[rick47591]

Hi everyone
Can anyone share their experience with switching to non-run flat tyres? My recently purchased like-new (< 500 miles) x5 40i has 20" Bridgestone run flats with regular steel suspension (no air suspension, no adaptive suspension). The fronts are 275/40/R20, the rears 315/35/R20 (edit: fronts 275/45/R20, rears 305/40/R20). The road quality where I live is average, and I didn't have the opportunity to test drive the car extensively prior to the purchase. I find its ride quality unpredictable. The car struggles on uneven roads, where it tosses me a bit, but on poor roads it has a jarring ride, unacceptable for a car at this price point. I drove the car for 2000 miles, lowered the tyre pressure to the minimum acceptable, and while that improved the ride quality by ~10%, it still is unacceptable to me. The whole experience has been disappointing because there is so much else to like about the current generation x5, but now I'm considering selling the car. As a last ditch effort, I'm looking into the option of switching to non-run flats. Where I live the only affordable option is Nitto tyres. My question is, considering that these are 20" wheels, does switching to a non-run flat make a significant difference? It will be an expensive experiment with uncertain results, therefore I'm hesitant. I've read people saying it doesn't make a big difference on the 20" because of the suspension setup. I've considered downsizing to 19" rims although it is a major cost, the car will look far less appealing, and it may still not solve the problem... or should I just sell the x5 and look somewhere else?

According to Tirerack.com, your X5 came with 20" tires 275/45-20 whereas it is the 21" tires that has the staggered setup 275/40-21 front and 315/35-21 rear in rft's.

My previous X5 had 20" rft's Bridgestone Alenza 275/45-20 and I got about 45,000 miles out of a set. I never had any problems with them and they tracked well plus rode well.

My current X3M40 has a staggered setup in 20". Fronts are 245/45-20 and rears are 275/40-20. My tires are Bridgestone Alenza 001 and these tires are summer performance rft's. In a few months, I plan to replace these tires with non-rft Michelin Ultra High-Performance All Season Pilot Sport All Season 4. I ordered my suv with a spare.

Tire pressures are at the recommended psi that is shown on the inside of the driver's door. Many dealerships will add more psi to the tires. I caught mine doing it and reported them to BMW. Now when I take my suv to the dealership, they do not adjust my tire pressure. At one time, I found my tire pressure to be 9 psi higher than recommended.

 

[Autoputzer]

According to Tirerack.com, your X5 came with 20" tires 275/45-20 whereas it is the 21" tires that has the staggered setup 275/40-21 front and 315/35-21 rear in rft's.

My previous X5 had 20" rft's Bridgestone Alenza 275/45-20 and I got about 45,000 miles out of a set. I never had any problems with them and they tracked well plus rode well.

My current X3M40 has a staggered setup in 20". Fronts are 245/45-20 and rears are 275/40-20. My tires are Bridgestone Alenza 001 and these tires are summer performance rft's. In a few months, I plan to replace these tires with non-rft Michelin Ultra High-Performance All Season Pilot Sport All Season 4. I ordered my suv with a spare.

Tire pressures are at the recommended psi that is shown on the inside of the driver's door. Many dealerships will add more psi to the tires. I caught mine doing it and reported them to BMW. Now when I take my suv to the dealership, they do not adjust my tire pressure. At one time, I found my tire pressure to be 9 psi higher than recommended.

The OP's in Saudia Arabia, and the tire and wheel options on X5's sold there are different.

It's standard practice to adjust tire pressures to three or four PSI over the "decal pressures" when the tires are warm. That's because the tires and the air in them heat up 30 to 40 degrees F, and that increases the pressure three to four PSI, as predicted by The Ideal Gas Law.

The loaners I get from BMW of Bubbaville usually have inder-inflated tires, to make the cars/SUV's ride better with the OE run-flat tires.

Good call on the Michelon PS A/S 4's. Michelins tend to need less pressure than other brands to wear evenly, particularly compared to Goodyear and Continental.

My next BMW will be a 330i or 530i, and it will get Michelin PS A/S 4's put on as part of new car prep. I'm done with run-flat tires.

 

[rick47591]

The OP's in Saudia Arabia, and the tire and wheel options on X5's sold there are different.

It's standard practice to adjust tire pressures to three or four PSI over the "decal pressures" when the tires are warm. That's because the tires and the air in them heat up 30 to 40 degrees F, and that increases the pressure three to four PSI, as predicted by The Ideal Gas Law.

The loaners I get from BMW of Bubbaville usually have inder-inflated tires, to make the cars/SUV's ride better with the OE run-flat tires.

Good call on the Michelon PS A/S 4's. Michelins tend to need less pressure than other brands to wear evenly, particularly compared to Goodyear and Continental.

My next BMW will be a 330i or 530i, and it will get Michelin PS A/S 4's put on as part of new car prep. I'm done with run-flat tires.

I have found that all tires will not only perform better but will last longer and with fewer problems when the tires are checked cold rather than warm. I do realize tire pressure will rise as the tires heat up. I check my tire pressure every time I start my X3 in the morning. If it is low, I will add to the recommended. If it is high, I will adjust to the recommended manufacturer's pressures. By doing so, I have gotten more tire mileage and fewer problems. My tires wear evenly. I have rft tires. My X3M40i is designed to ride quite firm due to the M-suspension and I love it.

 

[ctdaveo]

It appears that someone may have changed the OE tire setup, as others have pointed out.
But one should be careful when switching tires, especially going to a non-OE level tire. The OE tire manufacturer has spent 2 - 3 years working with BMW to supply a tire which meets BMW's exact requirements, including ride quality and handling. Going to a non-OE tire, or even a non-OE level tire, can cause problems. Unfortunately, this is often not seen until an emergency situation (braking, avoidance) occurs. Runflat tires have progressed greatly from when they first came out, with ride and handling qualities much closer to non-runflats. Remember that the tire is part of the suspension system, changing them is like changing to a different shock/strut.

 

[Autoputzer]

The OP

It appears that someone may have changed the OE tire setup, as others have pointed out.
But one should be careful when switching tires, especially going to a non-OE level tire. The OE tire manufacturer has spent 2 - 3 years working with BMW to supply a tire which meets BMW's exact requirements, including ride quality and handling. Going to a non-OE tire, or even a non-OE level tire, can cause problems. Unfortunately, this is often not seen until an emergency situation (braking, avoidance) occurs. Runflat tires have progressed greatly from when they first came out, with ride and handling qualities much closer to non-runflats. Remember that the tire is part of the suspension system, changing them is like changing to a different shock/strut.

The OP posted a picture of his door jamb placard, and it seems to show that 20" staggered is an OE option in Saudia Arabia.

Don't drink the "run-flat and BMW OE tire" Kool-Aid.

I have the master broadcast sheet (build sheet) for Frau Putzer's G01 X3 30i. The broadcast sheet shows all the "internal" options for the car. There are about 60 of then for Frau Putzer's X3. 19" all-season tires are available OE as both run-flat and non-run-flat. There are not different internal suspension options for the two types of tires.

The run-flats that came on my 2014 535i sucked... a lot. Putting non-run-flats on transformed the car. The run-flats on the X3, X5, X7, 330i, and 330e loaners I've had recently also sucked. BMW Of Bubbaville under-inflates the run-flats on loaners so customers don't say "This BMW rides like crap. I'm going to buy a Lexus/Audi/Porsche/Land Rover instead."

 

[IdriveUscream]

I do not like run flat tires and have experienced both noise and ride quality issues with all run flats I have owned. I have upgraded all my BMW tires to non-run flats and the ride quality is MUCH BETTER. I recommend Michelin Pilot Sport series tires.

 

[Autoputzer]

I have found that all tires will not only perform better but will last longer and with fewer problems when the tires are checked cold rather than warm. I do realize tire pressure will rise as the tires heat up. I check my tire pressure every time I start my X3 in the morning. If it is low, I will add to the recommended. If it is high, I will adjust to the recommended manufacturer's pressures. By doing so, I have gotten more tire mileage and fewer problems. My tires wear evenly. I have rft tires. My X3M40i is designed to ride quite firm due to the M-suspension and I love it.

I've made wear pattern vs. tire pressure into a little science project of sorts, measuring tread depth with a high-resolution (0.001"), digital tread depth gauge.

The conclusions vary greatly by vehicle and tire, but here are two data sets of optimal pressures for even wear patterns:

F10 535i, 245/40-19 Michelin PS 4S's: even tire wear is at 39 PSI front and rear. That's ~10% over the decal pressures for the front and 0% over for the rear.

G01 X3 30i, 245/45-19 Bridgestone Dueler H/P Sport AS, non-run-flats: 39 PSI front and rear. That's ~20% over decal pressures for the front and ~10% over for the rear.

Both the Michelins and the Bridgestones came with about 1/32" more tread depth in the two middle channels than in the two side channels. Also, both vehicles have more average wear on one side channel that the other. The 535i's tires wear more on the inside channel, typical of BMW passenger cars. The X3's tires wear more on the outside channel, typical of BMW SUV's. So, a little bit of over-inflation will extend tire life.

 

[ard]

It appears that someone may have changed the OE tire setup, as others have pointed out.
But one should be careful when switching tires, especially going to a non-OE level tire. The OE tire manufacturer has spent 2 - 3 years working with BMW to supply a tire which meets BMW's exact requirements, including ride quality and handling. Going to a non-OE tire, or even a non-OE level tire, can cause problems. Unfortunately, this is often not seen until an emergency situation (braking, avoidance) occurs.

lol.

Sure.

Runflat tires have progressed greatly from when they first came out, with ride and handling qualities much closer to non-runflats. Remember that the tire is part of the suspension system, changing them is like changing to a different shock/strut.

I will just add that BRIDGESTONE runflats are expecially horrific.

ANY tire will be better. There are other- far better- tires made with the runflat feature.

Experts online refer to "runflats" as if it were one single tire. Not a feature that many tires have. Yes, the crap cheap tires manufactures get for $10 a tire to toss on new cars are jsut that- crap. But people only see "oh its a runflat? I hate runflats"- and in this self-fulfilling way, they pick a non runflat and - surprise- its better. Validating their decision.

OP if you want the runflat feature, consider a higher quality choice.

 

[ard]

I've made wear pattern vs. tire pressure into a little science project of sorts,

Does this project control for alignment?

 

[Autoputzer]

Does this project control for alignment?

Yeah, it does.

I compare inside channel wear to outside channel wear. If the differences are large, it's a sure bet the alignment is out.

My last measurements (PS 4S's with 2800 miles on them) showed 0.34/32" and 0.26/32" more inside channel wear than outside channel wear on the front tires, with an average front tire wear of 0.75/32" of wear.... classic slight toe-out or excessive negative camber wear pattern.

I got the car aligned, and sure' nuff..the right front tire had 0.11 degrees of toe-out.

Science!

 

[Autoputzer]

Radial tires are called that because the cords in the sidewalls are only in the radial direction. Cords don't stretch, but they do bend easily.

Bias-ply or diagonal-ply had the cords going in multiple directions and that stopped the sidewalls from stretching in any direction. Consider a deflated basketball. It doesn't have a flat spot. Instead it has a concave area on the surface. That's because the total surface area of the ball is constant. The same phenomenon happens with bias-ply tires. The sidewalls above the contact patch don't really stretch. So, the contact patch tends to invert and go concave. That concentrates weight and wear around the edges of the contact patch, increasing side wear and reducing performance.

With radial tires, the sidewalls can easily stretch in the circumferential direction (90 degrees from the radial direction) That sidewall stretching is why radial tires have a bulge at the bottom even when properly inflated. The stretching sidewalls of a radial tire allow the contact patch to conform to the pavement (becoming flat) instead of trying to go concave.

Run-flats are radial tires, because the cords are only in the radial direction. But, that sidewall reinforcement greatly diminishes the sidewall's ability to stretch in the circumferential direction. So, they tend to behave like bias-ply tires (more wear along the sides of the tires, as if under-inflated). You can mostly fix that by really jacking up the pressure. But, then they ride like they're made of concrete.

The breakthrough in run-flats will come when they make a sidewall reinforcement that is rigid in the radial direction, but that can stretch in the circumferential direction. In the meantime, run-flats suck. The worst were the Goodyear LS2's that came on my 535i. No more run-flats for me... until that breakthrough.

 

[Autoputzer]

Does this project control for alignment?

I just got my Interwebs connection back at the house. Here's the wear data of my PS 4S's after 2800 miles. Yellow cells are user input. Green cells are calculated values. Down at the bottom, entering the rotation paths, the tread depth is shuffled to be used by the table for the next rotation's data.

In addition to excessive inside wear on the front tires, I had almost perfectly even wear on the left rear tire (outside channel vs. inside channel). Normally, the rear tires on BMW passenger cars have more wear in the inner half of the tread. So, something was abnormal there. It turned out that I had excessive toe-in on the right rear tire (+0.23 degrees). It looks like the excessive toe on the right rear cancelled out the normal excessive inner half wear caused by BMW's negative camber on the rear tires. Go figure.

I'd hit a small pot hole since my last alignment. But, the car was tracking fine, probably better than directly after the last alignment. My "tire whispering" data analysis caught these alignment problems before they did significant damage to the tires. The alignment was $145. The four PS 4S's were $1100. Alignments are cheap compared to tires.

I bumped the front pressure from 38 PSI to 39 PSI for the current rotation stint. My four-tire average for side vs. middle channel wear that the middle channels are wore 0.06/32" more than the side channels. I'd like that to be 0.12/32" per rotation stint, since the two middle channels were about 1/32" deeper than the side channels when the tires were new. That extra 0.12/32" of wear in the middle would square up the tires perfectly by the time they're worn out.

Notice that my average wear across all four channels on all four tires was 0.96/32" in only 2800 miles. Max-performance tires wear really fast when they're new. So, I make my first rotation stint half that of the following seven rotation stints. I determine the duration of the last seven rotation stints by dividing the tires' expected life by 7.5 (40000 miles / 7.5 = 5333 miles), with the first rotation stint being half that (2667 miles).

Frau Putzer's X3 had an average of about 0.25/32" more wear in the outside channels than the inside channels. I got it aligned (front toe was off), and that average went down to about 0.10/32" on the next rotation stint.

 

[rick47591]

Hi everyone
Can anyone share their experience with switching to non-run flat tyres? My recently purchased like-new (< 500 miles) x5 40i has 20" Bridgestone run flats with regular steel suspension (no air suspension, no adaptive suspension). The fronts are 275/40/R20, the rears 315/35/R20 (edit: fronts 275/45/R20, rears 305/40/R20). The road quality where I live is average, and I didn't have the opportunity to test drive the car extensively prior to the purchase. I find its ride quality unpredictable. The car struggles on uneven roads, where it tosses me a bit, but on poor roads it has a jarring ride, unacceptable for a car at this price point. I drove the car for 2000 miles, lowered the tyre pressure to the minimum acceptable, and while that improved the ride quality by ~10%, it still is unacceptable to me. The whole experience has been disappointing because there is so much else to like about the current generation x5, but now I'm considering selling the car. As a last ditch effort, I'm looking into the option of switching to non-run flats. Where I live the only affordable option is Nitto tyres. My question is, considering that these are 20" wheels, does switching to a non-run flat make a significant difference? It will be an expensive experiment with uncertain results, therefore I'm hesitant. I've read people saying it doesn't make a big difference on the 20" because of the suspension setup. I've considered downsizing to 19" rims although it is a major cost, the car will look far less appealing, and it may still not solve the problem... or should I just sell the x5 and look somewhere else?

Are you sure your X5 has 20" tires? According to Tirerack.com, the X5 comes in 3 different tire sizes. This is a 2021 X540i. I am assuming this is what year you have. According to tire rack, 20" factory tires are 275/45-20 both front and rear. Tire rack also says the factory tires for 21" are 275/40-21 Front and 315/35-21 Rear.

 

[rick47591]

I've made wear pattern vs. tire pressure into a little science project of sorts, measuring tread depth with a high-resolution (0.001"), digital tread depth gauge.

The conclusions vary greatly by vehicle and tire, but here are two data sets of optimal pressures for even wear patterns:

F10 535i, 245/40-19 Michelin PS 4S's: even tire wear is at 39 PSI front and rear. That's ~10% over the decal pressures for the front and 0% over for the rear.

G01 X3 30i, 245/45-19 Bridgestone Dueler H/P Sport AS, non-run-flats: 39 PSI front and rear. That's ~20% over decal pressures for the front and ~10% over for the rear.

Both the Michelins and the Bridgestones came with about 1/32" more tread depth in the two middle channels than in the two side channels. Also, both vehicles have more average wear on one side channel that the other. The 535i's tires wear more on the inside channel, typical of BMW passenger cars. The X3's tires wear more on the outside channel, typical of BMW SUV's. So, a little bit of over-inflation will extend tire life.

This is my 3rd BMW and I am very anal about my tire pressures. I've always kept or rather tried to keep my tires within the recommended tire pressures and have never had any problems such as more wear on inside or outside of tires. I've noticed my tires all wear equally. I don't like over or under inflating tires. It hinders performance. I want my tires to grip in dry, rain, and snow. I've got friends that are LEO's and they're seen many wrecks that were caused by over and under tire inflation. I've asked them for their opinion on recommended tire pressures and they tell me to use the factory recommendation. I've had both RFT's and non-RFT's and always get 45k miles on the tires before I decide to get a new set. I will only buy either a Michelin or a Bridgestone. I've had some of the other tire brands and none of them performed or lasted like the Micks or Bstones.

 

[Autoputzer]

This is my 3rd BMW and I am very anal about my tire pressures. I've always kept or rather tried to keep my tires within the recommended tire pressures and have never had any problems such as more wear on inside or outside of tires. I've noticed my tires all wear equally. I don't like over or under inflating tires. It hinders performance. I want my tires to grip in dry, rain, and snow. I've got friends that are LEO's and they're seen many wrecks that were caused by over and under tire inflation. I've asked them for their opinion on recommended tire pressures and they tell me to use the factory recommendation. I've had both RFT's and non-RFT's and always get 45k miles on the tires before I decide to get a new set. I will only buy either a Michelin or a Bridgestone. I've had some of the other tire brands and none of them performed or lasted like the Micks or Bstones.

I'm on my fourth BMW, although my second one was only around 59 days and 914 miles due to it being involved in an unfortunate mishap. Let's see your tread depth data for all those 45k-mile tires.

I used to blindly follow the car manufacturer's recommendation on tire pressures. But, I'd usually end up with extra wear on the sides. The first time I really noticed this was with some Goodyear RS-A's (all-season high-performance tires, often used on cop cars). So, over decades my "tire whispering" method evolved. The advent of the digital tread depth gauge made everything come together. My top five mileages for a set of tires are: 79k miles, 74k miles, 70k miles, 70k miles, and 68k miles. My lifetime average is 54k miles, and that includes a lot of high-performance tires.

The Bridgestones on Frau Putzer's X3 should be good for somewhere past 60k miles. My service writer at BMW of Bubbaville is terrified that I'll tell her other customers about that, and they'll be furious.. at her.

The Michelin PS's on the back of my E46 M3 would wear more in the middle at the recommended pressure. That's the only time I've seen an over-inflation wear pattern at the decal pressures.

Michelins are very sensitive to pressure. It's easy to over-inflate them causing extra wear in the middle of the tread. But, that means they're also easy to dial them in for almost perfectly even wear. So, if Michelin makes a type and size of tire I'm buying, they're my choice.

Bridgestones are less sensitive to high pressure than Michelins. Goodyear and Continentals need a lot of pressure to wear evenly. I never could get my run-flat Goodyear LS2's to wear evenly. My one set of Pirellis were somewhere in between.

 

[Autoputzer]

Are you sure your X5 has 20" tires? According to Tirerack.com, the X5 comes in 3 different tire sizes. This is a 2021 X540i. I am assuming this is what year you have. According to tire rack, 20" factory tires are 275/45-20 both front and rear. Tire rack also says the factory tires for 21" are 275/40-21 Front and 315/35-21 Rear.

The OP's in Saudi Arabia, where X5's come with different tire and wheel combinations than they do here in the US. See Post #16.

 

[rick47591]

I'm on my fourth BMW, although my second one was only around 59 days and 914 miles due to it being involved in an unfortunate mishap. Let's see your tread depth data for all those 45k-mile tires.

I used to blindly follow the car manufacturer's recommendation on tire pressures. But, I'd usually end up with extra wear on the sides. The first time I really noticed this was with some Goodyear RS-A's (all-season high-performance tires, often used on cop cars). So, over decades my "tire whispering" method evolved. The advent of the digital tread depth gauge made everything come together. My top five mileages for a set of tires are: 79k miles, 74k miles, 70k miles, 70k miles, and 68k miles. My lifetime average is 54k miles, and that includes a lot of high-performance tires.

The Bridgestones on Frau Putzer's X3 should be good for somewhere past 60k miles. My service writer at BMW of Bubbaville is terrified that I'll tell her other customers about that, and they'll be furious.. at her.

The Michelin PS's on the back of my E46 M3 would wear more in the middle at the recommended pressure. That's the only time I've seen an over-inflation wear pattern at the decal pressures.

Michelins are very sensitive to pressure. It's easy to over-inflate them causing extra wear in the middle of the tread. But, that means they're also easy to dial them in for almost perfectly even wear. So, if Michelin makes a type and size of tire I'm buying, they're my choice.

Bridgestones are less sensitive to high pressure than Michelins. Goodyear and Continentals need a lot of pressure to wear evenly. I never could get my run-flat Goodyear LS2's to wear evenly. My one set of Pirellis were somewhere in between.

I decide to change tires when it is below the tire indicator. I could get more mileage if I slowed down and quit driving fast around corners and quit racing from stoplight to stoplight. Plus, I normally drive 15-25mph over the limit on highways and interstates. I could also get more mileage if I got touring tires that were designed to get higher mileage but I want and buy high-performance tires. I'm more than happy to get 45k miles out of a set.

Goodyears?!!??! OMG, never would I ever buy them. They're known for having problems. I've known many people to have them and have to get their vehicle's front end aligned every 15k miles. They also do not run true. Most are out-of-round when installed and require lots of wheel weights to balance it out. I'll continue to keep my tire pressures at the manufacturer's recommendations.

 

[Autoputzer]

My two sets of Goodyears were OE tires. When I go tire shopping, Goodyears aren't on my candidates list. The RS-A's did what they were supposed to. They just needed more air pressure. The LS2's were miserable tires.

 

[agc3168]

Are you sure your X5 has 20" tires? According to Tirerack.com, the X5 comes in 3 different tire sizes. This is a 2021 X540i. I am assuming this is what year you have. According to tire rack, 20" factory tires are 275/45-20 both front and rear. Tire rack also says the factory tires for 21" are 275/40-21 Front and 315/35-21 Rear.

Yes, this X5 has a staggered OEM 20" wheel (style 738) setup fitted with Bridgestone Alenza RFTs. The fronts are 275/45/r20 on 9" wide rims, the rears are 305/40/r20 on 10.5" wide rims. BMW sells this setup as part of the X-line trim in the Middle East.

 

[agc3168]

You really want the front and rear rolling diameters to be the same. Otherwise, your stability control will be confused, but that's not the worst of it. Different rolling diameters, even from different tread depths of identical tires front and rear, will tear up the clutches in your xDrive transfer case. The BMW repair manual spec's a maximum of 2mm difference in tread depths front and back.

Do whatever you want, but if it was me I'd bite the bullet and get matching 9" wide wheels for the back and then get some quality (e.g. Michelin) non-run-flats all the same stock size (275/45-20). With AIR (alignment, inflation, rotation), your tire worries would be over for the next 100000 km.

New OE wheels can be bought for $650 each in the US.

Genuine OEM BMW Wheel Part# 36116883757 Fits 2019-2021 BMW: Up To 35% Off On Every Order And Guaranteed Fit When You Enter Your VIN | Genuine BMW MINI Parts

There's a glimmer of hope. I searched online and across tyre dealers in my city and found perhaps the only viable non-RFT option that fits my car's current wheel size (fronts 275/45/r20, rears 305/40/r20). The tyre is Hankook Ventus S1 Evo 3 summer tyre. Not as good as the Michelins, but I hope better than Nankang. Does anyone have experience with these Hankooks from the standpoint of ride quality, tread wear, etc.?