Replace all tires for a flat one?

He is just trying to sell you tires! The ABS system is not going to be affected by the mere 1/4 of tread gain on one tire. YOu have 4 ABS sensors each one working independently of the other. I don't know what tires you have now or the condition of such. But on my Explorer I have BF G's All terrain TA's the ones in the front right now, have 13/32 of tread the back have 15/32 tread yes they are only about 6 months old. So, is your dealer going to tell me that my ABS is out of tune because of 2/32 o tread difference. If he did I would get it in writing then take them to the better business. If your tires are down to less than 3/32 of tread depth then you should replace all of them. He may have said that it can't be fixed for saftey reasons because as a general rule most tire facilities will not repair a tire that is less than 3/32 of tread depth or the hole is within

3/4 of a sidewall. I hope this helps, But please don't beleive the ABS crap, thats a sales tactic meant to worry you into new tires. Much like telling a woman (my wife) that her brakes are wearing down. I looked at the brake pads to find over half of the of pad left, they were fine. But it was said in order to "SELL THE SAFTEY" issue.

Searcher1

Your dealer is an "ASSHOLE" Find a good/honest tire store and talk with them. Most of them will tell you what can/can't be safely repaired. I only go back to the dealer for factory recalls or defects.

What I would do is buy a new tire to match, take the spare which should be new and put that on. This way you have two new tires on the same axle. Then I use the other that had 15k on it for the spare.

Janet

Previously in rec.autos.makers.ford.explorer, Janet proclaimed :

unfortunately, the dealer is correct. In a 4wd system, *all* tires must be replaced. The uneven tread depth that a new tire would can really mess up your 4x4 drive train.

If you never put the vehicle in 4x4 then it isn't an issue.

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We had a similar situation on our Sport Trac at about 20000 miles. The dealer suggested putting the new spare on in place of the cut tire. (Tire was cut, but not clear through). That's what we did and have had no problems with ABS or 4wd. I think your dealer just wants to sell tires. H

Absolute claptrap. Get yourself a new and HONEST dealer. It doesnot work that way....

If you have a locking rear end, you should have the same sized and brand of tires with similar tread wear on both sides. Because, different sized tires will greatly increase the wear and tear on your locking assembly (clutches) because the tires are unable to spin at the same rate.

If you have a 4x4 It is great practice to keep the same sized and brand of tires with similar tread wear on all 4 corners. I always do, But unless it is full time 4x4, or you are in the habit of running around in four wheel drive on dry pavement, it really is not that critical as long as the new tire is the same sized and brand as the other 3. If you have the locking rear end, make sure you have two "matching" on the rear axel.

I have owned and driven 4x4 Ford trucks and Bronco's for 25 years. I always replace my tires in sets of 4, (the newest truck will be sets of 6 :-0) the only time I have lost a tire to a catastrophic failure and have not had all

4 tires last the life of the set, was when I punched 2 separate sidewalls on two consecutive weekends on a fairly new set of tires. These tires were purchased from Les Schwab tires, a regional North West dealer who has offered full on and off road, unlimited warranty which covers sidewall punctures since I have been driving, they replaced both for free.

If you are not running around on dry pavement in four wheel drive, have the single new tire of the same brand and size put on the front and you will be fine.

Good Luck

Nope. The differential will take up any such minor differences in tire circunference. And since 4x4 should only be used when the tires can slip anyway, that's *really* not true.

A locking rear end should not be locked unless traction is poor enough to allow the tires to slip. This means that even with the diff locked, a minor difference in tire circumference won't matter.

Yes, same brand and size. But tire size is nominal; small differences occur within the same model. Ever see race teams measure their tires with an eye to placing the different sizes on different corners to improve handling? And these are racing tires; hand made, to be as uniform as possible. Tires bought 'off the rack', so to speak, are not identical. See above for the locking rear end thing.

Why would anyone run around in four wheel drive on dry pavement?

25 years? Not to sound like I'm making fun of you, but your post does not reflect the experience of four-wheeling for 25 years.

BULLSHIT! Obviously you have Zero experience with locking rearends. They lock according to the TORQUE being applied to them. They have ZERO input as to the condition of the traction!!! You stomp the gas both axels are locked and driven, regardless of traction conditions. DUH!

I currently have Four 4x4's and 3 cars that have locking rearends. I have rebuilt and set up more rearends then you have owned in your lifetime. I have worn out, twisted 31 spine axels, stripped the axel splines off and even grenaded a couple Ford 9 inch rearends. I have a thorough understanding of the design and function from the inside out.

If you are going to correct someone you really ought to understand what the hell you are talking about...

Duh! I don't, know, maybe they are driving a FULL-TIME 4x4, or who knows, but my point was, since the vast majority of 4x4's never drive around in four wheel drive on dry pavement, there would be no issues... Do you just generally have trouble with reading comprehension?

Your comments reflect embarrassing mechanical & reading comprehension... No number of years is likely to correct that...

And, pray tell, on pavement, how much time does your locker spend locked? Use a little common sense.

Generally every time you take off with more then 1/4 throttle... That for many drivers is every time the start from a stand still.

If you are going to correct someone you really ought to understand what the hell you are talking about...

understanding

Previously in rec.autos.makers.ford.explorer, Big Bill proclaimed :

this took all of 2 minutes to find. There's dozens of resources out there that say the same thing:

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"AZGuy" wrote in message news: snipped-for-privacy@4ax.com...

Do you have any clue how the clutch pack in a factory ford "locking" rear end works, or even a conventional mechanical Detroit locker? Cause you question doesn't indicate that you do...

Ford sells a Trac-Lok clutch-plate limited slip differential as a locking differential, although it is not a true locker. They do not offer a true locker, you would have to install or have that installed yourself. So if you order you truck from Ford with a "locking differential", you really have a Trac-Lok clutch-plate limited slip differential.

A conventional open differential sends equal amounts of torque to both axle shafts. If one wheel spins because of lost traction, it is sustaining zero engine torque, so zero engine torque is also going to the wheel with traction. The most common limited slip differentials found in performance cars and trucks are of the cone or clutch type. Many cone or clutch type differentials use preload springs to help keep some tension on the unit at all times. There is torque applied to both axels, not just when there is slippage.

Limited Slips: (LSD's) come in a variety of designs. Most use friction plates, cones and/or gears to reduce slippage between each of the tires. these units have a dual power path from the differential case to the axle shafts. some power is transmitted through the spider gears to the side gears in the conventional manner. The remainder is transmitted by friction between the differential case and the clutch plates and the side gears. A certain amount of "clutch preload" is built into the unit in a static condition. Then, as load is applied to the differential, the separation forces between the spider gears and the side gears increases this clutch loading. This increase in friction provides for a good positive power flow from the case directly to the side gears. When traction is available to both wheels, the power going to the differential causes the plates to bind tightly together, giving even power to both wheels. However, in a situation where there is little or no traction available to either one wheel or the other, the amount of power that can be transmitted to the other wheel which has traction is dependent on the friction or "preload" in the clutch plates. High levels of "clutch preload" will result in good torque transfer but some chattering of the clutches during cornering may occur. Lower levels of preload results in minimal chatter but reduced levels of torque transfer to the wheel with traction. Because LSD's restrict true differential action, tire wear is accelerated. Changes in vehicle handling may also occur, particularly in short wheelbase vehicles. Wear rates on limited slip differentials are generally higher than on other types due to the reliance on friction to reduce wheel slippage. Also, special lubricants may be required to minimize rough and noisy operation.

differences

comprehension...

That's an interesting article but I fail to understand the actual theory behind their claim:

"As an example of different tire diameters resulting from tires worn to different tread depths,..." "While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain"

In the above example, the difference in rotation at 60mph would amount to 4 rpm. If you have 4WD then the the front axle is disconnected from the driveline on the roadway anyway. If you have AWD then the transfer case is viscous coupled, which allows slippage between the front and rear axles. So difference in wear between front and rear axles is insignificant.

If you have open diffs then the amount of difference in rotational speed between wheels on teh ame axle is also of no consequence. Even if you have limited slip diffs, slippage between two wheels on the same axle at

4 rpm is hardly anything compared to the amount of slippage that occurs normally when steering. I cannot see where this would put undue "strain" on anything.

Obviously if you put a different sized tire on, or a different manufacturer the differences in circumference wiould be magnified and at some point *could* be significant.

It sounds to me like this theory is in the best interest of tire merchants or services that perform "shaving" to match the diameters.

I'd be interested in some hard evidence that shows a cause and effect relationship of worn driveline parts and slightly mismatched tires such as what one would expect from wear.

-Fred W