RS wheel offset on GT3
08-31-2009, 04:12 AM
#1
Banned
Thread Starter
RS wheel offset on GT3
I have a question for you wheel and tire experts (I do know a thing or two myself).
Why can't you, or why shouldn't you, put the RS rear wheels with an offset of 51 on a regular GT3 which is running an offset of 63 with the 5mm spacer?
Actually, let me give you more info for my particular case. I have the CCW C-14 wheels with a 9" front and 12" rear in the 18" size and run them on street and track. The rear CCW's come with a 63 offset already so that you do not need the spacer. However, back when I was still using my stock wheels and switching between them and the CCW's I once forgot to take the spacer off when mounting the CCW's (or the dealer did this). Well with that combo the offset of the CCW was then 58; correct? It fit just fine and did not stick out of the rear wheel wells so I left it. Recently I bought some 7 mm spacers in anticipation of some other wheels that I was going to buy (and never did) so I tried them on the rear with my CCW's resulting in an offset of 56 and all is well. It fits fine and nothing looks silly or rubs anywhere.
So if I were to put on a set of stock RS rear wheels without any spacers, then it would only be another 5 mm out from my current setup (this is only 1/5 of an inch) Again, I think it would work fine and not look silly bringing the edge of the wheel right out to the edge of the fender but not past it (maybe a hair or two past it, but nothing ridiculous).
So what would be the problem with this??? It would change the rear track to that of the RS, and it would not be quite as tucked away into the wheel well, but that is all right?
Sure changes in offset and therefore track can affect the handling of a car, but it would be the same tracks as the RS since the front wheel offset and track is the same in both cars.
In fact, I think it would be a better match for my front CCW wheels which are 9" wide and are right at the limit of the fenders and actually stick out a bit at the top depending on camber settings. I know others have CCW 9" front wheels and must have noticed this. If the front 9" CCW wheels have the same offset as stock then they would stick out about 6 mm more, but if they reduced it to keep the inside wheel position the same to prevent rubbing of the fender liners, then they would stick out the full 0.5" width increase which is about 12 mm, OR about the same as if the rears had RS wheels without spacers which is an increase of 12 mm.
Is my math and wheel offset understanding correct here? And if so, then what would be wrong with using RS wheels on a regular GT3? 12mm is a liitle bit less than a half inch increase.
Why can't you, or why shouldn't you, put the RS rear wheels with an offset of 51 on a regular GT3 which is running an offset of 63 with the 5mm spacer?
Actually, let me give you more info for my particular case. I have the CCW C-14 wheels with a 9" front and 12" rear in the 18" size and run them on street and track. The rear CCW's come with a 63 offset already so that you do not need the spacer. However, back when I was still using my stock wheels and switching between them and the CCW's I once forgot to take the spacer off when mounting the CCW's (or the dealer did this). Well with that combo the offset of the CCW was then 58; correct? It fit just fine and did not stick out of the rear wheel wells so I left it. Recently I bought some 7 mm spacers in anticipation of some other wheels that I was going to buy (and never did) so I tried them on the rear with my CCW's resulting in an offset of 56 and all is well. It fits fine and nothing looks silly or rubs anywhere.
So if I were to put on a set of stock RS rear wheels without any spacers, then it would only be another 5 mm out from my current setup (this is only 1/5 of an inch) Again, I think it would work fine and not look silly bringing the edge of the wheel right out to the edge of the fender but not past it (maybe a hair or two past it, but nothing ridiculous).
So what would be the problem with this??? It would change the rear track to that of the RS, and it would not be quite as tucked away into the wheel well, but that is all right?
Sure changes in offset and therefore track can affect the handling of a car, but it would be the same tracks as the RS since the front wheel offset and track is the same in both cars.
In fact, I think it would be a better match for my front CCW wheels which are 9" wide and are right at the limit of the fenders and actually stick out a bit at the top depending on camber settings. I know others have CCW 9" front wheels and must have noticed this. If the front 9" CCW wheels have the same offset as stock then they would stick out about 6 mm more, but if they reduced it to keep the inside wheel position the same to prevent rubbing of the fender liners, then they would stick out the full 0.5" width increase which is about 12 mm, OR about the same as if the rears had RS wheels without spacers which is an increase of 12 mm.
Is my math and wheel offset understanding correct here? And if so, then what would be wrong with using RS wheels on a regular GT3? 12mm is a liitle bit less than a half inch increase.
08-31-2009, 09:27 AM
#2
Advanced
Join Date: Apr 2009
Location: Warwickshire, England
Posts: 54
Likes: 0
Received 0 Likes
on
0 Posts
From memory ( I'm on holiday, away from the RS
) the 997 GT3 rear wheels have 51 mm offsets and the RS ones 68mm. Both are fitted withh 5mm spacers from the factory. So if you tried to fit RS wheels on a standard GT3 the wheels would surely stick out too far and rub on the lip of the wheel-arches unless you only drove very sedately!
) the 997 GT3 rear wheels have 51 mm offsets and the RS ones 68mm. Both are fitted withh 5mm spacers from the factory. So if you tried to fit RS wheels on a standard GT3 the wheels would surely stick out too far and rub on the lip of the wheel-arches unless you only drove very sedately!
08-31-2009, 09:35 AM
#3
Banned
Thread Starter
From memory ( I'm on holiday, away from the RS) the 997 GT3 rear wheels have 51 mm offsets and the RS ones 68mm. Both are fitted withh 5mm spacers from the factory. So if you tried to fit RS wheels on a standard GT3 the wheels would surely stick out too far and rub on the lip of the wheel-arches unless you only drove very sedately!
) the 997 GT3 rear wheels have 51 mm offsets and the RS ones 68mm. Both are fitted withh 5mm spacers from the factory. So if you tried to fit RS wheels on a standard GT3 the wheels would surely stick out too far and rub on the lip of the wheel-arches unless you only drove very sedately!The offsets are the opposit of what you have. They are calculated from the mounting surface to center line of barrel. So as the centerline moves closer to face, the distance gets smaller and barrel of wheel moves further out increasing the track.
08-31-2009, 10:52 AM
#4
Advanced
Join Date: Apr 2009
Location: Warwickshire, England
Posts: 54
Likes: 0
Received 0 Likes
on
0 Posts
In my relaxed state I may have got the figures the wrong way round. The 997 RS has a wider rear track than the 997 GT3, and I thought this was down to the different offsets. Tried a set OEM GT3 wheels from my previous 997 GT3 on the RS and they did not come out as wide as the RS wheels do. Assumed the reverse would apply trying to fit RS wheels onto a GT3.
08-31-2009, 03:02 PM
#5
Banned
Thread Starter
In my relaxed state I may have got the figures the wrong way round. The 997 RS has a wider rear track than the 997 GT3, and I thought this was down to the different offsets. Tried a set OEM GT3 wheels from my previous 997 GT3 on the RS and they did not come out as wide as the RS wheels do. Assumed the reverse would apply trying to fit RS wheels onto a GT3.
Look at 2010 RS. All they did is tack on some fender extenders so the wheels do not stick out. The stock fender is still there in the same postion.
I think it more a requirement in Germany that wheels do not extend past fenders. Could be so tires are protected during high speed driving from materials flung at them from cars in front. Also it keeps them from flinging less material (rocks mostly) at cars behind you. Finally, it is a matter of asthetics that they not extend out past top of fender; that look really is not all that cool!
Like I said above, I am currently only 5 mm away from a 51 offset, and I think it will work just fine; although right at edge of top of rear fender or just slightly out (1 or 2 mm at most).
Anyone else want to chime in?
08-31-2009, 04:40 PM
#6
Track Day
Join Date: Jun 2007
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
Porsche is ultra conservative with offsets and so are the vast majority of people that purchase them
19X12 +51 WILL fit a narrow body. I know porsche knows best but im from the younger tuning crowd where flush fitments are one of the main reasons to get wheels from an aesthetic pov. Wider track is not a bad idea either.
Look at the tuning scene in europe. All about low offset flush fitments. Im not saying we should be stretching tires VW style but porsche wheels just get eaten by the fenders and look like crap no matter what.
Im running oem gt3 wheels with 14mm front and rear spacer on the street. This will put the offset to +54 It still looks i have +3 more mm and some so i see it as no problem. I ride it hard all the time no rubbing or anything and its not like we slam our porsches to tuck under the fender anyways.
My friend ordered some custom wheels 19 X 11.5 with +58 offset and was not too excoted about it. He ordered i believe +51 but they didnt make it for him like that insisting it wont fit. He is going to run 10mm spacers to make it look right.
So my understanding is that 19 X 12 +51 or 19 X 11.5 +45 all day long without it sticking out like a low rider and fronts can easily be
19 x 9 +45 to +50
You guys have no idea how mean these cars will look even with a narrow body with flush wheels. Everyone is just too scared to try something that is not traditional.
19X12 +51 WILL fit a narrow body. I know porsche knows best but im from the younger tuning crowd where flush fitments are one of the main reasons to get wheels from an aesthetic pov. Wider track is not a bad idea either.
Look at the tuning scene in europe. All about low offset flush fitments. Im not saying we should be stretching tires VW style but porsche wheels just get eaten by the fenders and look like crap no matter what.
Im running oem gt3 wheels with 14mm front and rear spacer on the street. This will put the offset to +54 It still looks i have +3 more mm and some so i see it as no problem. I ride it hard all the time no rubbing or anything and its not like we slam our porsches to tuck under the fender anyways.
My friend ordered some custom wheels 19 X 11.5 with +58 offset and was not too excoted about it. He ordered i believe +51 but they didnt make it for him like that insisting it wont fit. He is going to run 10mm spacers to make it look right.
So my understanding is that 19 X 12 +51 or 19 X 11.5 +45 all day long without it sticking out like a low rider and fronts can easily be
19 x 9 +45 to +50
You guys have no idea how mean these cars will look even with a narrow body with flush wheels. Everyone is just too scared to try something that is not traditional.
08-31-2009, 07:16 PM
#7
Banned
Thread Starter
Porsche is ultra conservative with offsets and so are the vast majority of people that purchase them
19X12 +51 WILL fit a narrow body. I know porsche knows best but im from the younger tuning crowd where flush fitments are one of the main reasons to get wheels from an aesthetic pov. Wider track is not a bad idea either.
Look at the tuning scene in europe. All about low offset flush fitments. Im not saying we should be stretching tires VW style but porsche wheels just get eaten by the fenders and look like crap no matter what.
Im running oem gt3 wheels with 14mm front and rear spacer on the street. This will put the offset to +54 It still looks i have +3 more mm and some so i see it as no problem. I ride it hard all the time no rubbing or anything and its not like we slam our porsches to tuck under the fender anyways.
My friend ordered some custom wheels 19 X 11.5 with +58 offset and was not too excoted about it. He ordered i believe +51 but they didnt make it for him like that insisting it wont fit. He is going to run 10mm spacers to make it look right.
So my understanding is that 19 X 12 +51 or 19 X 11.5 +45 all day long without it sticking out like a low rider and fronts can easily be
19 x 9 +45 to +50
You guys have no idea how mean these cars will look even with a narrow body with flush wheels. Everyone is just too scared to try something that is not traditional.
19X12 +51 WILL fit a narrow body. I know porsche knows best but im from the younger tuning crowd where flush fitments are one of the main reasons to get wheels from an aesthetic pov. Wider track is not a bad idea either.
Look at the tuning scene in europe. All about low offset flush fitments. Im not saying we should be stretching tires VW style but porsche wheels just get eaten by the fenders and look like crap no matter what.
Im running oem gt3 wheels with 14mm front and rear spacer on the street. This will put the offset to +54 It still looks i have +3 more mm and some so i see it as no problem. I ride it hard all the time no rubbing or anything and its not like we slam our porsches to tuck under the fender anyways.
My friend ordered some custom wheels 19 X 11.5 with +58 offset and was not too excoted about it. He ordered i believe +51 but they didnt make it for him like that insisting it wont fit. He is going to run 10mm spacers to make it look right.
So my understanding is that 19 X 12 +51 or 19 X 11.5 +45 all day long without it sticking out like a low rider and fronts can easily be
19 x 9 +45 to +50
You guys have no idea how mean these cars will look even with a narrow body with flush wheels. Everyone is just too scared to try something that is not traditional.
In my case I am running 18's with the same aspect ratio as the stock 19's, so the overall diameter is less and this also helps to easily clear the fender lip.
I am not necessarily looking to go to a 51 offset, but I see wheels for sale that I want, and somtimes they have the RS offset so I think I can't use them; this just allows for more wheels to choose from.
