GSF rim offset needed
09-17-18, 07:08 AM
#2
Hey-
No one has answered as I think this is a boring topic of little interest to most people, hahaha, not so for me. It is also very technical and potentially expensive. I'll give it a try...
It depends… Even the style of the wheels could play a role in determining clearance from calipers... The BBS made, OEM wheels that came with your car are excellent quality and are actually fully forged wheels, not flow formed etc... My advice is that you start by the material/manufacturing process as the basis of your choice as you don't want to put something of lesser quality and strength than what the manufacturer have already decided was needed for a car of that level of performance. Of course, a lot of people are rightfully so discouraged when they see the cost of fully forged wheels... they are not cheap my friend.
Once you made that decision (manufacturing process), style/looks and brand will come into play. All I'll say on that point is that I chose a satin/matte black finish on a multi spoke design that helps enormously with masking the dust from the OEM brake pads, which don't bother me one bit anyways. With my USB-2 color, they wheels look amazing.
Then you will have to decide if you are going to remain OEM size for the diameter and width of the tire. If you are, it will not be that difficult to get it done. However, if you are going for 20" diameter and/or also changing the width of the tires, you will have to do some math and there will be some risks associated with doing this. Not only the clearance for the clippers, but potential rubbing on the fenders as well as negative changes in performance. For example, changing the overall diameter of the tire will have acceleration and fuel economy implications as that variable (overall diameter) is directly related to transmission ratios, but also related with many other systems that measure and use individual wheel speed to determine a bunch of things. This is the opening of the rabbit hole for this topic, most people don't have the energy or interest to understand how deep it goes. Reading about the relationship between kingpin inclination and scrub radius (there's a lot into it) could help you understand the consequences of changing some of these variables, like tire width and offset. You should not consider using spacers to "correct" the look of any wheels if you can avoid it by buying the correct offset for those wheels from the beginning. Some people employ spacers on the OEM wheels to "better" the look of the car or because whatever wheels they are buying have an inadequate offset and its causing rubbing or some other problem. Its not that bad or wrong to go that route (spacers), all I'm saying is that there are no free lunches with this stuff and whatever one changes "over here" is going to have an effect "over there", if you understand what I'm saying.
I bought fully forged Yokohama AVS wheels, 20" diameter by 10" wide with a +30 mm offset for the back. For the front, I got 20" dimeter by 9.5" wide with a +40 mm offset.
If you consider what I wrote and go step by step, you will have a much higher chance of this change coming out as an upgrade not as a downgrade. Remember, most people in this forum love their cars, their sound and looks, and are willing to sacrifice some performance (maybe unknowingly) so their cars look the way they want. That is totally legitimate! Me on the other hand, fall on that very small group of irrational people that use this expensive thing mainly to make noise, **** people off, and scream down tracks and autocross with the ocasional restaurant and Starbucks. So I care a lot about the details; but also the looks.
No one has answered as I think this is a boring topic of little interest to most people, hahaha, not so for me. It is also very technical and potentially expensive. I'll give it a try...
It depends… Even the style of the wheels could play a role in determining clearance from calipers... The BBS made, OEM wheels that came with your car are excellent quality and are actually fully forged wheels, not flow formed etc... My advice is that you start by the material/manufacturing process as the basis of your choice as you don't want to put something of lesser quality and strength than what the manufacturer have already decided was needed for a car of that level of performance. Of course, a lot of people are rightfully so discouraged when they see the cost of fully forged wheels... they are not cheap my friend.
Once you made that decision (manufacturing process), style/looks and brand will come into play. All I'll say on that point is that I chose a satin/matte black finish on a multi spoke design that helps enormously with masking the dust from the OEM brake pads, which don't bother me one bit anyways. With my USB-2 color, they wheels look amazing.
Then you will have to decide if you are going to remain OEM size for the diameter and width of the tire. If you are, it will not be that difficult to get it done. However, if you are going for 20" diameter and/or also changing the width of the tires, you will have to do some math and there will be some risks associated with doing this. Not only the clearance for the clippers, but potential rubbing on the fenders as well as negative changes in performance. For example, changing the overall diameter of the tire will have acceleration and fuel economy implications as that variable (overall diameter) is directly related to transmission ratios, but also related with many other systems that measure and use individual wheel speed to determine a bunch of things. This is the opening of the rabbit hole for this topic, most people don't have the energy or interest to understand how deep it goes. Reading about the relationship between kingpin inclination and scrub radius (there's a lot into it) could help you understand the consequences of changing some of these variables, like tire width and offset. You should not consider using spacers to "correct" the look of any wheels if you can avoid it by buying the correct offset for those wheels from the beginning. Some people employ spacers on the OEM wheels to "better" the look of the car or because whatever wheels they are buying have an inadequate offset and its causing rubbing or some other problem. Its not that bad or wrong to go that route (spacers), all I'm saying is that there are no free lunches with this stuff and whatever one changes "over here" is going to have an effect "over there", if you understand what I'm saying.
I bought fully forged Yokohama AVS wheels, 20" diameter by 10" wide with a +30 mm offset for the back. For the front, I got 20" dimeter by 9.5" wide with a +40 mm offset.
If you consider what I wrote and go step by step, you will have a much higher chance of this change coming out as an upgrade not as a downgrade. Remember, most people in this forum love their cars, their sound and looks, and are willing to sacrifice some performance (maybe unknowingly) so their cars look the way they want. That is totally legitimate! Me on the other hand, fall on that very small group of irrational people that use this expensive thing mainly to make noise, **** people off, and scream down tracks and autocross with the ocasional restaurant and Starbucks. So I care a lot about the details; but also the looks.
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1BlinkGone (10-04-18)
10-03-18, 01:23 PM
#4
Pit Crew
Thread Starter
Thats a very nice setup you have on your GSF, are you on any lowering spring or aftermarket suspension?
Based on in what you said, I’m probably going to h e to run spacers on my fronts so I can fit the rims that I have.
Thank you you for the reply!!!
10-04-18, 12:14 AM
#6
Pole Position
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ModInJapan (10-04-18)
10-04-18, 11:14 AM
#7
Tech Info Resource
iTrader: (2)
Unless they're used to bring a wheel with a different offset back to the original centerline position. I agree, using spacers for "stance" with OEM wheels can cause premature wheel bearing failure especially if the car is used for autocross or road course driving.
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10-05-18, 11:00 AM
#8
Concur, and also to keep in mind that the factory clearances around the tire and the wheel well are not big at all for the GS-F... Just a few millimeters one way or the other and you are rubbing at full steering lock, or at max suspension travel. Based on this thread and curiosity, I put some hub-centric 15mm spacers on the front tires a couple of days ago... I just got them out a couple of hours ago, after being reminded of what we are talking about here. OEM wheels and tires have much more leeway for spacers. Aftermarket setups like the one picture on this thread or the one that I have, have very little space to play with.
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