Tire condition questions

[NHerron]

During 6 months of rebuilding the car I replaced the tie rod ends at one point. Like a dumbass I counted the amount of threads, called it good and replaced. Well I guess I forgot about getting an alignment done because after the build, I put on about 600 miles and noticed the tires edges were wearing bad. As soon I realized what I had done, I took it in to Les Shwab

Looks like everything on my AWD suspension was okay and in great shape they said but my Toe adjustment was whacked being 1" toed in on the front and a bit out on in the back as well. Jeez -now that I got an alignment I realized how much the car was fighting itself just to drive, it was like skiing down a hill with the skis pointed inwards...

Got on a rabbit trail there but figured it was worth mentioning. Anyway I measured all 4 tires today and the fronts are at 3/32" and rears are at 6/32". Being AWD, will the VC fry itself with such a difference in front to rear sizes? I'm needing to move across state about 400 miles soon and just want to be safe. When I get to my new job I will be able to buy tires at a very good discount so I'd like to wait if possible

The tires are NeoGen Nitto ditto genwackydooswhatever -size 17" for reference. Should I rotate front to back since the previous owner apparently never did? I know steer tires wear faster and it's the general rule I was taught to rotate, but just wanted to double check

Thanks guys and have a great Memorial day weekend

 

[steve]

Yes, rotate them.

I wouldn't worry about a 3/32 difference in tread depth or a reduction in diameter of 6/32" causing any damage to your VC. The Nitto NeoGen in a 215/45-17 tire is about 24.7" in diameter and your talking about a 0.1875" difference in diameter between the front and rear.

 

[Bouche Dag]

Get all four off the ground and measure the overall rolling circumference of all four tires.

As long as they're all within 3/4 of an inch of each other you will be okay. 3/32 difference is usually the cutoff but I would measure the circumference just to be safe.

Also, do not rotate them, you always want your better tires in the rear. Every tire manufacturer recommends that the tires with the deepest tread stay in the rear. You would only rotate them if they were 2/32 different.

Just fyi, I am an Apprentice Manager for Discount Tire Company, we deal with the AWD/4WD tire tread differences all the time.

 

[jtmcinder]

Get all four off the ground and measure the overall rolling circumference of all four tires.

As long as they're all within 3/4 of an inch of each other you will be okay. 3/32 difference is usually the cutoff but I would measure the circumference just to be safe.

Also, do not rotate them, you always want your better tires in the rear. Every tire manufacturer recommends that the tires with the deepest tread stay in the rear. You would only rotate them if they were 2/32 different.

Just fyi, I am an Apprentice Manager for Discount Tire Company, we deal with the AWD/4WD tire tread differences all the time.

Note to self: avoid Discount Tire; they seem to promote the Great Unwashed to management positions.

1a) What matters is the % difference in circumference, not something in inches.

1b) 3/4" is less than 1%; you can have a much larger difference than that before the VC will cook itself

2a) deeper tread in the rear is incredibly bad advice when the car is front heavy

2b) no manufacturer actually suggests the deeper tread in the rear

 

[PieEyedPiper]

Oh boy, not even sure I wanted to chime in after more of this Unwashed business..

I've far exceeded 1% and I have no related symptoms or known problems. I also have my "deeper tread" on the front. But that's only because I know my car well enough to make that desicion.

If I were going by something like this: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=52 I could see it quite plausible to listen to that large, lovely chart they have at Discount/America's Tire showing someone crashing/spinning out because of a loss of traction in the rear.

 

[NHerron]

The fronts have been through alot lately and figured they should take a vacation on the rear plus I won't drive through rain during this short time. And will be replacing all 4 after I start this job and access to the discount. So this time around, I'll be rotating every oil change so I don't run into these different wear rates again

Any additional suggestions ? I'll take any info from you guys, it's hard to come by good advice around my area

Hey quick q on these NeoGens. What psi would you guys use? I'm following the door tire placard for PSI. 32front 29rear

 

[Calan]

2a) deeper tread in the rear is incredibly bad advice when the car is front heavy

This.

All that nice tread on the rear tires won't mean jack when the ass end is up in the air from stomping on the brake pedal, and the weight gets transferred to the front.

There is a reason the front brakes do most of the work; that's where most of the weight ends up. I would rather have as much grip there as possible, rather than plowing through turns on bald tires while the nice rear tires skip merrily along.

 

[Cirus_93TSI]

Its generally not the tire manufacturer thats recommending the best tires go on the rear, its the shops selling the tires. Pretty much every major tire chain will either recommend or require the better tires go on the rear. Its kinda dual purpose, on one hand if a car spins out from having the more bald tires on the rear they fear being sued and held accountable, on the other hand your front tires wear faster so it keeps people coming back sooner for another pair of tires.
About a year ago when i used to work for tire kingdom (who also own merchants tire, NTB, and big O tires), they changed their policy to require the better tires be placed on the rear on any vehicle whose wheels were removed in their shops. If a customer buys 2 tires they are not even given a choice, either the new ones go on the rear or they will not install them. Same for rotations, buy an oil change and rotation and the company will refuse to rotate your tires if the rear has more tread, and employees can be fired for putting the good one up front.
At one point i watched a store manager have a 25 minute argument with a customer trying to disprove his point that all the weight shifts to the front when you hit the brakes and thats where the good tires should be, the customer eventually left to buy tires elsewhere because the manager refused to put new tires on the front and not the rear.

 

[Bouche Dag]

Note to self: avoid Discount Tire; they seem to promote the Great Unwashed to management positions.

1a) What matters is the % difference in circumference, not something in inches.

1b) 3/4" is less than 1%; you can have a much larger difference than that before the VC will cook itself

2a) deeper tread in the rear is incredibly bad advice when the car is front heavy

2b) no manufacturer actually suggests the deeper tread in the rear

I don't appreciate the personal attacks.



1) You're right. Won't argue with you there. You probably can get away with more than 3/4 inch difference but why risk it? Its a rule of thumb that I use and haven't had a problem yet.

2) http://www.michelinman.com/tires-101/buying-tires/how-to-choose/mixing-tires.page

http://continentaltire.custhelp.com/app/answers/detail/a_id/15/related/1

Not a manufacturer but a renowned tire dealer: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=52

Also if you search YouTube there is a video produced by Uniroyal where they show two cars going around a test track and hydroplaning. One with new fronts and the other with new rears. The fronts loses control and the rears maintain control.

 

[Bouche Dag]

This.

All that nice tread on the rear tires won't mean jack when the ass end is up in the air from stomping on the brake pedal, and the weight gets transferred to the front.

There is a reason the front brakes do most of the work; that's where most of the weight ends up. I would rather have as much grip there as possible, rather than plowing through turns on bald tires while the nice rear tires skip merrily along.

True but when the back end is light when you're smashing the brakes don't you want tread in the rear to maintain control of the rear axle? If your front tires are bald you can control the front end with the steering wheel all day long but you have nothing to control the back end with.

OP- Do whatever you want. TBH I would probably rotate them too. Just to squeeze more life out of the tires. Obviously the best thing to do is to have 4 awesome tires but I bet you'll be okay. Plus I think the deeper tread in the rear propaganda was designed for commuters. Not for seasoned drivers that know their cars and how they handle in every situation like us DSMers do. I am just presenting you with the knowledge that I've gained from working closely with tires and tire manufacturers for ~50 hours a week for the past four years.

 

[NHerron]

I just want a safe trip haha. I neglected to mention the tires are over 5 years old. Seems to me the tires never been rotated either. I figure the rears have lots more life in them since they don't see nearly as much abuse as the fronts do from steering and braking+cornering. The way I see it is the rears are along for the ride compared to the perils front encounter not to mention my latest screwup in the toe adjustment.

So it's not so much a traction issue as it is worrying of blowing a tire on my upcoming long trip. I love taking the route too, its an awesome drive with tight corners no traffic and freeway speeds so I'd like to enjoy it yaknow?
Is it cool to follow the tire placard on the door for these NeoGens?

 

[Calan]

I don't appreciate the personal attacks.

Cinder is just a crotchety old bastard, so don't take it personally (this coming from a crotchety old bastard...so you know he is REALLY bad).

He is one of the resident experts on handling though.

If your front tires are bald you can control the front end with the steering wheel all day long but you have nothing to control the back end with.

The front end of an AWD car that likes to oversteer doesn't like to turn even with new tires on it. Once the front tires are past the peak slip angle (sliding), the car is moving in a straight line; at that point, rear tire grip is pretty much meaningless.

Rear tire grip is obviously important for neutral handling, but it's more important during rearward weight transfer (launching/acceleration), or on RWD vehicles where you have some control over the rear of the car with throttle input.

 

[DSMTyson]

Dude. We are talking 3/32 of a difference. Its not like he's putting brand new tires on the front and putting completely bald ones on the back.

True but when the back end is light when you're smashing the brakes don't you want tread in the rear to maintain control of the rear axle? If your front tires are bald you can control the front end with the steering wheel all day long but you have nothing to control the back end with.

OP- Do whatever you want. TBH I would probably rotate them too. Just to squeeze more life out of the tires. Obviously the best thing to do is to have 4 awesome tires but I bet you'll be okay. Plus I think the deeper tread in the rear propaganda was designed for commuters. Not for seasoned drivers that know their cars and how they handle in every situation like us DSMers do. I am just presenting you with the knowledge that I've gained from working closely with tires and tire manufacturers for ~50 hours a week for the past four years.

 

[NHerron]

Dammit can someone help ME here? At least quote me in addition or something

 

[Bouche Dag]

The front end of an AWD car that likes to oversteer doesn't like to turn even with new tires on it. Once the front tires are past the peak slip angle (sliding), the car is moving in a straight line; at that point, rear tire grip is pretty much meaningless.

Rear tire grip is obviously important for neutral handling, but it's more important during rearward weight transfer (launching/acceleration), or on RWD vehicles where you have some control over the rear of the car with throttle input.

You do make a valid point. As I said in my last post I feel like the better tread in the rear is for commuters that drive all seasons. Not for people like us that understand their cars abilities and limitations in and out. And with regards to the 3/32nd difference, I really agree I don't think that's enough to affect the handling of the car. I would rather see just 2/32nd difference between the tires to rotate them in the OP's situation but I am not going to say rotating them is going to be unsafe.

 

[Bouche Dag]

Dammit can someone help ME here? At least quote me in addition or something

F*ck it dude. Just rotate them.

 

[jtmcinder]

Dammit can someone help ME here? At least quote me in addition or something

You asked two questions that I thought that we answered, but maybe it wasn't clear.

Will your VC be OK? Yes.

Should you rotate the tires? Yes.

 

[PieEyedPiper]

You asked two questions that I thought that we answered, but maybe it wasn't clear.

Will your VC be OK? Yes.

Should you rotate the tires? Yes.

Dammit can someone help ME here? At least quote me in addition or something

Missed one.

Can you go by the place card in the door jams for tire pressures? Yes.

 

[Calan]

Rotate them. Enjoy your drive/move. Be happy and sleep well.

And make sure your spare is in good shape just in case.

***

The tires should be marked as to what pressure they like, but they are all about the same. The door placard will be fine as CB said.

FWIW - I think I've inflated every set of daily driver tires I've ever owned over the last 30 years to something between 32-36psi, no matter what the brand, season, etc. The only time I've deviated from that is to go a little lower for a bit softer ride or better traction. It's more important that they are equal in pressure (and you have a good alignment) than it is to worry about an exact number.

 

[PieEyedPiper]

"The tires should be marked as to what pressure they like.."

Careful. We don't want to suggest that everyone just run outside and stick 55psi+ into their tires because the sidewall told them that was the maximum.

 

[Calan]

Ok. Good point. I guess most people here would assume "maximum" = "best".

 

[jtmcinder]

Tires rarely (if ever) are marked with a suggested pressure. They only have a max pressure and leave the suggestion to the car. After all, the maker of the tire doesn't have a clue what the car weighs.

 

[steve]

Let see if I have to chose between tires are are almost legally bald up front or not, I'll chose to put the better tires up front so I can steer the car out of the skid when the rear end comes loose.

I'm surprised nobody suggested chalking the sidewalls to see what tire pressure you should be using.

 

[jtmcinder]

In my experience, "chalking" is an autocrosser thing. If you run pressures as high as that on the street, you will not only wear the tire strangely, but it be more open to toe-induced damage and give a lousier ride. You want to let the sidewall work on the street. The only reason to go higher is gas mileage, but only with zero toe.

 

[NHerron]

Well ok then

I like the marking idea, looked it up and it makes sense for good inflation. But I don't think it will work so good on the front set. Just because the tires wore badly on the edge from toe being in about an inch for 600 miles..

Thanks again and I'll rotate them tomorrow