[txc10]

Hi, everyone,

Just a heads up for those interested in the BMW i8 - I just had my tires replaced after less than 8,000 miles - I had no idea that the tires would wear out that fast, especially with mostly driving in "Comfort" mode and not too spirited, honestly.

The service guys at Momentum BMW in Houston, TX, told me that my mileage was actually good compared to others, and that others had their tires replaced after only 4,000 miles!

For comparison, my bro's 2016 Porsche 911 still has 7/32 tread left, after 11,000 miles!

How about you all? How many miles did you all get per set of tires on the i8? Happy New Year!

[shawnhayes]

I put a thread on "another" forum showing mine worn out with 16,000 miles. Many of those miles were put on the BMW snow tire package, which is also wearing FAST.



Shawn

[MalibuBimmer]

Mine went in 10,000 miles.

BMW offers "free" maintenance. (It's built into the purchase price, so it's not free.) But that doesn't include wear and tear items. And all my 21st century BMWs have worn out their tires at an amazingly rapid rate. My Mercedes vehicles all got 20,000+ with Bridgestones.

[shawnhayes]

Originally Posted by MalibuBimmer

Mine went in 10,000 miles.

BMW offers "free" maintenance. (It's built into the purchase price, so it's not free.) But that doesn't include wear and tear items. And all my 21st century BMWs have worn out their tires at an amazingly rapid rate. My Mercedes vehicles all got 20,000+ with Bridgestones.

Do you think that's maybe the reason they perform so well?

In my 17 years of doing track HPDE's, a car is only as good as its tires. And, taking a really CRAPCAN car and putting really good slicks on it makes it unreal on track. Is the "star BMW" designation for the tire a formula for great handling out of the box because the tires are much softer and stickier than the treadwear rating says?

Shawn

[MalibuBimmer]

Could be, Shawn. But I've put on replacement tires (Dunlops and Bridgestones) on the 6 series cars and they seem to wear out quickly, too.

(Where in Virginia? My daughter's at UVA. I visit her a lot.)

[JasH]

Narrower tyres = proportionally higher wear

[shawnhayes]

Originally Posted by MalibuBimmer

Could be, Shawn. But I've put on replacement tires (Dunlops and Bridgestones) on the 6 series cars and they seem to wear out quickly, too.

(Where in Virginia? My daughter's at UVA. I visit her a lot.)

Interesting that the replacement tires wear. Are you running the same rubber, better rubber from tire rack, or what?

Lynchburg VA. South of Charlottesville. Just north of VIR - where most of my "living" actually occurs. The rest is just activities making the driving possible.

Shawn

[shawnhayes]

Originally Posted by JasH

Narrower tyres = proportionally higher wear

At first, this was the most ludicrous proposal ever.

UNLESS you are considering lateral cornering wear, but even then, the differences are MINIMAL.

Consider: one inch strip wide of rubber around a wheel. For straight line, it goes round and round. It cares not whether it is surrounded by five inches of tire on each side or NONE. The ground contact is the same, mile per mile. The wear for straight line driving is the same regardless of wide or narrow tire. Braking and hard acceleration are excluded.

When cornering, lateral traction is increased SLIGHTLY by wider tires. Wear will increase some on a narrow tire due to lateral slip, but just a little. Skinnier tires don't equal proportionally more tire wear.

Of note, the photo above - the tires that wore THE MOST were the rear. They are wider, and are used MUCH LESS on my car than the fronts. I spend most of the life of this car in electric mode. So, the rears should have worn much less - especially if your proposal is true. It's not.

Shawn

[YWGT3]

Originally Posted by shawnhayes

At first, this was the most ludicrous proposal ever.

UNLESS you are considering lateral cornering wear, but even then, the differences are MINIMAL.

Consider: one inch strip wide of rubber around a wheel. For straight line, it goes round and round. It cares not whether it is surrounded by five inches of tire on each side or NONE. The ground contact is the same, mile per mile. The wear for straight line driving is the same regardless of wide or narrow tire. Braking and hard acceleration are excluded.

When cornering, lateral traction is increased SLIGHTLY by wider tires. Wear will increase some on a narrow tire due to lateral slip, but just a little. Skinnier tires don't equal proportionally more tire wear.

Of note, the photo above - the tires that wore THE MOST were the rear. They are wider, and are used MUCH LESS on my car than the fronts. I spend most of the life of this car in electric mode. So, the rears should have worn much less - especially if your proposal is true. It's not.

Shawn

While I am perplexed about the excessive tire wear txc10 experiencing (mine are exceeding more than double of his tread life), I would have to agree with JasH that the narrower profile tires would experience greater wear, provided it is under spirited or track driving. The wider profile tires, under the same brand and specifications lasted markedly longer in my 911 Turbo. However, I would agree with you that the difference in wear would be deminimus if we're talking about daily public road driving. In regards to why your rear tires may have worn most despite the i8's all wheel drive configuration, it could possibly be due to the torque split ratio being biased toward the rears. In my MB CL63, where it's 100% rear wheel drive, I've been through two sets of rear tires, before having to replace the fronts.

[YWGT3]

Originally Posted by txc10

Hi, everyone,

Just a heads up for those interested in the BMW i8 - I just had my tires replaced after less than 8,000 miles - I had no idea that the tires would wear out that fast, especially with mostly driving in "Comfort" mode and not too spirited, honestly.

The service guys at Momentum BMW in Houston, TX, told me that my mileage was actually good compared to others, and that others had their tires replaced after only 4,000 miles!

For comparison, my bro's 2016 Porsche 911 still has 7/32 tread left, after 11,000 miles!

How about you all? How many miles did you all get per set of tires on the i8? Happy New Year!

I bought a sports car a while back and experienced abnormally high tread wear on its tires. Took it out on the track a little too early without properly breaking them in. Other than that, I'm perplexed as to why you're getting 4,000 miles on your set as I'm nearly tripling the tread wear while driving 90% of the time in sports mode.

[Amgeater2]

Originally Posted by txc10

Hi, everyone,

Just a heads up for those interested in the BMW i8 - I just had my tires replaced after less than 8,000 miles - I had no idea that the tires would wear out that fast, especially with mostly driving in "Comfort" mode and not too spirited, honestly.

The service guys at Momentum BMW in Houston, TX, told me that my mileage was actually good compared to others, and that others had their tires replaced after only 4,000 miles!

For comparison, my bro's 2016 Porsche 911 still has 7/32 tread left, after 11,000 miles!

How about you all? How many miles did you all get per set of tires on the i8? Happy New Year!

Wow... 8,000 miles is crazy, but 4,000 miles is ludicrous. So basically you are getting an oil change and tires ? Straight bs from BMW

[stressdoc]

We need a poll to gather information on tire wear. I have always gotten 20k+ miles on tires, even on the M3.

[shawnhayes]

Originally Posted by YWGT3

While I am perplexed about the excessive tire wear txc10 experiencing (mine are exceeding more than double of his tread life), I would have to agree with JasH that the narrower profile tires would experience greater wear, provided it is under spirited or track driving. The wider profile tires, under the same brand and specifications lasted markedly longer in my 911 Turbo. However, I would agree with you that the difference in wear would be deminimus if we're talking about daily public road driving. In regards to why your rear tires may have worn most despite the i8's all wheel drive configuration, it could possibly be due to the torque split ratio being biased toward the rears. In my MB CL63, where it's 100% rear wheel drive, I've been through two sets of rear tires, before having to replace the fronts.

For high speed and track driving, I admit, the slip angle would cause more wear.

But, I think you need to understand, I spend VERY little time in this car with the rear wheels powered. NEVER launched. NEVER raced. That's what my GT-R is for. This is my daily driver. I would guestimate that 80% of it's miles have been spent in pure electric (i.e. only front wheels powered), while the rears were freewheeling (or maybe regenerative braking?). So, for power reasons, the fronts which are narrower, should have worn quicker.

I think the rear compounds are softer than the fronts (because of sizes, but I could be terribly wrong). It is either that, or the rears are doing the regenerative braking and wearing because of that. Unknown to me at this time, but not easily explained with skinny vs. wide.

shawn

[YWGT3]

Originally Posted by shawnhayes

For high speed and track driving, I admit, the slip angle would cause more wear.

But, I think you need to understand, I spend VERY little time in this car with the rear wheels powered. NEVER launched. NEVER raced. That's what my GT-R is for. This is my daily driver. I would guestimate that 80% of it's miles have been spent in pure electric (i.e. only front wheels powered), while the rears were freewheeling (or maybe regenerative braking?). So, for power reasons, the fronts which are narrower, should have worn quicker.

I think the rear compounds are softer than the fronts (because of sizes, but I could be terribly wrong). It is either that, or the rears are doing the regenerative braking and wearing because of that. Unknown to me at this time, but not easily explained with skinny vs. wide.

shawn

You bring up a good point which could be the culprit to the excessive rear tread wear. Perhaps the preponderance of regenerative braking is being applied towards the rear set of tires, where there's larger contact and less hindrance on overall traction and control as opposed to applying most of the regenerative force towards the front. However, if the problem lies within the rubber compound, I'd be inclined to consider switching out the OEM wheels in order to accommodate a set of Michelin Pilot Super Sports for the better handling and reasonable tread life that I've experienced in other performance cars.

[MalibuBimmer]

My front and rear tires wore out at the same time. And quickly. So FWD makes sense for the fronts. Does regenerative braking actually involve the rears?

[Aye-eight]

Over 14'000 miles here, split between summer tires and winter tires. Still on first sets for both, and so far they both look like they can go another season. Driving speeds here in Switzerland are similar to the US. But I have taken the car to Germany a couple of times, each time covering a few hundred miles going as fast as possible.

But Swiss roads usually are in impeccable condition. I'm wondering if txc10 has to drive on particularly poor surfaces - like that grooved concrete you sometimes find in the US. I'm sure that would add to tire wear.

Also, did the wear pattern get inspected? Any indication of misalignment or incorrect pressure?

Finally, it might have to do with individual driving styles. You do see it in racing: some drivers get more life out of their tires than others, while not being slower. ;-)

[stressdoc]

I'm thinking Michelin Pilot super sports might be wise too. Higher wear rating (300), overall excellent tire. Not available here in 215/45/20, so one would need to move to a wider, lower profile size.

Please enter data for your tire wear on the poll thread.

[shawnhayes]

Originally Posted by stressdoc

I'm thinking Michelin Pilot super sports might be wise too. Higher wear rating (300), overall excellent tire. Not available here in 215/45/20, so one would need to move to a wider, lower profile size.

Please enter data for your tire wear on the poll thread.

Way ahead of you here...

(although maybe you thought of it before me, but I've had that tire in mind since the first two months I had it)

Pilot Super Sport 245/45 R20 will fit the front AND REAR of the staggered 7.5 / 8.5 Pure Impulse (and many other) i8's, AND fit the square 7.5 snow tire package, AND the square European 7.5 inch setup.

http://www.tirerack.com/tires/tires....SSXL&tab=Specs

Won't fit some of the Euro spec 7 inch wheels.

AND this setup should decrease understeer, and improve handling A LITTLE BIT.

Shawn

[shawnhayes]

Originally Posted by YWGT3

You bring up a good point which could be the culprit to the excessive rear tread wear. Perhaps the preponderance of regenerative braking is being applied towards the rear set of tires, where there's larger contact and less hindrance on overall traction and control as opposed to applying most of the regenerative force towards the front. However, if the problem lies within the rubber compound, I'd be inclined to consider switching out the OEM wheels in order to accommodate a set of Michelin Pilot Super Sports for the better handling and reasonable tread life that I've experienced in other performance cars.

Agree. I've been plotting Pilot Super Sports for over a year. Just not ready to pull the trigger until late January. I have my BMW winter tire and wheel package on now, which performs QUITE WELL in the snow.

Shawn

[Aye-eight]

Originally Posted by shawnhayes

For high speed and track driving, I admit, the slip angle would cause more wear.

But, I think you need to understand, I spend VERY little time in this car with the rear wheels powered. NEVER launched. NEVER raced. That's what my GT-R is for. This is my daily driver. I would guestimate that 80% of it's miles have been spent in pure electric (i.e. only front wheels powered), while the rears were freewheeling (or maybe regenerative braking?). So, for power reasons, the fronts which are narrower, should have worn quicker.

I think the rear compounds are softer than the fronts (because of sizes, but I could be terribly wrong). It is either that, or the rears are doing the regenerative braking and wearing because of that. Unknown to me at this time, but not easily explained with skinny vs. wide.

shawn

I think it's rather unlikely that the same tire has markedly different compounds for its different sizes. That would make things very unpredictable.

Having read through the car's brochure again, it seems the regen is done by the small motor-generator that sits in the rear. But it seems odd that this should lead to significantly higher tire wear, when the traction in e drive (and a good share of the torque in any event) comes from the front.

If the rear tires are really wearing that much faster, and the car is not constantly driven hard in Sport mode, I'd seriuosly have tire pressures and wheel alignment checked.

[363ny]

Originally Posted by shawnhayes

Way ahead of you here...

(although maybe you thought of it before me, but I've had that tire in mind since the first two months I had it)

Pilot Super Sport 245/45 R20 will fit the front AND REAR of the staggered 7.5 / 8.5 Pure Impulse (and many other) i8's, AND fit the square 7.5 snow tire package, AND the square European 7.5 inch setup.

http://www.tirerack.com/tires/tires....SSXL&tab=Specs

Won't fit some of the Euro spec 7 inch wheels.

AND this setup should decrease understeer, and improve handling A LITTLE BIT.

Shawn

HI Shawn,

If you go down this path - with Pilot Super Sport 245/45 R20 for the front and backs - I am very eager to hear your thoughts once you have some miles under your belt with this set up. I am very interested in doing the same. Love the MPSS tires - great overall ride, great transaction and very reasonable wear characteristics.

On a related note - I also wonder if the 8.5 rear wheels would fit the front and then I would purchase an extra 2 for the rear and I could run a square 8.5" wheel with the 245/45R20 all around? Anyone try this?

Jeff

[shawnhayes]

Originally Posted by Aye-eight

I think it's rather unlikely that the same tire has markedly different compounds for its different sizes. That would make things very unpredictable.

Having read through the car's brochure again, it seems the regen is done by the small motor-generator that sits in the rear. But it seems odd that this should lead to significantly higher tire wear, when the traction in e drive (and a good share of the torque in any event) comes from the front.

If the rear tires are really wearing that much faster, and the car is not constantly driven hard in Sport mode, I'd seriuosly have tire pressures and wheel alignment checked.

Tire pressures are spot on. So is alignment.

Many many tires use slightly different compounds for different sizes. They are not Dramatically different, but they are different.

Thanks for the hint on regen. I spend a lot of time trying to one pedal drive, not easy on the I8, but easy on the i3. I'll bet that's what's up with my wear.

Shawn