New tires on rear...why?

[CapriRacer]

Originally Posted By: ponderosaTX
Putting the good tires on the back may produce better handling and braking stability in the short run but it may be short-sighted because you cannot subsequently rotate your tires front-to-back (which is the only recommended form of rotation with unidirectional tires) without creating a WORSE handling imbalance. Why? The front tires generally wear faster than the rear tires (particularly on FWD cars) so at the time of rotation, the front/rear tread depth difference is GREATER than it would have been if you originally put the good tires on the front wheels.

Putting the better tires on the rear makes sense ONLY if you do not subsequently rotate the tires front to back.


And the point would be that the front (worn) tires would be replaced much more quickly and you'll be back to having 4 nearly the same wear tires and you can start the rotation procedures like nothing happened.

 

[ponderosaTX]

No. The point is that you can NEVER subsequently rotate your tires front-to-back if you put the better tires on the rear and you believe the "deeper tread tires must be on the rear" mantra. In over 40 years of driving, I have never owned a car (including several RWD vehicles) where the front tires did not wear significantly faster than the rears. If you are replacing one or two tires and the remaining tires have significant tread left, the conventional advice from manufacturers (dictated by their liability attorneys) is STUPID. When you subsequently rotate your tires front-to-back, you will have created a worse hazard (caused by differential front/rear tread depth) that you would have in the first place if you had ignored their advice and put the better tires on the front.

I once emailed the Michelin "experts" on this issue (after Costco forced me to put a road hazard replacement Michelin HydroEdge on the rear) and challenged them to respond to my argument. They never replied.

Let me re-issue the challenge to any tire engineer who accepts the "better tires always go the rear" mantra: show me how a subsequent front-to-back rotation does not create a worse hazard than originally putting the better tires on the front.

 

[Shannow]

I think that you just kicked a home goal.

Congratulations.

 

[CapriRacer]

Originally Posted By: ponderosaTX
.....Let me re-issue the challenge to any tire engineer who accepts the "better tires always go the rear" mantra: show me how a subsequent front-to-back rotation does not create a worse hazard than originally putting the better tires on the front.


Accepted.

First, the issue isn't about rotation. The issue is about safety. It's obvious that you've bought into the idea the deeper treaded tires on the rear are more safe or you wouldn't have worded your challenge that way.

Second, if tires have been rotated properly, then the issue of differing tread depths is moot - there isn't enough difference to cause a problem. The problem comes in when folks do NOT rotate their tire properly and the front tires are worn out and the rear tires still have a ton of tread left. In this case, we are trying to work our way out of a situation that shouldn't have existed in the first place.

But there is one additional scenario that needs to be discussed - and that's the situation where there used to be 4 identical tires and one or two of them were punctured.

From a safety point of view, it would be best to buy 4 new tires - however, most people would find the cost enough of a factor that it would be vetoed!

If that option is eliminated, then put the new tires on the rear - and live with the situation.

So, no matter how we slice this, the issue becomes one of safety. If we do things without regard to anything else, then 4 new tires is what should happen.

However, if we start to add additional elements to the equation, it now starts to become a matter of what compromise works best. If the risk of an accident isn't enough of a deterrant, then I would question your values.

- AND -

To answer your challenge directly:

When you replace tires in pairs and have a situation where you have deeper treaded tires on the rear, then rotation is NOT an option - and your challenge becomes moot.

 

[Astro14]

Originally Posted By: ponderosaTX
No. The point is that you can NEVER subsequently rotate your tires front-to-back if you put the better tires on the rear and you believe the "deeper tread tires must be on the rear" mantra. In over 40 years of driving, I have never owned a car (including several RWD vehicles) where the front tires did not wear significantly faster than the rears. If you are replacing one or two tires and the remaining tires have significant tread left, the conventional advice from manufacturers (dictated by their liability attorneys) is STUPID. When you subsequently rotate your tires front-to-back, you will have created a worse hazard (caused by differential front/rear tread depth) that you would have in the first place if you had ignored their advice and put the better tires on the front.

I once emailed the Michelin "experts" on this issue (after Costco forced me to put a road hazard replacement Michelin HydroEdge on the rear) and challenged them to respond to my argument. They never replied.

Let me re-issue the challenge to any tire engineer who accepts the "better tires always go the rear" mantra: show me how a subsequent front-to-back rotation does not create a worse hazard than originally putting the better tires on the front.


If the other tires are nearly new - then this discussion becomes semantics...what is "nearly new"? I bought a tread depth gauge to be able to measure, so that I can make an informed decision on rotation and/or replacement... But manufacturers need a simpler, more objective guideline than "significant tread depth"...what is that? 8/32"? 75% of original depth? So, they make it simple so that it's clear...

40 years of driving, while interesting and significant, includes bias ply tires (I had them too on my '70 Fairlane) and vehicle dynamics that do not apply to this discussion. I still have bias ply tires on the Packard, by the way, but all 4 tires have the same tread depth...

For a modern car, with modern tires, follow the advice that comes from extensive testing: Put the new ones on the rear. When the "faster-wearing" front tires do wear out, then put the next set on the rear. If they're close, now you can start a normal rotation.

Frequently, when folks buy 2 tires, the other 2 are close to being worn out anyway...

There are lots of high-performance cars that have staggered fitments, and on those, this discussion is moot...

The final point is this: doing the safest thing is the same as doing the most economical thing when you consider the cost of an accident; repair, insurance, or, heaven forbid personal injury or death. Even the minor damage to my Volvo (I was rear-ended by a distracted driver in December) cost over $4,000 to repair. I got off cheap, accidents can be far, far worse.

Saving a few bucks by rotating your tires is quickly wiped out by the cost of an accident, so do the smartest, the most economical thing - and follow the recommendation that results in the highest safety.