Winter Tyre Info and Discussion Thread ( Keep related chat here please)

[sapphireblack]

I'm fast approaching commitment point and would appreciate other views/opinions.

Despite Camskills suggestion to avoid 315 rears winters they have to be viable as so many wheel sets with them appear in Germany.

So my choices are down to two. 275/315 winters as direct substitutes for summer tyres. These would be RoF Continental without * rating, OR *Pirelli 285 40 all round but are not RoF.

[RossC]

So my choices are down to two. 275/315 winters as direct substitutes for summer tyres. These would be RoF Continental without * rating, OR *Pirelli 285 40 all round but are not RoF

There’s no chance I would risk running a staggered set up unless they were * marked. Would always choose * over runflats or not.

Any reason why you’re not choosing The Pirelli Ice and Snow? Star marked and runflats available in 315/35/20 and 275/40/20. I appreciate the price is far from appealing.

Of course, if you’re going 285 all round, no need to worry about the * rating, but again, runflat options are limited.

I’m in the same predicament but will likely go 285 all round, and perhaps not worry too much about runflat.

[sapphireblack]

RoF Pirelli * winters are a laughable price, I had a quote this week of £1800. They can be bought cheaper of course but still need fitting and the mobile fitting guys in these parts won't fit RoF.

I've been leaning towards * 285 40s and although these only became a factory option on the F series variants I can't see why using them on E series cars would be a problem. Non RoF is a bonus imo, I have a space saver and gunk kits already. The square set up is a bonus too.

Where that leads my thoughts to is any RoF options in 285 40. Non * rated perhaps but wouldnt matter.

[sid10]

Hi RossC
I have a set of the X6 wheels for sale on here along with a few others , the offset on the rear wheels is et21 , they are 72.6 centre bore so would need to be machined to 74.1 as they are different centre bores on the rear wheels to the X5 .
The X5 runs et 40 on the rears on 20" , et38 on the 21" so the X6 wheels would fill the arches a bit better being et21 extra 19mm on the 20" & 17mm on the 21" or you could try will they fit.com
regards
sid10
ps I am in Cumbria if you wanted to view .

[RossC]

Non * rated perhaps but wouldnt matter.

I would agree that non * rated would be fine in a square setup. No stagger means no problem, the rolling radii should be identical providing it’s the same batch of tyres.

I am in Cumbria if you wanted to view .

Thank you for the info Sid, but finding someone locally willing to machine the wheels wouldn’t be something I’d be looking to do. I also won’t put non * rated tyres on to my X5 unless the tyres are square front to back.

My ideal option for now is a set of 20’s, 10J Front, 11J Rear, and 285/40/20 all round. Like sapphire black, I may go for the 275 and 315 option, but the star rated Pirelli’s are eye wateringly expensive, and 315 wide winter tyres sound less than ideal.

[X5Sport]

What you need to check on the different rims is the actual sidewall height as the angle variance between the two sizes will affect the rolling radius. Think of a right angle triangle with the tip uppermost. On one rim size the sidewall might be the vertical side and will have a fixed length. On the wider rim the sidewall angle will change but given the sidewall height is fixed, the ‘tip’ of the triangle will move downwards. That could put the effective depth of the tyre (sidewall and tread depth) out of tolerance as far as BMW are concerned. A square setup means rims and tyres are the same sizes.

Try it with a ruler and you will see what I mean. A 150mm sidewall is 150mm high when vertical, but now change the angle and the height will reduce compared to a vertical line because the sidewall is a fixed dimension. That difference might be enough to cause trouble because it changes the overall rolling radius (by double the different (in mm), because it’s a circle. I don’t have any of the actual tyres or rims to try it to see whether it is or isn’t enough to put the rim/tyre combination out of tolerance but maths doesn’t lie.

[sapphireblack]

It is a complex business for sure . My door pillar tyre chart only references 19" m&s tyres of 255 50 19, we know that is intended for "square," 9" wheels.

The F86 for example, uses a summer configuration of 285/10" & 325/11.5" and has 285 40 20 "square" set up winter's on 10 & 10.5" rims. I am of the opinion that would also happily work on an E71 as a half inch difference on the rear wheels is negligable.

In addition to that BMWs * marked Pirelli winter in 285 40 20 is not a RoF either, a bonus imo. I have abandoned all thoughts of staggered winter tyres now, it may be I abandon this altogether and stay with the uninspiring 9 x 19 set I already have albeit they have non * rated tyres but are a balanced square set just like 285 40 20s all round would be.

[sapphireblack]

I'm getting bored and irritated with conflicting and inaccurate info from tyre dealers and not actually obtaining statements from BMW. They either duck the question or are incapable of producing an answer. So, here are some schematics demonstrating physical differences. This seems to immediately dispell one statement from yesterday that a 285 40 20 will be taller and upset the transmission. Well that can't be the case as BMWs suggested 255 50 19 is also taller by a very similar amount.

Here are BMWs 315 35 20 compared to their winter suggestion of 255 50 19, followed by 315 35 20 compared to a 285 40 20 on an 11" rim

Also the front comparisons, 275 40 20 > 255 50 19 and finally, 275 40 20 > 285 40 20

I think what this tells me is the variables here are pretty constant and near identical to BMWs only written suggestion of 255 50 19. I think i'm happy to 'gamble' on * Pirelli winters of 285 40 20 all round as it's 'square' and almost the same nominal ride height gains. On non RoF Vs RoF even that may not actually matter, and once again lets not forget the 285 40 20 * Pirelli winter non RoF is BMWs actual specification for the F86 and possibly others. The only difference is a half inch wider rear wheel on an E71. A 285 tyre though is fully endorsed for use on an 11" rim

[sid10]

Hi the biggest problem is will the insurance cover none standard tyres ?
many mot test stations are refusing to mot cars with stretched tyres.
As the car is labelled with the correct tyres for the car you really dont stand a chance if involved in an accident , even putting spacers on a car can invalidate insurance , I phoned this morning about putting a roof rack on my sons car to be told that it would invalidate his insurance as it is a none factory fitted option , the world has gone mad .

[sapphireblack]

My insurers (NFU) are rather laid back compared to many of the more obvious names. They don't even need to be advised of winter tyres use, which they have put in writing too.

I am starting to wonder if the entire business of winter tyres when domicile in the UK has any true relevance at all.

There are no stretched tyres in my proposals, a 285 tyre on an 11" rim is within the parameters set out as safe and permissible.

Revoking insurance because of roof rack use is utterly ridiculous and stupid. Whoever they are, out them publicly.

[RossC]

What you need to check on the different rims is the actual sidewall height as the angle variance between the two sizes will affect the rolling radius. Think of a right angle triangle with the tip uppermost. On one rim size the sidewall might be the vertical side and will have a fixed length. On the wider rim the sidewall angle will change but given the sidewall height is fixed, the ‘tip’ of the triangle will move downwards. That could put the effective depth of the tyre (sidewall and tread depth) out of tolerance as far as BMW are concerned. A square setup means rims and tyres are the same sizes.

Try it with a ruler and you will see what I mean. A 150mm sidewall is 150mm high when vertical, but now change the angle and the height will reduce compared to a vertical line because the sidewall is a fixed dimension. That difference might be enough to cause trouble because it changes the overall rolling radius (by double the different (in mm), because it’s a circle. I don’t have any of the actual tyres or rims to try it to see whether it is or isn’t enough to put the rim/tyre combination out of tolerance but maths doesn’t lie.

My hope was that as 285's are essentially too big for the front, and 285's are essentially too small for the rear, then an equal measurement would be more than likely, within tolerance, but hadn't done the calculations...

Here are BMWs 315 35 20 compared to their winter suggestion of 255 50 19, followed by 315 35 20 compared to a 285 40 20 on an 11" rim...

Some great detailed info there, but missing, what I think, the most important calculation of whether 10J 285's and 11J 285's would create a different rolling radius.

Thankfully:



Unless I'm missing something, that's a win

[StuBeeDoo]

I am starting to wonder if the entire business of winter tyres when domicile in the UK has any true relevance at all.

I've been thinking along the same lines. I have had winter tyres for all our cars for many years, but I'm changing tack. Wor Lass's recently-purchased C3 Picasso needs new tyres and I'm planning on having Michelin CrossClimate+ fitted, rather than buy a second set of wheels and tyres for winter use. If it wasn't for her having to use the car for her job (she's a community nurse), she wouldn't have to drive in inclement weather at all. She only does <7k miles a year.

This coming winter will probably be the last I get out of the Pirelli Sottozeros I have for the F25. Depending on our experience with the Michelins, I may well replace my winter tyres with all-weather ones but still just use them in the winter. Let's face it - how often do we get a full-on winter in the UK??

[sapphireblack]

Well after all my research the deal on the 20" wheels set I was buying has gone sour yesterday

I already have the factory endorsed 19" set with brand new (non* non RoF) tyres and if it snows I'll fit them. I may treat them to a refurb now, though that means I waste £70 having the new rubber fitted last week. But, my perfectionist nature will probably get the better of me at some point

[sid10]

I just bought a set of style 491s in black , just need some winter tyres now !

[sapphireblack]

So now its wallet raping time for * Pirelli's then