wider back tyres, why?

Merv B · 12-12-2010, 01:48 PM

Hi all

I am thinking of fitting winter tyres to my SE 320D's 17 alloys and then getting some other alloys possibly MV3 18s for summer. Any that I have seen advertised tend to have 8.5J rears and 8J fronts, but what is the advantage of wider rear tyres? Would they be a waste of time on my 2-litre diesel car or should I just get another set of 17s to save phaffing about with insurance etc.

Any comments appreciated.

Merv

AlanQS · 12-12-2010, 02:01 PM

Wider tyres on the driven wheels for better grip. And they look good. Your car is optimised for 17" wheels and the bigger wheels and tyres - outwith the race track - are purely for bling.

Merv B · 12-12-2010, 02:02 PM

Would a wider tyre not be more prone to aquaplaning? Already had one incident and don't fancy reliving it.

Em135eye · 12-12-2010, 02:11 PM

Just to balance the argument, my 335d has the same width tyres all round. 225/45 17". Handles very well and tyres are much cheaper. Handy when running a tyre munching car!

Legion5 · 12-12-2010, 02:16 PM

Even slightly wider tires are significantly more prone to aquaplaning, thankfully it has more to do with the front than the rear. However if your rear tires are significantly wider than your front ones without adjusting the suspension you'll get snap oversteer, which is very dangerous, which is why it's better to keep the stagger somewhat close to stock. The other good news is that your tire selection has a lot to do with aquaplaning resistance. So if you pick a better tire and go slightly wider in front and wider in the rear you'll be fine.

On a 2 liter diesel you won't be making enough power to take advantage of wider rear tires and you'll actually reduce performance because of the added rolling resistance and weight of wider tires. That's why economy cars have such narrow tires, because it makes the most of their small engines. Cars with big engines can usually just power through the rolling resistance and weight and they need the extra grip so it's worth it to go wide.

Realistically a 265mm rear tire and 235mm front will not give you any significant flaws on a 10" / 8.5" wheel setup so on these cars you don't have to try to force yourself to use overly thin tires. What you want to do is get the best looking wheels and just put the tires closest to the stock width that don't look too thin. You won't have any major problems if you follow that. However due to the issues mentioned above it would be silly to try to put a wider tire if your wheel doesn't require it because you'll incur no benefit.

Merv B · 12-12-2010, 03:07 PM

Thanks for the comments. Looks like 17s might be the sensible option then. Should I be wary of E36/E46 alloys or will they fit?

If it is okay I might post a pic tomorrow of the rims I have as it would be good to know what style they are.

Cheers

Merv

doughboy · 12-13-2010, 06:11 AM

If you're going for 8J rims all round (17 or 18) you need offset of ET34, that's the important number, not whether some fleebay guy says they'll fit an E46 or not.

If you want staggered setup, like msport, with 8.5j rears (17 or 18) then you need ET37 for the rears.

BTW -I bougth my MV3 reps for winters at 8J all round (they just sold me 4 front wheels instead of a staggered set).

Merv B · 12-13-2010, 06:40 AM

Thanks for the info dough boy, all useful stuff.

By the way can anyone tell me what style the rims I have are? I have looked at the alloy wheel guide link on here and I think they are Style 159s.

Thanks again.

Merv B · 12-13-2010, 06:47 AM

If anyone can tell me how to convert the images so they appear as thumbnails rather than taking up all of the screen please let me know. Sorry by the way for everyone who has had to zoom out.

And yes my car really needs a wash!

Merv B · 12-15-2010, 10:38 AM

Hello again. Can anyone shed some light on what style alloys I have.

HighlandPete · 12-15-2010, 11:12 AM

Quote:

Originally Posted by Merv B

Hello again. Can anyone shed some light on what style alloys I have.

Star Spoke, Style 159 (8x17 ET34) Option 2CZ on the original E90/1 series cars.

HighlandPete

Merv B · 12-15-2010, 11:17 AM

Pete appreciate the reply

Still got lots to learn so thanks for any help.

Merv

Boyd1963 · 12-15-2010, 11:55 AM

Quote:

Originally Posted by Merv B

And yes my car really needs a wash!

Call that dirty? Mine looks more black than silver at the minute. It's just too cold to wash it.

Merv B · 12-15-2010, 12:11 PM

I am tempted to give it the full detailing works from clay to wax this weekend now I dont need to go anywhere until January

ALF_E90 · 01-05-2011, 09:24 AM

Given the superb ride quality on the 17x8 wheels and 225/45/17 non-RFT winter tyres all round, I am seriously tempted to sell my style 162 staggered 18" alloys and get another set of 17x8's to run the same size summer as winter tyres. I do a lot of miles so ride quality and replacement cost are important, mpg seems better as well, and I really hate the typical modern car "grip over handling" thing and prefer the drive on the narrower tyres - particularly with the softer SE setup.

Em135eye · 01-05-2011, 09:40 AM

ALF - I'm with you there!

17s, non staggered on non RFTs ride brilliantly. However I like 162s a lot. Do shout if you want to sell them just in case...

kaishang · 01-05-2011, 09:44 AM

Quote:

Originally Posted by 335diesel

ALF - I'm with you there!

17s, non staggered on non RFTs ride brilliantly. However I like 162s a lot. Do shout if you want to sell them just in case...

You have the M-sport suspension though don't you?

Do you think there is any different between SE suspension and RFTs and M-sport suspension and conventional tyres?

HighlandPete · 01-05-2011, 10:12 AM

Quote:

Originally Posted by kaishang

You have the M-sport suspension though don't you?

Do you think there is any different between SE suspension and RFTs and M-sport suspension and conventional tyres?

I'd say they can be totally different. A bit of personal experience, but also the views of other experienced drivers. SE cars can be very bouncy on some wheel sizes/tyre setups. There appears to be some strange 'harmonics' going on in these suspensions. Some combinations just seem to hit the mark, other setups are weird indeed.

Was speaking with an experienced salesman at one of our Scottish dealers a while back about trying a specific car to get a feel for the ride quality for that model. He was pretty clear that these E9* cars are very spec/age/tyre sensitive. So I got him to open up a bit. He's found from his own experience that one car will feel totally different from another even of a similar spec'. His advice was don't test one car thinking it will be the same in another same spec' car, from a different sales plot. Try the exact used car you are hoping to buy, to test the ride qualities.

Personaaly I'd opt for sport suspension and conventional tyres, as being more predictable and controlled than an SE setup with RFTs.

HighlandPete

Em135eye · 01-05-2011, 10:16 AM

Quote:

Originally Posted by kaishang

You have the M-sport suspension though don't you?

Do you think there is any different between SE suspension and RFTs and M-sport suspension and conventional tyres?

I do - I suspect SE suspension and RFT tyres would be annoying but not tried them except on a 535d - which was a pain.

Only tried M Sport suspension and RFTs (18s on a loan car, 17s on mine before non RFTs went on).

M Sport on 17s with non RFTs really is a good set up - worth trying out.

kaishang · 01-05-2011, 10:32 AM

Mmm, I asked because I have SE suspension and 17" RFTs so interested to see how it compares. I'm quite happy with the ride. Should go for a mutual test drive if I'm in Cornwall

Em135eye · 01-05-2011, 11:04 AM

Kaishang - always welcome! I would assume 3ers with SE suspension handle better than 5ers.

Merv B · 01-05-2011, 11:13 AM

Well having looked at several alloys I think I will get some 17in 159 or 188s to put winter tyres on. Saves messing about with the insurance company and also having read the cracked rims thread I dont fancy the hassle of cracking 18s especially as my job involves going to see farmers and nipping over to Ireland now and again where potholes are lets say an issue.

So if anyone has some 159 or 188 style rims you are wanting to flog give me a shout.

12-12-2010, 01:48 PM	#1
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	wider back tyres, why? Hi all I am thinking of fitting winter tyres to my SE 320D's 17 alloys and then getting some other alloys possibly MV3 18s for summer. Any that I have seen advertised tend to have 8.5J rears and 8J fronts, but what is the advantage of wider rear tyres? Would they be a waste of time on my 2-litre diesel car or should I just get another set of 17s to save phaffing about with insurance etc. Any comments appreciated. Merv
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12-12-2010, 02:01 PM	#2
AlanQS Colonel 243 Rep 2,811 Posts Drives: Jaguar XE P250 HSE Join Date: Jan 2008 Location: Glasgow iTrader: (0) Garage List 2016 430i m-sport G ... [0.00]	Wider tyres on the driven wheels for better grip. And they look good. Your car is optimised for 17" wheels and the bigger wheels and tyres - outwith the race track - are purely for bling.
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12-12-2010, 02:02 PM	#3
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Would a wider tyre not be more prone to aquaplaning? Already had one incident and don't fancy reliving it.
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12-12-2010, 02:11 PM	#4
Em135eye Banned 175 Rep 4,302 Posts Drives: M135i Join Date: Jul 2009 Location: South West iTrader: (0) Garage List 2014 BMW M135i 5 door [0.00]	Just to balance the argument, my 335d has the same width tyres all round. 225/45 17". Handles very well and tyres are much cheaper. Handy when running a tyre munching car!
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12-12-2010, 02:16 PM	#5
Legion5 Major 175 Rep 1,379 Posts Drives: e92 Join Date: Dec 2007 Location: USA iTrader: (12)	Even slightly wider tires are significantly more prone to aquaplaning, thankfully it has more to do with the front than the rear. However if your rear tires are significantly wider than your front ones without adjusting the suspension you'll get snap oversteer, which is very dangerous, which is why it's better to keep the stagger somewhat close to stock. The other good news is that your tire selection has a lot to do with aquaplaning resistance. So if you pick a better tire and go slightly wider in front and wider in the rear you'll be fine. On a 2 liter diesel you won't be making enough power to take advantage of wider rear tires and you'll actually reduce performance because of the added rolling resistance and weight of wider tires. That's why economy cars have such narrow tires, because it makes the most of their small engines. Cars with big engines can usually just power through the rolling resistance and weight and they need the extra grip so it's worth it to go wide. Realistically a 265mm rear tire and 235mm front will not give you any significant flaws on a 10" / 8.5" wheel setup so on these cars you don't have to try to force yourself to use overly thin tires. What you want to do is get the best looking wheels and just put the tires closest to the stock width that don't look too thin. You won't have any major problems if you follow that. However due to the issues mentioned above it would be silly to try to put a wider tire if your wheel doesn't require it because you'll incur no benefit. __________________ Clean cars are happy cars! CANON PHOTOGRAPHER Last edited by Legion5; 12-12-2010 at 03:52 PM..
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12-12-2010, 03:07 PM	#6
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Thanks for the comments. Looks like 17s might be the sensible option then. Should I be wary of E36/E46 alloys or will they fit? If it is okay I might post a pic tomorrow of the rims I have as it would be good to know what style they are. Cheers Merv
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12-13-2010, 06:11 AM	#7
doughboy Major General 1545 Rep 8,970 Posts Drives: 2018 M2 Comp 6MT Join Date: Jan 2009 Location: UK iTrader: (2)	If you're going for 8J rims all round (17 or 18) you need offset of ET34, that's the important number, not whether some fleebay guy says they'll fit an E46 or not. If you want staggered setup, like msport, with 8.5j rears (17 or 18) then you need ET37 for the rears. BTW -I bougth my MV3 reps for winters at 8J all round (they just sold me 4 front wheels instead of a staggered set).
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12-13-2010, 06:40 AM	#8
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Thanks for the info dough boy, all useful stuff. By the way can anyone tell me what style the rims I have are? I have looked at the alloy wheel guide link on here and I think they are Style 159s. Thanks again. Attached Images
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12-13-2010, 06:47 AM	#9
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	If anyone can tell me how to convert the images so they appear as thumbnails rather than taking up all of the screen please let me know. Sorry by the way for everyone who has had to zoom out. And yes my car really needs a wash!
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12-15-2010, 10:38 AM	#10
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Hello again. Can anyone shed some light on what style alloys I have.
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12-15-2010, 11:17 AM	#12
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Pete appreciate the reply Still got lots to learn so thanks for any help. Merv
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12-15-2010, 12:11 PM	#14
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	I am tempted to give it the full detailing works from clay to wax this weekend now I dont need to go anywhere until January
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01-05-2011, 09:24 AM	#15
ALF_E90 Second Lieutenant 16 Rep 280 Posts Drives: E91 330i - see classifieds... Join Date: Dec 2010 Location: Winchester iTrader: (0)	Given the superb ride quality on the 17x8 wheels and 225/45/17 non-RFT winter tyres all round, I am seriously tempted to sell my style 162 staggered 18" alloys and get another set of 17x8's to run the same size summer as winter tyres. I do a lot of miles so ride quality and replacement cost are important, mpg seems better as well, and I really hate the typical modern car "grip over handling" thing and prefer the drive on the narrower tyres - particularly with the softer SE setup.
	Appreciate 0 Quote

01-05-2011, 09:40 AM	#16
Em135eye Banned 175 Rep 4,302 Posts Drives: M135i Join Date: Jul 2009 Location: South West iTrader: (0) Garage List 2014 BMW M135i 5 door [0.00]	ALF - I'm with you there! 17s, non staggered on non RFTs ride brilliantly. However I like 162s a lot. Do shout if you want to sell them just in case...
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01-05-2011, 10:32 AM	#20
kaishang Colonel 54 Rep 2,197 Posts Drives: 2010 E90 330d Join Date: Jul 2010 Location: London iTrader: (0)	Mmm, I asked because I have SE suspension and 17" RFTs so interested to see how it compares. I'm quite happy with the ride. Should go for a mutual test drive if I'm in Cornwall
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01-05-2011, 11:04 AM	#21
Em135eye Banned 175 Rep 4,302 Posts Drives: M135i Join Date: Jul 2009 Location: South West iTrader: (0) Garage List 2014 BMW M135i 5 door [0.00]	Kaishang - always welcome! I would assume 3ers with SE suspension handle better than 5ers.
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01-05-2011, 11:13 AM	#22
Merv B Private First Class 8 Rep 150 Posts Drives: 2005 320D SE Join Date: Feb 2010 Location: Lancs iTrader: (0)	Well having looked at several alloys I think I will get some 17in 159 or 188s to put winter tyres on. Saves messing about with the insurance company and also having read the cracked rims thread I dont fancy the hassle of cracking 18s especially as my job involves going to see farmers and nipping over to Ireland now and again where potholes are lets say an issue. So if anyone has some 159 or 188 style rims you are wanting to flog give me a shout.
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