17's vs. 18's performance

[Brucelee]

I don't see how this would be possible!

Originally Posted by KronixSpeed

correct me if im wrong...i ve been told 17 to 18 ....you lose 1second off your 0-60
and for a porsche boxster...this is not good. i too am considering this 17 to 18 change in rim size. my car is lowered 1.3 inches and with an 18 inch rim...look out.

i say get the 18, but find the lightest rim on the market...

[savinor]

When changing from 17 to 18" rim the tire size is also changed (lower profile). The results are almost the same diameter wheel. Therefore no change in the 0-60 time.

[mjw930]

Generall, 0-60 times are effected by 2 things, weight and size. Assuming the same weight and size the straight line performance is unchanged.

I'm looking for information about the car's driving dynamics, especially in demanding conditions, I'm not concerned with 0-60 times.

Ok, here's the situation, The original owner acknoledges the swap of the factory 17's with MM 17" Cup 3's (turbo twist). He had no qualms and the wheels are in mint condition. I have the selling dealer in a position that they will offer me some compensation either in a check or new tires. They are a Mercedes dealership so they handle Michelin's (what I want).

Now, the tough decision, do I take the cash and try to find some reconditioned or take off factory 18's or do I keep the Aftermarket 17's and use the cash to put new tires on them? Also, with the MM's I have 7.5" and 9" widths so I have the option of doing 225/45x17 on the front. Here's my dilema, do I put the "N1" spec Michelin "Rib" Pilot Sports in the 205/50 and 255/40 sizes or go with the new PS2's (I have these on the V70R and love them) in the 225/45 and 255/40 size?

Decisions descisions........

Mark
'03 Boxster S

[savinor]

I had 17" on my 99 base model and have 18" on my 2000 S. The handling is somewhat different because of suspension but the 18" wheels have almost no sidewall flex and the ride is not signifcantly different. A little harder but after 20 minutes you don't notice it. The 18" combination take tires out of the equation until the tire start to slide sideways.

[FASTBMW]

I heard that the rear suspension needs to be beefed up when you upgrade to 18". Something about porsche upgrading the rear body or something. Did I hear incorrect?

[savinor]

I believe the upgrade came in 1998 or 1999. At that time 18" was offered as an option.