What Size PSS for OEM 19" Wheels?

[TahoeM3]

Originally Posted by M4GTS

Hi Folks

Reading this for the first time I can't believe the M5 has a 10" wide wheel with a 295 section tyre. Isn't this outside the recommended parameters for a 10" wheel and consequently a bad idea for the M3/4 also?

For those of you with 295 'M5' sized tyres on the rear, have you tried it with the standard 255 fronts and does/would it create too much of an inbalance?

Cheers

I kept the stock 255 fronts when I added 295 rears and have had no problems.

[soapman72]

Has anyone here moved from the BMW spec 255 front /275 rear Pilot Super Sports to the generic Super Sports? According to the specs shown at Tire Radk, the generics look to be about 1/2" wider. I was thinking about trying these instead of moving up to larger tires, if I will see an improvement in traction.

Thoughts?

[CanAutM3]

Originally Posted by soapman72

Has anyone here moved from the BMW spec 255 front /275 rear Pilot Super Sports to the generic Super Sports? According to the specs shown at Tire Radk, the generics look to be about 1/2" wider. I was thinking about trying these instead of moving up to larger tires, if I will see an improvement in traction.

Thoughts?

If you look at the table in the OP, the tread of the generic 255-275 are in fact 0.7" wider than the F8X specific ones. Further, the longitudinal "grooves" in the rear tires are less wide on the generic than on the OE PSS (see this thread). So the generic offer quite a bit more rubber on the road.

I would also like to hear feedback from that setup. I had the same on my E9X and really liked it. My buddy who bought my E92 from me parked it next to my F82 when it was still shod with the 255-275 OE tires. It was surprising to see how the generic 255-275 on the E9X sat much squarer and squatter compared to the specific ones on my F82. I might consider that setup when my 275/295 are worn down.

[solodkyg]

what's your general opinion on 265/35/19 - 285/35/19 setup? or do you think other options discussed here would be better setups for a DD

[CanAutM3]

Originally Posted by solodkyg

what's your general opinion on 265/35/19 - 285/35/19 setup? or do you think other options discussed here would be better setups for a DD

I would rather opt for the generic 255-275/35R19 over the 265-285/35R19 option. If you look at the table in my OP, the generic 275 offers a wider tread than the 285. The generic 255's tread is slightly narrower than the 265, but it is not really in the front that more grip is needed. Further, the generic 255-275 option is less expensive to boot .

[solodkyg]

thanks for your feedback, much appreciated

[Ian1973]

I'm going with the standard front and upsizing the rear...

255/35
295/30

[ssabripo]

Having used 255/275 OEM sizes, and now 275/295 /35 sizes - which worked pretty good so far, I think the best possible combo will be:

265/35f and 295/30 rears. That's what I'm going with next, and have a friend who has this (not in bimmerpost) who tracks all the time and loves this combo. I drove his car and on OEM suspension it felt more planted and natural than the 275/295 combo, with almost no discernable difference in looks than mine; hell, I say it looked even better (slightly wider look in rear, with just a tad more wheel gap in front).

will post with more info once I do it.

[CanAutM3]

Originally Posted by ssabripo

Having used 255/275 OEM sizes, and now 275/295 /35 sizes - which worked pretty good so far, I think the best possible combo will be:

265/35f and 295/30 rears. That's what I'm going with next, and have a friend who has this (not in bimmerpost) who tracks all the time and loves this combo. I drove his car and on OEM suspension it felt more planted and natural than the 275/295 combo, with almost no discernable difference in looks than mine; hell, I say it looked even better (slightly wider look in rear, with just a tad more wheel gap in front).

will post with more info once I do it.

Please also post how DSC/MDM behaves with this setup, as you will be running a reverse stagger in terms of diameters (26.3" front and 26.0" rear).

[ssabripo]

Originally Posted by CanAutM3

Please also post how DSC/MDM behaves with this setup, as you will be running a reverse stagger in terms of diameters (26.3" front and 26.0" rear).

yep, will do. That was also my concern from our previous conversations, but I actually thought his car behaved better than mine in terms of DSC. MDM i dont think will be a fair assesment until I have it one and try it on mine, given I'm driving the Euro MDM and he is still on US MDM, but DSC definitely looked as good if not better than my setup (engaged less in slight slips, engaged more rapidly in harder slips and traction).

i'll do a full analysis when time comes, but I'm gonna drive the crap out of these 275/295 tires in the next few weeks until I can eat up some of the thread and have an excuse

[Mperial]

Originally Posted by CanAutM3

Please also post how DSC/MDM behaves with this setup, as you will be running a reverse stagger in terms of diameters (26.3" front and 26.0" rear).

Question: Would the reverse stagger of this setup amount to merely a negligible intrusion of DSC/MDM for street-only use and only pose a problem if tracking the car? And what about those who've coded Euro MDM?

[CanAutM3]

Originally Posted by Mperial

Question: Would the reverse stagger of this setup amount to merely a negligible intrusion of DSC/MDM for street-only use and only pose a problem if tracking the car? And what about those who've coded Euro MDM?

I can definitely feel more DSC/MDM (Euro-MDM in my case) useless interventions when running either my square track setup or my winter setup. I find it rather annoying. A reverse diameter stagger would only make matters worse IMO.

[GPS/M4]

Originally Posted by CanAutM3

Pics as requested:

Stock suspension and no spacers.

Still running this setup? Have you had any problems? I've upgraded mine with a Turner tuning module and an aFe Magnum Force intake. I think I need to upsize my tires to help put the power to the pavement. I have heard from some others on this thread that 275/295 setup will work even with 10mm spacers. What do you think?

[ShePearl]

Great thread.

I've been pondering over tire sizes for my soon-to-be arrived BBS FI-R as well.

From my calculations, it seems to me that 265/35/R19 and 295/30/R19 are the most suitable sizes. They are closest to the stock diameter.

19" = 482.6 mm

M4 stock Michelin PSS
Front : 255/35/R19 => 482.6 + (89.25 x2) = 661.1 mm diameter (330.55 mm radius)
Rear : 275/35/R19 => 482.6 + (96.25 x2) = 675.1 mm diameter (337.55 mm radius)

New tire:
Front : 265/35/R19 => 482.6 + (92.75 x2) = 668.1 mm (334.05 mm radius)
Rear : 295/30/R19 => 482.6 + (88.5 x2) = 659.6 mm (329.8 mm radius)

Other options:
275/30/R19 => 482.6 + (82.5 x2) = 647.6 mm (323.8 mm radius)
285/35/R19 => 482.6 + (99.75 x2) = 682.1 mm (341.05 mm radius)
285/30/R19 => 482.6 + (85.5 x2) = 653.6 mm (326.8 mm radius)
305/30/R19 => 482.6 + (91.5 x2) = 665.6 mm (332.8 mm radius)

305/30/R19 for rear is closer than 295/30/R19 to the stock (275/35/R19) diameter/radius. However, from my reading around, it seems that 305 won't fit without camber adjustments..

[CanAutM3]

Originally Posted by evo2point0

Great thread.

I've been pondering over tire sizes for my soon-to-be arrived BBS FI-R as well.

From my calculations, it seems to me that 265/35/R19 and 295/30/R19 are the most suitable sizes. They are closest to the stock diameter.

19" = 482.6 mm

M4 stock Michelin PSS
Front : 255/35/R19 => 482.6 + (89.25 x2) = 661.1 mm diameter (330.55 mm radius)
Rear : 275/35/R19 => 482.6 + (96.25 x2) = 675.1 mm diameter (337.55 mm radius)

New tire:
Front : 265/35/R19 => 482.6 + (92.75 x2) = 668.1 mm (334.05 mm radius)
Rear : 295/30/R19 => 482.6 + (88.5 x2) = 659.6 mm (329.8 mm radius)

Other options:
275/30/R19 => 482.6 + (82.5 x2) = 647.6 mm (323.8 mm radius)
285/35/R19 => 482.6 + (99.75 x2) = 682.1 mm (341.05 mm radius)
285/30/R19 => 482.6 + (85.5 x2) = 653.6 mm (326.8 mm radius)
305/30/R19 => 482.6 + (91.5 x2) = 665.6 mm (332.8 mm radius)

305/30/R19 for rear is closer than 295/30/R19 to the stock (275/35/R19) diameter/radius. However, from my reading around, it seems that 305 won't fit without camber adjustments..

I don't know how much of the thread you read, but the 295/35R19 is actually closer to stock size than the 295/30R19.

Further, going with a 265/35-295/30 combo will have you running a larger diameter front vs rear. That is opposite to stock and will through off the DSC/MDM calibration and cause a lot of useless interventions.

Another benefit of the 275-295/35 combo is the possibility to use the rear tires in the front thus limiting the purchase to only two tires.

[ShePearl]

Originally Posted by CanAutM3

I don't know how much of the thread you read, but the 295/35R19 is actually closer to stock size than the 295/30R19.

Further, going with a 265/35-295/30 combo will have you running a larger diameter front vs rear. That is opposite to stock and will through off the DSC/MDM calibration and cause a lot of useless interventions.

Another benefit of the 275-295/35 combo is the possibility to use the rear tires in the front thus limiting the purchase to only two tires.

Indeed. You right. 295/35 is slightly closer to 275/35 (compared to 295/30) in diameter.
295/35/R19 => 482.6 + (103.25 x2) = 689.1 mm (344.55 mm radius)

[ShePearl]

Originally Posted by CanAutM3

Further, going with a 265/35-295/30 combo will have you running a larger diameter front vs rear. That is opposite to stock and will through off the DSC/MDM calibration and cause a lot of useless interventions.

Another benefit of the 275-295/35 combo is the possibility to use the rear tires in the front thus limiting the purchase to only two tires.

As for the DSC/MDM interventions due to diameter differences,
Stock : 255/35-275/35 = 14 mm (rear is larger)
265/35-295/30 = 8.5 mm (front is larger)
275/35-295/35 = 29.5 mm (rear is larger)

To me, going with 265/35-295/30 seems to provide smaller front-to-rear diameter differences. Can you elaborate on the useless DSC/MDM interventions due to larger diameter differences ?

[CanAutM3]

Originally Posted by evo2point0

As for the DSC/MDM interventions due to diameter differences,
Stock : 255/35-275/35 = 14 mm (rear is larger)
265/35-295/30 = 8.5 mm (front is larger)
275/35-295/35 = 29.5 mm (rear is larger)

To me, going with 265/35-295/30 seems to provide smaller front-to-rear diameter differences. Can you elaborate on the useless DSC/MDM interventions due to larger diameter differences ?

Read the thread, it is all there

DSC/MDM anticipates and detects loss of traction by monitoring speed differences between the different wheels. By running a smaller diameter in the rear, the rear wheels will need to spin faster to cover the same distance. This will trick DSC/MDM in thinking that the rear wheels are slipping more than they should be.

I can clearly feel this behaviour when running either my square track tires or winter tires, where DSC/MDM makes much more useless interventions. A 265/35-295-30 setup has a smaller rear tire diameter than the front, which is even worse than a square setup, hence DSC will believe the rear wheels are slipping even more.

Note, as per Michelin, the PSS diameters are as follows:
255/35R19 661mm
265/35R19 669mm
275/35R19 675mm
295/35R19 689mm
295/30R19 661mm

255/35-275/35 = 14 mm (rear is 2.12% larger) -> STOCK SIZE
265/35-295/30 = -8 mm (rear is 1.20% smaller)
275/35-295/35 = 14 mm (rear is 2.07% larger) -> Pretty darn close to stock

[ShePearl]

Originally Posted by CanAutM3

Read the thread, it is all there

DSC/MDM anticipates and detects loss of traction by monitoring speed differences between the different wheels. By running a smaller diameter in the rear, the rear wheels will need to spin faster to cover the same distance. This will trick DSC/MDM in thinking that the rear wheels are slipping more than they should be.

I can clearly feel this behaviour when running either my square track tires or winter tires, where DSC/MDM makes much more useless interventions. A 265/35-295-30 setup has a smaller rear tire diameter than the front, which is even worse than a square setup, hence DSC will believe the rear wheels are slipping even more.

Note, as per Michelin, the PSS diameters are as follows:
255/35R19 661mm
265/35R19 669mm
275/35R19 689mm
295/30R19 661mm

255/35-275/35 = 14 mm (rear is 2.12% larger) -> STOCK SIZE
265/35-295/30 = -8 mm (rear is 1.20% smaller)
275/35-295/35 = 14 mm (rear is 2.07% larger) -> Pretty darn close to stock

Cheers for the informative update.

In that case, I might as well stick with the stock 255/35-275/35 generic PSS option (if generic PSS indeed are 0.7 inch wider than F8X/F1X specific PSS).
FWIW, BBS FI-R 19" are 0.5 inch wider than 19" stock wheels. (9.5J front, 10.5J rear compared to 9J front and 10J rear of the stock wheels).

[ShePearl]

Originally Posted by CanAutM3

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.

While we're at it, I'd like to ask this question regarding DSC/MDM interventions due to differences in diameter (rolling radius).
Would weight difference in wheels matter in this case as well? or only rolling radius of the wheel & tire combined. If one opt for lighter wheel (compared to the stock 19" wheels), would this make any impact on the stock DSC/MDM calibrations ? (Lighter wheel requires less power to rotate/accelerate and stop/decelerate).

[CanAutM3]

Originally Posted by GPS/M4

Still running this setup? Have you had any problems? I've upgraded mine with a Turner tuning module and an aFe Magnum Force intake. I think I need to upsize my tires to help put the power to the pavement. I have heard from some others on this thread that 275/295 setup will work even with 10mm spacers. What do you think?

Nope. This setup came off on November 15th in favor of the winter setup .

Joke aside, I am still very pleased with the 275-195/35R19 combo with 5mm spacers in the rear. It will be coming back on on April 15th. I can't wait .

I found that the rear tires protruded too much for my liking with 12mm spacers. I think 8mm would be ideal. As for the front, I believe any spacer would cause rub when the wheels are steered. The 275/35 being both wider and taller than the 255/35 come very close to the fender liners even without spacers.

[M4GTS]

Do you need rear spacers with the BMW specific 295 rear?