do i have to replace all four tires? had a flat...

at home service is always sort of a gray area.. with oil changes and things like that for warranty purposes we accept proof of purchase of oil/parts as long as they seem to be installed properly its acceptable

with tire rotation etc theres no real way to "prove it" but if all 4 tires wear out evenly (ie you buy 4 tires, and they ALL wear out at the same time, the tire companies put up much less fight for warranty purposes. regardless of what/how many tires are being warrantied, 9/10 times im asked tread depths on all 4 tires in 3 places (inner tread, outer tread, center tread) these measurements will show over/under inflation, lack of rotation, improper alignment etc in most cases

sorry for the TJ!

back on topic sorta.. here is the michelin video circ was talking about, the very beginning of the video even calls needing 2 tires a "situation" ie not the norm

http://www.michelinman.com/tire-care...artire-change/


to the OP.
more info would be helpful in making a good decision too. actual tread depth measurements rather than %, the model of the tires in question etc.

if you do 2 tires, just be sure they are identical to the other two on your VX (size, tread pattern and speed rating, if they are factory dueler HTs be weary, there are 3-4 different types of dueler HT out there). and as stated before, make sure the new tires wind up on the rear both for traction and for the sake of your TOD

just to put into perspective, on a non awd vehicle 5/32 of tread is considered the max we will allow tires on one axle to differ to ensure ride quality/predictability and the VX essentially has a differential between the front and rear

Sorry it took me so long to reply. I ended up buying all four new... I got the michelin LTX A/S partly because they were on sale and my only other optionwas some off brand... I got them in 265/60 R18 will attach a pic when I get back to a computer... :) thanks for all the extra info as well everyone!!

http://lh3.ggpht.com/_IrD_7X7VmMQ/TK...928_131239.jpg

Looks alot better than with the stock sized tires I think... :)

Quote:

---

Originally Posted by etlsport

if you talk to michelin directly they will always advocate 4 tires. I watched that video as part of a training seminar with michelin/bf goodrich, goodyear, bridgestone and falken

before showing the video i believe their words were "if you MUST put two tires on" but they never recommend only two

the problem is as stated before, your best traction does need to be on the rear of the vehicle exactly as shown in that video. but you also need to rotate your tires.

just yesterday i had a customer come in with a $1200 set of LT tires where two had worn out after 12k miles.. i called up goodyear, the first thing they asked was for history of tire rotations. after verifying the tires had been rotated, air pressure was correct and the alignment had been periodically checked, goodyear gave him an $700 credit towards new tires. in my experience if you dont have documented rotations, you can kiss any sort of mileage warranties goodbye

also the video shows the lesser of two evils. think about it, the way the rear tires give out on the "wrong" car... do you really want those tires on the front of your car? you may not spin, but you still have greatly reduced steering control and stopping ability.

---

The tire guy selling you the tires and working on commision recomends buying 4 tires instead of 2? Gee I am sure that doubling his commision has nothing to do with that. That attachment is copied right off the Michelin web site. I am sure if there were a safety issue they would mention it. On all sites I checked it never stated you must replace 4 just recomended and then if you replace 2 put them on the rear. Seems tome since tires dont wear at the same speed you can always rotate them based on vehicle wear. After all if all tires had to be the exact same size you would not be able to rotate them at all.

Seems like the bottom line is that replacing all four is better than just replacing two, but the extent to which it matters is up for debate.

toast - Nice lookin' VX you got there!

toast, nice choice of tire.. they are great tires

circ, if i was trying to sell him tires sure your theory would hold water, but what do I have to gain from Toast buying 2 or 4 tires? and sure im sure the reps were trying to get me to sell more tires, but its the same as any sales pitch, if you go and buy brand new TV, the salesman will probably try to sell you new cables and maybe a new DVD player. is it a waste of money to buy these things? possibly. but you will also use many more features of that new tv with a new dvd player as opposed to a 3 year old one. you have to decide whether or not you will benefit from the purchase.

Our factory dueler HTs come with 11/32 of tread.. to be at 40% of useable tread remaining on the tire his tread depth would have had to have been around 5-6/32. Any snow tire has its wear indicators at 6/32 of tread... ie even at that depth dedicated snow tires dont work in the snow!.


here is another video showing stopping distances with worn tires

http://www.metacafe.com/watch/249831...h_do_you_need/


is putting two tires on a toyota camry going to hurt the car? no.
but on an AWD you bet it will over work the transfer case in rain and snow.

the vx responds negatively to variation of 4-5 psi of pressure in tires. you think little pressure difference will change the size of a tire by 1/3 of an inch? it doesnt, but having a tread depth difference of 5/32 does. at that difference the new tires are traveling a full inch farther per rotation than the worn ones

your logic is lucid.

Quote:

---

Originally Posted by etlsport

toast, nice choice of tire.. they are great tires

circ, if i was trying to sell him tires sure your theory would hold water, but what do I have to gain from Toast buying 2 or 4 tires? and sure im sure the reps were trying to get me to sell more tires, but its the same as any sales pitch, if you go and buy brand new TV, the salesman will probably try to sell you new cables and maybe a new DVD player. is it a waste of money to buy these things? possibly. but you will also use many more features of that new tv with a new dvd player as opposed to a 3 year old one. you have to decide whether or not you will benefit from the purchase.

Our factory dueler HTs come with 11/32 of tread.. to be at 40% of useable tread remaining on the tire his tread depth would have had to have been around 5-6/32. Any snow tire has its wear indicators at 6/32 of tread... ie even at that depth dedicated snow tires dont work in the snow!.




here is another video showing stopping distances with worn tires

http://www.metacafe.com/watch/249831...h_do_you_need/


is putting two tires on a toyota camry going to hurt the car? no.
but on an AWD you bet it will over work the transfer case in rain and snow.

the vx responds negatively to variation of 4-5 psi of pressure in tires. you think little pressure difference will change the size of a tire by 1/3 of an inch? it doesnt, but having a tread depth difference of 5/32 does. at that difference the new tires are traveling a full inch farther per rotation than the worn ones

---

2 new tires is as good as 4 new ones. The question was did the poster NEED to buy 4? I maintain he did not. Of course being fresh minded this morning I have a question.

If 4 new tires are always required what happens when you buy road hazard warranties on tires from these manufacturers? Do they say as a result of the blowout you need 4 new tires here you go free of charge? No! When it comes to making the purchasing decision on tires with their money its slap one tire on it and your good to go dont worry about it you're safe its fine it wont hurt the car at all.

Things that make you say HMMMMMMMMMMM

Quote:

---

Originally Posted by circmand

2 new tires is as good as 4 new ones. The question was did the poster NEED to buy 4? I maintain he did not. Of course being fresh minded this morning I have a question.

If 4 new tires are always required what happens when you buy road hazard warranties on tires from these manufacturers? Do they say as a result of the blowout you need 4 new tires here you go free of charge? No! When it comes to making the purchasing decision on tires with their money its slap one tire on it and your good to go dont worry about it you're safe its fine it wont hurt the car at all.

Things that make you say HMMMMMMMMMMM

---

you caught me circ. toast would have been fine with just replacing 1 tire on his vehicle, but i talked to his tire salesman last week and he agreed to cut me in on the commission if he bought multiple tires. and well it just wasnt worth splitting the commission on 2 tires with his tire salesman and the guy we paid to put the nail in the road to make his tire go flat in the first place

the example i gave about goodyear and rotations.. the 2 rear tires were at 4/32 the two fronts were at 8/32, goodyear warrantied all 4 equally because it was a 4wd pickup. and that wasnt even a road hazard problem

and yes in the past i have warrantied multiple tires on a single road hazard claim to keep the vehicle safe. bottom line is if you work with your salesman, they will work with you

i never said he couldnt do it, i said why would you? no its not as safe, i think we can agree on that. if its not as safe AND it can do damage to your vehicle why would you ever replace just 2?

Quote:

---

Originally Posted by etlsport

you caught me circ. toast would have been fine with just replacing 1 tire on his vehicle, but i talked to his tire salesman last week and he agreed to cut me in on the commission if he bought multiple tires. and well it just wasnt worth splitting the commission on 2 tires with his tire salesman and the guy we paid to put the nail in the road to make his tire go flat in the first place

the example i gave about goodyear and rotations.. the 2 rear tires were at 4/32 the two fronts were at 8/32, goodyear warrantied all 4 equally because it was a 4wd pickup. and that wasnt even a road hazard problem

and yes in the past i have warrantied multiple tires on a single road hazard claim to keep the vehicle safe. bottom line is if you work with your salesman, they will work with you

i never said he couldnt do it, i said why would you? no its not as safe, i think we can agree on that. if its not as safe AND it can do damage to your vehicle why would you ever replace just 2?

---

Show me the Isuzu post that states that the owner needs to replace all 4 tires in the event any tire becomes a set diameter different than any of the others. I know there are warnings on some cars. A lot of that came from the 70s when people started putting larger and wider tires on their cars and these much larger tire differences presented a challenge to the AWD system. However if it was a reality that a couple of MMs difference actually harmed the vehicle I am sure Isuzu and other manufacturers would not only warn but state it violated the warranty. Once again the question was not whether is was better to get 2 or 4 tires but whether it was necesary.

I appreciate your humor in the post. I often see that when logic is no longer on a persons side. Make a joke make up a ludicrous statement that was never made and infer it was the other persons position but that just doesnt work.

I will admit total defeat when I see the Isuzu post as well as credible link as to where it came from. After all any one can post anything on the internet and claim they are an expert.

I think this is what you meant to say...

Quote:

---

Originally Posted by circmand

http://www.vehicross.info/gallery/da...l-awesome1.jpg

---

Quote:

---

Originally Posted by vt_maverick

I think this is what you meant to say...

---

Now that is is funny!!!!!!!!!!!!!!!!!

well the VX manual clearly states to use tires of the same size and load rating.. the height difference between a new tire and a tire with 5/32 of tread (assuming 11/32 of tread on the new tire) provides roughly the same height disparity as a 245/60/18 compared to a 255/60/18

The ability of four-wheel drive and all-wheel drive vehicles to divide the engine's horsepower between its four tires is especially useful on loose or slippery surfaces such as sand and dirt, as well as on wet, icy or snow-covered roads. However it's important to remember that in order to transfer this extra power, the four-wheel drive and all-wheel drive vehicle's driveline mechanically connects the tires so they work in unison.

Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail.

This necessitates that four-wheel drive and all-wheel drive vehicles use tires that are very closely matched. This is because different diameter tires roll a different number of times each mile as a result of the variations in their circumferences. Tire diameter variations can be caused by accidentally using different sized tires, tires with different tread designs, tires made by different manufacturers, different inflation pressures or even tires worn to different tread depths.

As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. 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.

This makes maintaining the vehicle manufacturer's recommended tire inflation pressures and using "matched" tires on all wheel positions necessary procedures to reduce strain on the vehicle's driveline. Using "matched" tires means all four tires are the same brand, design and tread depth. Mixing tire brands, tread designs and tread depths may cause components in the vehicle's driveline to fail.

Mismatched tires or using improper inflation pressures for all-wheel drive and four-wheel drive vehicles can also result in immediate drivability problems. Some Control Trac equipped vehicles in 4Auto mode may exhibit a shutter on acceleration and/or a noise from the front driveline and transfer case while driving. Some all-wheel drive and four-wheel drive vehicles may exhibit axle windup or binding while driving. Some four-wheel drive vehicles (manual or electronic shift) with a two-wheel drive mode may refuse to shift "on the fly" into 4x4 Auto or 4x4 High at highway speeds.

Rotating Tires

Because the front and rear tires of all-wheel drive and four-wheel drive vehicles perform different duties while accelerating, braking and cornering, tire rotation is important to even out, and maintain equivalent treadwear of all of the vehicle's tires to minimize potential driveline stresses.

If the vehicle is equipped with a matching road wheel and full-sized spare tire, they should be integrated into the vehicle's rotation pattern at the first tire rotation. This will allow all five of the vehicle's tires to share in the workload and wear at similar rates. In the event that a single tire is damaged and has to be removed from service, this will allow the tread depth equivalent spare tire to be used with the remaining three tires.

If the spare is not integrated into the vehicle's tire rotation pattern, it will not match the tread depth of the four worn tires on the ground when called into service. Additionally, if a single tire is replaced by the full size spare tire, hopefully the new replacement tire can remain as the spare tire until the other four tires have worn out and need to be replaced.

Replacing Pairs of Tires or Individual Tires

There are several suggestions that have been offered to drivers who are replacing pairs or individual tires on their four-wheel drive and all-wheel drive vehicles. Some vehicle manufacturers recommend that all tires maintain the same rolling radius and circumference, while others suggest that all tire circumferences remain within 1/4- to 1/2-inch of each other. Other vehicle manufacturers recommend that all four tires remain within 2/32-, 3/32- or 4/32-inch of each other, or within 30% of each other in relative remaining tread depth.

Regardless of the vehicle manufacturer's recommendations, the least stressful application is when all four tires are the same tire brand, tread design and equivalent tread depth.

Before buying pairs or individual tires for all-wheel drive and four-wheel drive vehicles, drivers should read their vehicle's owners manual or contact the dealer's service department for confirmation of their specific vehicle's requirements.

As published in their vehicle owner's manual,
Audi "rolling radius of all 4 tires must remain the same" or within 4/32-inch of each other in remaining tread depth.
Porsche Cayenne within 30% of the other tire on the same axle's remaining treadwear.
Subaru Within 1/4-inch of tire circumference or about 2/32-inch of each other in remaining tread depth.

unnecessarily long post is unnecessarily long!

On second thought maybe this is a more appropriate picture:

http://i249.photobucket.com/albums/g...pock_mccoy.jpg