Varying tire widths yet same size

[ahyeah]

I was looking at the spec sheet for the Continental ContiSport 5P that came stock on the S3. There's a couple different versions in 235/35R19 aspect yet they quite different width dimensions. The first is the OE tire, I believe. What is up with the other two? I see no difference in the 2nd tire other than tread width. The third has a different speed rating, slightly shallower tread, and is listed as "RO2 Audi" instead of "AO". Is the last tire (a full .5" wider) a shallower tread depth to maintain rolling radius?? As this demonstrates not all 235 width tires measure the same, is that also true of the 35% aspect ratio? All three are listed as 815 revs per mile (fwiw). Do they all have the same sidewall height or do they vary because the true width varies?:

235/35R19
"AO Audi"
91Y XL
UTQG 240 AA A
Max Load: 1356
Tread depth: 10/32
Weight: 21lbs
Tread width: 8.2"
Revs per mile: 815

235/35R19
"AO Audi"
91Y XL
UTQG 240 AA A
Max Load: 1,356
Tread depth: 10/32"
Weight: 21 lbs.
Tread width: 8.5"
Revs per mile: 815

235/35ZR19
"RO2 Audi"
91Y XL
UTQG 240 AA A
Max Load 1,356 lbs.
Tread depth: 9/32"
Weight: 22 lbs.
Tread width: 8.8"
Revs per mile: 815

https://www.tirerack.com/tires/tires...3&autoModClar=

[ahyeah]

And in general, how accurate are the manufacturer's dimensions? Looking at the OE Pirelli P Zero that now comes on the S3 in the US, the tread with is 7.6" yet another version in the same "size" is listed as having a 9" width!

[bakedcorn]

Not sure if this helps:

The "AO" marking signifies that this tire is approved and fitted as original equipment by Audi. These tires can be mixed with standard non-homologated tires.

An Audi R01/R02 is a compound of tire that is "matched" to the car, it is also a narrower shoulder so does not foul on the arches or running gear of the car.
Geared towards R and RS models.

[MathildaS3]

Pirelli almost always runs narrow for the indicated size.

[ahyeah]

Not sure if this helps:

The "AO" marking signifies that this tire is approved and fitted as original equipment by Audi. These tires can be mixed with standard non-homologated tires.

An Audi R01/R02 is a compound of tire that is "matched" to the car, it is also a narrower shoulder so does not foul on the arches or running gear of the car.
Geared towards R and RS models.

That helps. By "shoulder" do you mean the side profile of the tire would be more squared off? Assuming the extra width isn't causing rubbing, aside from the added weight what would be the drawback of fitting these tires as opposed to the AO design? Is it possible they have an identical rolling diameter and sidewall height yet are .5" wider?

[ahyeah]

Oh I wouldn't buy these tires, I'm just curious about the variations in size since I'm in the market for summer tires. The new PS4s are tempting, but I may just stick to the PSSs for their proven stiffness. And, conveniently, they should be one of the widest treads available in the 235/35 size if manufacturer specs are to be believed.

[WildHareMS]

Pretty much all tires in a 235/35-19 are going to have different footprints. The width of a tire vary greatly from manufacturers, and as you're seeing even in the same manufacturer. The overall width of the tire, 235, probably doesn't change at all. That being said, 235mm is actually close to 9 1/4"...and you'll notice none of the advertised tread widths come anywhere near that. So don't think of the 235 as being an actual width of tread when shopping.


Sent from my iPhone using Tapatalk

[rex_racer]

Generally speaking a tire's size is accurate across manufacturers when it comes to diameter. When you are looking at tire width, tires between and within manufacturers will vary along width and shoulder curvature. Even though they are listed as the same width, that number is never truly representative. Its best to look at the tires specs which lists out the actual width as measured on a specified rim. Those numbers tend to be very accurate and should be used when selecting tires for wheels and dictating clearance.