Mercedes-Benz 2009 SL-Class Operator's Manual page 346

Technical data
Rims and tires
Same size tires
Model
Rims (light alloy)
Wheel offset
18,19
Winter tires
18 Radial-ply tires
19 Not available as factory equipment.
20 Must be used in conjunction with Tire Pressure Monitoring System (U.S. vehicles) or Advanced Tire Pressure Monitoring System (Canada vehicles) only.
344
SL 550
SL 550 (Sport Package)
SL 600
SL 600 (Sport Package)
8.5 J x 18 H2
1.38 in (35 mm)
255/40 R18 95V M+S.
or
255/40 R18 95V M+S.
20
MOExtended
SL 63 AMG
8.5 J x 18 H2
1.18 in (30 mm)
255/40 R18 95V XL (Extra
Load) M+S.
SL 63 AMG
SL 63 AMG (Performance Package)
SL 65 AMG
8.5 J x 19 H2
1.18 in (30 mm)
255/35 R19 96V XL (Extra Load)
M+S.