Where to Install New Pairs of Tires?

[ProAuto]

Normally, it is recommended that all four tires should be replaced at the same time for optimal performance and most importantly safety.

If replacing two tires is the only feasible option, a new pair of tires should go on the REAR.

I did a research and looked for definitive information and references. The following are excerpts and references:-

(At first, I thought I should summarize the contents from various source. However, for this specific topic, the original source are well written already)

From RMA (Rubber Manufacturers Association) - Tire Care & Safety

Replacing Two (2) Tires - When a pair of replacement tires is selected in the

same size and construction as those on the vehicle, the two newer tires

should be installed on the rear axle. Generally, new tires with deeper tread will

provide better grip and evacuate water more effectively, which is important

as a driver approaches hydroplaning situations. Placing greater traction on

the rear axle on wet surfaces is necessary to prevent a possible oversteer

condition and loss of vehicle stability.

Replacing One (1) Tire- Replacing a single tire on a vehicle can have an

adverse effect on suspension systems, gear ratios, transmission, and tire tread

wear. If single tire replacement is unavoidable, it is recommended that the

single new tire be paired with the tire that has the deepest tread and both be

placed on the rear axle. Placing greater traction on the rear axle on wet

surfaces is necessary to prevent a possible over steer condition and loss of

vehicle stability.

You should also know more about Oversteering and Understeering. These terms are related to the position we should install new pair of tires.

> [Clip] Should I put new tires in the front or back? by Michelin USA

Oversteer

Oversteer is when the rear wheels of the vehicle describe a larger turning radius (than intended) as when compared to the front wheels. In other word, the front wheels tend to turn more than intended, and this has the effect of “throwing” the rear of the vehicle out and away from the intended line of travel.

Vehicles that have a lot of oversteer are described as “twitchy”. Reducing engine power when the rear end slips often brings the vehicle back to the intended line of travel.

Braking does not help to cure oversteer and may actually make it worse because braking causes a weight shift to the front, making the rear relatively lighter and even more prone to lose grip.

A well-designed vehicle does not have the tendency to slip until the rear tyres reach their traction limit, and this of course very much depends on the tyre design, the overall weight distribution of the vehicle, the road surface conditions and on specific suspension design of the particular vehicle.

Fortunately, most modern road cars are designed so that if oversteer occurs, it happens gradually and progressively, giving the driver ample opportunity to take corrective action.

Tyre and road surface conditions are probably the biggest contributors of oversteer. An extreme (and dangerous) oversteer condition is when the rear of the vehicle skids so much that it spins out of control.

Understeer

Understeer is when the front tyres reach their traction limit before the rear tyres. As a result, the front end of the vehicle describes a larger radius of travel than intended, compared to the rear of the vehicle. In other words, the vehicle turns in a wider arc than intended but no skidding occurs.

If the car understeers, and no corrective action is taken, the result is a wider arc than intended, but the car remains stable.

(In simple terms, imagine going around a sweeping bend to the left with a tree on each side of the road. If you hit the tree on the right side of the road, you understeered and if you hit the one on the left side, you oversteered.)

Understeer can be dealt with by reducing power, together with gentle, judicious braking. This shifts the vehicle's weight to the front, allowing the front wheels to regain traction and, thus, control.

Most vehicles are designed to have slight understeer since most drivers will instinctively ease off on the throttle and apply the brakes when a skid begins to develop.

=References=

“Should I put new tires in the front or back?” by Michelin USA https://www.youtube.com/watch?v=oa9hzcjdi5Q

“Tire Care & Safety” by RMA (Rubber Manufacturers Association) http://www.rma.org/prod…/be-tire-smart-tire-safety-brochure/

“Drive safely on wet roads” by Michelin North America, Inc.http://www.michelinman.com/US/en/safe-driving/tips.html

“Buying New Tires? Tire Mounting Tips – Replacing Two tires? Remember : New Tires Go On The Rear” by Firestone Complete Auto Care http://www.firestonecompleteautocare.com/cf/tires/buying-new-tires-tire-mounting-tips/

"Oversteer Understeer" via http://www.thestar.com.my/Story/?file=%2F2005%2F6%2F19%2Ffeatures%2F11210746&sec=features

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[northernjohn]

I was under the impression that you rotate the tires as the one on the tires all wear differently depending on where they are.

[JLT]

And we''re getting this lesson because???

Or is it just a surreptitious advert that the moderators haven't picked up on yes?

[luk AJ]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

[northernjohn]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

In the west we were always told to keep are eye on the right front tire. that is one of the reasons for rotating tires to give them all the same wear. Assuming you start all at the same time and the same quality of tire.

[Thailand]

And we''re getting this lesson because???

Or is it just a surreptitious advert that the moderators haven't picked up on yes?

n

Looks like an infomercial from a forum sponsor to me?

[luk AJ]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

In the west we were always told to keep are eye on the right front tire. that is one of the reasons for rotating tires to give them all the same wear. Assuming you start all at the same time and the same quality of tire.

One tire can wear much faster compared to the others because of traction point, air pressure or uneven outlining.

[kaptainrob]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

ProAuto prefaced the info advising replacement of all 4 tyres.

In a country dominated by rear wheel drive SUV's and pick-ups it makes more sense to fit (2 only) new tyres to the rear for reasons outlined in the article.

You are correct however, given minimal rear wear on a vehicle with front wheel drive, new tyres on front will provide better traction, not necessarily safer braking.

Tyre blow-outs on passenger vehicles are virtually NIL these days. Loss of pressure/flat tyre usually discovered long before it becomes a danger.

Tyre rotation, front to back same side, is good practice and evens out shoulder wear, saves you money.

"More and more cars have slso different size between front and back" ... incorrect.

[luk AJ]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

ProAuto prefaced the info advising replacement of all 4 tyres.

In a country dominated by rear wheel drive SUV's and pick-ups it makes more sense to fit (2 only) new tyres to the rear for reasons outlined in the article.

You are correct however, given minimal rear wear on a vehicle with front wheel drive, new tyres on front will provide better traction, not necessarily safer braking.

Tyre blow-outs on passenger vehicles are virtually NIL these days. Loss of pressure/flat tyre usually discovered long before it becomes a danger.

Tyre rotation, front to back same side, is good practice and evens out shoulder wear, saves you money.

"More and more cars have slso different size between front and back" ... incorrect.

Incorrect? I have BMW 5 and front tires are different from rear (from factory)

[kaptainrob]

It depends if you have front or back traction. Tires will alway wear faster on the axel with traction. These days most cars have front wheel traction so IMO new tires should replace the old front tires. Furthermore if a tire blows on one of the front wheels its is far more dangerous and more difficult to control the steering. IMO simple rule, replace the worn tires with new once but same brand and specification. Always replace per set of two. Changing tires from back to front or the other way around is imo not beneficial. More and more cars have slso different size between front and back.

ProAuto prefaced the info advising replacement of all 4 tyres.

In a country dominated by rear wheel drive SUV's and pick-ups it makes more sense to fit (2 only) new tyres to the rear for reasons outlined in the article.

You are correct however, given minimal rear wear on a vehicle with front wheel drive, new tyres on front will provide better traction, not necessarily safer braking.

Tyre blow-outs on passenger vehicles are virtually NIL these days. Loss of pressure/flat tyre usually discovered long before it becomes a danger.

Tyre rotation, front to back same side, is good practice and evens out shoulder wear, saves you money.

"More and more cars have slso different size between front and back" ... incorrect.

Incorrect? I have BMW 5 and front tires are different from rear (from factory)

"More and more ...." you forgot to mention Ferrari or Lamborghini ... all fairly common vehicles for farangs 555

[luk AJ]

If you compare a BMW 5 with a Ferrari, it just proofs you don't know much about cars...

[CMKiwi]

Yes it is common for vehicles to have different size tyres/tires in the front and rear. That is only if you look at the width..... I have never seen any 4 wheel vehicle to have different diameter wheel/tyres. That would be rather dangerous I would think.

Normally its `skinny` tyres in the front with `fatter`tyres in the rear.

i.e 185/70-15 and 205/60-15

In this instance they are both 15 inch tyres but with different width and profile. 185 is the width with a 70% height profile for the front and a 205 width and 60% height profile for the rear tyre.

There are lots of websites that go into great detail about tyres/profiles and even gearing/speed differences in relation to tyre size.

[kaptainrob]

Yes it is common for vehicles to have different size tyres/tires in the front and rear. That is only if you look at the width..... I have never seen any 4 wheel vehicle to have different diameter wheel/tyres. That would be rather dangerous I would think.

Normally its `skinny` tyres in the front with `fatter`tyres in the rear.

i.e 185/70-15 and 205/60-15

In this instance they are both 15 inch tyres but with different width and profile. 185 is the width with a 70% height profile for the front and a 205 width and 60% height profile for the rear tyre.

There are lots of websites that go into great detail about tyres/profiles and even gearing/speed differences in relation to tyre size.

Out of Thailand's 25 top selling vehicles can you name those with different sizes front and rear?

It is only common on high end (usually imported) models and sports cars or as (often illegal) aftermarket fitment.

[luk AJ]

Yes it is common for vehicles to have different size tyres/tires in the front and rear. That is only if you look at the width..... I have never seen any 4 wheel vehicle to have different diameter wheel/tyres. That would be rather dangerous I would think.

Normally its `skinny` tyres in the front with `fatter`tyres in the rear.

i.e 185/70-15 and 205/60-15

In this instance they are both 15 inch tyres but with different width and profile. 185 is the width with a 70% height profile for the front and a 205 width and 60% height profile for the rear tyre.

There are lots of websites that go into great detail about tyres/profiles and even gearing/speed differences in relation to tyre size.

Out of Thailand's 25 top selling vehicles can you name those with different sizes front and rear?

It is only common on high end (usually imported) models and sports cars or as (often illegal) aftermarket fitment.

BMW is not imported ....it seems you still try to claim you are a specialist he he...

[kaptainrob]

Yes it is common for vehicles to have different size tyres/tires in the front and rear. That is only if you look at the width..... I have never seen any 4 wheel vehicle to have different diameter wheel/tyres. That would be rather dangerous I would think.

Normally its `skinny` tyres in the front with `fatter`tyres in the rear.

i.e 185/70-15 and 205/60-15

In this instance they are both 15 inch tyres but with different width and profile. 185 is the width with a 70% height profile for the front and a 205 width and 60% height profile for the rear tyre.

There are lots of websites that go into great detail about tyres/profiles and even gearing/speed differences in relation to tyre size.

Out of Thailand's 25 top selling vehicles can you name those with different sizes front and rear?

It is only common on high end (usually imported) models and sports cars or as (often illegal) aftermarket fitment.

BMW is not imported ....it seems you still try to claim you are a specialist he he...

You're the argumentative type, obviously. Here's a few facts to put this to bed ....

We are discussing tyre fitment in Thailand, in general terms, not model specifics. Hence your claim of "more and more.... was incorrect.

I've asked a Q. unanswered as yet ... which out of Thailand's top 25 vehicles are fitted with different size tyres front and rear?

BMW 5 series are ASSEMBLED in Thailand from imported CKD packs. Guess which country manufactures them? I've visited the plant and even the works which supplies the steel ... do you know where that is?

And yes I do have the expertise, ex BMW Parts Dealer, Pirelli tyres wholesale and retail. Rebuilding engines for 45 years and motorsports driver, sport scar club president (Aus).

[luk AJ]

Impressive, my respect and my sincere appologies. I would better have befriended you iso upset you. I have a BMW tuned with ESS supercharger. I could learn a lot from guys like you. Sorry for my earlier comments