MB fan2

I just put 255/35-20 Michelin Pilot Sport on 20x8.5 ET30 wheel in the front - did not drive on it yet, but the tire touches the suspension bolt on the top. Was anyone successful fitting 255/35-20 in the front? If so, what tire brand and what wheel size and offset? Can anything be done to that suspension bolt and what?

245/35-20 is 4 to 5mm less in diameter, but since it is "recommended" size, those 4 to 5mm must make a difference.

Also, put 285/30-20 on 20x9.5 ET18 - no visible problems, but again I did not drive on those yet.

Any help/advice (other than going to "recommended" 245/275) is much appreciated.

Thanks in advance.

SL BRABUS

Go to brabus-usa.com website they should have the proper fitting information.
Good luck !

mantylar

I have 255/30R20 & 305/25R20 ContiSportContact 2's installed on my SL600. I have put about 1,700 miles on them with no problems, and my car has been lowered. My installer, Carnutz in Bellevue, WA said that this the only 20 inch tire setup they recommend for SL's.

160over90

mantylar,

Nice set-up. Do the rear 305/25 20" stick out a little past your rear fenders - hard to tell from the picture. I'm looking for a more aggresive look for the rear and my currrewnt set-up - which is what Brabus reccomended for tires just ain't doing the trick....

mantylar

Here is a rear view pic. My wheels are BBS LM's 9.5 X 20 front and 10.5 X 20 rear. I don't know what the offset is. Carnutz has installed 20's on quite a few R230 SL's and they have never had any problems.

MB fan2

I posted the same question on the SL55 forum, but it was moved to tires/wheels. The issue is SL specific - that is why it was posted on R230 SL forums and not on tires/wheels.

Anyway...if anyone has info to contribute please feel free to do it here or tire/wheels forum. I will check both.

niceshoes

Here's a few reasons why you would want to stay within the recommended tire sizes. Taken from: http://www.1010tires.com/wheeltech.asp#plus

Plus Sizing

Plus sizing your wheel & tire combination was designed to enhance vehicle performance and looks by allowing fitment of larger diameter rims and lower profile tires. The theory is that while making these changes, you keep the overall tire diameter within 3% of the original equipment tires. This is important because larger variances can cause problems with transmission shift points which can decrease fuel mileage. It can also confuse braking system computers which can even lead to brake failure.

Here's the rule of thumb for "plus sizing":

Plus 1:
Increase section width by 10mm
Decrease aspect ratio by 10 points
Increase rim diameter by 1 inch

Plus 2:
Increase section width by 20mm
Decrease aspect ratio by 20 points
Increase rim diameter by 2 inches.

This is not exact, but it will usually get you in the right ballpark. We always recommend consulting with the people you are purchasing the wheels and tires from to ensure fitment.



That site also has a pretty handy tire plus size calculator: http://www.1010tires.com/TireSizeCalculator.asp

Based on the factory tire size of the SL500: 255/40-18 and 285/35-18, the 255/35-20 and 285/30-20 that you are trying to use may not be a good idea since they are almost a full inch taller than factory tire diameter.

It looks like the 255/30-20 and 305/25-20 combo puts you closest to the overall diameter of the OE tires on the SL500.

Just my 2cents.

MB fan2

Thanks for the math lesson. I wasn' t asking what size to use or what is recommended. I am doing business with Tire Rack for the last 8 years and most of the time was telling them the fitment I want as they are, for obvious reasons, are very conservative in their fitment suggestions. The point is that many people responding are not "hands on" guys I want to hear from. The question (if anyone was successful in using 255/35-20 upfront on R230 SL)was only for people with 20s on SL or "tuners" installing them.