the car

Since I'm lowering the car, #1 doesn't make much sense. I'm really not interested in making the car slower off the line, either. The 19s (245/35-19 front + 275/30-19 rear) are almost perfectly matchd in rolling diameter when compared the the stock 225/55-16s- and I think the 19s still say 'performance' rather than 'player', which sort of suits who I am a bit better.

That's not to take away from guys who are running 'Dubs... the cars look pimp! Since I will be driving this car 100 miles per day, the 19s just make more sense...

Pics soon!

 

I'd run 19s; 20s just don't look right on a SC3/4 the whole wheel itself isn't big enough

20s on a LS430 looks correct as well on other Mercedes like the S500, etc... they actually have a little bit of sidewall

 

anything beyong 17 inches is for "LOOKS"..

past 17 inches is when the wheel starts to not HELP but also HURT acceleration. Added weight..etc...diameter..etc.

REALLY, 19 and 20 is not much difference..but dubs lookHORRIBLE on SC's..

I think the ideal situation is to put 18x in the front and 19s in the back w/some 35 or 45 radials......

TRUST me, you'll LOVE that look.

 

Nope: do not stagger the wheel diameters on the SC- the car's wheel wells are not designed for it, and you'll need to SLAM the front of the car to get the wheel-well gaps to look the same.

I don't know why people think doing different diameters front & rear is so cool- what is the benefit? It's okay to do on NSXs or C5 Corvettes, but they were designed for this, and have smaller wheelarches in the front to keep the proportions correct. On other cars, you'll look like 'Lil Abner driving a 67 Nova.

Also, Traction Control and ABS functions will likely be affected if the tire diamters aren't kept almost the same front & rear.

 

I too never understood the desire for this setup...I mean what benefits are you suppose to gain with a staggered diameter setup?

 

The whole concept of the D rule in wheels and tires is to maintain the outside diameter of the tire+wheel unit. The maintenance of the outside diameter to factory spec is necessary for correct speedometer, ABS, Traction Control and Transmission shifting ECU settings to some extent.

As an example, the factory 16 wheel and tire have aprox a 25.5" overall outside diameter. The 17 inch wheel and appropriate D+1 tire maintain the same 25" diameter. The 18" wheel and the appropriate D+2 tire maintain the same 25" diameter. The only thing that gets BIGGER is the wheel and what gets smaller is the sidewall width. Each D+ reduces the sidewall width by 1/2" per side. So a D+2 18 inch wheel has 1" less of sidewall. This is how this works.

The benefit of thinner sidewalls is quicker response in cornering, less sidewall roll and firmer handling. The downside of thinner sidewalls is harsher ride, premature suspension wear (struts and springs and control arms) and of course the every present real danger of wheel damage. It goes without much thought that when you have less sidewall, you open the propensity up for cracked wheels or bent rims should you hit any obstruction in the road like a pothole or a steep abrupt seam.

The 18" D+2 will not make your car look lowered or fill the wheelwell up. You will simply minimize the sidewall profile and mazimize the look of the wheel. D+1 and D+2 tires and wheel fittings need and deserve constant vigilance with correct tire inflation. An under inflated D+ combo is very dangerous.

The 19" D+3 reduces the sidewall thickness by 1 1/2" per sidewall for a total reduction of 3" of sidewall!!!. Your ride will be harsh for sure depending upon the amout of road feel you desire. Frankly a look that most would say is showcar/showroom oriented. I would personally stay away from D+3 fitments in the SC400 if it is a daily driver.

I have D+1 17"s (8" + 10") for winter and D+2 18"s (8.5 + 10") for summer on my SC. I personally would never consider D+3 fitments for my daily driver, some amount of practicality has to be exercised IMHO.

 

anything over 17s is for looks? I beg to differ spank you very much

it is on some cars but on others it isn't... the SC with its HUGE wheel area happens to fit this exception

3piece 18x10 rims would provide excellent traction and a great race rim...

the 17" rule is only if you want to run drag radials; and they aren't that great for handling

 

def no on 20s. someone else said theyre too big and will hurt your car and fender and all that crap.... if your hitting a turn at 20+mph, your screwed. 19s are hitting it kind of close, but 18s i think are perfect. i got 18x10s and they look really good.

go to tirerack.com and check it out and see how it looks

 

You can do 20's safely so long as you get the correct OFFSET and WIDTH and you run the right size tires. People run into problems when they try to go too extreme (like trying to get too much lip)

Also, the overall height increase with 20's actually works out BETTER IMO because you can get that "perfectly" lowered look w/o sacrificing ground clearance for body kits...(but you'll need coilovers...springs won't cut it...and if you're serious about handling peformance, you wouldn't get just springs anyways...)

I have 20's on my GS430 and I burn through canyons just fine racing guys in various cars with 16"/17"/18"/19" wheels and I burned them all...if I was to go any faster, I'd be sh!ttin' in my pants...I'm talking about taking turns at 80-90MPH and breaking the rear end loose (on purpose...cuz I like that "semi-drifting" feel )...not some granny style 20MPH turns...

With the correct offset/width/tiresize, you should be able to TUCK your wheel w/o rubbing...

So far as 19" vs 20" is concerned, unless you doing some SERIOUS performance driving (professional level), just get whichever you think looks better...personally, I like this look (w/o the chrome)...this is a SC with a AutoCouture body kit and 20" AutoCouture Indicator wheels...I mean come on, other than the ghetto chrome, does this look "wrong" to anyone??

 

Yup, looks like too much wheel

19" and polished or Anthracite colored would be sweet