What Size PSS for OEM 19" Wheels?

[dmk08]

Originally Posted by CanAutM3

In what sizes?

If they are in the same 255-275/35R19 size as the OEM, look at the table in my OP. The non-specific (generic) offer a 0.7" wider contact patch front and rear. The generic rears also have thinner grooves in the thread and therefore have more rubber on the road compared to the specific 275/35R19 PSS.

They are 275/295. I just didn't expect as much of a difference as I got from a 20mm upgrade esp w/ a shorter sidewall.

[TahoeM3]

Originally Posted by Brosef

awesome review - thank you. so how is ride comfort? any pictures you could post would obviously be a great favor to many of us

Just do it already!

Honestly, it makes a huge difference in the way the car drives, handles, and looks. The car should definitely have come like this from the factory...the only reasons I can think of for why it didn't are that BMW purposely wanted to limit performance either to keep it from being faster than the M5/M6 or to leave room for improvement with GTS. Either way, the car is dramatically improved with these wider tires.

[JoeFromPA]

Everything I know about contact patches tells me going to wider tires with the same tire design and same compound should not yield a better traction experience. (i know the size of the void areas may have changed)

That being said - if the experience is this much better - awesome.

My theory is that BMW deliberately under-tired the car because:

1. It can do amazing things with 255/275 michelin PSS
2. They had michelin tweak the PSS to be more wet-friendly from the factory
3. They prepared to sell a perf package

[gthal]

Originally Posted by JoeFromPA

Everything I know about contact patches tells me going to wider tires with the same tire design and same compound should not yield a better traction experience. (i know the size of the void areas may have changed)

That being said - if the experience is this much better - awesome.

My theory is that BMW deliberately under-tired the car because:

1. It can do amazing things with 255/275 michelin PSS
2. They had michelin tweak the PSS to be more wet-friendly from the factory
3. They prepared to sell a perf package

I agree but I also think the compound on the BMW PSS may be different... hence good wet traction but perceived lower traction in the dry. As we know, manufacturers will have specifically designed versions of a tire for their car (the PSS on my C7 Z51 was notably stickier than any other PSS I have experienced and Chev commented the outer half was almost an r compound compared to the PSS on the non-Z51 C7). So, going to a generic PSS may actually have a sufficiently different design (tread surface, carcass, compound) to improve performance in the dry.

Clearly speculation but it seems to match up with both the positive experiences people have had with alternate sized PSS and the negative experiences people have with OEM PSS on the M3/4.

[JoeFromPA]

Yes, I definitely think my PSS is not consistent with others. I've got ~6k miles on mine now and the tire noise is quite notable - a pretty unusual finding for PSS. Tire pressures are fine, wear is good, so this is just a loud wearing tire.

I'm looking forward to switching it up when the time comes, as I feel the stock tires leave a good amount to be desired - they are pricey, are loud now, and don't produce enough traction under WOT.

[gthal]

Originally Posted by JoeFromPA

Yes, I definitely think my PSS is not consistent with others. I've got ~6k miles on mine now and the tire noise is quite notable - a pretty unusual finding for PSS. Tire pressures are fine, wear is good, so this is just a loud wearing tire.

I'm looking forward to switching it up when the time comes, as I feel the stock tires leave a good amount to be desired - they are pricey, are loud now, and don't produce enough traction under WOT.

I hope to wear out mine soon and replace them with Potenza RE-11 in a 255/285 size.

[CanAutM3]

Originally Posted by JoeFromPA

Everything I know about contact patches tells me going to wider tires with the same tire design and same compound should not yield a better traction experience. (i know the size of the void areas may have changed)

I don't know how much of the thread you have read, but there are many misconceptions and myths out there regarding tire behaviour and performance.

The most common myth is that contact patch size (area) is equal to the tire load divided by the tire pressure (or L=P*A) . The reason this is not valid is because the load is shared between the tire pressure and the tire carcass (L=P*A + Fc). For instance, if you reduce the pressure of a tire from 40psi to 20psi, you will not double the contact patch area. In the same respect, if double the load on a tire, the contact patch area does not double. The carcass behaves similarly to a spring, where the more a tire needs to deform to carry a load, the more of the load is carried by the carcass. For this reason, in some cases, going with a wider contact patch also yields a larger contact patch area and hence more grip. There comes a point of diminishing return though, and the trick is to find the sweet spot.

IMHO, on the F8X, that sweet spot does not seem to reside with the stock widths of 255 and 275.

[Mr.D]

CanAutM3, from the original post it isn't clear which 275/295 set-up you have purchased. I'm assuming the OE M5 295s for the rears?

If so, I look forward to hearing your feedback once you have installed.

I ordered the OE M5 rear tires and plan to install the moment I take second delivery of my car. While I was doing my Euro Delivery trip I found the stock tires lacking in traction through gears 1-3 under WOT.

Cheers

[CanAutM3]

Originally Posted by Mr.D

CanAutM3, from the original post it isn't clear which 275/295 set-up you have purchased. I'm assuming the OE M5 295s for the rears?

I ordered the OE M5 rear tires and plan to install the moment I take second delivery of my car. While I was doing my Euro Delivery trip I found the stock tires lacking in traction through gears 1-3 under WOT.

Cheers

Not sure what is not clear . Going with 275-295 in 35 profile implies the OE M5 rear tires.

Good choice on your purchase, you'll love the setup .

Originally Posted by Mr.D

If so, I look forward to hearing your feedback once you have installed.

It's all in my OP, look under the "EDIT" section .

[TahoeM3]

Originally Posted by CanAutM3

Not sure what is not clear . Going with 275-295 in 35 profile implies the OE M5 rear tires.

Good choice on your purchase, you'll love the setup .



It's all in my OP, look under the "EDIT" section .

There are two different types of MPSS in 295/35/19. To answer his question, the one he wants is the BMW spec one, which is the one from the M5.

[TahoeM3]

Originally Posted by Mr.D

CanAutM3, from the original post it isn't clear which 275/295 set-up you have purchased. I'm assuming the OE M5 295s for the rears?

If so, I look forward to hearing your feedback once you have installed.

I ordered the OE M5 rear tires and plan to install the moment I take second delivery of my car. While I was doing my Euro Delivery trip I found the stock tires lacking in traction through gears 1-3 under WOT.

Cheers

Yes, that's correct...the BMW spec version, which is the OEM M5 rear tire.

[CanAutM3]

Originally Posted by TahoeM3

There are two different types of MPSS in 295/35/19. To answer his question, the one he wants is the BMW spec one, which is the one from the M5.

Yes, there is the Mercedes OE and BMW OE 295/35R19, but my OP is clear about using the BMW OE from the M5 .

Further, the Mercedes OE one does not offer a contact patch as wide as the BMW OE one .

[Greg FEightytwo]

Can someone post photos of what their wheels look like with wider tires on them with the specs? I have HRE wheels same specs as the stock 437m wheels except better offset in the front. I wanted to put one size up on width but not sure what it will look like?

Thanks,

Greg

[CanAutM3]

Pics as requested:

Stock suspension and no spacers.

[JTO24]

Looks really good! Glad to hear the set-up is working out well.

[JoeFromPA]

That is the first M4 I have actually felt was as gorgeous as an m3. Well done sir - Silverstone + black wheels + black tips = perfect

[CanAutM3]

Originally Posted by JoeFromPA

That is the first M4 I have actually felt was as gorgeous as an m3. Well done sir - Silverstone + black wheels + black tips = perfect

Those are actually the MPE Ti tips and are not blacked-out. They developed a nice patina and certainly pop much less than the OE chrome tips.

[Mr.D]

Apologies for the confusion on my question - I read two options for 275/35 and 295/35 and didn't note the 30 aspect ratios for those tire widths. Your original post was clear and I was the foggy one!

In any event, pics looks great.

More importantly, how is the ride/handling/traction?

[Padfan9]

I don't like the look of the tires bubbling over the wheels.

I am waiting for my Klassens to come in. 9.5 front and 11 rear. + 20 and + 40.

I think you are missing the top 2 tire options.

I am either going with

265/35/19 and 295/30/19

OR

265/35/19 and 305/30/19

[CanAutM3]

Originally Posted by Padfan9

I don't like the look of the tires bubbling over the wheels.

I am waiting for my Klassens to come in. 9.5 front and 11 rear. + 20 and + 40.

I think you are missing the top 2 tire options.

I am either going with

265/35/19 and 295/30/19

OR

265/35/19 and 305/30/19

My poll is specific about tires for the OEM 19" wheels, so a 305 would be too large for a 10" wheel.

Further, the front/rear combinations I posted all respect the OEM front-to-rear diameter stagger to not upset the DSC/MDM calibration. A 265/35 and 295/30 combo has the rear at a smaller diameter than the front and would yield a lot of useless DSC/MDM intervention.

[Padfan9]

Originally Posted by CanAutM3

My poll is specific about tires for the OEM 19" wheels, so a 305 would be too large for a 10" wheel.

Further, the front/rear combinations I posted all respect the OEM front-to-rear diameter stagger to not upset the DSC/MDM calibration. A 265/35 and 295/30 combo has the rear at a smaller diameter than the front and would yield a lot of useless DSC/MDM intervention.

Can you expand on that point?

What would you recommend i do for the perfect set up?

For 9.5 et 20 and 11 et 40 ?

I was told 255/35/19 and 295/30/19 or 265/35/19 and 305/30/19. Is that best? I want wider and more aggressive, flush with the wider 9.5 and 11 but don't want rubbing.

[CanAutM3]

Originally Posted by Padfan9

Can you expand on that point?

What would you recommend i do for the perfect set up?

For 9.5 et 20 and 11 et 40 ?

I was told 255/35/19 and 295/30/19 or 265/35/19 and 305/30/19. Is that best? I want wider and more aggressive, flush with the wider 9.5 and 11 but don't want rubbing.

Ideally, you would want a rear tire that has a diameter ~2.3% larger than the front. The 255/35 - 305/30 is the better of the two options you mention with the rear 1.1% larger, but it is still not ideal.

If the rear wheel rolling radius (tire diameter) is smaller than supposed to, it needs to spin faster to travel the same distance. The DSC system will be under the impression that the rear tire is slipping more than it actually is and will therefore make interventions way before traction is actually lost. This can be quite annoying. I run a square setup (same diameters front and rear) for winter and do get a lot of useless DSC intervention.

Recommended wheel width for a 305/30R19 tires are between 10.5" and 11.5" with 11" being the ideal width.