Han Solo

Our project Boxster is supposed to have option M413 wheels but after research I've discovered that at some point those were swopped out for M396 wheels. So the size comparison is...

M413 fronts 7.5 x 18 ET 50
M396 fronts 7 x 17 ET 55
M413 rears 9 x 18 ET 52
M396 rears 8.5 x 17 ET 50

So wider tread but larger diameter. Overall OEM tire diameter could be matched from the 17" to the 18" by going with 225/40R18 front (25.1") and 265/45R18 rear (25.3") so there shouldn't be problems with ABS or TC.

But would we experience rubbing from the wider tread? Does the larger mass of the wheel have negative consequences in handling?

racer

Mine had the 7.5 and 9 x 18 wheels (sport design wheels, not turbo look wheels). Rubbing was never an issue (I ran 225/275 RA1s and 225/265 street tires)

I never ran 17's, but when someone who did ran my car, they thought steering response was quicker, likely due to shorter sidewalls. from a $$ perspective, I considered a spare set of 17's since rubber was cheaper a few years ago.. but in the end I sold the car.

I would think any larger mass would hinder suspension (bump absorbtion) and acceleration as a general rule.