991.2 GTS Tire/Wheel Sizes
03-26-2019, 01:09 PM
#1
Three Wheelin'
Thread Starter
991.2 GTS Tire/Wheel Sizes
So, after much research I decided on getting a new set of HRE lightweights.
20" just like OEM and the same width of 9" width front and 12" width on the back.
For anyone trying to figure out the proper offset to get them flush, I have done tons of research and arrived at 44 offset front and 45 offset rear.
I will of course take pics and show how good or bad my research actually was in getting them flush.
Now the question is which tires to get.
I have decided on Michelins for sure and get out of the Pirelli PZeros.
Questions are:
1. Which Michelin should I choose for Summer only driving and NO track use?
2. Should I increase the tire size from stock and go wider on front and rear?
Thanks to all of you tire guys who know how all of this stuff fits.
20" just like OEM and the same width of 9" width front and 12" width on the back.
For anyone trying to figure out the proper offset to get them flush, I have done tons of research and arrived at 44 offset front and 45 offset rear.
I will of course take pics and show how good or bad my research actually was in getting them flush.
Now the question is which tires to get.
I have decided on Michelins for sure and get out of the Pirelli PZeros.
Questions are:
1. Which Michelin should I choose for Summer only driving and NO track use?
2. Should I increase the tire size from stock and go wider on front and rear?
Thanks to all of you tire guys who know how all of this stuff fits.
03-26-2019, 03:29 PM
#4
Explain research. If they are the same width wheels and you know the factory off set, would you not just measure how far out you want to move and subtract that from factory off set?
My 4S has 56 off set, so if I went with 45 off set I moved the wheel out 11mm. Little less than a half inch.
Is this not straight math? What am I missing?
looks like off set on GTS factory is 63 rear so you moved out 18mm or .708 of an inch or 45/64”
My 4S has 56 off set, so if I went with 45 off set I moved the wheel out 11mm. Little less than a half inch.
Is this not straight math? What am I missing?
looks like off set on GTS factory is 63 rear so you moved out 18mm or .708 of an inch or 45/64”
03-26-2019, 04:44 PM
#5
Burning Brakes
03-26-2019, 05:58 PM
#6
Three Wheelin'
Thread Starter
Good2Go: If you had the answer to the offset, I wish you would have posted it months ago when multiple people asked repeatedly what the proper offset should be to get our wheels flush.
As far as the math, it's not quite that simple. You are dealing with mm's, so if you are off by 1mm in your measurements (very easy to be) then you are not flush.
You would also need to know where flush with fender actually is which requires a straight edge down the side of the fender (perfectly level) and then measure from the rim.
You need to take into consideration what the sidewall of the tire will be and what brand of tire you expect to use. Again, we are talking mm's here, not inches.
If you go too far you will be looking like an offload vehicle and shoot tons of debris all over the sides and back hips of the car potentially causing paint damage.
If you don't go far enough then you just wasted 10-12k on aftermarket wheels and didnt succeed on getting the wheels where you wanted them to be and look nearly stock.
I had numbers from all different vendors and owners from 44-47 front offset and 44-46 rear.
In the end I settled on fairly aggressive offsets with 44 front (the farthest anyone suggested) and 45 rear which was the average of what I was told..midway between most and least.
As far as the math, it's not quite that simple. You are dealing with mm's, so if you are off by 1mm in your measurements (very easy to be) then you are not flush.
You would also need to know where flush with fender actually is which requires a straight edge down the side of the fender (perfectly level) and then measure from the rim.
You need to take into consideration what the sidewall of the tire will be and what brand of tire you expect to use. Again, we are talking mm's here, not inches.
If you go too far you will be looking like an offload vehicle and shoot tons of debris all over the sides and back hips of the car potentially causing paint damage.
If you don't go far enough then you just wasted 10-12k on aftermarket wheels and didnt succeed on getting the wheels where you wanted them to be and look nearly stock.
I had numbers from all different vendors and owners from 44-47 front offset and 44-46 rear.
In the end I settled on fairly aggressive offsets with 44 front (the farthest anyone suggested) and 45 rear which was the average of what I was told..midway between most and least.
03-26-2019, 06:04 PM
#7
Good2Go: If you had the answer to the offset, I wish you would have posted it months ago when multiple people asked repeatedly what the proper offset should be to get our wheels flush.
As far as the math, it's not quite that simple. You are dealing with mm's, so if you are off by 1mm in your measurements (very easy to be) then you are not flush.
You would also need to know where flush with fender actually is which requires a straight edge down the side of the fender (perfectly level) and then measure from the rim.
You need to take into consideration what the sidewall of the tire will be and what brand of tire you expect to use. Again, we are talking mm's here, not inches.
If you go too far you will be looking like an offload vehicle and shoot tons of debris all over the sides and back hips of the car potentially causing paint damage.
If you don't go far enough then you just wasted 10-12k on aftermarket wheels and didnt succeed on getting the wheels where you wanted them to be and look nearly stock.
I had numbers from all different vendors and owners from 44-47 front offset and 44-46 rear.
In the end I settled on fairly aggressive offsets with 44 front (the farthest anyone suggested) and 45 rear which was the average of what I was told..midway between most and least.
As far as the math, it's not quite that simple. You are dealing with mm's, so if you are off by 1mm in your measurements (very easy to be) then you are not flush.
You would also need to know where flush with fender actually is which requires a straight edge down the side of the fender (perfectly level) and then measure from the rim.
You need to take into consideration what the sidewall of the tire will be and what brand of tire you expect to use. Again, we are talking mm's here, not inches.
If you go too far you will be looking like an offload vehicle and shoot tons of debris all over the sides and back hips of the car potentially causing paint damage.
If you don't go far enough then you just wasted 10-12k on aftermarket wheels and didnt succeed on getting the wheels where you wanted them to be and look nearly stock.
I had numbers from all different vendors and owners from 44-47 front offset and 44-46 rear.
In the end I settled on fairly aggressive offsets with 44 front (the farthest anyone suggested) and 45 rear which was the average of what I was told..midway between most and least.
Hope it works out.
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03-26-2019, 06:16 PM
#8
If I had to do it again I'd go 21" in the rear and run a 325/35/21 MPS4S(This size will NOT mess up the speedo or any sensors.. Its diamater is 0.01" larger than stock). Front 20" and bump it up to 255/265.
03-26-2019, 06:17 PM
#9
Three Wheelin'
Thread Starter
Psourcery: Why? Because the new 992's are staggered? Just curious what benefit you would get. I know the 21's would be more susceptible to dents from potholes with smaller sidewall...
03-26-2019, 06:22 PM
#10
More traction as I'm RWD.
In the 20" setup there are no good tire options out there to go wider unless it's a compromise on rubber.. I have Cup 2 and don't want to downgrade the tire.
In the 20" setup there are no good tire options out there to go wider unless it's a compromise on rubber.. I have Cup 2 and don't want to downgrade the tire.
03-26-2019, 06:28 PM
#11
For 991.2 GTS with CLs based on my understanding the closest to OEM wheel fitment is Turbo, Turbo S fitment.
Also after market wheels have many initiatives.
1. Design and color without too much attention to weight saving.
2. Weight saving targeting lightweight wheels.
3. Different sizes targeting advanced car setup in case you plan to tune.
PS. After my Experience with after market wheels i will never order again a CL car....
You cannot go wrong with HRE R101LWs.
Also after market wheels have many initiatives.
1. Design and color without too much attention to weight saving.
2. Weight saving targeting lightweight wheels.
3. Different sizes targeting advanced car setup in case you plan to tune.
PS. After my Experience with after market wheels i will never order again a CL car....
You cannot go wrong with HRE R101LWs.
Last edited by nilaz; 03-26-2019 at 06:45 PM.
03-26-2019, 07:15 PM
#12
Burning Brakes
03-26-2019, 07:19 PM
#13
my 20” wheels have 305/30/20. 30 side walls. You state 325/35/21. Now you have a larger wheel with larger side wall? I would think this would increase the circumference of the wheel/tire. I don’t think the 20mm width would change much.
Am I missing something or do you have a typo.
03-26-2019, 07:25 PM
#14
Why do you need 21” wheels to get 325 width?
03-26-2019, 07:31 PM
#15
lost me. I would assume the difference from 20” to 21” would be 1”. Are you saying the circumference is only .01” difference? I just measured my 20” wheels and the diameter is 20”. Are you saying 21” wheels are not 21”?
my 20” wheels have 305/30/20. 30 side walls. You state 325/35/21. Now you have a larger wheel with larger side wall? I would think this would increase the circumference of the wheel/tire. I don’t think the 20mm width would change much.
Am I missing something or do you have a typo.
my 20” wheels have 305/30/20. 30 side walls. You state 325/35/21. Now you have a larger wheel with larger side wall? I would think this would increase the circumference of the wheel/tire. I don’t think the 20mm width would change much.
Am I missing something or do you have a typo.
Michelin Pilot Sport 4S
325/25ZR21
102Y XL BSW 27.4"13.2"11.5-12.5"12"9.5/32"XL1874 lbs50 psi28.7 lbs760
^The bolded part "27.4" is the rolling diameter of the tire.
Here is the stock Pirelli P Zero tire size/rolling diameter:
305/30ZR20
99Y SL BSW 27.3"12.5"10.5-11.5"11"9/32"SL1709 lbs51 psi29 lbs762
27.3 inches..
So excuse me. I'm very tired.. The difference is 0.1".. Still nothing to set off any alarms or sensors.. The car won't know. The rolling diameter changes ever so slightly as the tire wears out anyway.
I'm running Pilot Sport CUP 2 in the same stock size as the pirelli and it's rolling diameter is 27.2".. My speedo and all systems function flawlessly.
There is a 345/30/20 CUP 2 but if feel as if that's too wide for the rear 12" wheel and the rolling diameter for that is 27.7".. I'm sure that would work but it's too tall for my taste.