Tires, tires, tires

7006 messages, Last post on Oct 29, 2009 at 11:24 AM

You are in the Maintenance & Repair Forum. Your Host is mr_shiftright

What is this discussion about? Tires, Wheels, Steering

Edmund's Feature Article: Tire Safety: Don't Ignore the Rubber on the Road

For dedicated winter tires, also have a look at the Snow/ice winter tires discussion topic.

Outline

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#2389 of 7006 inflation and contact patch by hpulley4 Jan 21, 2003 (7:39 am)
Tire inflation directly affects the shape of the contact patch. By increasing the pressure you'll make the patch narrower which can help some when driving in snow. Narrower tires will have a narrower contact patch, even at a lower pressure, which is why narrow tires generally work better in winter (World Rally Car ice tires are just 100mm wide!). Pumping up the pressure will also give you increased gas mileage but a rougher ride and possibly uneven (centre) wear. Performance all-season tires are generally not great in snow. To get an all-season rating all you have to do is make the tread pattern sufficiently empty, it doesn't have to pass any sort of winter tests or be any good in snow. Winter tires with the mountain and snowflake symbol must pass an actual test to get that rating.
#2390 of 7006 $100 Club by ryoken Jan 21, 2003 (8:02 am)
I'm usually lucky to get out of Costco under $200. Anybody take their luxury-brand cars to Costco for tires? Would you trust those guys to mount tires on an Infiniti, Lexus, or BMW?
#2391 of 7006 Steve by bretfraz Jan 21, 2003 (8:03 am)
"Club" membership varies. My parents spend a small fortune there every year; Costco sends them love letters and all kinds of special notices. I'm not that excessive but I still spend a lot of $$$ there. I have the willpower to actually walk out of Costco without purchasing a thing. That ain't easy, believe me. I'm headed back to Costco today, anyway. I think I saw a Rio 900 MP3 player for $129 the other day. Gotta go check it out!!
#2392 of 7006 $200 Club (OT) by steve_ HOST Jan 21, 2003 (8:19 am)
lol, I finally quit renewing my card. Fortunately we get a lot of visitors that belong Steve, Host
#2393 of 7006 shelf life of tires by steve_ HOST Jan 30, 2003 (3:16 pm)
I did a brief search in here but don't see where anyone had a definitive answer to the question of how long a tire will last - either stored in the tire warehouse or on the rim or as a spare. There must be a reason they stamp a date code on them.... Steve, Host
#2394 of 7006 A while back, someone posted that Costco by malachy72 Jan 30, 2003 (9:36 pm)
gives lifetime balance and rotation when you have the tires mounted there. This past summer I bought 2 tires at Costco and paid additional $ to have the 2 others balanced and remounted. I went back today for the rotation and the Mgr. said that I had to pay to have the 2 other tires balanced with the rotation service because it wasn't a lifetime deal as I hadn't purchased the tires there, only had paid for the balance and mounting. I told him that I had purchased the tires there, just not at the time of the last purchase. He researched on his data base, confirmed my story, and the balance and rotation was gratis on all 4 tires. Just a heads up on purchasing from source outside Costco and expecting lifetime service because Costco did the mounting.
#2395 of 7006 Re Shelf life on tires by capriracer Jan 31, 2003 (3:46 am)
It is hard to give a definitive answer to this question because temperature has such a strong effect. Let's start with the date code thing! This is a governement regulation dating from the 1970's. Prior to that time every tire manufacturer used a different system, so a standard system was put in place. One of the reasons for the date coding in the first place is to be able to track improvements. Unlike cars, which have model year changes a tire looks pretty much the same from the time a line is introduced, until it is obsoleted. There maybe a thousand changes from beginning to end. So being able to tell when a tire was produced (and where!), allows the manufacturer to judge the effect these changes have on performance. Now to shelf life. The biggest problem in this area is the amount of antioxidants (AO's) in the rubber, which will vary with the particular component being studied - tread will be different that sidewall, white sidewall will be different than black sidewall, etc. When a tire is in use, the flexing of the tire allows the AO's to migrate. But when a tire is not in use, the AO's are bond up in the rubber matrix. With a new (or used) tire, the surface of the rubber is attacked by the oyigen and ozone, and the AO's provide soething besides the rubber to attack. However the longer a tire is inactive, the more the AO's are used up, and since these are not being replenished by the supply below the surface, the rubber gets attacked. All of this is dependent on the temperature. If you remember high school chemistry, reactions double with every 10 F increase in temp. So a tire stored at 70F would last twice as long as 80F. I have these container units that many are storing tires in nowadays. I just cringe!! But let me give you a feel for this sort of thing. A tire ought to be sold within a year of production. It is probably OK to sell within 2 years. Any tire older than 6 years ought to be suspect. Anything over 10 ought to be replaced. Hope this helps.
#2396 of 7006 Thanks Capriracer by steve_ HOST Jan 31, 2003 (9:05 am)
I nosed around the net a little and it looks like UV exposure can be a big factor too. Some auto restorers claim to have drug 60 year old tires out of storage and found them useable, at least for the auto shows. Michelin claims that some of their aviation tires can last 30 years. The US DOD has a report that concludes anything over 5 years old should be replaced! I'm buying a 5+ year old low mileage car next month and I'm curious to see how the tires hold up - it's been running summer and winter tires so actual mileage on each set is less than 18,000 miles. Steve, Host
#2397 of 7006 Speed Rating Question by pghtiburon Jan 31, 2003 (10:55 am)
I have a 2001 Hyundai Tiburon and I need to a get a set of new tires. The stock tires (which weren't that great to begin with) had a V speed rating. The tires I'm thinking of getting (Yokahama Avid T4) have a T speed rating. Some tire shops are telling me that I shouldn't drop so much in speed rating, but I can't ever imagine driving over 118 mph so I don't particularly see what the big deal is. Any advice?
#2398 of 7006 Re: Speed Rating by ryoken Jan 31, 2003 (11:24 am)
I believe their recommendation is based mainly on liability. Manufacturers put tires on the car that can handle the car's top speed. They (and tire shops) don't want you to buy the T tires, go 130mph, have a blowout, and then sue them. S or T rated tires are plenty for normal daily commutes. Just know that there's an extra danger to going over the tire's limit, and if you sell the car with those tires on it, you should make sure the new owner knows, as you wouldn't want them to sue you, either. Other than that, I don't see what the big deal is, either.