[Crassus]

Hello
Last week my front tyres were finally worn to the point that they were questionably legal and thus I had an excuse to ditch the runflats.

The car is:

• More settled and pliant over road imperfections.
• Steering is lighter and more direct.
• Tyre roar over 40mph is noticeably muted.

Non-runflats have completely transformed my car. Previously every road dip, rivet or imperfection would be transferred straight to my body. The car was not uncomfortable but at times felt fidgety on uneven roads.

Many imperfections are now absorbed by the tyres and not the chassis or my body. The ride quality is noticeably more sophisticated and less busy even on smooth roads.

What I did not expect is the car to feel more direct. Because the tyre is absorbing more of the road, I can now run higher PSI which has resulted in lighter and more direct steering.

Honestly. If you have an X3, X1, X5, F30 3-Series or any BMW with runflats, then this is the BEST and most UNDERRATED upgrade you can give to your car. The ride quality, road and steering feel of my car now feels perfect.

Peter_R recommended:

2 x Pirelli P Zero Rosso (BMW) 245/45 R19 Y (98), Asymmetrical
2 x Pirelli P Zero Rosso (BMW) 275/40 R19 Y (101), Asymmetrical

However hardly anyone stocks them and one tyre retailer that does, only has fronts. Therefore I opted for a more widely available tyre which is simply the Pirelli PZERO non-runflat with the same load and speed rating as my runflats. The same tyres are also used by certain Jaguar and Mercedes cars.

I can confirm that a week into owner I have not suffered any transfer case issues.

Because my F25 is well equipped and I was unimpressed by the X3 G20 without adaptive dampers, I see no reason to change car.

Also, the new tyre smell is lovely everytime I approach the car or step outside. However it won't last much longer.

[Peter_R]

@Crassus

Good to hear! I would not expect you to get any transfer casing issues with new tyres.

Unless I am mistaken, it looks like there is a typo! Have a read of your paragraph below again!

However hardly anyone stocks them and one tyre retailer that does, only has fronts. Therefore I opted for a more widely available tyre which is simply the Pirelli PZERO non-runflat with the same load and speed rating as my non-runflats. The same tyres are also used by certain Jaguar and Mercedes cars.

Don't you mean?

Therefore I opted for a more widely available tyre which is simply the Pirelli PZERO non-runflat with the same load and speed rating as my runflats.

Anyway, because of the hard seats associated my BMW xDrive 30d MSport (F25) and the fact that I now cover low mileage and do not wish to run a diesel anymore, I have moved to a 67 plate Audi Q5 S line 2.0 TFSI.

[Crassus]

Originally Posted by Peter_R

@Crassus

Good to hear! I would not expect you to get any transfer casing issues with new tyres.

Unless I am mistaken, it looks like there is a typo! Have a read of your paragraph below again!


Don't you mean?


Anyway, because of the hard seats associated my BMW xDrive 30d MSport (F25) and the fact that I now cover low mileage and do not wish to run a diesel anymore, I have moved to a 67 plate Audi Q5 S line 2.0 TFSI.

I was very aware of potential transfer issues as people some people who have bought non-star marked tyres or those of lesser quality have had issues. This is why I stuck with Pirelli.

Typo fixed!

Congrats on the Audi Q5. I drove the TDI last year and was amazed by how refined and smooth the car drives. The sports seats were very comfortable too! With the same alloy size it has more generous tyre profile than the F25. Even with sport suspension the ride was very comfortable.

I splurged on a new set on the X3 because we intend to keep it after the PCP deals. We do 7,000miles per year in and I averaged 45mpg on the motorway last week.

On the 4 miles nursery run and commute to work it's just 5-7 mpg off our 2017 1.2TSI hatchback. Reliability is very good and servicing are even a bit less than the hatchback.

Most crucially the surge emission surcharge for cars over £40k has temporarily put me off buying a new car as only a highly specced new car would justify upgrading. £155 to £515 in annual emissions tax is quite a jump.

Further more some engines have seen reduced performance or unfavourable engine/gearbox maps after WLPT, so I'm happy to keep the F25 for a couple of more years.

[arsalan321@hotmail.com]

Did you find any degradation in handling and stability, since RFTs are firmer on the edges? or is it the same?

[Crassus]

Originally Posted by arsalan321@hotmail.com

Did you find any degradation in handling and stability, since RFTs are firmer on the edges? or is it the same?

Because I have alignment/tracking scheduled for this Saturday I haven't pushed the car hard and am mainly driving my second car until then.

So far, there is no degradation in handling and the car does not feel spongy. If anything it's more agile and steers more direct because I can run higher tyre pressure without the ride feeling fidgety or bouncy.

The car very much feels like an athletic BMW SUV but now with the added benefit of a more settled ride when you don't want to feel every road imperfection in your body.

Remember that the tyre load rating, the compound of prestige pirelli tyres approved for 189mph and alloys size remains the same.

The car feels enhanced rather than changed in character.

Two months ago I had the X1 without non-runflats as a loaner and it was more pleasant to drive than an X1 with runflats I drove two years ago.

That' pretty much pushed me to buy the car the tyres it deserves.

It took a few days for the tyres to be broken in but now the car feels utterly fantastic to drive regardless of speed or road service.

I'm blushing with joy as it feels like I'm driving a new and improved car.

[arsalan321@hotmail.com]

I moved from R19 to R17 both Runflats, and there is significant improvement.

My R17s are with winter tyres, so may try non runflats on R19s in summer.

Is there any regulation around non-runflats if one does not have a spare wheel in the boot? (UK specific)

[Riick]

I switched to Firestone Indy 500 summer performance tires a while ago. Car handles like it's on rails.

[Crassus]

Originally Posted by arsalan321@hotmail.com

I moved from R19 to R17 both Runflats, and there is significant improvement.

My R17s are with winter tyres, so may try non runflats on R19s in summer.

Is there any regulation around non-runflats if one does not have a spare wheel in the boot? (UK specific)

Not. It's not a legal requirement to carry a spare. Many new cars don't even have a spare wheel but are instead equipped with a tyre repair kit which you can buy on Amazon for not much money and enable you to temporarily repair a puncture until it can be professionally repaired or replaced.

The only thing that matter to some insurance companies is that your tyres have the same load and speed rating as the ones your car was equipped with from new.

[omasou]

re: the transfer case issue.

I had not heard of "transfer case issue" until I purchased my last set of tires for my previous X5. I was planning to only replace the rears, when my shop and TireRack confirmed that on all wheel drives there cannot be more than a X% or X/10th difference in tire size between front to back. Is this what you were referring?

https://www.tirerack.com/tires/tiret....jsp?techid=18

or was this mentioned b/c the tire sizes purchased are different from stock?

[Riick]

If you buy all 4 tires the exact same make/model/size at the same time you're fine. Rotate every oil change.

[________]

Originally Posted by omasou

re: the transfer case issue.

I had not heard of "transfer case issue" until I purchased my last set of tires for my previous X5. I was planning to only replace the rears, when my shop and TireRack confirmed that on all wheel drives there cannot be more than a X% or X/10th difference in tire size between front to back. Is this what you were referring?

https://www.tirerack.com/tires/tiret....jsp?techid=18

or was this mentioned b/c the tire sizes purchased are different from stock?

Tires have to be the same diameter across axles, with a tolerance of 1% (if two tires are a little worn in one axle and you replace only 2, it should be fine).

It's a bigger concern when choosing staggered tires to ensure they're the same diameter (which OP's are).

[Crassus]

Originally Posted by Riick

If you buy all 4 tires the exact same make/model/size at the same time you're fine. Rotate every oil change.

Originally Posted by omasou

re: the transfer case issue.

I had not heard of "transfer case issue" until I purchased my last set of tires for my previous X5. I was planning to only replace the rears, when my shop and TireRack confirmed that on all wheel drives there cannot be more than a X% or X/10th difference in tire size between front to back. Is this what you were referring?

Yes that's what I'm reffering too. The reason why some tyres for premium/performance cars are expensive is because they are manufactured to a standard that results in minimal variation in rolling circumference.

Cheaper tyres sometimes have less stringent quality control and the variation in rolling circumference can be greater than the tolerance of the transfer case - the tyre marking don't guarantee exact measurements down a centimetre.

These variations can be greater or smaller depending on how the tyre performs under load, cold/warm weather or certain tyre pressure levels.

Some people put cheap/affordable non-runflats on their xDrive cars and suffer no issues while some hear grinding noises from the word go.

As @OnerDriver mentioned, staggered arrangements are especially vulnerable.

Most crucially tyres are non-refundable so if you put them on and notice grinding noises after a day or two of driving brand new tyres then you will face the outlay on another set that won't throw off the transfer case.

That's a financial gamble I was unwilling to make and given that the running cost of the car are very sensible, I don't mind spending a bit extra on tyres.

[omasou]

Originally Posted by Crassus

Hello

...

Peter_R recommended:

2 x Pirelli P Zero Rosso (BMW) 245/45 R19 Y (98), Asymmetrical
2 x Pirelli P Zero Rosso (BMW) 275/40 R19 Y (101), Asymmetrical
...

This is the stock size on my X4 M40i. Have you run this size before?

I ask, b/c I noticed BMW is running a square setup on the GO2 and thought it might be due to customer complaints about replacing 4 tires when they think they only need two?

So, Since the car has a rear wheel bias; I'd appreciate some input on tire wear front to back w/staggered setups. Do you find that you the rears are wearing significantly faster than the fronts?

Based on my driving style, I'm thinking I'll wear out the front outer shoulders and they'll need to be replaced along w/the rears?

Thoughts?

[oVeRdOsE.]

having quattro for years, with a 40/60 distribution, all 4 wheels a wearing about at the same rate.

On the xdrive, so far so good, on the 245-45 actual setup. All 4 are around 12/32, too soon I know.

This summer , ill put 245 in front and 275 on read on nice style 132 wheels.
Hopefully, they'll wear around the same rate to keep the diameter difference in the 1% margin.

[________]

Originally Posted by oVeRdOsE.

having quattro for years, with a 40/60 distribution, all 4 wheels a wearing about at the same rate.

On the xdrive, so far so good, on the 245-45 actual setup. All 4 are around 12/32, too soon I know.

This summer , ill put 245 in front and 275 on read on nice style 132 wheels.
Hopefully, they'll wear around the same rate to keep the diameter difference in the 3% margin.

My car wears at the same rate as well.

No need to rotate as someone mentioned above. BMW never recommended rotating tires on any car.

And it's not 3%, it's 1%. 3% is something else (industry standard recommendation for ideal braking performance and correct speedometer)

[Crassus]

Originally Posted by omasou

This is the stock size on my X4 M40i. Have you run this size before?

I ask, b/c I noticed BMW is running a square setup on the GO2 and thought it might be due to customer complaints about replacing 4 tires when they think they only need two?

So, Since the car has a rear wheel bias; I'd appreciate some input on tire wear front to back w/staggered setups. Do you find that you the rears are wearing significantly faster than the fronts?

Based on my driving style, I'm thinking I'll wear out the front outer shoulders and they'll need to be replaced along w/the rears?

Thoughts?

My setup is also staggered from factory:
245/45 R19 Y (98)
275/40 R19 Y (101)

Over the course of 16,000 miles from new tyre wear has been even across front and rear which is very good given that 80% of my driving is on rough twisty B-roads. Only during the recent 3 months have the front outer started grating away like cheese.

I have full alignment/tracking scheduled tomorrow and it will likely sort out the excessive toe out that has resulted in excessive wear on front outside edges.

Going forward I will keep a close eye on tyre wear and do alignment as soon as I discover uneven tyre wear. After all, tracking is just 20% of the cost of new tyres.

[oVeRdOsE.]

Originally Posted by OnerDriver

My car wears at the same rate as well.

No need to rotate as someone mentioned above. BMW never recommended rotating tires on any car.

And it's not 3%, it's 1%. 3% is something else (industry standard recommendation for ideal braking performance and correct speedometer)

thanks , edited.

1% seems very low. Front wheels diameter VS rear wheel diameter should be in the 1% margin?
People who doing track, will have more than this because of tire wear.

anyway, I wont take any chances, and put some same size tire. I was thinking about 285 at the rear, but it got 1% VS the 245. Ill get some 275 instead.



3% of the OEM diameter for ''speedometer'' is as per owner choice at the end, you can go 8% if you want, it wont break anything. I you are aware that the 60 is the new 65 i.e..
Braking distance VS diameter should be negligible in those 3% margin. width and tire quality is way more important.

[omasou]

The Tire Rack article, I posted above and my conversation with them (about my X5) said the difference should not exceed 12% to avoid transfer case issues. The article also shows recommendations differ based on manufacture. BMW is not listed in the article.

[________]

Originally Posted by omasou

The Tire Rack article, I posted above and my conversation with them (about my X5) said the difference should not exceed 12% to avoid transfer case issues. The article also shows recommendations differ based on manufacture. BMW is not listed in the article.

It's not in the article as you mentioned, but if they indicated you can mismatch your tires by 12% on the phone, I hope they also offered you warranty for the replacement of your transfer case.

Cheers

[omasou]

Originally Posted by OnerDriver

It's not in the article as you mentioned, but if they indicated you can mismatch your tires by 12% on the phone, I hope they also offered you warranty for the replacement of your transfer case.

Cheers

Reading it closer, I suppose it could be written better...

"... while others suggest that all tire circumferences remain within 1/4- to 1/2-inch of each other. Other vehicle manufacturers recommend that all four tires remain within 2/32-, 3/32- or 4/32-inch of each other, or within 30% of each other in relative remaining tread depth..."

if we take the low end 2/32" compared to a new tire at 10/32" that's a 20% difference, correct?

Reading the section calling out the manufactures, Porsche says up to 30% but on the same axle but Audi says 4/32" which could be as high as 40%, right? Or is my math way off?

1%-3% seems way too low, no?

I alway wondered why BMW didn't offer an M w/all wheel drive (excluding the latest M5 and X cars)...now I think I know why.

[________]

Originally Posted by omasou

Reading it closer, I suppose it could be written better...

"... while others suggest that all tire circumferences remain within 1/4- to 1/2-inch of each other. Other vehicle manufacturers recommend that all four tires remain within 2/32-, 3/32- or 4/32-inch of each other, or within 30% of each other in relative remaining tread depth..."

if we take the low end 2/32" compared to a new tire at 10/32 that's a 20% difference, correct?

Reading the section calling out the manufactures, Porsche says up to 30% but on the same axle but Audi says 4/32" which could be as high as 40%, right? Or is my math way off?

1%-3% seems way too low, no?

No, because you're comparing the differences in tread depth, not in the overall diameter. The 1% is against the overall diameter. The Porsche figure seems to be the tread depth comparison.

[omasou]

Originally Posted by OnerDriver

No, because you're comparing the differences in tread depth, not in the overall diameter. The 1% is against the overall diameter. The Porsche figure seems to be the tread depth comparison.

Ah, I'm talking about replacing a worn tire(s) of the proper size and ratio. Your talking about how to determine if a specific staggered setup will work.

Whew. Thanks for clarifying that and sorry it took so long to get in the same page.