Conti EFC 275 on apex 9.5

jbalabas · 02-26-2024, 11:53 AM

I'm getting ready to get stock up on tires for the season. Do you see any issues runnin a 275 EFC on an apex 9.5 wide rim for track purposes??

SYT_Shadow · 02-26-2024, 01:17 PM

It won't provide optimum support, but it'll work ok

M3SQRD · 02-26-2024, 02:53 PM

Quote:

Originally Posted by SYT_Shadow

It won't provide optimum support, but it'll work ok

Really? I’m used to: 295 on 10.5”, 285 on 10” , and 275 on 9.5”.

So you’d run: 275 on a 10”, 285 on 10.5”, and 295 on 11”?

SYT_Shadow · 02-26-2024, 02:58 PM

Quote:

Originally Posted by M3SQRD

Really? I’m used to: 295 on 10.5”, 285 on 10” , and 275 on 9.5”.

So you’d run: 275 on a 10”, 285 on 10.5”, and 295 on 11”?

I don't think anything bad will happen, but remember the oem uses a 10" wheel on a 265 in the e9x zcp
A 275 on a 10.5 looks awfully happy as well. I suppose 9.5 in 275 is within tire spec, but if I can get some more support, better

M3SQRD · 02-26-2024, 04:28 PM

Quote:

Originally Posted by SYT_Shadow

I don't think anything bad will happen, but remember the oem uses a 10" wheel on a 265 in the e9x zcp
A 275 on a 10.5 looks awfully happy as well. I suppose 9.5 in 275 is within tire spec, but if I can get some more support, better

BMW is all over the place on tire sizes and wheel widths. Our f22 240ix has a 245 tire on an 8” wide wheel + a 225 on a 7” wide wheel, and on our g20 340ix it has a 255 tire on an 8.5” wide wheel + a 225 on an 8” wide wheel. The base f8x uses a 255 on a 9” wide wheel + a 275 on an 10” wide wheel, and, as you pointed out, the e9x M has a 265 on a 10” wide wheel + a 245 on a 9” wide wheel. For BMW, there is no correlation between tire size and wheel width! I would not use BMW as a definitive source on tire sizes and wheel widths

BoilerUP · 02-27-2024, 05:00 AM

I've run 275/35R18 Conti ECFs on the front of my ATS-V with 18x9.5 wheels for two years now on circuit (295 rear on 10.5s), they do just fine. Did a 1:41.5 at Barber this past Saturday on a set of ECFs on the final lap of their 26th session.

I will note ECFs run a bit wide for size, so consider that if your fitment is close.

FWIW, Cadillac's OE wheels for the ATSV are 9w with 255s front, 9.5w with 275s rear.

02-26-2024, 11:53 AM	#1
jbalabas Private 33 Rep 60 Posts Drives: f82 Join Date: Oct 2022 Location: canada iTrader: (0)	Conti EFC 275 on apex 9.5 I'm getting ready to get stock up on tires for the season. Do you see any issues runnin a 275 EFC on an apex 9.5 wide rim for track purposes??
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02-26-2024, 01:17 PM	#2
SYT_Shadow ///M Powered for Life 11489 Rep 10,329 Posts Drives: E90M/E92M/M4GTS/M4GT4/X5M Join Date: Sep 2010 Location: Greenwich, CT iTrader: (2)	It won't provide optimum support, but it'll work ok __________________ DIY: S65 Rod Bearings E9X PFC Z54 BBK on F8X BK harness bar + seats: fit 6 tires in an M3 do88 Cooling Goodies GTS Twins: GTMore project
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02-27-2024, 05:00 AM	#6
BoilerUP Enlisted Member 36 Rep 36 Posts Drives: Cadillac ATS-V Join Date: Feb 2023 Location: New Albany, IN iTrader: (0)	I've run 275/35R18 Conti ECFs on the front of my ATS-V with 18x9.5 wheels for two years now on circuit (295 rear on 10.5s), they do just fine. Did a 1:41.5 at Barber this past Saturday on a set of ECFs on the final lap of their 26th session. I will note ECFs run a bit wide for size, so consider that if your fitment is close. FWIW, Cadillac's OE wheels for the ATSV are 9w with 255s front, 9.5w with 275s rear.
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