Flat tires

[Gasser]

http://flyingsummers.com/2006/02/02/fame/

I had a flat tire on my delivery flight. After that I had three more: once landing in Kansas City, then the nose wheel on a flight back from dropping a friend at Van Nuys (so two short hops), and the last at St. Louis when I taxied out of the FBO's ramp.

The last one was a drag since I *must* have hit something on the taxiway. I preflighted carefully (always very intense on the preflight with the whole family in the plane). We were parked overnight. If the tire was flat we wouldn't have taxied out of the spot. But a hundred yards down the taxiway it went to 0 psi.

The Keystone cops would have looked efficient compared to the crew that came to "help." They had FIVE guys working by the hour to get it on a cart to tow back to a hangar and wanted to static test the wheel to make sure there were no defects before they put a new tube on it. I fired them. They still submitted a bill for $1,900.

Oh ,my goodness. Makes my 200 dollar bill sound free.
My front has been the only one that's been up since I've bought it. Maybe its next.

I will say, changing a tire and tube is easy. It's criminal if they try to make it into an ordeal.

I think I'm going to run them at 39 psi which is just under 10% over. Hopefully ill get 1000 more hours before mine go flat in the hanger

[carym]

This might be a slight creep in the thread, but still related to tires. I have now gone through my second set of mains after about 650 hours. The nose is still OK, but I will probably change it as well just to be safe. I was wondering if others think that 325 hours per set of mains is too little? I don't check the pressure very often and this may be why I am going through the mains this often. However, I don't remember using so much rubber on my C310. I am just looking for some re-assurance, or else appropriate casting stones at me for poor technique

[Gasser]

I think I've been guilty of neglect on pressures and I also think our long wings cause a little more wandering around slightly while we are waiting on these really efficient wings to stop flying causing a little more wear on the tires.
I'm going to take the advice on running a little higher pressures and keep up with them better to see if this helps my wear.

Now my flat problem, I think is only tube related. Not completely sure if the lower pressures contribute to increased incidence of perforated tubes. Maybe a bigger deformation of the tire on touchdown with the lower pressure causes more friction inside and a higher pressure will reduce this. Time will tell.

[Gnomad]

I got a flat in May while attempting a NC to AZ flight. First refueling stop in Arkansas, stretched legs used bathroom etc... Did a quick preflight and back into the plane. Only took a quick glance at the tires, but definitely looked as I always do. Taxied about 3/4 mile to the end of the runway and as I made the 90degree turn to pull up to the line, the tire came off the hub. Thump thump thump...immediately knew something was wrong and shutdown. Had my own set of keystone cops on hand for awhile, but they did manage to get my left main off the ground onto a tug and we walked it all the way back. Upon inspection, there WAS a hole in the tube, but never found any object puncturing the tire. Unfortunately the sidewall took some damage during the ordeal and had to be replaced, wheel was saved though!

During the tire change, took a look at the PSI on the other two tires and they were both low. Totally my bad as I also have neglected checking the pressure regularly due to it being a pain. Lesson learned!

I called Stuart at Dillon's Aviation to confirm a question before jacking the plane, during that call he was very insistent on keeping the tires over the recommended PSI. Confirms what others are saying here, they keep all their flight school planes over PSI.

Anyway, never came to a final conclusion as to what happened to cause the flat, whether the hole in the tube came first, or was caused by the tire/wheel separating from low PSI, but I am very aware now when landing, not to jam the brakes and cut over for the closest exit as it would suck to have a tire come off the rim at that speed. I was lucky it happened where it did!

[Rich]

I went to Michelin tubes some years back to cut down the leak-down rate, but had Goodyear tubes for years before that. For whatever reason I've never yet had a flat in 11 years.

Main tire life early on was about 320 hours, but better recently. Might be because of the more reliably inflated tires. Loss of tire pressure now is very slow compared to the Goodyear tubes.

All things being equal, planes with spring-steel main legs tend to wear tires a bit more than those fitted with oleos. That's because in the former, lateral tire-scrubbing happens as the plane transitions between the airplane weight being supported by the mains and being supported by the wings. The LG legs don't just flex up and down, they also deflect inward and outward.

[smoss]

I just had a flat on a main, with what looked like a puncture hole in the the corner area of the tube/tire (where the rolling surface meets the sidewall), but nothing at all in the tire or wrong with the tire, which is only 6 months old. The tube was a Goodyear, and was 5 years old. When I had the tires changed, the mechanics said no need to change the tubes... obviously should have in retrospect. I just cut open the tube to inspect it, and it had what looks like a stretch, or wear mark almost all the way around the inside of the tube in the outside corner area where the hole was, and from the inside, it looks like it just had a little crack that finally popped through. I replaced it with an Aero Classic Leakguard tube, since that's all my shop had on hand. Anyone have any experience with these? I'm thinking of ordering some Michellins and replacing all of them, as the remaining tires still have old tubes on them which obviously do wear out!

[Rich]

I just had a flat on a main, with what looked like a puncture hole in the the corner area of the tube/tire (where the rolling surface meets the sidewall), but nothing at all in the tire or wrong with the tire, which is only 6 months old. The tube was a Goodyear, and was 5 years old. When I had the tires changed, the mechanics said no need to change the tubes... obviously should have in retrospect. I just cut open the tube to inspect it, and it had what looks like a stretch, or wear mark almost all the way around the inside of the tube in the outside corner area where the hole was, and from the inside, it looks like it just had a little crack that finally popped through. I replaced it with an Aero Classic Leakguard tube, since that's all my shop had on hand. Anyone have any experience with these? I'm thinking of ordering some Michellins and replacing all of them, as the remaining tires still have old tubes on them which obviously do wear out!

Many recommend that when you change tires, you always replace the tubes as well. The rationale is that over time the tires and tubes stretch. When you put a new un-stretched tire on with a stretched tube, the tube has to wrinkle and these become stress areas. I also figure that these compounds do degrade over time and the tube is what holds the air - not the tire.

[CFIDave]

This might be a slight creep in the thread, but still related to tires. I have now gone through my second set of mains after about 650 hours. The nose is still OK, but I will probably change it as well just to be safe. I was wondering if others think that 325 hours per set of mains is too little? I don't check the pressure very often and this may be why I am going through the mains this often. However, I don't remember using so much rubber on my C310. I am just looking for some re-assurance, or else appropriate casting stones at me for poor technique

I would say that 325 hours on DA42 tires is actually doing quite well. That's about the same wear as what we got on our DA40's tires. Consider that the DA42 has exactly the same size tires supporting 50% more weight than a DA40. We're already beginning to see some tire wear on our new DA42's tires, despite being extremely careful to avoid hard braking and keeping heels on the floor.

During training (on a flight school's DA42 ) I learned that DA40-style braking and pedal pressures will result in flat-spotting of DA42 tires. So I've had to teach myself not to make the first turn-off after landing anymore!

Back to the original topic, on our DA40 we swapped out our original Goodyear tubes for Bridgestone and never experienced the repeated flat tires that other DA40 owners w/Goodyear tubes experienced.

[carym]

I would say that 325 hours on DA42 tires is actually doing quite well. That's about the same wear as what we got on our DA40's tires. Consider that the DA42 has exactly the same size tires supporting 50% more weight than a DA40. We're already beginning to see some tire wear on our new DA42's tires, despite being extremely careful to avoid hard braking and keeping heels on the floor.

During training (on a flight school's DA42 ) I learned that DA40-style braking and pedal pressures will result in flat-spotting of DA42 tires. So I've had to teach myself not to make the first turn-off after landing anymore!

Yes, the main reason for the change is I flat spotted one of my mains (and now the chord shows through) on the Alaska trip 2 weeks ago. I think it happened when I had to brake really, really hard to avoid going off the end of the runway at Healy River. Another reason why it was a bad day (that's another story).

[smoss]

Sounds like no one has any experience yet with the Aero Classic Leakguard tubes. I guess I'm the guinea pig.