Arc8 in 18x10ET25 and 18x9ET42 tyre sizings?

Willy Sea · 03-10-2022, 08:07 AM

Planning on fitting the above rims to a coupe with standard suspension.

Tyre sizing 234 45 18 for the front, given a big caliper may be on the cards later and the ET of 42, will spacer with bolts either 15 or 17mm, while at the rear ET25 will run 265 40 18's (No spacer)

Any comment and or advice from the readers here? having run these wheels on our 3.0si coupe with 225 40 18 tyres and 255 35 18's and no rub this combo should work OK on the Z4M. On the 3 litre coupe the tyres were probably on maximum sized rims, (stretch I think is the term here) hence the size upgrade on the vehicle switch
Thanks for reading.

Willy Sea · 03-10-2022, 08:11 AM

Footnote to the above. Jeepers guys sorry about the size of pix.
This week we have added to the car pictured Konisportpaket adjustable shocks. H&R ARB's and a set of drilled and slotted discs.

MBan · 03-17-2022, 11:51 PM

Very nice!

How do you find the Koni shocks?

86Zed · 03-18-2022, 09:21 AM

I run the following setup, similar to what Apex recommends. Great support by the way, definitely suggest you send them an email as well.
https://support.apexraceparts.com/hc...-Fitment-Guide

Front - 18X9 E30 245/35/R18 w/ 5mm spacer (2-3 deg of negative camber)
Rear - 18x10 E25 275/35/R18

Slight rubbing on the front under full compression hard cornering (track), no street issues

Willy Sea · 03-19-2022, 12:41 AM

Quote:

Originally Posted by MBan

Very nice!

How do you find the Koni shocks?

Transformed the car. Along with the H&R arb's. Set to soft, as out of the box, and the arbs too. Time to tinker. The drilled and slotted discs are (more) help as well, in the anchors away department.

grannyknot · 03-19-2022, 08:34 AM

My M coupe currently has 245/35-19 ET31 on the front and 275/35-19 ET25 on the rear with no rubbing, lowered with H&R coilovers.
So I would think that setup your planning would be fine.
Here are two calculators that will allow you to play around with different configurations to see what works.
https://www.blocklayer.com/tire-size-calculator.aspx

https://www.1010tires.com/Tools/Whee...et-Calculator#

grannyknot · 03-24-2022, 07:20 AM

Quote:

Originally Posted by grannyknot

My M coupe currently has 245/35-19 ET31 on the front and 275/35-19 ET25 on the rear with no rubbing, lowered with H&R coilovers.
So I would think that setup your planning would be fine.

I bought this car last Oct. and it has been in storage all winter.
I just removed all the wheels yesterday and there is some rubbing on the plastic wheel well liner on the rear, sorry about that.
I removed the rear spring and added a 5mm urethane shim, it seems to be fine now.

3002 tii · 03-27-2022, 09:26 AM

Those fitments are taller than factory specs, that plus wider wheels you run more risk or rubbing. I would drop down 1 profile in height

03-10-2022, 08:07 AM	#1
Willy Sea Private First Class 55 Rep 165 Posts Drives: BMW M Coupe S54, E36 M3 Evo, Join Date: May 2019 Location: New Zealand iTrader: (1)	Arc8 in 18x10ET25 and 18x9ET42 tyre sizings? Planning on fitting the above rims to a coupe with standard suspension. Tyre sizing 234 45 18 for the front, given a big caliper may be on the cards later and the ET of 42, will spacer with bolts either 15 or 17mm, while at the rear ET25 will run 265 40 18's (No spacer) Any comment and or advice from the readers here? having run these wheels on our 3.0si coupe with 225 40 18 tyres and 255 35 18's and no rub this combo should work OK on the Z4M. On the 3 litre coupe the tyres were probably on maximum sized rims, (stretch I think is the term here) hence the size upgrade on the vehicle switch Thanks for reading. Attached Images
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03-10-2022, 08:11 AM	#2
Willy Sea Private First Class 55 Rep 165 Posts Drives: BMW M Coupe S54, E36 M3 Evo, Join Date: May 2019 Location: New Zealand iTrader: (1)	Footnote to the above. Jeepers guys sorry about the size of pix. This week we have added to the car pictured Konisportpaket adjustable shocks. H&R ARB's and a set of drilled and slotted discs.
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03-17-2022, 11:51 PM	#3
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	Very nice! How do you find the Koni shocks?
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03-18-2022, 09:21 AM	#4
86Zed Get off my lawn 932 Rep 1,158 Posts Drives: 6MT Join Date: Sep 2015 Location: USA iTrader: (7) Garage List 2023 GR Corolla [0.00] 2022 BMW X3 M40i [10.00] 2007 BMW Z4M Coupe [0.00] 2002 BMW 325xiT [0.00] 1991 BMW 318is [0.00]	I run the following setup, similar to what Apex recommends. Great support by the way, definitely suggest you send them an email as well. https://support.apexraceparts.com/hc...-Fitment-Guide Front - 18X9 E30 245/35/R18 w/ 5mm spacer (2-3 deg of negative camber) Rear - 18x10 E25 275/35/R18 Slight rubbing on the front under full compression hard cornering (track), no street issues
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03-19-2022, 08:34 AM	#6
grannyknot Captain 951 Rep 781 Posts Drives: 2008 Z4M coupe Join Date: Oct 2021 Location: toronto iTrader: (0)	My M coupe currently has 245/35-19 ET31 on the front and 275/35-19 ET25 on the rear with no rubbing, lowered with H&R coilovers. So I would think that setup your planning would be fine. Here are two calculators that will allow you to play around with different configurations to see what works. https://www.blocklayer.com/tire-size-calculator.aspx https://www.1010tires.com/Tools/Whee...et-Calculator# Attached Images __________________ 2008 E86 M coupe
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03-27-2022, 09:26 AM	#8
3002 tii Lieutenant General 2282 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.22]	Those fitments are taller than factory specs, that plus wider wheels you run more risk or rubbing. I would drop down 1 profile in height __________________ Follow for latest mods
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