19" vs. 18" Wheels/Tires
 

Can anyone of you who have switched from 18" wheels/tires to a 19" set please comment on the difference in handling/performance? I currently have my stock 18's but would like to know the performance difference.

Thanks.

You'll find that there are highly polarized views on the topic. However, few will argue that the common goal is to reduce unsprung weight and rotational while not compromising strength and reliability . Personally, I run 19's on my vehicle. And, for the reasons previously mentioned, I am very pleased with how they perform over the oem 18's . That's not to say that I couldn't have accomplished the same with 18's, however, the set that I have now met all of the criteria .

Thanks Johnny - and I agree - but then 17's would be even lighter. Is there any consensus on the best performance combination for tire/wheel size?

The fastest Boxsters on the west coast are on 17s. The new lightweight Boxster Spider 19s are pretty good and comparable in performance but the tires are 2X the price of the same width in 17 inch and selection of quality 19" tires is still limited. Those drivers that shred a lot of race rubber run 17s for that reason.

Not necessarily, as far as I know my aftermarket 19's are lighter than any oem 17's .

Really? My 17s are 19lbs -F and 21.5-R. I have seen some exotic high $$$ 19 wheels that were lighter but it is rare. I have also seen some 35lb 19" replicas :eek: .

Certain that it is , 17's are far more appropriate for track use than 19's . There's simply not enough rubber to run 19's under those conditions . However, for street "tuning" there's a practical application for running lighter, larger diameter wheels .

What wheels are you running?

One piece forged Champion RS 98's . The rears are around 19 lbs. and the front are 18 lbs..

+ 1, 17's faster on the track, I use 17's on the track and 18's for the street. :)

OZ Alleggerita HLT 18 X 8 are 17.4 # and rears are 18 X 9 are 18.6 # Lightest wheels I found.

I have Einkei NT03's and the 18's are 19 and 21lbs I believe. Not the absolute lightest but great for the price.

My BBS 3-piece 17x10's are lighter though... :cool: Those don't fit the Box unfortunately.

Johnny,

I am looking at a set of tires/wheels for winter wear that are 19" and the rear tires are currently 295/30's. The tire calculator shows them to be comparable to my stock 255/40/17's. The offset would go from 55 to 67. You seem to have much more tire/wheel knowledge than I. Do you think these will fit okay?

S.

Well, to begin with, in my opinion 295 is too wide a tire for any application regarding a 986 boxster; let alone for winter use. As far as offset in concern, +67 (I suspect these are 996 wheels) is way too high for your vehicle. Therefore, if you're determined to use them, then you're going to have to bring the offset down to around +45, and replace the tires with something more suitable . In fact, you'll be hard pressed to find much in the area of 19 inch winter tires. Personally, I would stick with a 17 inch wheel package for winter driving .

My plan is actually use my existing 17's for snow and use new wider for Summer/Performance tires. I want the best wheel-well fit (best filling the well) on best performing wheels such as Carrera Lights or similarly lighter wheels.

Even if the 19" weigh less than the 17's, the effective mass (moment of inertia) is much higher. Simply put, the weight is farther from the axis of rotation.

I currently have 18's 225-F / 265-R on my 02 S, and am going back to 17's. The 18's were great until I did all my suspension mods (PSS9's, solid everything, etc.) but now I want a little more sidewall. When it breaks loose, it happens suddenly.

Also, I am getting some lightweight, Forged rims so the wheel weight will go down significantly. Weight reduction is my plan of attack for now, since I have a heavily modded 3.4L which puts out a lot of power already.

The big rims look great but have their downsides.

I disagree with you assertion . Ultimately, it comes to reducing unsprung weight and rotational mass. If the overall circumference is consistent, regardless of diameter the the lighter wheel will create less inertia .

Here are some guidelines to follow if you're looking to upgrade to 19 inch wheels:

Front Fitment :

Wheels - 19 X 8 to 8.5 with offsets ranging from +35 to 45 depending how aggressive you want your set-up to be .

Tires - 225 to 235 width

Rear Fitment :

Wheels - 19 X 9.5 to 10 10 with offsets ranging from +35 to 45 . Again, depending how aggressive you want your set-up to be .

Tires - 275 to 285 width

This is what my set-up consists of :

19 X 8 +31 235/35/19

19 X 10 +31 275/30/19

Johnny...I want some of those Salmon steaks!

As always, your car is a real looker...