Downsizing wheels to 17"

I've had this idea in my mind for a little while now. Base models were delivered with a 17x7, and 17x9 with 205/50 & 255/40 tires fr/rr respectively. I like the idea of getting more meat, but if I do it Id like be looking at something like a 17x8 or 17x8.5 and 17x10 or even 17x11 setup. I havent looked into tires at all, but I wonder a few things and looking for anyone with experience with this. This likely would be a 'track-day' setup which would allow me to get some stickier tires. Share some pics too... I know I've seen it scoffed at, but I love those 3-piece Speedline wheels that were on the 993, but Im open to any cool pics, especially if at 'full-tilt' I tried to search and it seems all the racecars were running 18" wheels so I wonder if there is actually a benefit by going down a size. so. Is there a realistic gain in less rotating mass by downsizing?

If you are going to buy a new set of wheels, you may want to consider going with the GT3 wheel set up of 8.5x18 and 11x18. Wider footprint and stiffer sidewalls for the track will help you more that thinner wheels and more sidewall. Conversely, you will get a softer ride on the street with what you are proposing with the 17s because you will have more sidewall. You can weigh the different wheels and tire sizes to see what you have in tradeoffs. But in reality, it will take you years of tracking you car amd experience to notice any difference in weight savings. But you will notice the difference in grip pretty quickly.

@GC996 I had been considering these wheels. Seems like they would be a good fit both width and offset, but hard to say... Just something I had been considering https://rennlist.com/forums/market/1382031

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You have an incredible car that you can turn it into a 996 GT3 killer on the track. But to do that, it starts with looking at what's different about the GT3 than your Carerra (other than the engine) and then replicate or further upgrade suspension, brakes, wheels, tires, etc. Fwiw, I would go with 8x18 and 10x18, or 8.5x18 and 11x18 wheels and the appropriate tire sizes for the wheels. You may not agree with me now, but I can guarantee that after a year of tracking your car. You will be complaining that the wheel/tire combination you are consideting has the handling and responsiveness of driving around on basketballs.

245/45R17 285/40R17 Do it. I've been eyeing 17's Have you dyno'd your car?

If you don't have them, get yourself a good set of adjustable coilovers and sway bars. You are going to need them to dial it in.

Haha. He�s already corner balanced, too.

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You've suggested this before when I was discussing downforce in another thread. I have rebuilt GT3 coilovers, Eibach sway bars and as @996love mentioned, got it all corner balanced already. I think I will keep this in mind for later, as my Michelin Pilot Sport 4S are new and are likely to age out before I kill the tread, so I should do that first. @Moatilliatta 285 on an 11" wheel?! I could probably squeeze those on my current wheels, though mine are 18" ... most wheels I have looked at are not lighter than my Hollow Spokes so luckily the temptation is low.

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You are missing the point, the Gt3 set up is with 8.5x18 in the front and 11x18 in the rear with 235x40x18 and 295x30x18. More rubber width in the front and more sidewall with less rubber width in the rear and more sidewall will need to be accounted for. Your Gt3 coilovers were designed for Gt3 specs. Now you are changing the variables to reflect completely different wheel and tire sizes. There is a reason why a GT3 runs the wheel sizes it runs, with the suspension it has, with the specs it runs. I am not telling you not to do it. I am just telling you that you will have characteristics that you will need to account for. You won't know any better as a novice driver. But as soon as you get into a 996 that has been properly set up for the track, you will notice the difference. With that set up, i would look for the rear end to get really squirelly.

This calculator will help in tire size comparisons. https://tiresize.com/calculator/ This APEX link will help with wheel size and tire size combos. Obviously the more you deviate from standard sizes the more suspension adjustments you may need to make to compensate for changing characteristics and fitment. https://apexwheels.com/fitment-guide...-fitment-guide

How wide your trying to go?

I switched to 17s, but in OEM sizes. I did this for more comfort and to run all seasons in the correct OEM size. I retained my 18s for more spirited use down the road.

17s on all seasons! The car feels totally different than my last 996 (on 18s). Granted suspension could be the difference, but it felt better on 18s. Much more responsive. So, I’m looking for 18’s and suspension changes over the next few months. One of my biggest complaints about the 18s before was how hard it jolted over bumps. I actually thought about getting 17’s back then. Now i realize… it’s still hard on rough roads. It’s a sports car

I went from 17" original Porsche wheels to 18" Porsche Sport Techno hollow spoke wheels and didn't notice any difference in ride quality.

No question. If you want a more cush drive, you want taller sidewalls, but you will loose responsive handling characteristics on the track and canyon carving. Hey, I run 235x40x18 and 285x35x18 Michelin all seasons on a set of 8 and 10 Carerra 2s for the street. Cushy ride, but sucks for handling response. Too much sidewall for the wheel size. For the track and faster driving, I run 225x40x18 and 285x30x18 on another set of 8s and 10s. With the proper set-up, the handling and rotation is exceptional. It's also important to recognize that the 996 needs appropriate staggering of wheel/tire sizes. You run less staggering on a Cayman by design, but it creates a bunch of handling problems with a 996. Too wide of a patch up front versus rear will create a squirrelly rear end among other issues. Add in a collection of unconventional width and sidewall sizes and you have a mess during performance driving. Sure, you can make adjustments with the coilover and sway bar settings to adjust, but it certainly is alot easier and cheaper to run conventional specs. Everyone should take a look at APEX wheel sizes and recomended tire size pairings. It's a great tutorial.

It seems intuitive that a shorter sidewall will flex less and race tires have stiff sidewalls, also to reduce flex, still it's interesting, why do some folks prefer taller sidewalls for track work, @zbomb is one? I'm not a fan of ultra low profile rubber but there must be an optimum Trade-Off between performance and sidewall. 996 cup tires are relatively tall.

It's like anything we all get involved in, its like drinking thru a fire hose. It takes time to sort thru what works and doesn't work with actual experience. The learning curve speeds up quite a bit if you immerse yourself in the PCA track community. There is no perfectly right or wrong answer. Just consequences that you have to deal with as it pertains to set-up. But there are common sense practices that develop to save folks time and money.

An interesting set of tests on tire width on wheel sizes for track times. You Tube