Couple of observations on my summer tire set...?

[sjeupie]

Hi all,

My Z4 23i is still standing in winter storage but it was a nice sunny Sunday so I felt like properly cleaning the summer rims that are lying in my garage, now that I can easily get to the backside, before getting them on in a month or so.
I've never driven them; purchases my Z4 just before Christmas with its winter wheels and tires on, but I took a closer look at the RFT summer set yesterday (18") and I noticed a couple of things:

- 2 of the 4 tires clearly are in worse condition than the other 2. I assume these were placed in the rear...?
- 1 of those 2 is in a clearly worse shape than the other, especially towards the outside. No even wear. Allignment?
- When rolling the wheels trough my garage, some of them could simply stand straight by themselves. Others would fall over (towards the exposed side if fitted on the car). Result of uneven wear?
- I happen to have a 2 times 225/35/R18 and 2 times 225/40/R18. Now this was a surprise...? Do all Z4's come with differents sizes front to back? The 35's are the worn set btw.

My car has run 40.000km. I suspect 90% of that to be driven on the summer set. Could it be that the last owner replaced 2 of the 4 tires and put on 40's instead of 35's on? Maybe to place the rear of the car 5mm higher in the rear? Sounds odd to me though...

Attached a picture to show the big difference in wear between two tires.


What do you guys think? Play safe and replace all 4 and ask for proper allignment?

[paris1]

First, the wear differential you're seeing rear to front is typical of the Z4. That's why when I switched from RF tires to non-RF I bought a tire I knew would be around for a while (Bridgestone Pole Position S-04) because I know I'll need to buy a second set for the rear when they're shot and the fronts are only half way gone. Second, you clearly have an alignment issue on the one with the greater outside shoulder wear. All this is part of the joy of owning a BMW. Nothing unusual here. Also, the staggered wheel size front to rear is common on this model and if I were you, I'd jettison all four and replace them with non-RFTs. You won't believe the difference in ride quality!

[sjeupie]

Thank you Paris1, you've confirmed my assumptions.

The 35's are most worn. Those were in the back. So I guess nothing has been replaced.
They are ready for the garbage bin imho. To bad I don't know which tire was placed where; that would have helped in the alignment.

Anyway, I'll look a bit around for a new set. Thnx for your suggestion on the Bridgestones. I've seen the Michelin PS PS2 (ZP for runflat) and Continental ContiSportContact 2 N2 coming by as well already. I'll check the forum cause surely this has been discussed already, and check for prices as well. Non RF are about 25% cheaper as well I saw, so that helps...!

[bigendbob]

I just bought these for my 23i here in the UK from Tyreleader Germany,
294 style wheel.
Goodyear Eagle F1 Asymmetric 2 225/40 R18 92Y XL Front
Goodyear Eagle F1 Asymmetric 2 255/35 R18 94Y XL Rear
Front and rear wheel not interchangeable.
Non RFT but way better handling, steering, noise and grip.

Your sizes seem a bit odd.

[paris1]

Originally Posted by sjeupie

Thank you Paris1, you've confirmed my assumptions.

The 35's are most worn. Those were in the back. So I guess nothing has been replaced.
They are ready for the garbage bin imho. To bad I don't know which tire was placed where; that would have helped in the alignment.

Anyway, I'll look a bit around for a new set. Thnx for your suggestion on the Bridgestones. I've seen the Michelin PS PS2 (ZP for runflat) and Continental ContiSportContact 2 N2 coming by as well already. I'll check the forum cause surely this has been discussed already, and check for prices as well. Non RF are about 25% cheaper as well I saw, so that helps...!

Those are both good tires. You'll find the majority of owner's here prefer the Michelin PSS, which I considered, but opted for the Bridgestones because of cost considerations.

[sjeupie]

Originally Posted by bigendbob

I just bought these for my 23i here in the UK from Tyreleader Germany,
294 style wheel.
Goodyear Eagle F1 Asymmetric 2 225/40 R18 92Y XL Front
Goodyear Eagle F1 Asymmetric 2 255/35 R18 94Y XL Rear
Front and rear wheel not interchangeable.
Non RFT but way better handling, steering, noise and grip.

Your sizes seem a bit odd.

Good eye! I didn't look correctly and it is indeed 255/35/R18 instead of 225. The size differense front to back makes a lot more sense now.

I love the 294 btw. Got the 293 for summer myself though, and 290 for winter.

[jparnes1]

It's normal to get inside wear on the rear tires due to the camber. Some people opt for a square set up for improved handling and this also lets you rotate the tires.

[airmarc]

Originally Posted by jparnes1

It's normal to get inside wear on the rear tires due to the camber. Some people opt for a square set up for improved handling and this also lets you rotate the tires.

Very true about the camber. I also found out (the hard way) that the RH rear tire will actually wear faster than the LH rear due to the drive train location.

And FYI, I too switched from the original stock RFTs to Non RFTs, and then decided to go back to the newest 3rd generation RFTs, the technology and ride is dramatically better these days. Very happy with them.

[paris1]

Originally Posted by airmarc

Very true about the camber. I also found out (the hard way) that the RH rear tire will actually wear faster than the LH rear due to the drive train location.
I just had an alignment at a my local dealer and am always amazed at the difference in camber front:rear. -2 degrees + in the rear and no where near that at the front.

And FYI, I too switched from the original stock RFTs to Non RFTs, and then decided to go back to the newest 3rd generation RFTs, the technology and ride is dramatically better these days. Very happy with them.

Good to know, but they're still ungodly expensive!

[jparnes1]

Originally Posted by airmarc

Very true about the camber. I also found out (the hard way) that the RH rear tire will actually wear faster than the LH rear due to the drive train location.

And FYI, I too switched from the original stock RFTs to Non RFTs, and then decided to go back to the newest 3rd generation RFTs, the technology and ride is dramatically better these days. Very happy with them.

You can rotate the tires side to side to even out that wear pattern.

[sjeupie]

So, narrowed my search down to two sets of tires. The Michelin Super Sports are not available for the rear axle (255/35/R18) so the 'obvious' choice is a no-go. Leaves me, for now, with:

Michelin Pilot Sport 4
Front 225/40 ZR18 92Y XL
Rear 255/35 ZR18 94Y XL
Fuel: rating C
Rain: rating A
Noise: rating 71db
Cost: CHF 625 (USD 650)

Goodyear Eagle F1 Asymmetric
Front 225/40 R18 92Y XL (mfs)
Rear 255/35 R18 94Y XL (mfs)
Fuel: rating C
Rain: rating A
Noise: rating 67db
Cost: CHF 570 (USD 595)

The odds are in favour of the Goodyears it seems. These are 'mfs' tires, which implies rim protection. No idea what that actually physically changes to the tire. For the same price they are available without the rim protection. Any experiences anyone? It sounded like a nice addition to have.

Anyone some final remarks before I pull the trigger? The Bridgestones and Continental's were all 'worse' on paper so I skipped them straight away.

[Wozich]

I have the Michelin PS4 tyres on mine. PS4's are new and were released this year, while the Goodyear Eagle F1 Asymetric 2 are quite old. There is a new Asymetric 3 tyre out now.

But I'm very satisfied with the Michelin PS4, much better than the OEM Bridgestone RFT's in terms of comfort and grip (wet and dry). No idea how it compares to the Goodyear, many people on this forum recommend them, so you probably can't go wrong with both of them.

[Karnidge]

Rim protection is a little rubber lip that sticks out past the wheel.

[paris1]

Originally Posted by Karnidge

Rim protection is a little rubber lip that sticks out past the wheel.

Don't pretty much all tires have that? Some are a little more pronounced than others.

[sjeupie]

Originally Posted by paris1

Don't pretty much all tires have that? Some are a little more pronounced than others.

High profile tires often do not. I guess because the sidewall bulbs out enough anyway to protect the rim.