May be I should try to add what information I can on OEM tires.
It’s the vehicle manufacturer who decides what tires get applied to his vehicle. There is a “spec sheet” that outlines what is required. This sheet ranges from a minimum of info (size, tread pattern type) to a complete description of all performance parameters (wet traction, snow traction, rolling resistance, etc.) Vehicle manufacturers generally specify quite a bit of the performance envelope – some the entire envelope! – and this is what creates the impression that the tires are “cheap”, meaning low quality.
To an engineer, quality has 3 components – consistency, compliance to design intent, and design intent. It’s this last one that seems to drive the impression of poor quality more than anything else in OEM tires.
Let me give you an example: Some vehicle manufacturers really push the envelope on rolling resistance. Rolling resistance can be improved (on a given tire) by sacrificing tread wear and / or traction, especially wet traction. Most vehicle manufacturers couldn’t give a “hoot” about tread wear and this is usually the item that is compromised. Also, the road surfaces used to determine the wet traction level by the OEM are sometimes quite different than some locales, leading to a situation where the vehicle manufacturer thinks the tire has an acceptable level of wet traction, but a significant number of owners experience issues. Left to their own devices, tire manufacturers would sacrifice RR for wet traction. I think you’ll find very few complaints about wet traction on tires that are strictly aftermarket designs.
So I think you’ll find that most complaints on OEM tires are about wet traction and treadwear.
Let me talk about tread wear for a moment.
Most new vehicle purchasers expect the vehicle to go a long distance (or time) before they have to perform maintenance. Some don’t even THINK about oil changes!
Many folks aren’t aware of (or don’t want to be bothered with) tire rotations, so when 20,000 miles comes and the front tires are worn out (on their FWD), they are surprised. Sometimes the front tires have alignment wear and, of course, the vehicle dealer (who can’t get reimbursed for doing an alignment) blames the tires (which he doesn’t warranty!) and sends the owner to the tire dealer.
The owner also looks on the internet for the mileage warranty for the tire and sees – say – 60,000 miles.
Here’s what the owner doesn’t realize:
1) Their rear tires still have plenty of wear left, and if they had rotated their tires, they would have gotten 40,000 miles – which is a respectable number.
2) The 60,000 mile wear warranty doesn’t apply to OE tires.
3) The 60,000 mile wear is a marketing position, not a guarantee.
I think the above situation occurs more often on inexpensive cars, and that’s why you hear more complaints about tires on these cars. To add to this many “expensive” cars are high performance cars and the tires are part of the performance package and they don’t wear very well BY DESIGN! Design intent can at least be explained.
Another factor in this “low OEM quality” equation is the HUGE population a particular OEM tire represents compared to an aftermarket tire. A car factory can produce up to 250,000 cars a year – that’s a million (!!!) tires. A tire factory may produce 50 million tires a year spread out over 1,000 different size / design combinations. So even a big runner for a tire factory is small potatoes compared to what an OEM factory consumes. This means that even small problems get magnified in the marketplace.
There’s quite a bit more I can add, but maybe it would be best if I let everyone chew on this for a while.