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I've never triedto buy non-stock wheels before, so I apologize if I'm making this seem too complicated. Trying to understand as I go.
Originally Posted by alexasa
If you know 19x8.5 et32 barely fits then you know everything you need to know about backspacing.
True! That's a moment of clarity for me. Everything can be calculated from that. Do we know what barely fits in the rear?
Originally Posted by alexasa
You're never going to rub fender on stock suspension regardless of poke because there simply isn't enough travel.
I did not know that. I know I've read that modifying the the suspension and camber changes what wheel sizes/measurements can be used. Didn't know stock suspension 100% prevented fender lip rub.
You don't hear people talking about the rear because there is more than enough room for this AWD car.
I'm not sure what exactly is the ultimate inner clearance but it's something around 10.5et57 (probably more like 10.5et60). C63 guys run 10.5et50-57 on 305's - again there is not really an issue as people are typically speccing a more aggressive wheel the stock and less aggressive than a 10.5 due to AWD. (C63 sedan rear fender clearance is identical to our cars)
Regarding front fender rub, @toosteeley once said in this thread, "as per many posts in this thread and the experience of many members, an 8.5" wide rim in the front needs to be +30 offset. Anything more and you risk touching the inner control arm. Anything less and you will rub the inner fender." So maybe front fender rub is an issue?
My math says that for the 8.5" wheel with 30 ET, you get 140mm of backspacing. Likewise, I'll call the complementary measurement from hub mounting surface to front, or face, of wheel frontspacing, which leads to conversations on fender lip rub and 'poke'. The above ideal wheel would have 76mm frontspacing. The stock 7.5" wheel 33ET has 62.25mm frontspacing.
For the 9" wheel I'm considering, with a 37 ET modified down to 25 ET using 12mm spacer, I would get 139.3 mm backspacing (good!) and 89.3mm frontspacing (scary). That's a full inch of poke vs stock, and a half inch vs the 8.5" wheel.
Does my math seem right?
Is there a fender rub issue with stock suspension?
Am I missing any other points to consider?
Thanks.
Last edited by GermanCarShow; Jun 10, 2022 at 12:09 PM.
Regarding front fender rub, @toosteeley once said in this thread, "as per many posts in this thread and the experience of many members, an 8.5" wide rim in the front needs to be +30 offset. Anything more and you risk touching the inner control arm. Anything less and you will rub the inner fender." So maybe front fender rub is an issue?
My math says that for the 8.5" wheel with 30 ET, you get 140mm of backspacing. Likewise, I'll call the complementary measurement from hub mounting surface to front, or face, of wheel frontspacing, which leads to conversations on fender lip rub and 'poke'. The above ideal wheel would have 76mm frontspacing. The stock 7.5" wheel 33ET has 62.25mm frontspacing.
For the 9" wheel I'm considering, with a 37 ET modified down to 25 ET using 12mm spacer, I would get 139.3 mm backspacing (good!) and 89.3mm frontspacing (scary). That's a full inch of poke vs stock, and a half inch vs the 8.5" wheel.
Does my math seem right?
Is there a fender rub issue with stock suspension?
Am I missing any other points to consider?
Thanks.
You're on the right track.
the 9 inch wheel with corrected offset to fit using a spacer will poke past the fenders by a considerable amount.
There's a set of Brabus wheels available near me, which I assume are going to be (heavy) cast wheels, but they're already wearing Pilot Sport 4S tires and are at a great price.
8.5Jx19H2 ET50 (would need 20mm spacers for C43)
235/40r19 (26.4" diameter)
10.0Jx19H2 ET45
295/30r19 (26.0" diameter)
Question 1: Are 20 mm spacers safe for race track and autocross?
Question 2: That 10" wide wheel with measly 45mm offset is going to poke out a full 1 inch past stock wheels. I assume that means fender rub under cornering forces (body lean)?
There's a set of Brabus wheels available near me, which I assume are going to be (heavy) cast wheels, but they're already wearing Pilot Sport 4S tires and are at a great price.
8.5Jx19H2 ET50 (would need 20mm spacers for C43)
235/40r19 (26.4" diameter)
10.0Jx19H2 ET45
295/30r19 (26.0" diameter)
Question 1: Are 20 mm spacers safe for race track and autocross?
Question 2: That 10" wide wheel with measly 45mm offset is going to poke out a full 1 inch past stock wheels. I assume that means fender rub under cornering forces (body lean)?
those wont work. specifically the rear will stick out very far.
read the thread. proper specs have been listed many times.
read the thread. proper specs have been listed many times.
That's what I figured. Not a lot in the thread about rear wheel fitment with 10" wide wheels. I did a search for "x10" and only found two posts: one person saying they were doing that, with ET38, and one reply about that being "too aggressive".
That's what I figured. Not a lot in the thread about rear wheel fitment with 10" wide wheels. I did a search for "x10" and only found two posts: one person saying they were doing that, with ET38, and one reply about that being "too aggressive".
That's over $2,000, way over my budget.
if your budget is $2000 for wheels and tires its probably not enough. especially with todays prices. if its just wheels for 2k you are probably gunna end up with some crappy cast wheels. you really need to expand the budget if you want new wheels. You may be able to find used for 2k but i dont think new.
for your reference because you dont want to search the thread for posts by me. you are searching for the wrong thing. but most who have ran 10 or I think 10.5j wheels are running et55. maybe et57.
recommended for front is 19x8.5j et 28-32 depending on if you are lowered or not. higher et is better if not lowered. for rear 19x9.5j is best for balance to front. run et 45-55. closer to 45 is better to match front. I run et49 and am happy. tires can be 235-245-255 for front and 265-275-285 for rear. get the proper aspects for 19s.
if your budget is $2000 for wheels and tires its probably not enough.
Yes, I'm trying to do this on the cheap. I see very few C450/C43 stock wheels available. If these Brabus wheels with good Pilot Sport 4s tires had only been 9.5 in the rear instead of 10.0 - so close! Seller marked down to $500!!! Can't buy two new tires for that, let alone 4 wheels + 4 tires.
EDIT: I guess FB Marketplace links don't work here??
Last edited by GermanCarShow; Jun 13, 2022 at 03:48 PM.
you can machine the rear of the hub in some situations to reduce the aggressiveness - but that is all too much tire in the rear and I could never safely say this without seeing the wheels in person.
20mm are fine if you get the proper extended lugs or even DRA style spacers with the proper conical, etc. and torque to spec.
IDK. If you are on a tight budget keep perusing the used market but don't confine yourself too tightly - there is a ton of modification you can do if you're willing to spend the time.
Question 2: That 10" wide wheel with measly 45mm offset is going to poke out a full 1 inch past stock wheels.
The issue with using these rims in the rear isn’t the rim itself (it’s fine) it’s the 295 tires. The rims would need to be in the +50et range to fit those tires into the fender, or you’d need to switch to 275 tires.
you can machine the rear of the hub in some situations to reduce the aggressiveness - but that is all too much tire in the rear and I could never safely say this without seeing the wheels in person.
20mm are fine if you get the proper extended lugs or even DRA style spacers with the proper conical, etc. and torque to spec.
IDK. If you are on a tight budget keep perusing the used market but don't confine yourself too tightly - there is a ton of modification you can do if you're willing to spend the time.
- I don't think I'd bother with modifying wheels.
- For my most expensive option, all-new equipment, I asked our sponsor about these: https://stancewheels.com/sf03/ They can supply a set of these for between the prices of the TSW & Enkei. I specified qty 4 of 8.5x19 ET47 so I could rotate front-rear and use 15mm spacers on the front, and also so I could hopefully reduce understeer.
Originally Posted by toosteeley
There’s a lot of flexibility on the rear. With a 10” wide rear rim, anything between +55 and +40et will work with a 265 or 275 tire.
Pics for reference. 20x10 rim with 275/30/20 PS4S tires, lowered on H&R estate springs. 0 issues with any of these setups.
+50et (tons of room)
+45et (perfect IMO)
+40et (aggressive, but no issues)
Thanks for the details on 10" wheels in the rear. I won't be modifying my $uspension any time soon.
Originally Posted by toosteeley
The issue with using these rims in the rear isn’t the rim itself (it’s fine) it’s the 295 tires. The rims would need to be in the +50et range to fit those tires into the fender, or you’d need to switch to 275 tires.
- If I get these inexpensive cast Brabus wheels with Pilot Sport 4s already mounted, I could afford to replace the rears with new PS4s tires in proper size.
- I would eventually want to put on Comp tires.
Thanks to everyone for help, feedback, information. This is a great forum!!
one thing also to note, is some members like a very aggressive fitment while others such as Alexasa and myself will like a little more conservative fitment. From the beginning we did not want any poke. IMO that 10j wide rear with 275 et45 is sticking out. just because the top shoulder of the tire is sticking in doesnt make it a proper fitment. Its a look. Some like it as Toosteeley does. nothing wrong with it. Some don't, like myself. I want the face of the wheel to be flush with the fender at most. not exceeding it.
IMO that 10j wide rear with 275 et45 is sticking out. just because the top shoulder of the tire is sticking in doesnt make it a proper fitment. Its a look
I totally agree that looks are subjective. For the record, my setup with +40et is pretty much flush with the rear fenders. Wasn’t by choose, however. My preference would have been a +45et offset, but these rims had limited fitment. +50et just had far too much room to the fender compared to the front so it looked unbalanced. Just IMO of course.
Last edited by toosteeley; Jun 15, 2022 at 08:22 AM.
Also depends on the car. On my wagon, I feel a more aggressive setup in the rear compliments the look of the larger rear propositions. May not suit a sedan or coupe as much.
rear is really funky, from certain angles it will look flush and others poking. German is also not lowering which changes the usable offset by as much as 15-20mm.
So, I'm talking with one of our wheel sponsors about one of their brands of wheels. If I'm going to spend the cash on new wheels (remember, I'm a cheap skate), then I think I'd want to get a square 8.5" wide setup for all four corners for two reasons:
- Common knowledge that these cars push, or understeer, in corners. I'm thinking that leaving the rears at stock 8.5 width and expanding the front to 8.5 width will help remove some push. No, it will never be an Elise, Miata, or S2000, but if it helps, it helps.
- Track tires on the front will definitely wear on the outer edge first (stock suspension = not enough neg camber). It's known that street tires wear on the inner edge, so I'm thinking that on the track, rear track tires may wear pretty evenly on stock suspension. Being able to rotate tires (wheels) front-to-back myself will be easy and could extend tire life for more track sessions.
Of course, the wheels would have to be sized to fit directly on the rear, and then I'd be using spacers and longer lug bolts up front to make a proper fitment there.
Comments??
Last edited by GermanCarShow; Jun 15, 2022 at 01:14 PM.
So, I'm talking with one of our wheel sponsors about one of their brands of wheels. If I'm going to spend the cash on new wheels (remember, I'm a cheap skate), then I think I'd want to get a square 8.5" wide setup for all four corners for two reasons:
- Common knowledge that these cars push, or understeer, in corners. I'm thinking that leaving the rears at stock 8.5 width and expanding the front to 8.5 width will help remove some push. No, it will never be an Elise, Miata, or S2000, but if it helps, it helps.
- Track tires on the front will definitely wear on the outer edge first (stock suspension = not enough neg camber). It's known that street tires wear on the inner edge, so I'm thinking that on the track, rear track tires may wear pretty evenly on stock suspension. Being able to rotate tires (wheels) front-to-back myself will be easy and could extend tire life for more track sessions.
Of course, the wheels would have to be sized to fit directly on the rear, and then I'd be using spacers and longer lug bolts up front to make a proper fitment there.
Comments??
19x8.5et32 fits front and rear great. 19x8.5et30 is safer to clear front inner suspension but will be slightly pokey on stock suspension (front). (each brand has slight variances within 1mm and can rub at 19x8.5et32 depending on brand, etc.)
these cars have decent front camber from factory.
otherwise, totally agree.
There's at least a couple guys running winter setups in this type of fitment if you go digging.
That surprises me about the rear, with it being so much less offset from stock. It should poke 17mm or more. I guess you're saying there's room for that under the rear fender of a sedan with stock suspension?
^ some quick math says a 8.5" rim is ~38mm less than a 10" rim = 19mm less offset needed to fit the rear. If +50 to +45 is the ideal offset for the rear on a 10" rim, that would mean +31 to +26 offset on a 8.5" rim would have the same visual "fit". Therefore, alexasa's comment re 19x8.5 et32 for the rear makes perfect sense.
Just pulled the trigger on Fittipaldi FSF03 forged 19X8.5 35mm and 19X10 45mm. 2021 C43 coupe. I got a killer deal on them but they are blue, well not for long…. Going to my man James Terry for a refinish @MrSpeedCoatings. Tires will be Michelin PS4 235/40ZR19 front and 275/35ZR19 rear. Thinking I will unfortunately need 5mm spacer on front but ESC says not compatible. anyone have a link for proper 5mm spacer? Planning H&R springs. Fitment should be spot on with 5mm front?
Never did post the results. 5mm front was perfect IMHO, decided to skip the springs. Real happy with the fitment and stance. The ride and handling with the Michelins is an amazing transformation. The weight savings helped too!
Last edited by dowheelies; Jun 16, 2022 at 10:04 AM.
Reason: Deleted pic
^ some quick math says a 8.5" rim is ~38mm less than a 10" rim = 19mm less offset needed to fit the rear. If +50 to +45 is the ideal offset for the rear on a 10" rim, that would mean +31 to +26 offset on a 8.5" rim would have the same visual "fit". Therefore, alexasa's comment re 19x8.5 et32 for the rear makes perfect sense.
That makes sense. I was comparing against ET of stock 18x8.5 and 19x8.5 and was thinking that the 19mm would be too much poke. Our math is similar, I just didn't think about the 10" wheels fitting, I assumed 8.5 sticking out 19mm would be too much. Thanks for the perspective.
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