991 20" Rims
03-12-2016, 08:19 PM
#46
Ok the problems you will face apart from the problems I headline above is the expense the expense the expense to do it right you need to change the front struts to coilovers and it's golden...
When Porsche or any car company design a car they think future proofing way way before you do, why do you think there is so much air under the wheel arches and that's why a lot of people lower the car, Porsche start off basics and Spoon Feed the fan boys and girl with improvements with each generation more refinement means more cash in the bank .... If you seen the new Audi led dash you know it's coming to the 911 it's already started on the 991 dash next will be self parking, why do you think the 991 has Electric steering system, you just have to read between the lines,
I remember when I wanted to mod my Porsche I want to Porsche and ask if I could do X and they said No '' that's not possible anything I ask it was always a Noooooooo so I got my own PIWIS computer so I can turn on all the no that's not possible...
So my advice to you is stop with the 'I hear people say' and do, if you want to do somthing cool to your car do it no matter the consequence, experiment, if somthing brakes , replace it and don't do that again hahaha, you don't even have to listen to me ,, it's your car don't let it just sit there looking like everyone's have fun with it ,,, i do ,,,, smile
One more thing,,, bore scoring every car suffer from this not just Porsches why do you think cars lose horse power over time and need an engine rebuild, its just marketing by garages to make more money off you when you go in for a Service and then offer you and extended warranty with the other hand, it's the hard sell, it's in there best interest to scare the living daylights out of you about all the potential looming disasters that can happened to your car, so don't worry about the voodoo and enjoy happy motoring ...
The following users liked this post:
myw (02-19-2020)
03-15-2016, 08:09 AM
#51
Totally true. Except you left out one very important word: larger diameter TIRE.
For more than 50 years Porsche increased WHEEL diameter while keeping TIRE diameter CONSTANT. Commonly called plus-sizing, this is what everyone thinks of when they talk about the 991.
Well, this is different. For the first time- EVER- Porsche did not PLUS-size http://www.tirerack.com/tires/tirete....jsp?techid=25 they UP-sized! Instead of the wheel diameter increasing while tire diameter stayed the same, now with the 991 for the first time ever they increased BOTH!
Not just one but several significant advantages arise from this one change.
1. Decreased rolling resistance. A larger tire rolls over bumps more easily. This also contributes to a smoother ride.
2. Increased sidewall height. The sidewall is the first part of the suspension to absorb bumps. Again, improved ride. Rims better protected from bumps.
3. Increased stability. The shape of the tire patch affects responsiveness and stability. http://www.tirerack.com/tires/tirete....jsp?techid=10
4. Increased grip. Since they did not reduce width but increased length the tire patch just got bigger.
These may not sound like much but they are, and they really add up. There's a recent video where AP talks about this and briefly shows a comparison of the tire patches with something like a 23% increase. The tire only got about 5 or 10% wider, so therefore at least half the increase came from the larger diameter.
Against all this the only real disadvantages are weight and effective gearing- both of which are negated by Porsche increasing horsepower at the same time.
For more than 50 years Porsche increased WHEEL diameter while keeping TIRE diameter CONSTANT. Commonly called plus-sizing, this is what everyone thinks of when they talk about the 991.
Well, this is different. For the first time- EVER- Porsche did not PLUS-size http://www.tirerack.com/tires/tirete....jsp?techid=25 they UP-sized! Instead of the wheel diameter increasing while tire diameter stayed the same, now with the 991 for the first time ever they increased BOTH!
Not just one but several significant advantages arise from this one change.
1. Decreased rolling resistance. A larger tire rolls over bumps more easily. This also contributes to a smoother ride.
2. Increased sidewall height. The sidewall is the first part of the suspension to absorb bumps. Again, improved ride. Rims better protected from bumps.
3. Increased stability. The shape of the tire patch affects responsiveness and stability. http://www.tirerack.com/tires/tirete....jsp?techid=10
4. Increased grip. Since they did not reduce width but increased length the tire patch just got bigger.
These may not sound like much but they are, and they really add up. There's a recent video where AP talks about this and briefly shows a comparison of the tire patches with something like a 23% increase. The tire only got about 5 or 10% wider, so therefore at least half the increase came from the larger diameter.
Against all this the only real disadvantages are weight and effective gearing- both of which are negated by Porsche increasing horsepower at the same time.
Thank you that was very imforitave, food for thought,, the car drives the same just smoother than before, and in some weird away faster, also notice the coasting has improved,,, I thought I was going mad but after reading your comments it's sort of makes sense now .... Interesting...
11-15-2016, 11:48 AM
#52
Your car looks great! I am about to by my first 997.2 CS and my buddy has 991 20" Carrera wheels with tires for me to install. Just to clarify your setup without rubbing:
991 Wheels and tires
Front: 245 with 5mm spacers or adjustable coil-overs ?
Rear: 295 no spacer required ?
Thanks for you input on the forum!
991 Wheels and tires
Front: 245 with 5mm spacers or adjustable coil-overs ?
Rear: 295 no spacer required ?
Thanks for you input on the forum!
01-14-2017, 12:00 AM
#54
Just an update re 991 wheels on a 997, YOU will require 7mm spacer up front {NOT A 5mm SPACER} as i have suggested in earlier posts, I've tried to correct this error in an edit but i am getting errors when trying to update older post that I've made ,,, all is still well running 20' wheels on a 997 in 2017,,,, I'll let you know if the wheels fall off or if any problems that i may or may not encounter ..... but still hoping to go too centerlocking wheels at some point in the futher.....
The following users liked this post:
myw (02-19-2020)
02-15-2020, 08:52 PM
#55
Rennlist Member
Bumping this thread.
Just put 20" Carrera wheels on my 997.
Fronts came with 245/35/20. Fitting them on, the tires hit the top of the spring perch. Added 5mm spacers, still too close to the spring perch and contact with the inner fender lining when turning. Removed the spacers and switched to a 235/35/20. Enough clearance to the spring perch now, very light rub on the inner fender lining at full lock. I think it will be fine.
Fronts: 235/35/20. 20x8.5 +51
Rears: 295/30/20. 20x11 +55 effective (with 15mm spacer).
06 911s with PASM (stock springs)
Just put 20" Carrera wheels on my 997.
Fronts came with 245/35/20. Fitting them on, the tires hit the top of the spring perch. Added 5mm spacers, still too close to the spring perch and contact with the inner fender lining when turning. Removed the spacers and switched to a 235/35/20. Enough clearance to the spring perch now, very light rub on the inner fender lining at full lock. I think it will be fine.
Fronts: 235/35/20. 20x8.5 +51
Rears: 295/30/20. 20x11 +55 effective (with 15mm spacer).
06 911s with PASM (stock springs)
Last edited by arscottp; 02-21-2020 at 09:44 AM.
The following 4 users liked this post by arscottp:
02-16-2020, 03:44 PM
#56
Pro
Didn’t someone post something back awhile ago about the engineers at Porsche actually felt that 18 inch wheels were the ideal size for performance, weight and ride characteristics but the final decision was made to go with 19 because of market trends, competition and consumer perceptions on wheels sizes on performance cars?
Last edited by Kuhl997.2!; 02-16-2020 at 04:14 PM.
02-16-2020, 03:50 PM
#57
Rennlist Member
Not sure.
Im sure you can argue either way. The new GT3 RS comes with 20s in the front and 21s in the rear.
Personally I like the way the 20s look. No difference in ride or handling that I can tell so far.
Im sure you can argue either way. The new GT3 RS comes with 20s in the front and 21s in the rear.
Personally I like the way the 20s look. No difference in ride or handling that I can tell so far.
