Option code X38 - wider front fenders
08-17-2023, 05:33 PM
#61
Rennlist Member
Carlos,
The 8" et 70 wheel is 12.7 mm wider than the 7.5" wheel. 5mm of that is closer to the engine, 7.7 mm is further away from the engine Thus, the centerline of the wheel/tire tread is 1.35 mm further out than the 7.5" wheel. My old body/brain is not capable of experiencing any difference in the drivability associated with scrub radius.
There is a VERY noticeable at full lock right or left when the 8" et52 wheels are mounted on the car).
Gary
The 8" et 70 wheel is 12.7 mm wider than the 7.5" wheel. 5mm of that is closer to the engine, 7.7 mm is further away from the engine Thus, the centerline of the wheel/tire tread is 1.35 mm further out than the 7.5" wheel. My old body/brain is not capable of experiencing any difference in the drivability associated with scrub radius.
There is a VERY noticeable at full lock right or left when the 8" et52 wheels are mounted on the car).
Gary
Last edited by Gary Knox; 08-17-2023 at 05:37 PM.
08-17-2023, 07:29 PM
#62
ET52
Hmmmmm! that 8" et 52 wheel would have been strange as original equipment on the 928, as that offset significantly changes the scrub radius for the steering (I also have a set of 18" OE Porsche Sport Design wheels with 8" et 52 offset for the front)
The 17X8 et 70 offset CupII wheel essentially locates the center of the front wheel in exactly the same place as the 17X7.5 et 65. Therefore the scrub radius is unchanged. I drive the '95 with both the 17" Cup II wheels and the 18" Sport Design wheels. I like the appearance of the Sport Design wheels on the car (avatar pix), but it drives much better with the Cup II's (either 7.5 et65 or 8 et70 on the front).
Gary
The 17X8 et 70 offset CupII wheel essentially locates the center of the front wheel in exactly the same place as the 17X7.5 et 65. Therefore the scrub radius is unchanged. I drive the '95 with both the 17" Cup II wheels and the 18" Sport Design wheels. I like the appearance of the Sport Design wheels on the car (avatar pix), but it drives much better with the Cup II's (either 7.5 et65 or 8 et70 on the front).
Gary
08-17-2023, 08:15 PM
#63
Rennlist Member
I will ponder what you said. I believe one of us may have an incorrect assumption, but I am not sure who yet! Either way, let us hope neither of us experuences a drivability difference associated with scrub radius, since I understand that to be a bad scenario!Last edited by hernanca; 08-17-2023 at 08:21 PM. Reason: My good friend, Claire Hitty.
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Gary Knox (08-18-2023)
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08-18-2023, 04:23 PM
#65
Rennlist Member
Carlos,
Quote: "And this is what throws into question the importance of the front et65. Why would Porsche itself deviate so far from it with et52 front wheels if it is so important and no other changes were made?"
That is what had me flabbergasted (erudite term, I know) when I saw the part number and the offset of those wheels. It is inconceivable to me, based on experience with both a '94 and a '95 928 having 8" et52 wheels mounted on the front that one would ever have left the factory equipped that way - unless there was significant suspension modification. And why would P-car company have done that for a very small number of X38 optioned cars when they already had the Cup II 'winter wheel' for the rear of the 911 in production as 8" et 70?
A mystery indeed!!!
PS: A bit more searching, and I find the 8' X 17 et 52 cup II wheels were OE on some narrow body 993's - not sure where in the world they were shipped, as I'd thought essentially all US 993's with Cup II's were 7" et? fronts and 9" et 55 rears. SO - P-car company did have these in the their parts inventory.
Quote: "And this is what throws into question the importance of the front et65. Why would Porsche itself deviate so far from it with et52 front wheels if it is so important and no other changes were made?"
That is what had me flabbergasted (erudite term, I know) when I saw the part number and the offset of those wheels. It is inconceivable to me, based on experience with both a '94 and a '95 928 having 8" et52 wheels mounted on the front that one would ever have left the factory equipped that way - unless there was significant suspension modification. And why would P-car company have done that for a very small number of X38 optioned cars when they already had the Cup II 'winter wheel' for the rear of the 911 in production as 8" et 70?
A mystery indeed!!!
PS: A bit more searching, and I find the 8' X 17 et 52 cup II wheels were OE on some narrow body 993's - not sure where in the world they were shipped, as I'd thought essentially all US 993's with Cup II's were 7" et? fronts and 9" et 55 rears. SO - P-car company did have these in the their parts inventory.
Last edited by Gary Knox; 08-18-2023 at 04:52 PM.
08-28-2023, 09:23 AM
#66
Rennlist Member
The cup-II summer wheels that came from the factory with my car (as I have all maintenance and other paper work), including option X38: 8" * ET70 on the fronts, and 9" * ET55 on the rears.
The 3rd German owner of my car also bought cup-II winter wheels, that are 7,5" * ET 65.
The 3rd German owner of my car also bought cup-II winter wheels, that are 7,5" * ET 65.
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Jaktomaten (08-28-2023)
08-28-2023, 09:54 AM
#67
The cup-II summer wheels that came from the factory with my car (as I have all maintenance and other paper work), including option X38: 8" * ET70 on the fronts, and 9" * ET55 on the rears.
The 3rd German owner of my car also bought cup-II winter wheels, that are 7,5" * ET 65.
The 3rd German owner of my car also bought cup-II winter wheels, that are 7,5" * ET 65.
The parts marked with pen on the paper where installed some time in the 90’s
04-22-2024, 02:56 PM
#68
The fenders are wider!
but they are wider towards the front of the car. It’s actually just barely visible to the eye and I could probably not spot it without having a second car with the same wheel/tire setup next to it. If you look at the car straight from the front the X38 will not let you see as much of the tire as the regular fender will. Looking at the arch of the fender from the front the regular fender will go more straight up towards the top of the wheel arch and the X38 will go more out in a bulge towards the top. Overall width is not affected but the fender is slightly wider in front of the wheel.
English is not my first language but I hope you will
understand anyway.
04-22-2024, 05:01 PM
#69
Rennlist Member
Would you be able to confirm if the fenders are steel or alumnium?
04-22-2024, 07:07 PM
#71
Rennlist Member
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Rob Edwards (04-23-2024)
04-23-2024, 01:49 AM
#73
Rennlist Member
Thanks so much. This is such valuable documentation of the x38 option
04-24-2024, 08:14 PM
#75
Addict
Rennlist Member
Rennlist Member
I believe those phone consoles were made by TechArt. My 5sp GTS came with one.
What is this piece, cell phone mount?? - Rennlist - Porsche Discussion Forums
Green 928 for sale in MD - Rennlist - Porsche Discussion Forums
What is this piece, cell phone mount?? - Rennlist - Porsche Discussion Forums
Green 928 for sale in MD - Rennlist - Porsche Discussion Forums
