17x9.5 +10 on NB 911SC

[s2k9k]

Bought some wheels from an owner of a 83 911sc targa. He was running 215/45 up front and 255/40 in the rear. Wheels are 17x8 +25.4 and 17x9 +10.5 according to the previous owner when he had them built for his G body. He mentioned no need to relocate oil lines, shave suspension bolts or anything.

I’m about to order tires and wondering if this truly will fit? They are bbs e87.

[mark4ton]

that's amazing. can't wait to see them mounted. I have 17x8 and 9.5 on my 87 Carrera. I'm not sure on the offset of them, I bought them with the same "they were on a SC" and ended up having to use a spacer on the rear due to the toe and camber bolts.

[s2k9k]

Originally Posted by mark4ton

that's amazing. can't wait to see them mounted. I have 17x8 and 9.5 on my 87 Carrera. I'm not sure on the offset of them, I bought them with the same "they were on a SC" and ended up having to use a spacer on the rear due to the toe and camber bolts.

So instead of shaving the bolts a spacer took care of it? How about the oil lines or quarter panel lips? Any mods there?

[Bill Verburg]

Originally Posted by s2k9k

Bought some wheels from an owner of a 83 911sc targa. He was running 215/45 up front and 255/40 in the rear. Wheels are 17x8 +25.4 and 17x9 +10.5 according to the previous owner when he had them built for his G body. He mentioned no need to relocate oil lines, shave suspension bolts or anything.

I’m about to order tires and wondering if this truly will fit? They are bbs e87.

The front 8ET25.4 is fine w/ 215/45 x17 tires they are a good match for 9s w/ 245/40 but in your case the rear wheels have an unfortunately high o/s, The 9 ET10.6 moves the wheel out placing any tire uncomfortably close to the rear fender lips, more so w/ a 255/40.

You may be able to get away w/ it w/ ride height and camber restrictions.

for the rear 9 ET15 would be a much better setup.

as for the BBS wheels pictured no way a 9.5 & 10 will fit on an SC/Carrera

max w/o doing crazy mods is 8ET25.4(though 8ET27 would be better) and 9.5ET19

you could fit 235 and 275 tires on these, but they would require a lot of work and restrictions as to set up, 225/45 and 255/40 on them fit like a glove w/ no major issues except maybe at the front lips. There a shave would be desirable,

I have seen 9 & 10 on SC/Carrera but the tires are still limiting and it's not a happy fit at all.

[s2k9k]

Originally Posted by Bill Verburg

The front 8ET25.4 is fine w/ 215/45 x17 tires they are a good match for 9s w/ 245/40 but in your case the rear wheels have an unfortunately high o/s, The 9 ET10.6 moves the wheel out placing any tire uncomfortably close to the rear fender lips, more so w/ a 255/40.

You may be able to get away w/ it w/ ride height and camber restrictions.

for the rear 9 ET15 would be a much better setup.

as for the BBS wheels pictured no way a 9.5 & 10 will fit on an SC/Carrera

max w/o doing crazy mods is 8ET25.4(though 8ET27 would be better) and 9.5ET19

you could fit 235 and 275 tires on these, but they would require a lot of work and restrictions as to set up, 225/45 and 255/40 on them fit like a glove w/ no major issues except maybe at the front lips. There a shave would be desirable,

I have seen 9 & 10 on SC/Carrera but the tires are still limiting and it's not a happy fit at all.

Thank you so much for responding. I’ve gone through so many of your posts to see if maybe you’ve answered this question. Thank you for commenting.

So you mentioned a 215 up front on the 8 would be fine. You think I can get away with a 225? I was thinking of going with Falken Azenie tires.

Not looking to do 10s as I saw you mentioned that. Just the 9.5ET10.5 in the rear is what worries me. Maybe a 245 tire on it would be best since the falkens do run a little wider than usual?

If push comes to shove, I’ll roll the fender lips all around to clear.

[mark4ton]

my front fender are rolled. thats all for clearance.

Originally Posted by s2k9k

So instead of shaving the bolts a spacer took care of it? How about the oil lines or quarter panel lips? Any mods there?

[Bill Verburg]

Originally Posted by s2k9k

Thank you so much for responding. I’ve gone through so many of your posts to see if maybe you’ve answered this question. Thank you for commenting.

So you mentioned a 215 up front on the 8 would be fine. You think I can get away with a 225? I was thinking of going with Falken Azenie tires.

Not looking to do 10s as I saw you mentioned that. Just the 9.5ET10.5 in the rear is what worries me. Maybe a 245 tire on it would be best since the falkens do run a little wider than usual?

If push comes to shove, I’ll roll the fender lips all around to clear.

I like 8 & 9 215/45 & 245/40 x17 a lot, the front 8ET25/4 wheel is fine that's what I have w/ 225/45 x17 tires on a really low car. Your issue is the rear wheel o/s, and I would double and triple check that as it's a really odd ET for a 9, usually 8 will be ET10.6 and 9s ET15) 9ET 10.6 moves the whole wheel and tire assembly outboard ie closer to the lips. I like to see less than 114mm of tire front space w/ Falken 615s your rear has ~111mm f/s which is fine, w/ 255/40 it's ~120mm which is not good

if the 9s were ET15 then you could run 255/40 rear

You want to match f/r
8 & 9 is goo 215/45 & 245/40 is good
225/45 & 255/40 would be good if they fit

You only need to worry about trailing arm hardware & oil lines is w/ a 275/40 on a 9.5 ET 19 where there is ~159mm of tire b/s and ~121mm of tire f/s

[s2k9k]

Originally Posted by Bill Verburg

I like 8 & 9 215/45 & 245/40 x17 a lot, the front 8ET25/4 wheel is fine that's what I have w/ 225/45 x17 tires on a really low car. Your issue is the rear wheel o/s, and I would double and triple check that as it's a really odd ET for a 9, usually 8 will be ET10.6 and 9s ET15) 9ET 10.6 moves the whole wheel and tire assembly outboard ie closer to the lips. I like to see less than 114mm of tire front space w/ Falken 615s your rear has ~111mm f/s which is fine, w/ 255/40 it's ~120mm which is not good

if the 9s were ET15 then you could run 255/40 rear

You want to match f/r
8 & 9 is goo 215/45 & 245/40 is good
225/45 & 255/40 would be good if they fit

You only need to worry about trailing arm hardware & oil lines is w/ a 275/40 on a 9.5 ET 19 where there is ~159mm of tire b/s and ~121mm of tire f/s

What’s the best method to double check the offset on a rim if it’s not stamped on it?

[Bill Verburg]

Originally Posted by s2k9k

What’s the best method to double check the offset on a rim if it’s not stamped on it?

Easiest way to measure is shown here
2x rubber bands
2x stiff laths that cross the wheel but don't touch the tire


measure perpendicular from the back lath to the wheel mounting surface this is backspace(b/s)

measure the distance from lath to lath, or if there is no tire measure across the wheel outer edge to outer edge, this is edge to edge(EE)

all units in mm, be very careful of parallax error

ET = EE/2 - b/s

+ means wheel is more in than out
- means the wheel is more out than in

you could do similar for front but the back is easiest

SC/Carrera wants an ET10.6, a 9ET15 or a 9.5ET19
the wider the wheel and tire the wiggle room for ET

[s2k9k]

Originally Posted by Bill Verburg

Easiest way to measure is shown here
2x rubber bands
2x stiff laths that cross the wheel but don't touch the tire


measure perpendicular from the back lath to the wheel mounting surface this is backspace(b/s)

measure the distance from lath to lath, or if there is no tire measure across the wheel outer edge to outer edge, this is edge to edge(EE)

all units in mm, be very careful of parallax error

ET = EE/2 - b/s

+ means wheel is more in than out
- means the wheel is more out than in

you could do similar for front but the back is easiest

SC/Carrera wants an ET10.6, a 9ET15 or a 9.5ET19
the wider the wheel and tire the wiggle room for ET

Not sure if I’m doing this right. I’m getting a ET -20 after doing my math for the rear wheel.

[Bill Verburg]

Originally Posted by s2k9k

Not sure if I’m doing this right. I’m getting a ET -20 after doing my math for the rear wheel.

That looks like a BBS wheel, they use a different lip design from Fuchs or other wheels

but the formula still holds

Like I said it's easy for parallax error to creep in
It's hard to tell from here but it looks to me like a
BBS wheel
Bead width 9.5"
Overall width 10.4"(264mm) ie EE width
backspace 118mm
ET14.5+/- due to any errors in measurement

if so the ET for that wheel is a little low for a 255/40 tire as it is pushed a bit further out than ideal you could probably get away w/ a 255/40 but it's going to be tight at the lips

again whatever you decide

215/45 & 245/40 is an easier fit and will generally be a better performer w/ a stockish 3.0 or 3.2 engine

or

225/45 & 255/40, harder to fit and will rob some zip due to taller and heavier tires

[s2k9k]

Installed the tires today. Will be getting an alignment, euro lowering and 4 corner balance next week sometime.

No rubbing on oil lines, suspension bolts or fender lips. Once I add a bit more camber it’ll be even better. Very excited. Ended with 225/45 and 255/40
Fallen rt615k tires.

[Bill Verburg]

Originally Posted by s2k9k

Installed the tires today. Will be getting an alignment, euro lowering and 4 corner balance next week sometime.

No rubbing on oil lines, suspension bolts or fender lips. Once I add a bit more camber it’ll be even better. Very excited. Ended with 225/45 and 255/40
Fallen rt615k tires.

Looks good at that ride height, going much lower will probably cause issues in back

so it appears that you have 8ET25.4 and 9.5 ET15

here's mine an inch or more lower
8ET25.4 225/40 & 9.5ET19 255/40 x17

[s2k9k]

Originally Posted by Bill Verburg

Looks good at that ride height, going much lower will probably cause issues in back

so it appears that you have 8ET25.4 and 9.5 ET15

here's mine an inch or more lower
8ET25.4 225/40 & 9.5ET19 255/40 x17

Do you know how much camber your running to be able to go to your ride hight? Looks so much better at that hight. Rolled fenders on yours? My fenders are not rolled yet and idk if I will or not too.

[Bill Verburg]

Originally Posted by s2k9k

Do you know how much camber your running to be able to go to your ride hight? Looks so much better at that hight. Rolled fenders on yours? My fenders are not rolled yet and idk if I will or not too.

fronts are shaved not rolled, ET27 would more the wheels inboard for a better fit
camber is -1

rear has a minimal shave from when I ran 275s. the ET19 move the wheel in ~5mm more than yours
camber is -2

I don't believe that you will be able to lower yours that much due to the rear width and ET

[mark4ton]

you'll definitely need to roll your fenders, if you want to enjoy the drives. thats a pretty aggressive fitment. nice looking wheels

[s2k9k]

Originally Posted by mark4ton

you'll definitely need to roll your fenders, if you want to enjoy the drives. thats a pretty aggressive fitment. nice looking wheels

Been driving spirited with it and no rubbing so far at all. Might still roll them to be safe but honestly no issues what so ever as of now.

If I do lower the car a little more I might rub but some negative camber would take care of that. Really happy with fitment.

[Mr. Merk]

We've installed a similar BBS setup on a Carrera recently

17x8” et36 (1” / 6.5”) up front (rs012) and 17x9.5” et17 (2.5” /6.5”) in the rear (rs013). We added a 7mm spacer up front to get us to et29

If I had to do it again I might eliminate the spacer and try to squeeze an et23 to get another .5" exterior lip. The ET29 is a really happy fit with WEVO camber plates.

Car is lowered on KW V3 spindles to 25F/24.5 rear and looks great. Crossing fingers for no clearance issues once we have the alignment dialed in.

[Bill Verburg]

Originally Posted by Mr. Merk

We've installed a similar BBS setup on a Carrera recently

17x8” et36 (1” / 6.5”) up front (rs012) and 17x9.5” et17 (2.5” /6.5”) in the rear (rs013). We added a 7mm spacer up front to get us to et29

If I had to do it again I might eliminate the spacer and try to squeeze an et23 to get another .5" exterior lip. The ET29 is a really happy fit with WEVO camber plates.

Car is lowered on KW V3 spindles to 25F/24.5 rear and looks great. Crossing fingers for no clearance issues once we have the alignment dialed in.

JMO but 8ET27 fits better, if the ET is lower you lose room at the lip and gain at the shock, if you go higher you gain room at the lip but lose it at the shock.

biggest front I've ever seen on an SC/Carrera is Driven97s 9ET33.3 w/ a 245/40 tire

not sure it's worth the effort to go wider than 225/on an 8,

[Steve W]

Originally Posted by Mr. Merk

We've installed a similar BBS setup on a Carrera recently

17x8” et36 (1” / 6.5”) up front (rs012) and 17x9.5” et17 (2.5” /6.5”) in the rear (rs013). We added a 7mm spacer up front to get us to et29

If I had to do it again I might eliminate the spacer and try to squeeze an et23 to get another .5" exterior lip. The ET29 is a really happy fit with WEVO camber plates.

Car is lowered on KW V3 spindles to 25F/24.5 rear and looks great. Crossing fingers for no clearance issues once we have the alignment dialed in.

I have a setup almost the same as what you describe above, and two sets of wheels with the same widths/diameter. I would not bother going any larger.

In the front the challenges you will run into are the AC hoses if any above the left front wheel need to be relocated higher. Also with wide tires and bringing the strut that close inboard with the camber plates, the seam around the strut tower well will cut into and interfere with the tire on compression. Guys usually hammer that in. On the fender, you'll need to roll the fender, and if the tire is wide, you may need to try to massage a few mm the fender out with a roller. You want to make sure you have the wheel inboard enough on ET or the tire can also rub not necessary at the fender lip where you rolled it, but inside the fender above it in high compression. At lock to lock on the steering wheel, the tire will rub against the fender well both on the front and back turn to turn, and above in the well with spirited driving on compression while turning such as in mountain twisties. You'll need to install rack stops on the steering rack to limit rack extension. You can find those on Amazon, or some of the aftermarket Porsche suspension suppliers. Onc set of my wheels I run 225s, and another 245s. Camber is at -3.5 to get the room.

At the rear, not so much a problem, esp if you put in a lot of camber (I run -3.5 w 255s on one set, 275s on another) but if you go too low, with wide tires, under high compression, such as in cornering, the tire will rub, not so much a fender lip problem, but the fender hip above it on the upper rearside. Even if you have big torsion bars (30+) and bigger sway bars, and your shocks on its stiffest settings. With the tire rub, under hard cornering, the outside tire will act like it's undergoing some braking, which can make for some unwanted handling behavior (and smells). So do that enough and the paint above it will burn such seen on some track car 911s. You should test and measure your suspension under full compression (easier with torsion and sway bars bars loose) and set your shock bump stops accordingly, and after take a look at how much travel you have left before hitting them. 25f and 24.5r is very low.