Tire replacement criteria

[DXB]

Pardon another noob question. On pre-flight today I noticed an unevenly worn spot on my 2.5 year old left main Goodyear (pic below). The central grooves are nearly gone at a single spot, but not entirely gone.  I have mostly broken my  habit of hitting the brakes too early on landing - but obviously i could do better.  I checked the Goodyear tire maintenance manual on replacement criteria:

https://www.goodyearaviation.com/resources/pdf/aviation_tire_care_3_2017.pdf

But I'm still confused. Quoting from the manual: "Inspect treads visually and check remaining tread. Tires should be removed when tread has worn to the base of any groove at any spot, or up to 1/8 of the tire circumference."  These seem like conflicting criteria.  It's pretty close to the base at a single spot, but not for 1/8 the circumference. Other places in the manual emphasize fabric exposed as a criteria, which is certainly not the case here.  

Questions:

1. Is it cool to just keep an eye on this spot for now?

2. If so, would it be wise to replace the tire the next time it has to go in for other maintenance, with so little tread remaining, or if I'm careful can I expect much more life out of this tire?

3. Should the tire be changed urgently when the groove disappears at that one spot or only if fabric is visible? 

[MooneyMitch]

Based on my experience, and strictly my opinion, I would replace.

You have stated tendencies to brake too early upon touchdown which has obviously resulted in skidding the tire, wearing that spot on your tire.

It is quite possible on your next skid, that tire will lock up on that low spot and blow out.

You don't want that to happen as it can be quite inconvenient and quite expensive, unnecessarily.

It would make much more sense to correct the issue now, rather than later.

My opinion only. 

[gsengle]

Remember you can wear a single spot on a tire if the tire is not balanced. Basically the heavy spot rotates to the bottom and ends up being the touch down spot over and over....


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[Andy95W]

I wouldn't worry about it but definitely keep an eye on it.  That's just me, though.

If it concerns you excessively, resolve to replace it at your next annual and monitor it until then.

[carusoam]

There is a way to keep from accidently over braking....

I found First what was causing my challenge, Then went the other direction...

I liked wearing heavy boots while flying my M20C.  Mostly to keep my toes warm.

Flat spotted my tire Often this way.  No feeling of the rudder or the brake, leads to locked up brakes.

fell upon the solution while wearing some cool sperry docksiders(boat shoes). The thin, soft, rubbery, sole makes it pretty easy to tel if your toes are on the brakes or not.  Don't put your toes on the brakes.  That is not a good resting position....

Last experiment... If the Sperry docksiders work, then the Sperry driving shoes should be even better...

Yes, Sperry has a driving shoe with a Thinner, softer, more segmented sole for the ultimate feeling with the toes to the brakes.

Its taken me about 17 years to come up with this idea.  I know there is a thread around here for what other people use for flying shoes...

I intend to get a few more hours with the new shoes before writing endlessly about how great they are...

See if they show up here...   http://www.zappos.com/p/sperry-hamilton-driver-1-eye-ash/product/8457759/color/7543?ef_id=U427MQAAAM0oVU2e:20170521030511:s

Best regards,

-a-

 

[Sean S]

According to the Goodyear guidance, the tire is still good. I would probably order a tire and tube in the next few weeks to have handy because the wear is getting close.  Store the tire/tube in a controlled environment, not the hot/cold hangar. Check your tire before/after every flight.

[MB65E]

Keep flying and watching it!

If you don't like it change it.

-Matt

[AZM20C]

If you can't see any cord, you are good, in my non professional opinion. 

[M20F]

Personally I would replace because it is easy/cheap to do yourself and better then blowing a tire in the middle of nowhere which will be very expensive. 

Even with no brakes Mooneys are susceptible to scuffing because the wing keeps flying after you contact the ground. If there is a decent cross wind it can slide the plane across and scuff.  It is also critical in my opinion to dump the flaps before hitting the brakes.  If you touch the brakes with full flaps unless the plane is almost stopped you are going to scuff. 

i just use cheap tires and tubes and replace whenever needed (keep a spare handy). 

[N201MKTurbo]

That tire has a lot of life in it. 

I had a partner once and I could tell how many landings he did by the number of flat spots on the tires. If I replaced the tire on every flat spot I would be doing it weekly.

Remember, the brakes are only for hold short lines. Land short and slow. The goal is to not use brakes on the runway, but if the end is rapidly approaching, do what you have to do.

[Tom]

For what it's worth, Mike Busch's take:

"As a general rule, if the damage is deep enough to expose fabric or cord...the tire is unairworthy and should be replaced before further flight."

https://www.avweb.com/news/savvyaviator/The-Savvy-Aviator-12-Tire-TLC-188586-1.html

Personally I'd make sure to have a replacement available and just check that spot every pre-flight (in addition to the other side and making sure the brake wasn't hanging).  No need to replace it until it gets worse, though it's reasonable to do now if it makes one more comfortable.   

[MooneyMitch]

My opinion again........our tires and tubes are the only thing between our beautiful Mooneys and terra firma, while in that environment.

Keeping tires in top quality condition is a relatively inexpensive method of preventing unnecessary situations that can cause a major inconvenience and possible damage to ones self, to passengers and/or to aircraft.

I prefer to spend an ounce of prevention, while mitigating risk as much as possible without being fanatical in the process.

In short, I'd rather spend a relatively small amount of dollars with prevention now, rather than risk spending more dollars with a potentially more expensive and uncomfortable situation in the future.

I use the same analogy with my motorcycle tires. They are the only object between me and the pavement!  It's simply not worth it to me to try and stretch the life out of a tire in lieu of safety and inconvenience.

Again, with that flat spot, and with my experience, when one does skid that tire again, it will stop on that low spot with the strong potential for the blow out.

That tire is not going to improve, it will continue to degrade.

Is it worth the risk?  Not at all. My opinion only, just my 2 cents.

[carusoam]

Another reason to land 'on speed'.

With flaps down, on the ground...  ground effect is pretty strong.  The Mooney is pretty light on its feet for a while.

It doesn't take much brake pressure to lock up a wheel or two.

 

Hmmm, with a slightly flat spotted tire... it meets the AW to continue to use it.  It also has enough meat on it for maximum braking experiments if you are going to replace them....

 

PP thoughts only...  not a CFI.

Best regards,

-a-

[DXB]

Thanks - Good discussion though it's clearly a split opinion on the immediate future of this particular tire.  I'm gonna order a new tire and tube and keep an eye on the spot for now. If the spot doesn't progress rapidly, I'll get it swapped when it has to go to the shop for another reason. I'd love to learn how to change it myself, but the added cost of buying my own jacks and a tail weight seems a little impractical at this point.

BTW this thin spot is likely my own dang fault and likely resulted from an incident that is a bit of a wake up call after getting increasingly confident in my short field skills. It turns out that being on speed 95% of the time is not good enough.  And not going around at a short field after finding oneself at 85mph over the threshold comes with far greater liability than the cost of a tire and tube replacement - I depleted some luck reserve on that one. 

[Skates97]

Just now, DXB said:

Thanks - Good discussion though it's clearly a split opinion on the immediate future of this particular tire.  I'm gonna order a new tire and tube and keep an eye on the spot for now. If the spot doesn't progress rapidly, I'll get it swapped when it has to go to the shop for another reason. I'd love to learn how to change it myself, but the added cost of buying my own jacks and a tail weight seems a little impractical at this point.

BTW this thin spot is likely my own dang fault and likely resulted from an incident that is a bit of a wake up call after getting increasingly confident in my short field skills. It turns out that being on speed 95% of the time is not good enough.  And not going around at a short field after finding oneself at 85mph over the threshold comes with far greater liability than the cost of a tire and tube replacement - I depleted some luck reserve on that one. 

I have a flat spot that looks just like that on each of my mains. I know exactly when it happened, landing on 8R at KCNO shortly after getting my plane. I was just practicing landings and came in faster than I should have. It's not really an issue there because 8R is 7,000' long, which is one of the reasons I took the short hop there to practice. However, I tried to slow down enough to make the 1st turn off (at about 1,900') so I wouldn't have to taxi back as far. Pushed too hard on the brakes, heard the tires screech, immediately let off the brakes and rolled to the next turn off, thankful that I didn't have two flat tires... I haven't locked up the tires since. I keep an eye on them every pre-flight and haven't noticed any progression. I plan on just replacing them at my next annual unless I notice a progression in the wear.

[Bartman]

21 hours ago, gsengle said:

Remember you can wear a single spot on a tire if the tire is not balanced. Basically the heavy spot rotates to the bottom and ends up being the touch down spot over and over....


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A long time ago I used to feel what I thought was an unbalanced tire vibration just after rotation. For the past few years I always tap the brakes just after rotation to stop tire rotation on the mains, followed by immediate gear retraction. My plane had new tires when I bought her, and I have only replaced them once in nearly 1,000 hours. The current mains are worn more than the OP photo and have been for a while. I'd keep flying and watch, and as said above, I strive not to use the brakes on the runway unless the trees at the end are getting tall very quickly.

I land a lot slower that I used to. 

[HRM]

7 hours ago, Skates97 said:

I have a flat spot that looks just like that on each of my mains. I know exactly when it happened, landing on 8R at KCNO shortly after getting my plane. I was just practicing landings and came in faster than I should have. It's not really an issue there because 8R is 7,000' long, which is one of the reasons I took the short hop there to practice. However, I tried to slow down enough to make the 1st turn off (at about 1,900') so I wouldn't have to taxi back as far. Pushed too hard on the brakes, heard the tires screech, immediately let off the brakes and rolled to the next turn off, thankful that I didn't have two flat tires...

Thanks Skates, my BTDT-LOL for the day! My first "serious trip" in my E took me to Clearwater Airpark (Florida/CLW), a tiny little strip bordered by a golf course and a housing area. Classic little FBO with old (but not bold) pilot codgers sitting on rockers passing judgement on the landings. I came in waaaay too fast and literally stopped, screeching, a few feet from the end of the runway. It took a few of them out of their chairs and drew even more out of the pilot's lounge. I left tire on that runway and had a very sheepish, shameful walk to the counter . 

[gsxrpilot]

What @M20F said. Be sure to retract flaps before touching the brakes on landing.

BTW... I'm in the keep flying, those tires are just fine, group.

[RobertGary1]

I've flown far worse. No worries. Keep an eye on it like you do all tires. Won't get a flat because of a flat spot. The cut would need to go clear through the cord and into the tube, which isn't any different for a new tire. It's different than a car tire. 

-Robert

[N201MKTurbo]

FWIW,

The flat spots are the last place to wear. If you run them long enough they will even out.

Also, when the cord starts to show, you have five more layers left!

[buddy]

Keep flying, I wouldn't replace the tire.

[Danb]

Balancing out the group I'd change the tire, hot runways and lots of ground effect is upon us.

[N201MKTurbo]

Just go look at the tires at the local flight school. They are nothing but flat spots. They usually change them when the cord starts to show. They would go broke otherwise. The place I was renting the Seneca II from last year made you sign a form that said if you put a flat spot on a tire below the tread it was $500. He said he collected about 4 a year.

Edited May 22, 2017 by N201MKTurbo

[Raptor05121]

My tires are 10x worse than that. I barely have any tread left on mine. No cords showing, but telling how high pitch my "squeek" is, I know I have thinner rubber than other airplanes. I'm ordering new here soon.

[Tommy]

Guess the question is : what would be the worst thing that can happen to fly with a tire like that?

Open to suggestions and whoever can scare the living daylight out of DXB takes the prize!