17x8.5 et15 w/ 235's, fitment issue in front?

[Azure]

Size: 17.0 x 8.5
Bolt Circle: 5:120
Offset: 15
CB: pfs

These are the specs on my potential rim selection. It's either these, or the same rim style, in 17x8's with et40 and 18mm spacers - the latter (the 17x8's) list the correct hubcentric diameter for the E28 (72.5).

I know the 8.5" width is within spec for an E28 all around, as that's only 213mm of rim, my question is, will that extra 7mm offset outward cause a fitment issue with 235s and lowering springs?

Secondly, what the hell is a "pfs" centerbore? These rims are listed as fitting an E34 so I would think they'd bolt onto the E28.. no?

I checked Shawn D's tire wheel and tire database, and didn't see a comparable setup to refer to, likewise, I don't have Excel on my Mac, so I can't use the fitment calculator contained within I've heard about.

Thanks!

[T_C_D]

[QUOTE="Azure"]Size: 17.0 x 8.5
Bolt Circle: 5:120
Offset: 15
CB: pfs

These are the specs on my potential rim selection. It's either these, or the same rim style, in 17x8's with et40 and 18mm spacers - the latter (the 17x8's) list the correct hubcentric diameter for the E28 (72.5).

I know the 8.5" width is within spec for an E28 all around, as that's only 213mm of rim, my question is, will that extra 7mm offset outward cause a fitment issue with 235s and lowering springs?

Secondly, what the hell is a "pfs" centerbore? These rims are listed as fitting an E34 so I would think they'd bolt onto the E28.. no?

I checked Shawn D's tire wheel and tire database, and didn't see a comparable setup to refer to, likewise, I don't have Excel on my Mac, so I can't use the fitment calculator contained within I've heard about.

Thanks![/QUOTE]

They are going to rub the strut tube.
Todd

[FastFiver]

I'm running 235/45 R17 in front, but with 8in wide front tires and wheels with 20mm offset. No rubbing to speak of.


[Edit by FastFiver on [TIME]1113254302[/TIME]]

[Azure]

[QUOTE="TCD"]They are going to rub the strut tube.
Todd[/QUOTE]

I thought a lower offset bought the rim closer to the fender lip.. so if an ET22 is ideal, an ET15 would be farther away from the strut? What am I missing - is there something else besides offset coming into play?

[Rich in Tupelo]

The 235's will rub even with a 20 offset if the car is lowered. You will need to roll the fenders. Best size for 17's on the front in normally a 225/45/17 on a 17*8 rim with et20. At least from what I have seen.

Rich

[T_C_D]

[QUOTE="TCD"]They are going to rub the strut tube.
Todd[/QUOTE]

[QUOTE="Azure"]I thought a lower offset bought the rim closer to the fender lip.. so if an ET22 is ideal, an ET15 would be farther away from the strut? What am I missing - is there something else besides offset coming into play?[/QUOTE]

The wheel is 8.5" wide. The ideal offset changes with the width of the wheel. A 8" wide wheel with offset 20 has a total of 121.6mm of wheel towards the strut tower from the hub. A 8.5 et15 wheel has 122.95. Add a 235 tire to that and you'll likely be rubbing the strut tube. It really depends on the tire itself.

Todd

[Edit by TCD on [TIME]1113259884[/TIME]]


[Edit by TCD on [TIME]1113259913[/TIME]]

[Azure]

[QUOTE="TCD"]They are going to rub the strut tube.
Todd[/QUOTE]

[QUOTE="Azure"]I thought a lower offset bought the rim closer to the fender lip.. so if an ET22 is ideal, an ET15 would be farther away from the strut? What am I missing - is there something else besides offset coming into play?[/QUOTE]

[QUOTE="TCD"]The wheel is 8.5" wide. The ideal offset changes with the width of the wheel. My 16x8.5 et20 with 225 tires rubbed.
Todd[/QUOTE]

Ok, thanks Todd. My thought was that the rim, being .5" wider (about 12mm) meant it would run about 6mm closer to the strut than an 8" wide rim, which in turn, would be compensated for by the offset (+15), bringing it 5mm away from the strut tower again.. effectively making the hub-to-back side rim measurement the same as an 8" +20 rim (give or take a mm) ie, it would sit as close to the strut as an 8" +20 rim, because the offset (+15 vs +20) compensated for the extra intrusion on the strut side.

It probably seems weird I'm asking this in the first place, but the ET15 rim in 8.5" is cheaper than the ET40 8" rim once you add the 18mm spacers for each corner.

Edit: Just read your edit, we're on the same page. Thanks.

[Edit by Azure on [TIME]1113260378[/TIME]]

[Edit by Azure on [TIME]1113260565[/TIME]]

[Shawn D.]

[QUOTE="Azure"]My thought was that the rim, being .5" wider (about 12mm) meant it would run about 6mm closer to the strut than an 8" wide rim, which in turn, would be compensated for by the offset (+15), bringing it 5mm away from the strut tower again.. effectively making the hub-to-back side rim measurement the same as an 8" +20 rim (give or take a mm) ie, it would sit as close to the strut as an 8" +20 rim, because the offset (+15 vs +20) compensated for the extra intrusion on the strut side.[/QUOTE]

Azure, your thoughts are correct. Using my calculator, I find:

An 8.0" wide wheel with 20mm offset has 5.3" backspacing and 3.7" frontspacing.

An 8.5" wide wheel with 15mm offset has 5.3" backspacing and 4.2" frontspacing

Thus, they have the same clearance to the strut. However, an 8.5" et15 wheel is a poor choice, IMO. They'll stick out 1/2" futher and and look goofy on the front, and you'll have massive interference in the rear that can't be rolled/trimmed out. I wouldn't get these wheels.

[Jon in Richmond]

Glen,

I know that Mike, The Green Hornet, runs BBS 17x 8.5 RK's. I believe that they are et15 and he has no rubbing issues. You might want to check with him on this.

Jon

[Shawn D.]

[QUOTE="Jon in Richmond"]I know that Mike, The Green Hornet, runs BBS 17x 8.5 RK's. I believe that they are et15 and he has no rubbing issues. You might want to check with him on this.[/QUOTE]

Yes, the BBS RKs in 17x8.5 do have a 15mm offset (there are also 17x8 et35 and et40 RKs). I'll be a monkey's uncle if he's running these with 235s and has no fitment problems.

[BDK]

Uuuuh, I put the wifes BBS RX's on my E28 they were 17x8.5 et 15 with 235's and no rubbing except when turned to full lock....

they didn't rub in the rear either, can't esplain it but I did.....

How does 17x9et8 show up on the chart...

[Azure]

Thus, they have the same clearance to the strut. However, an 8.5" et15 wheel is a poor choice, IMO. They'll stick out 1/2" futher and and look goofy on the front, and you'll have massive interference in the rear that can't be rolled/trimmed out. I wouldn't get these wheels.

I'm not sure how they could cause such massive interference on the rear when you can squeeze a 255 on a 9" rim back there... however you're the wheel and tire guru, not me!

Edit: As far as the goofiness goes, I actually think they'd look pretty cool, as there's likely to be a deeper "dish" on the 8.5 ET15 than the 8" ET40 with spacers.. and there's still only 213mm of rim width anyway.. the tires are still going to be wider, whether I go with a 225 or 235 width.

I know that Mike, The Green Hornet, runs BBS 17x 8.5 RK's. I believe that they are et15 and he has no rubbing issues. You might want to check with him on this.

All I could dig up for his email was a hotmail address from 2yrs ago on the old board.. hope it's still current, thanks for the info Jon!

[Edit by Azure on [TIME]1113274593[/TIME]]

[Shawn D.]

Uuuuh, I put the wifes BBS RX's on my E28 they were 17x8.5 et 15 with 235's and no rubbing except when turned to full lock....

they didn't rub in the rear either, can't esplain it but I did.....

How does 17x9et8 show up on the chart...

Umm... how much have your rear fenders been rolled/trimmed? Are you sure you mean "et8"?

Thus, they have the same clearance to the strut. However, an 8.5" et15 wheel is a poor choice, IMO. They'll stick out 1/2" futher and and look goofy on the front, and you'll have massive interference in the rear that can't be rolled/trimmed out. I wouldn't get these wheels.

I'm not sure how they could cause such massive interference on the rear when you can squeeze a 255 on a 9" rim back there... however you're the wheel and tire guru, not me!

Edit: As far as the goofiness goes, I actually think they'd look pretty cool, as there's likely to be a deeper "dish" on the 8.5 ET15 than the 8" ET40 with spacers.. and there's still only 213mm of rim width anyway.. the tires are still going to be wider, whether I go with a 225 or 235 width.

You are leaving out a KEY FACTOR when you say "you can squeeze a 255 on a 9" rim back there" -- can you guess what that is? Offset! Those wheels listed are 26mm offset or greater, so they're about 1/2" further inboard than your proposed wheels.

By "goofy" I meant ghetto -- I don't like the look when wheels and tires stick out of the wheel well. Sure, a deeper dish would look great.

[Azure]

You are leaving out a KEY FACTOR when you say "you can squeeze a 255 on a 9" rim back there" -- can you guess what that is? Offset! Those wheels listed are 26mm offset or greater, so they're about 1/2" further inboard than your proposed wheels.

By "goofy" I meant ghetto -- I don't like the look when wheels and tires stick out of the wheel well. Sure, a deeper dish would look great.

I understand about the offset.. if you can fit a 255 back there on an ET26 rim (a la throwing stars), then doesn't the math hold relatively true that I should be able to fit a 235 back there on an ET15? That is, the rim sticks out 10mm further, but the tire, being 20mm shallower, will be back inside the fender by around 10mm on the outside... thus negating the offset.. putting me pretty close to the same fender position as the ET26 9" 255.. give or take a mm or two.

I hear what you're saying with the ghetto remark.. I don't think it'll look too bad though.

Now tell me to quit trying to fit a square peg in a round hole, and buy the damn 8" ET40's with 18mm spacers already.

[The Green Hornet]

Yes my RK's are 8.5 and et 15..I also run 235/40/17 with no rubbing issues to report...They work just fine for me..Yes my rear fenders are rolled..Hope this helps..Mike...

[Shawn D.]

Well, with the replies from BNC and The Green Hornet, I'd say that's enough info to say they'll work OK.

[BDK]

Umm... how much have your rear fenders been rolled/trimmed? Are you sure you mean "et8"?

They are 17x9 Et8 Remotecs, yes I love the Remotecs, they're forged and weigh in at 21.5#'s

Just wondering as I had already removed the rear subframe and the wheels don't have tires on them but here is what I think they may look like....





Here is the set on an E34


So what do you think Unca ShawnD??

[Edit by BNC on [TIME]1113307840[/TIME]]


[Edit by BNC on [TIME]1113308108[/TIME]]

[BDK]

Btw, Those would look awesome on TCD's 745i!!!!

[Shawn D.]

Umm... how much have your rear fenders been rolled/trimmed? Are you sure you mean "et8"?

They are 17x9 Et8 Remotecs, yes I love the Remotecs and they come in at 21.5#'s

So what do you think Unca ShawnD??

Do you remember when TCD got wheels that had the same specs as as your Remotecs supposedly have? They didn't fit. I think et8 is incorrect -- they're probably et18. Would you do some measurements for me?

I like the look of your Remotecs, but I don't care for the look where the wheel is wider than the tire. I also think the front wheel/tire on that E34 sticks too far out.

Yes my RK's are 8.5 and et 15..I also run 235/40/17 with no rubbing issues to report...They work just fine for me..Yes my rear fenders are rolled..Hope this helps..Mike...

Mike, what brand/model tires are you running?

[BDK]

Sure, I'll do some measurements for you...what do you want?? front spacing and rear spacing...give me a day or two...

Thanks again for your Wheel Wisdom....

I think these are tooo big for the E28 but would look awesome on an E34,E23 and still I would like to see them on Todds 745i

[Shawn D.]

Sure, I'll do some measurements for you...what do you want?? front spacing and rear spacing...give me a day or two...

Front spacing can easily be calculated, but isn't easy to measure. I'd like you to measure backspacing by laying a straightedge (it could be a piece of angle iron, wood, or square tubing, so long as it's perfectly straight and has a square edge that you can measure accuately from) across the rear face of the wheel, then measuring perpendicularly between that straightedge and the mounting face (where the wheel contacts the hub). Also, if the tire is off, measure the width from outside-to-outside and inside-to-inside (at the bead area, which is where wheel size is calculated). Thanks!

Thanks again for your Wheel Wisdom...

You're welcome!

[BDK]

No problem!!

[Azure]

So what do you think Unca ShawnD??

Check out that dishiness! I think those rims are the hotness!

..although I do agree with Shawn D, the tire should be wider than the rim.. it just looks "more correct".

As for the rims I'm lookin at, I guess I'll go ahead with the 17x8.5 et15s and not bother with spacers.. I like the sound of that much better. Woot! Gimme some dish!

Thanks for all the help guys!

[Edit by Azure on [TIME]1113337106[/TIME]]