max front wheel size
04-29-2005, 10:43 PM
#46
Rennlist Member
05-02-2005, 01:50 AM
#47
Rennlist Member
17X9's from CCW with 245/40/17 Kumho MX's.
They fit quite nicely with no rubbing so far. We'll see as the miles rack up.
They fit quite nicely with no rubbing so far. We'll see as the miles rack up.
Last edited by ninefiveone; 10-06-2013 at 12:37 PM.
)
05-02-2005, 02:11 AM
#49
Three Wheelin'
Thread Starter
Join Date: Jul 2001
Location: San Francisco, CA Porsche: '92 968 Blk/Cashmere
Posts: 1,699
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ninefiveone
17X9's from CCW with 245/40/17 Kumho MX's.
They fit quite nicely with no rubbing so far. We'll see as the miles rack up.
They fit quite nicely with no rubbing so far. We'll see as the miles rack up.
05-02-2005, 03:28 PM
#52
Race Director
"6.75" backspacing but I don't know what that translate to in terms of mm's of offset."
Assuming a flange-thickness of 0.375", then your 17x9" wheels measure 9.75" outside-width.
OFFSET = backspacing - (W/2) = 6.75 - (9.75/2) = 48mm offset
"2.25" - 57 mm offset front 9" wheel
1.75" - 45 mm offset rear 10" wheel"
Something doesn't look right. Hugh & Serge, both you guys have early-offset cars, but those offsets are similar to a late-offset car. They have +20-30mm than stock! How are you measuring the rim-widths? From outside-to-outside of the rim-flanges? Or between the flanges where the tyre bead sits???
Assuming a flange-thickness of 0.375", then your 17x9" wheels measure 9.75" outside-width.
OFFSET = backspacing - (W/2) = 6.75 - (9.75/2) = 48mm offset
"2.25" - 57 mm offset front 9" wheel
1.75" - 45 mm offset rear 10" wheel"
Something doesn't look right. Hugh & Serge, both you guys have early-offset cars, but those offsets are similar to a late-offset car. They have +20-30mm than stock! How are you measuring the rim-widths? From outside-to-outside of the rim-flanges? Or between the flanges where the tyre bead sits???
Last edited by Danno; 05-02-2005 at 05:32 PM.
05-02-2005, 06:01 PM
#53
Rennlist Member
Offsets change when you go from a 7 or 8" factory wheel to a 10" wheel. This is exactly why a set of 6 and 7" fuchs will fit on a late offset car.
The above offsets are correct for the CCW wheels. I have confirmed them with another CCW owner.
I re-read your post Danno. I now see what you're saying. But honestly, do the minor technicalities really matter as long as you're not pushing the absolute maximum width?
The above offsets are correct for the CCW wheels. I have confirmed them with another CCW owner.
I re-read your post Danno. I now see what you're saying. But honestly, do the minor technicalities really matter as long as you're not pushing the absolute maximum width?
05-02-2005, 10:27 PM
#54
Race Director
"Offsets change when you go from a 7 or 8" factory wheel to a 10" wheel. This is exactly why a set of 6 and 7" fuchs will fit on a late offset car."
Offsets may or may not change, it depends upon how you configure your wheels. A set of 16x6/7" Fuchs has exactly the same 23.3mm offset as a 16x7/8" set. However, the narrower ones will have 0.5" less rim on both the outside and inside edges, thus allowing them to fit on a late-offset car. However, you'll only be able to run a 205/55-16 and 225/50-16 tyre combo.
"do the minor technicalities really matter as long as you're not pushing the absolute maximum width?"
No it doesn't matter that much as long as things don't rub. I'm just afraid that Chris may end up with tyres that rub if he goes with those wheels and I want to confirm all the measurements. I thought I had gone with sizus maximum wheels on my car because I had made all the measurements and extrapolated the upgrade with minimal clearances. But after fitting them, I can see there's still some room to work with. So the numbers are the key to extracting the last bit of performance out of these things.
Went out and re-measured my wheels to confirm the specs:
BBS-F: 17x10.5", 11.25" outside-width, 7.00" backspacing = 35mm offset
BBS-R: 17x11.5", 12.25" outside-width, 7.375" backspacing = 32mm offset
So I'm running +9-12mm more offset than stock. Which gives me the following additions over my stock 16x7/8" Fuchs:
Fuchs-F: 16x7" -> BBS 17x10.5" = +2.25" on inside, +1.25" on outside edge
Fuchs-R: 16x8" -> BBS 17x11.5" = +2.00" on inside, + 1.50" on outside edge
So on both wheels, I'm adding the majority of the extra width on the inside edge. Same thing with your wheels. When I use the actual outside-width measurements (assuming same +0.375" flange thickness as my wheel), the offset-increase isn't so extreme:
CCW-F: 17x9", 9.75" outside-width, 6.75" backspacing = 47mm offset
CCW-R: 17x10", 10.75" outside-width, 6.75" backspacing = 35mm offset
So you're running +12-25mm more offset than stock. Which splits the extra width like this:
Fuchs-F: 16x7" -> CCW 17x9" = +2.00" on inside, +0.00" on outside edge
Fuchs-R: 16x8" -> CCW 17x10" = +1.375" on inside, +0.625" on outside edge
As you can see, on your front wheels, you've added ALL of the extra width on the inside rim-edge, leaving maximum clearance on the outside. I'm just worried that Chris won't be as fortunate with that 17x9.5" wheel he's looking at. Don't want him to go through what Adrial did.
"Darn you Danno!
My girlfriends always told me size didn't matter! LOL! "
She's lying to you Sean! All the girls I've talked to lately have been more forthcoming about their needs and desires without whitewashing it in societal political-correctness. Although they do have some disagreements on size. There's these two sisters and they argue about this size thing all the time. One of them insists that "humongous" is completely adequate while her sister argues that nothing short of "obscenely monstrous" would do....
Offsets may or may not change, it depends upon how you configure your wheels. A set of 16x6/7" Fuchs has exactly the same 23.3mm offset as a 16x7/8" set. However, the narrower ones will have 0.5" less rim on both the outside and inside edges, thus allowing them to fit on a late-offset car. However, you'll only be able to run a 205/55-16 and 225/50-16 tyre combo.
"do the minor technicalities really matter as long as you're not pushing the absolute maximum width?"
No it doesn't matter that much as long as things don't rub. I'm just afraid that Chris may end up with tyres that rub if he goes with those wheels and I want to confirm all the measurements. I thought I had gone with sizus maximum wheels on my car because I had made all the measurements and extrapolated the upgrade with minimal clearances. But after fitting them, I can see there's still some room to work with. So the numbers are the key to extracting the last bit of performance out of these things.
Went out and re-measured my wheels to confirm the specs:
BBS-F: 17x10.5", 11.25" outside-width, 7.00" backspacing = 35mm offset
BBS-R: 17x11.5", 12.25" outside-width, 7.375" backspacing = 32mm offset
So I'm running +9-12mm more offset than stock. Which gives me the following additions over my stock 16x7/8" Fuchs:
Fuchs-F: 16x7" -> BBS 17x10.5" = +2.25" on inside, +1.25" on outside edge
Fuchs-R: 16x8" -> BBS 17x11.5" = +2.00" on inside, + 1.50" on outside edge
So on both wheels, I'm adding the majority of the extra width on the inside edge. Same thing with your wheels. When I use the actual outside-width measurements (assuming same +0.375" flange thickness as my wheel), the offset-increase isn't so extreme:
CCW-F: 17x9", 9.75" outside-width, 6.75" backspacing = 47mm offset
CCW-R: 17x10", 10.75" outside-width, 6.75" backspacing = 35mm offset
So you're running +12-25mm more offset than stock. Which splits the extra width like this:
Fuchs-F: 16x7" -> CCW 17x9" = +2.00" on inside, +0.00" on outside edge
Fuchs-R: 16x8" -> CCW 17x10" = +1.375" on inside, +0.625" on outside edge
As you can see, on your front wheels, you've added ALL of the extra width on the inside rim-edge, leaving maximum clearance on the outside. I'm just worried that Chris won't be as fortunate with that 17x9.5" wheel he's looking at. Don't want him to go through what Adrial did.
"Darn you Danno!
My girlfriends always told me size didn't matter! LOL! "
She's lying to you Sean! All the girls I've talked to lately have been more forthcoming about their needs and desires without whitewashing it in societal political-correctness. Although they do have some disagreements on size. There's these two sisters and they argue about this size thing all the time. One of them insists that "humongous" is completely adequate while her sister argues that nothing short of "obscenely monstrous" would do....
Last edited by Danno; 05-02-2005 at 11:01 PM.
05-03-2005, 10:08 AM
#55
Rennlist Member
Wish I had helpful facts to help this conversation. I did not take the time to measure them before I had mounted them. I assume my 9" rims are measured from bead to bead, and not flange to flange. But my eye does tell me that there's a good amount of offset in the rim. All things being equal (and I know they're not since a 16X8 phone dial is completely different from a 17X9 custom 3 piece wheel) there's significantly more "hub" on the phone dial than on the CCW. Compared to how the car sat before with 16X8's all around, the increase in width is all on the inside.
05-03-2005, 01:15 PM
#56
Race Director
"m. All things being equal (and I know they're not since a 16X8 phone dial is completely different from a 17X9 custom 3 piece wheel) there's significantly more "hub" on the phone dial than on the CCW."
Funny thing is on the 951 Fuchs, the 16x8" one has a thicker flange than the 16x7". So the 16x8" is actually 9" wide on the outside and the 16x7" is 7.75" wide. Threw me off for a while there...
Here's some more pictures of 951s with CCW wheels:
Funny thing is on the 951 Fuchs, the 16x8" one has a thicker flange than the 16x7". So the 16x8" is actually 9" wide on the outside and the 16x7" is 7.75" wide. Threw me off for a while there...
Here's some more pictures of 951s with CCW wheels:
