Normal stretch? 9.5 on 255-30

bmw5858 · 08-10-2019, 06:22 AM

Hi guys!

So I just installed my new wheel on, and I was wondering what the hell is this stretch? On a 255 you can put a 10 inch wide wheel. This is a 9.5... I don't understand..!!!? Is it normal?!

These are pirelli p zero runflat tire OEM, 255-30-20 in the rear. Front is ok

Alpine-F80 · 08-10-2019, 08:17 AM

I think the fact it's a run flat has something to do with it, plus 255 is definitely on the smaller side for a 9.5". I have 9.5 rears with 255 runflats as well (Continental) and they also look stretched, but the rim guard still protrudes way past wheel, it's kinda weird.

I always assumed it had to do with the super stiff runflat sidewall which doesn't "stretch" like a normal tire, but maybe someone else knows more.

FBMWWINS · 08-10-2019, 02:34 PM

On a 9.5J wheel 255 and 265 sizes are usually the recommended ones, with 275 being the max. So really there should not be any issues in this regard. If you are on good terms with your tire shop/buddy, I would just drive by there and have some other wheels NON-run flat fitted on for testing purpose in order to exclude this one. The test is quickly done.

bmw5858 · 08-10-2019, 03:47 PM

Quote:

Originally Posted by F06WINS

On a 9.5J wheel 255 and 265 sizes are usually the recommended ones, with 275 being the max. So really there should not be any issues in this regard. If you are on good terms with your tire shop/buddy, I would just drive by there and have some other wheels NON-run flat fitted on for testing purpose in order to exclude this one. The test is quickly done.

Yeah I know it's the right size of tire on wheel... but how the hell its that stretch.. normally on a 255 you can go 8.5 to 10J max! I can understand that sidewall is 30, but... I don't know! Here's another picture.

FBMWWINS · 08-10-2019, 04:34 PM

Indeed and as said I would just run a quick test if possible at a local tireshop or somewhere where they have this size of tires and try possibly a NON-runflat tire to exclude that as potential culprit.
Another thing that comes to my mind but is just a thought, could be that the rims you have are not ideal for accommodating the extra thickness of the sidewalls of run-flat tires and that the rear size accentuates this? I cannot think of anything else but would definitely drop by the local tireshop and check/test by mounting a non-flat tire on the rear and see what the outcome is.

Gen13 F36 · 08-10-2019, 04:48 PM

If that runflat look like that stretch then it be defeating the purpose. It might collapse if you ever get a puncture. Looks bad.

bmw5858 · 08-11-2019, 06:28 AM

I might get new tire then... I don't know how it is that stretch honestly... not so sure about the look too. Is it that bad? Le can I drive like this without problem?

kern417 · 08-11-2019, 03:30 PM

a 255 is absolutely not the right tire for a 9.5" wheel. The rule of thumb is that the tire width should be 1" wider than the wheel width. That's because Tires are measured across the entire width outside to outside, but wheel width is measured inside where the tire bead sits.

A 9.5" wheel is made for a 10.5" tire i.e. 275. Anything less will show some stretch.

Regulator · 08-11-2019, 04:17 PM

I have 255's on my 9.5" wheel. Stretch isn't even close to what I'm seeing from OP. Must have something to do with it being runflat. I would have loved to put 235/35/19 & 275/30/19 on my car, but there have been reports of this size rubbing.

Back Wheel - Continental DWS 255/35/19 on a 19x9.5 +43 wheel.

Front Wheel - Continental DWS 225/40/19 on a 19x8.5 +35 wheel.

Alpine-F80 · 08-11-2019, 07:02 PM

So I think it's a bit of both, 255 is slightly small for a 9.5, plus the run flat sidewall. Clearly these Pirelli's run small because here's mine (9.5 on 255/35 Conti runflat) — keep in mind OP's was 255/30 so that also attributes in appearance of stretch. Mine has some stretch on sidewall but rim protector still protrudes pretty substantially...I almost want to say to verify tire and wheel size, something doesn't seem right.
[IMG]https://i.ibb.co/YZ4rFTW/EC980-D7-C-...F1-F878-C9.jpg[/IMG]

kern417 · 08-12-2019, 06:33 AM

Quote:

Originally Posted by Regulator

I have 255's on my 9.5" wheel. Stretch isn't even close to what I'm seeing from OP. Must have something to do with it being runflat. I would have loved to put 235/35/19 & 275/30/19 on my car, but there have been reports of this size rubbing.

If you had a 30 aspect ratio tire then it would show more stretch. And some tire brands build more narrow than others. But this isn't a "runflat" specific issue. I've had similar fitment running large wheels with narrow non-runflat tires. It amplifies the effect.

blumagic · 08-12-2019, 07:59 AM

edit, i'm dumb i thought they were square. what is the front width?

stretch looks even between the front and back.

Quote:

Originally Posted by bmw5858

zole2112 · 08-12-2019, 08:41 AM

Mine has 9.5" with 255/35/19 and looks like this, not sure what's up with yours OP. I have Go-Flat Michelin PSS

bmw5858 · 08-12-2019, 10:30 AM

Quote:

Originally Posted by zole2112

Mine has 9.5" with 255/35/19 and looks like this, not sure what's up with yours OP. I have Go-Flat Michelin PSS

Difference is you have a 35 sidewalk, which give the tire more space to stretch. I don't know, maybe pirelli has a different look, curve and aspect that other tire.

kern417 · 08-12-2019, 01:35 PM

Quote:

Originally Posted by bmw5858

Difference is you have a 35 sidewalk, which give the tire more space to stretch. I don't know, maybe pirelli has a different look, curve and aspect that other tire.

Exactly, the difference is the aspect ratio. If you consider the geometry, it makes sense that reducing the sidewall will increase the effect of stretch.

And I tried looking it up but couldn't confirm that Pirelli runs narrow. But I'd bet that plays an effect too.

Jeff_335 · 08-12-2019, 04:19 PM

the problem is: pirelli lol

Pirelli are always super skinny compared to michelin. Michelin are known to 'run wide' for their size.

bmw5858 · 08-13-2019, 07:23 AM

Quote:

Originally Posted by Jeff_335

the problem is: pirelli lol

Pirelli are always super skinny compared to michelin. Michelin are known to 'run wide' for their size.

Exactly!

I'll simply put new tire on the wheel! 235-35-20 and 265-30-20 in the rear, with non runflat tire! Hopefully it will correct the problem!

sukhparm.7 · 08-13-2019, 03:01 PM

Here's 255 PS4S on 9.5 although it's not as bad as yours still pushed in a little.
Friend of mine has exact same wheel but a different 255 tire and his side wall looks more straight with the wheel.
I was told that sometimes mounting technique makes a difference but I think it's the tire itself and 255 being small for 9.5

jh_f30 · 08-14-2019, 12:07 AM

All you need is like 20 degrees of camber and air suspension! #stancelife!

kern417 · 08-14-2019, 06:33 AM

Quote:

Originally Posted by sukhparm.7

Here's 255 PS4S on 9.5 although it's not as bad as yours still pushed in a little.
Friend of mine has exact same wheel but a different 255 tire and his side wall looks more straight with the wheel.
I was told that sometimes mounting technique makes a difference but I think it's the tire itself and 255 being small for 9.5

Throwing it out there one more time so hopefully folks will catch on.

Those are 19" wheels. On 20" wheels, you'll see much closer to the stretch that OP has because of the shorter sidewalls.

I feel like I'm talking to a brick wall, but good luck with the swap. 265 will make a bigger difference than switching to non-runflats.

08-10-2019, 06:22 AM	#1
bmw5858 Lieutenant 193 Rep 494 Posts Drives: bmw 340i 2018 Join Date: Dec 2012 Location: Montreal iTrader: (0)	Normal stretch? 9.5 on 255-30 Hi guys! So I just installed my new wheel on, and I was wondering what the hell is this stretch? On a 255 you can put a 10 inch wide wheel. This is a 9.5... I don't understand..!!!? Is it normal?! These are pirelli p zero runflat tire OEM, 255-30-20 in the rear. Front is ok Attached Images __________________ Bmw 435M 2014 Convertible SOLD! Bmw 340i X drive 2018 New orange sunset, Manual transmission, M performance I & II, M performance front lip, side extension rear diffuser, tinted windows. : SOLD Back in old N55 love! Bmw 335 EBII M performance edition : ER Downpipes, VRSF Chargepipe, VRSF HD 6.5 Intercooler, BM3 Stage 2 93 octane, MPPSK, H&R Spring
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08-10-2019, 08:17 AM	#2
Alpine-F80 Second Lieutenant 201 Rep 253 Posts Drives: 2017 M3 Join Date: Sep 2018 Location: Northern Virginia iTrader: (1)	I think the fact it's a run flat has something to do with it, plus 255 is definitely on the smaller side for a 9.5". I have 9.5 rears with 255 runflats as well (Continental) and they also look stretched, but the rim guard still protrudes way past wheel, it's kinda weird. I always assumed it had to do with the super stiff runflat sidewall which doesn't "stretch" like a normal tire, but maybe someone else knows more.
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08-10-2019, 02:34 PM	#3
FBMWWINS Captain 604 Rep 909 Posts Drives: M8C Coupé & M240i Coupé Join Date: Nov 2011 Location: Europe iTrader: (0)	On a 9.5J wheel 255 and 265 sizes are usually the recommended ones, with 275 being the max. So really there should not be any issues in this regard. If you are on good terms with your tire shop/buddy, I would just drive by there and have some other wheels NON-run flat fitted on for testing purpose in order to exclude this one. The test is quickly done.
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08-10-2019, 04:34 PM	#5
FBMWWINS Captain 604 Rep 909 Posts Drives: M8C Coupé & M240i Coupé Join Date: Nov 2011 Location: Europe iTrader: (0)	Indeed and as said I would just run a quick test if possible at a local tireshop or somewhere where they have this size of tires and try possibly a NON-runflat tire to exclude that as potential culprit. Another thing that comes to my mind but is just a thought, could be that the rims you have are not ideal for accommodating the extra thickness of the sidewalls of run-flat tires and that the rear size accentuates this? I cannot think of anything else but would definitely drop by the local tireshop and check/test by mounting a non-flat tire on the rear and see what the outcome is.
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08-10-2019, 04:48 PM	#6
Gen13 F36 Brigadier General 1599 Rep 3,752 Posts Drives: 428i Gran Coupe Join Date: Nov 2017 Location: Los Angeles, CA iTrader: (1)	If that runflat look like that stretch then it be defeating the purpose. It might collapse if you ever get a puncture. Looks bad.
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08-11-2019, 06:28 AM	#7
bmw5858 Lieutenant 193 Rep 494 Posts Drives: bmw 340i 2018 Join Date: Dec 2012 Location: Montreal iTrader: (0)	I might get new tire then... I don't know how it is that stretch honestly... not so sure about the look too. Is it that bad? Le can I drive like this without problem? __________________ Bmw 435M 2014 Convertible SOLD! Bmw 340i X drive 2018 New orange sunset, Manual transmission, M performance I & II, M performance front lip, side extension rear diffuser, tinted windows. : SOLD Back in old N55 love! Bmw 335 EBII M performance edition : ER Downpipes, VRSF Chargepipe, VRSF HD 6.5 Intercooler, BM3 Stage 2 93 octane, MPPSK, H&R Spring
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08-11-2019, 04:17 PM	#9
Regulator Private 70 Rep 65 Posts Drives: 15' 335i xDrive Join Date: Nov 2016 Location: CO iTrader: (0)	I have 255's on my 9.5" wheel. Stretch isn't even close to what I'm seeing from OP. Must have something to do with it being runflat. I would have loved to put 235/35/19 & 275/30/19 on my car, but there have been reports of this size rubbing. Back Wheel - Continental DWS 255/35/19 on a 19x9.5 +43 wheel. Front Wheel - Continental DWS 225/40/19 on a 19x8.5 +35 wheel. Last edited by Regulator; 08-11-2019 at 04:22 PM..
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08-11-2019, 07:02 PM	#10
Alpine-F80 Second Lieutenant 201 Rep 253 Posts Drives: 2017 M3 Join Date: Sep 2018 Location: Northern Virginia iTrader: (1)	So I think it's a bit of both, 255 is slightly small for a 9.5, plus the run flat sidewall. Clearly these Pirelli's run small because here's mine (9.5 on 255/35 Conti runflat) — keep in mind OP's was 255/30 so that also attributes in appearance of stretch. Mine has some stretch on sidewall but rim protector still protrudes pretty substantially...I almost want to say to verify tire and wheel size, something doesn't seem right. [IMG]https://i.ibb.co/YZ4rFTW/EC980-D7-C-...F1-F878-C9.jpg[/IMG]
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08-12-2019, 08:41 AM	#13
zole2112 Modder of everything I own 147 Rep 491 Posts Drives: 2013 335i Xdrive Join Date: Mar 2017 Location: Appleton, WI iTrader: (0)	Mine has 9.5" with 255/35/19 and looks like this, not sure what's up with yours OP. I have Go-Flat Michelin PSS Attached Images __________________ 2013 BMW 335xi F30 N55 PWG/VRSF DP/ER CP/Injen CAI/AA FMIC/JB4 map 7/Fuel= E50 w/ E85:93oct/Stock LPFP & HPFP/CATuned coilovers/Megan Racing Rear Swaybar/Powerflex Rear Subframe Bushing Inserts/Dual aFe Power Mach Force Mufflers/Resonator Delete/MHD & BMS Race BEF Last edited by zole2112; 08-14-2019 at 12:17 PM..
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08-12-2019, 04:19 PM	#16
Jeff_335 Private First Class 102 Rep 116 Posts Drives: 2014 335i Join Date: Oct 2016 Location: Quebec iTrader: (2)	the problem is: pirelli lol Pirelli are always super skinny compared to michelin. Michelin are known to 'run wide' for their size.
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08-13-2019, 03:01 PM	#18
sukhparm.7 Second Lieutenant 48 Rep 225 Posts Drives: 2015 335i Msport Join Date: Aug 2017 Location: Barrie iTrader: (0)	Here's 255 PS4S on 9.5 although it's not as bad as yours still pushed in a little. Friend of mine has exact same wheel but a different 255 tire and his side wall looks more straight with the wheel. I was told that sometimes mounting technique makes a difference but I think it's the tire itself and 255 being small for 9.5 Attached Images
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08-14-2019, 12:07 AM	#19
jh_f30 Lieutenant Colonel 1306 Rep 1,827 Posts Drives: 2013 335i Sportline Auto RWD Join Date: Aug 2017 Location: Bay Area, CA iTrader: (2)	All you need is like 20 degrees of camber and air suspension! #stancelife! __________________ 2013 F30 335i RWD ZF Melbourne Red ~Remus Sport Axleback~VRSF Chargepipe~VRSF Catless Downpipe~GPlus FMIC~HR Sport Springs~Active Autowerke OBD Flash Tune Stage 2~
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