Advice on buying a new car..

iggibar said:

TCS can be a problem, but I've never heard of that problem due to replacing a new wheel or two with the same manufacturer. Te differences are too small. The only times I know of it happening is when people buy a new tire from a different manufacture as the rest, which apart from different diameter and circumference(can lead to more or less rolling per mile), they also have a different rolling resistance. People usually do this with cheap tires, which usually have much worse rolling resistance. If it has better rolling resistance, the problem is easier to cover up, but tread wear is still increased. When I read statements of people saying they are replacing a tire, I usually think of replacing the old with a new of same manufacturer. There are other problems too that can arise, but nothing is more serious than drivetrain damage.

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Subaru says if you run tires different (worn with new, etc. anything that will make a noticable difference in overall diameter) it can damage the center differential. I think the tire thing only really matters with cars with true AWD systems, like Subarus, VWs and Audi. Many of the new "AWD" cars aren't really AWD, they are front wheel drive that turn to 4wd when the front wheels start to slip.

Regarding the topic of having to replace all 4 tires on an AWD vehicle if one tire needs to be replaced due to a flat/damage due to a flat...it certainly depends a lot of how many miles are on the tires.

If the tires only have 10-15k on them...then the tread depth difference issue (3 existing tires vs. the single new tire)...certainly won't be as dramatic. But if all 4 tires have more like 40k+ on them (when the flat occurs)...and depending on what the max. mileage is for the tires...it may be a great idea to replace all 4 tires anyway...simply for the reason that all 4 tires may need to be replaced soon any way.

If the tires are in more of a "gray-area" (let's say 25-30k miles)...wouldn't all of the places that sell tires LOVE for you to think that all 4 tires NEED to be replaced. They certainly stand to make more money selling you 4 new tires...rather than just selling you 1 new tire to replace the bad/damaged one.

AND depending on how damaged the flat tire is (physically no longer usable vs. just a slow leak due to a puncture). A "slow leak" tire due to a puncture (assuming the puncture is in the tread area of the tire & not the tires side wall)...this tire can be repaired via a "plug". And a "plug kit" costs less than $5.00.

I've repaired MANY a "slow-leak" tire with a plug...and it performed perfectly for years & years and many many miles. So every punctured tire does not necessarily need to be immediately replaced either with a new tire (something else tire sales folks would like you to believe).

Just some food for thought.

- Nick

iggibar said:

TCS can be a problem, but I've never heard of that problem due to replacing a new wheel or two with the same manufacturer.

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Nor do I have actual or anecdotal experience confirming this. It's something I read about.

pigoo3 said:

If the tires are in more of a "gray-area" (let's say 25-30k miles)...wouldn't all of the places that sell tires LOVE for you to think that all 4 tires NEED to be replaced. (?)

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Well, maybe so, but my source was Consumer Reports, and I don't think they are in cahoots with tire manufacturers or retailers.

And of course, some tire punctures can be fixed and the tire can last for tens of thousands of miles. It's only when it can't be fixed that this TCS business would come into play.

As far as how many miles / how much tread wear would trigger such a response... The article I read didn't go into that much detail. But, when I replaced a tire on my Mitsubishi last month, there were only 10,400 miles on them. The tire dealer suggested putting the new tire on the rear until it had worn some so that the tendency to pull to that side if it were put on the front would be avoided. So there must be something to this varying tire tread conundrum.

Sorry folks, I didn't mean to derail the thread. I've heard the anecdotes from tire salesmen in the past and was just curious what the reasoning was.

toMACsh said:

So there must be something to this varying tire tread conundrum.

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Sure there is...it's called tire salespersons wanting to sell tires!

Sorry...many times I look at things with a "cynical-eye"...especially when it involves someone trying to remove money $$$ from my wallet. If someone is trying to sell someone something...they are almost always going to err on the side of the decision that involves them making money.

With automobile related issues...most drivers don't know enough about them to make an educated decision when a tire salesperson, auto mechanic, or auto parts store presents them with info. These folks sell things that are unnecessary to many folks on a regular basis...preying on their lack of automobile knowledge.

I'm certainly not saying that these folks (salespersons, mechanics, etc.) are ALWAYS trying to ripoff consumers...but many times consumers are purchasing things they don't need...or don't need right now (tires, brakes, exhaust systems, tune-ups, windshield wipers, shocks, etc.).

I think there are "perfect world" situations...and "real world" situations.

Maybe in a "perfect world" (where everyone has unlimited amounts of money)...maybe (technically) it would be "better" to replace all 4 tires on an AWD vehicle when one tire suffers damage & needs to be replaced.

But in the "real world" where folks can be living paycheck to paycheck (and one tire goes bad on the car)...many folks cannot afford to spend $400-$600 on a set of 4 new tires...just because one tire needs to be replaced.

And in the "real world"...there are many many things that automobile owners don't do that will MUCH MORE seriously effect the life of their vehicle than not replacing all 4 tires on an AWD vehicle when one tire goes bad (flat). #1 example...not doing regular oil changes.

Not doing regular oil changes is going to have a MUCH larger impact on the life of the car...than not replacing all 4 tires on an AWD vehicle when one tire goes bad.

A more realistic (middle of the road) tire solution would be...only replace two tires...the two tires on the same axle. So if one front tire needs to be replaced...then replace both front tires. And when the tires need to be rotated...the two (new) front tires go to the rear...and the two rear tires go to the front.

- Nick

As for tires I agree you do not have to buy all 4 but it is highly advisable to buy both front or rear depending on which had the damaged tire.
If you have a flat and the rim comes into contact with the bottom of the tire the internal belt damage is done and I would not trust it at highway speeds for extended periods.
Plugs are ok if the right plug is used which requires removing the tire from the rim and internally bonding the plug-patch.
Tires over the age of 10 years have already started to breakdown regardless of appearance.
Remember tires and brakes keep you and everyone around you from becoming a statistic.

I'm not sure if I should be giving advice about finding economical vehicles...




Personally, if I had to look for a car right now, I'd be looking at the Camry. It may not be the least expensive car on the market, but my wife walked away from this...



She now drives a 2007 Toyota 4Runner that we were basically given when my parents could no longer drive. It now has 100K miles on it and has only needed basic maintenance and wear item replacement.

Wow, Nick, you are cynical!
You do realize that the sentence you quoted from my post related to a tire already purchased, right? And the tire dealer was not trying to sell me more than one tire, just advising me on where this one tire should be positioned.

I did a quick search, and here is one link from that:
How to Replace Tires on AWD Cars | eHow

I would say that if an AWD vehicle owner was being advised by a mechanic not to have all four tires replaced (unless they have an irreparable tire after driving on a new set for 50 miles) should be suspicious. That is, if this shop could also do the replacement of the TCS, then they're trying to squeeze more money out of you!

toMACsh said:

Wow, Nick, you are cynical!

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Cynical comes from interacting with lots & lots of folks over the years (professionals) who either:

- really don't know what they're doing
- know what they're doing...but are trying to take advantage of a customer
- don't realize how much I know

Being a total DIY person...I have lots of knowledge about lots of things. So I usually have a VERY good idea when I'm interacting with a person if they are being truthful about what they are recommending...or trying to "pull a fast one" on a customer.

For example...the average auto owner has absolutely no idea:

- what causes brake problems on a car
- how the braking system on a car works
- what parts are involved in the braking system
- the difference between a worn out part & a good part

So if this average person goes to a mechanic and the mechanic says they need "xyz" brake part...since they don't know anything about car brakes...how can they really make an informed decision? So they just do what the mechanic says (necessary or not).

Ever see those commercials on TV where various national chain auto repair places advertise that they will inspect your car for "free"?? One example that comes to mind are "Meineke Car Car Centers".

How many folks do you think go there for a "free inspection"...and actually leave without buying or needing anything (or are told they "need" something)?? I'm going to say...not many.

That's because that's the "ploy" of these sorts of places. They "lure" the average person who knows nothing about automobiles into their shops for a "free inspection".

But just like the saying goes "There's no such thing as a free lunch."...there's no such thing as a "free inspection". When someone goes to one of these places...they're going to be told they "need" something. This is where being "cynical" comes from.

When you have 30+ years if DIY auto repair experience...have owned probably over 30-40 cars in that time (doing 90%+ of the repairs on them)...including pulling & replacing engines & transmissions. When you do (me) interact with an auto mechanic...they're going to have a very difficult time "pulling a fast one". And when they try to...I know immediately...and then I just walk away.

toMACsh said:

You do realize that the sentence you quoted from my post related to a tire already purchased, right? And the tire dealer was not trying to sell me more than one tire, just advising me on where this one dire should be positioned.

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You're right. I was in a hurry when I read & responded to your post ...and I missed that detail.

- Nick

Hey, here's another link with better news for some AWD owners, including Subaru owners!

http://www.4x4abc.com/4WD101/diffautoAWD_AWD.html


But, sadly, and aggravating to say the least, these experts contradict the above...

http://askville.amazon.com/replace-tires-AWD-car/AnswerViewer.do?requestId=2651049

Like I mentioned in an earlier post...with any topic we discuss...there will always be "perfect world" solutions...and "real world" solutions.

What if some unfortunate person has multiple flat tires in a 1-2 year time span (one flat tire at a time)?? Are they really going to have to spend $400-$600 on a new set of 4 tires each time they get a flat on their AWD vehicle??

A family of 4 with a household income of $30,000/year can't afford to spend this kind of money when they get 1 flat tire on an AWD vehicle.

This is where I was also saying that the mileage on the three "good" tires makes a big difference on what solution is used.

With this topic...maybe in a perfect world replacing all 4 tires when one tire is bad on an AWD vehicle would be the ideal solution. But in the real world where folks don't have $400-$600 to spend every time they have 1 bad tire...replacing less than all 4 tires is more reasonable.

Here's a list of "perfect world" things all of us should do...but don't:

- exercise daily
- don't over eat
- brush teeth 2x/day
- don't smoke cigarettes
- don't drink alcohol
- no road rage
- maintain a healthy weight (66% of Americans are over-weight or obese)
- don't yell at the wife
- eat more vegetables
- etc. etc.

In the "real world"...very very few of us are batting 1000 on the list above.

So when 1 tire is bad on an AWD vehicle...in a "perfect world" replacing all 4 tires may be the best thing to do. But in the "real world" where things aren't perfect...and not everyone can afford it...replacing fewer than all 4 tires is probably what's going to happen.

- Nick

toMACsh said:

Hey, here's another link with better news for some AWD owners, including Subaru owners!

http://www.4x4abc.com/4WD101/diffautoAWD_AWD.html


But, sadly, and aggravating to say the least, these experts contradict the above...

Why do I need to replace all 4 tires on my AWD car when only 2 are bad?

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The first article mentions that the Subaru Impreza has a different AWD system than the rest of the Subaru models is wrong. They all run the exact same system, depending on transmission.

Manuals get full-time all wheel drive with 50/50 torque split front-to-rear under normal conditions. Viscous coupling locking differential in the center inside the transaxle case, activates when wheels start to slip. Torque apportion from 80/20 tro 20/80.

4spd autos get automatic all wheel drive with 90/10 torque split front-to-rear under normal conditions (80/20 from 1996; 60/40 on Subaru Forester from 2009 and on). Electronically controlled hydraulic multi-plate transfer clutch installed instead of the center differential in the transaxle's tailshaft. Sensors monitor parameters such as wheel slippage, throttle position and braking, to help determine needed torque distribution to the rear axle.

And the new CVTs have a system similar to the autos. The only Subaru model that is different is the WRX STi. That has a DCCD (Driver-controllable Center Differential) system, so that the driver can control the power split, but will still transfer power to the wheels that have grip.

I'm going to have to agree with the Car Talk guys on their response. That falls more in line with what I've heard and read on Subarus. On a side note, my Impreza comes with a donut spare, so Subaru obviously thinks that it will be fine running a donut for a short period of time.

pigoo3 said:

Like I mentioned in an earlier post...with any topic we discuss...there will always be "perfect world" solutions...and "real world" solutions.

What if some unfortunate person has multiple flat tires in a 1-2 year time span (one flat tire at a time)?? Are they really going to have to spend $400-$600 on a new set of 4 tires each time they get a flat on their AWD vehicle??

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That depends on how much they've driven between flats, not how many months. So maybe the smart thing to do is save the three tires with 20,000 miles on them in case another one gets damaged beyond repair. You might get "lucky" that the other three new tires would have about the same mileage.

A family of 4 with a household income of $30,000/year can't afford to spend this kind of money when they get 1 flat tire on an AWD vehicle.

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That's the whole point, saving money. Replace all 4 when it is called for (as I said, not if the other tires have low mileage - ok, I exaggerated, using 50 miles if I recall) or spend even more to do it later AND replace the differential or other TCS components. Thus, if you can't afford either option, don't buy an AWD vehicle.

This is where I was also saying that the mileage on the three "good" tires makes a big difference on what solution is used.

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Several posts from different people have said the same, as do some of the "experts" linked.

With this topic...maybe in a perfect world replacing all 4 tires when one tire is bad on an AWD vehicle would be the ideal solution. But in the real world where folks don't have $400-$600 to spend every time they have 1 bad tire...replacing less than all 4 tires is more reasonable.

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Not necessarily. Depends on the mileage and the risk factor for mechanical failure, as outlined above, and above that.

Here's a list of "perfect world" things all of us should do...but don't:

- exercise daily
- don't over eat
- brush teeth 2x/day
- don't smoke cigarettes
- don't drink alcohol
- no road rage
- maintain a healthy weight (66% of Americans are over-weight or obese)
- don't yell at the wife
- eat more vegetables
- etc. etc.

In the "real world"...very very few of us are batting 1000 on the list above.

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I'm good on all of those. Really. (I do use 4 letter words from time to time, but that's not on the list. Darn!)

So when 1 tire is bad on an AWD vehicle...in a "perfect world" replacing all 4 tires may be the best thing to do. But in the "real world" where things aren't perfect...and not everyone can afford it...replacing fewer than all 4 tires is probably what's going to happen.

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And perhaps selling the vehicle with a bad differential because they can't afford to fix it...