Originally Posted By: smithph
At one time (20 plus years ago) tire manufactures would grade the tires coming off the line with a mark on the bead (so it would not show once mounted on the rim). Those that graded out as top tier (visual inspection, air inflation test, and spin balance test) went to auto manufactures and all others went to the replacement market unless they were judged blems or unsafe. At the time auto manufactures wanted the oem tires to be quite and and have good ride quality (and not much else, just those items that help influence the sale of the car). It was not good to have tires requiring excessive lead weights hanging off the rim on a new car, not much eye appeal. I do not know if this practice still takes place but one would hope manufacturing capability has improved to the point it is not required anymore.
Well .....ah..... where to start?
To my knowledge, the practice of sorting tires existed more than 40 years ago and exists today. I really didn't want to go into this because it is complex and there isn't any standardization within the industry, but it isn't exactly like SmithPH described, so perhaps it would be good to clear up some misconceptions.
For as far back as I can go - and that would be 40 years (my sources run out before that) vehicle manufacturers have specified what they wanted for tires and the tires were specially designed and built to those specifications - and they were different than what would be designed (and built) if the tire manufacturers were left to do it themselves.
There are traction specifications, ride specifications, rolling resistance specs, dimension specs, etc. Wear is not pretty high on the list of important specs.
The spec sheet is fairly brief, but long. The spec sheet consists of an item (Generally an ASTM Test number) and a performance minimum value. It has so many different items that it can run into 2 pages.
While most of the specifications are for design, some of the specifications are for manufacturing tolerances - such as balance and uniformity (think of it as "roundness" but that isn't quite accurate.) In the manufacturing process, tires are marked and sorted in various ways. I don't know that I ever saw markings on the bead, but markings on the sidewall are common. Paint dots, wax dots - later ink jet spots and letters - now some are using dyes that show up only under black light.
So the OEM gets the best tires, and a slightly lower grade would go to the aftermarket. And this is where it gets a bit sticky.
When the OEM annouces a tire program it is generally 2 years before the first tire has to be delivered. Since mold takes 4 to 6 months to get, the tread pattern has to be agreed upon in the first year and a half - and then fine tuning of the construction can take place up to a month before start of production (SOP).
BTW, this process is called qualification and the company I work for has a staff of engineers stationed in Detroit, Tokyo, and Frankfort, as well as other cities near the engineering centers for the vehicle manufacturers - all dedicated to getting tires qualified.
Interestingly, the price that the OEM pays isn't decided after tire is designed. It's decided well before start of production. I don't understand this process well (the sales guys like to make it seem like magic), but my impression is that it takes place about a year before SOP. It is timed to give the tire guys enough time of get a ballpark idea of what the tire will cost to produce, but not enough time to finalize this. I suspect the timing is more driven by the OEM's accounting and marketing departments rather than the purchasing department.
Part of what gets factored into the price is the generation of what are called "downstreams" - tires that don't meet the OEM manufacturing tolerances. A new tire size will have no market for these tires, so it will be months before the first tire is sold (punctures!), so the tires sit in the warehouse.
Sometimes the OE's specs are soooo tight, that a lot of downstream tires get generated, and it may be years until the inventory gets to reasonable level. This is a cost to the tire manufacturer - and hopefully it is passed on to the OEM for specifying a new size (probably, not!)
The first step in the qualification proces are the things that cost the least. The whole idea of this is to reduce the time and expense of testing different versions of the proposed tire.
So the tread pattern is generally first followed by laboratory tests (Force and moment, rolling resistance), followed by on vehicle tests (ride, traction, handling, noise) and lastly durability and wear tests.
It's the ride evaluations that are the most arduous. Ride engineers seem to have to justify their existence so they frequently reject all the samples submitted. This means a delay of 4 weeks while more groups of tires are built.
And it goes around and around. Renerally the ride engineers run out of time and have to take the best compromise that they find. Remember I said the molds have to be ordered 6 months before SOP, but testing continues - This is why!
So there is some truth to the OP's statement about OE tires being higher quality. However, the system of sorting tires is gradually disappearing as the manufacturing processes become more refined. For some tires, there isn't any difference at all between the OE and the replacement market.
But I want everyone to get this clearly.
A tire that comes with a new car or truck is designed specifically for that car or truck. So a tire in a different size with the same name on the sidewall will be different - sometimes dramatically, sometimes not. So be very careful when evaluting a tire that came on a new car. It's more a reflection of the car manufacturer than the tire manufacturer.
At one time (20 plus years ago) tire manufactures would grade the tires coming off the line with a mark on the bead (so it would not show once mounted on the rim). Those that graded out as top tier (visual inspection, air inflation test, and spin balance test) went to auto manufactures and all others went to the replacement market unless they were judged blems or unsafe. At the time auto manufactures wanted the oem tires to be quite and and have good ride quality (and not much else, just those items that help influence the sale of the car). It was not good to have tires requiring excessive lead weights hanging off the rim on a new car, not much eye appeal. I do not know if this practice still takes place but one would hope manufacturing capability has improved to the point it is not required anymore.
Well .....ah..... where to start?
To my knowledge, the practice of sorting tires existed more than 40 years ago and exists today. I really didn't want to go into this because it is complex and there isn't any standardization within the industry, but it isn't exactly like SmithPH described, so perhaps it would be good to clear up some misconceptions.
For as far back as I can go - and that would be 40 years (my sources run out before that) vehicle manufacturers have specified what they wanted for tires and the tires were specially designed and built to those specifications - and they were different than what would be designed (and built) if the tire manufacturers were left to do it themselves.
There are traction specifications, ride specifications, rolling resistance specs, dimension specs, etc. Wear is not pretty high on the list of important specs.
The spec sheet is fairly brief, but long. The spec sheet consists of an item (Generally an ASTM Test number) and a performance minimum value. It has so many different items that it can run into 2 pages.
While most of the specifications are for design, some of the specifications are for manufacturing tolerances - such as balance and uniformity (think of it as "roundness" but that isn't quite accurate.) In the manufacturing process, tires are marked and sorted in various ways. I don't know that I ever saw markings on the bead, but markings on the sidewall are common. Paint dots, wax dots - later ink jet spots and letters - now some are using dyes that show up only under black light.
So the OEM gets the best tires, and a slightly lower grade would go to the aftermarket. And this is where it gets a bit sticky.
When the OEM annouces a tire program it is generally 2 years before the first tire has to be delivered. Since mold takes 4 to 6 months to get, the tread pattern has to be agreed upon in the first year and a half - and then fine tuning of the construction can take place up to a month before start of production (SOP).
BTW, this process is called qualification and the company I work for has a staff of engineers stationed in Detroit, Tokyo, and Frankfort, as well as other cities near the engineering centers for the vehicle manufacturers - all dedicated to getting tires qualified.
Interestingly, the price that the OEM pays isn't decided after tire is designed. It's decided well before start of production. I don't understand this process well (the sales guys like to make it seem like magic), but my impression is that it takes place about a year before SOP. It is timed to give the tire guys enough time of get a ballpark idea of what the tire will cost to produce, but not enough time to finalize this. I suspect the timing is more driven by the OEM's accounting and marketing departments rather than the purchasing department.
Part of what gets factored into the price is the generation of what are called "downstreams" - tires that don't meet the OEM manufacturing tolerances. A new tire size will have no market for these tires, so it will be months before the first tire is sold (punctures!), so the tires sit in the warehouse.
Sometimes the OE's specs are soooo tight, that a lot of downstream tires get generated, and it may be years until the inventory gets to reasonable level. This is a cost to the tire manufacturer - and hopefully it is passed on to the OEM for specifying a new size (probably, not!)
The first step in the qualification proces are the things that cost the least. The whole idea of this is to reduce the time and expense of testing different versions of the proposed tire.
So the tread pattern is generally first followed by laboratory tests (Force and moment, rolling resistance), followed by on vehicle tests (ride, traction, handling, noise) and lastly durability and wear tests.
It's the ride evaluations that are the most arduous. Ride engineers seem to have to justify their existence so they frequently reject all the samples submitted. This means a delay of 4 weeks while more groups of tires are built.
And it goes around and around. Renerally the ride engineers run out of time and have to take the best compromise that they find. Remember I said the molds have to be ordered 6 months before SOP, but testing continues - This is why!
So there is some truth to the OP's statement about OE tires being higher quality. However, the system of sorting tires is gradually disappearing as the manufacturing processes become more refined. For some tires, there isn't any difference at all between the OE and the replacement market.
But I want everyone to get this clearly.
A tire that comes with a new car or truck is designed specifically for that car or truck. So a tire in a different size with the same name on the sidewall will be different - sometimes dramatically, sometimes not. So be very careful when evaluting a tire that came on a new car. It's more a reflection of the car manufacturer than the tire manufacturer.
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