"Scuff" flat tires, anyone else?

I've recently had a few main gear "scuff" flat tires on my -6A, looking for advice to stop these tube failures:



The tire looks fine, feels smooth throughout the interior, no tire exterior damage visible. Tire and tube were assembled with talc powder, inflation to 45 - 50 psi. Tubes are Michelin Airstops. Also trimmed wheelpants fiberglass to increase clearance between tire and wheelpants. Yesterday's flat followed a grass strip landing and takeoff.

Considering removing more fiberglass from wheelpants (or even removing wheelpants), and maybe replacing the tires.

Anyone else have similar experiences? Suggestions to fix?

Thanks!

There is really no way to stop the tube from scuffing inside the tire. From the picture it looks like the tube may have been pinched when initially installed which will always lead to this type of failure.

When installing tubes use tire talc. Remove the valve stem and inflate the tube inside the tire before mounting the tire on the rim. Once the wheel is on inflate/deflate several times before installing the valve core. Inflate to desired pressure and your done.

Good practice is to always install a new tube when installing new tires.

zilik said:

There is really no way to stop the tube from scuffing inside the tire. From the picture it looks like the tube may have been pinched when initially installed which will always lead to this type of failure.

When installing tubes use tire talc. Remove the valve stem and inflate the tube inside the tire before mounting the tire on the rim. Once the wheel is on inflate/deflate several times before installing the valve core. Inflate to desired pressure and your done.

Good practice is to always install a new tube when installing new tires.

Click to expand...

I too follow each and every one of these comments. I've had people look at me funny when doing tires and tubes just because of all the gyrations I go through to be certain things are seated nicely and not pinched.

zilik said:

There is really no way to stop the tube from scuffing inside the tire. From the picture it looks like the tube may have been pinched when initially installed which will always lead to this type of failure.

When installing tubes use tire talc.

Click to expand...

Just had this failure myself. What is tire talc? Is it any different than the talcum powder I used?

slip

https://www.aircraftspruce.com/catalog/lgpages/tiretalc.php

Not sure if its any different than household talcum powder...except the higher price -- $8.50.

-Jim

I've used cornstarch for 30 years, worn out at least 15 sets of main tires and never had a tube failure.

That scuffing also looks like a grain of sand was between the tube and tire. I had exactly the same thing happen on my -10 nosegear and found the culprit....not quite as big as a grain of rice.

Best,

always check the inside of the tire for any imperfections, punctures, stones, or any type of gremlins. the helo transport tire had a flat and this was the culprit. the damaged tube looked just like yours and the inside of the tube had a damaged area the same size as the damaged tube. never had a main go flat. had a few nose wheel flats though. i replace the tubes on condition. use lots of baby powder. make sure the rims are clicking metal to metal before final tightening.

Try making the tube completely white with talc when assembling. I believe these types of failures are from localized extreme stretching. Not sure what causes that - might be some interaction of the tire flexing and the tube "inchworming" as it interacts with the flexing system. I just know that I had a fair number of them early on, but haven't had one since using tons of talc (baby talc from the store).

Don't destroy you wheel fairings trying to solve this problem

My subfairings are so close to the tire that they almost touch (sometimes do) the tire in static mode. Several good suggestions here. I put the tire talc on the tube and inside the tire. Install the tube inside the tire with the tube partially inflated to discourage folds; align the tube stem and tire weight dots; install the hub release the air in the tube and refill to operating pressure is my process but detail inspection and multiple inflate, deflate and re-inflate cycles sound good to me.

I was using the cheaper tires from ACS last year because of their shape with Michelin Airstop tubes. I had two flats then bought a new one of the type that failed twice and two different Goodyear tires for side by side visual and weight comparison. I included photographs and data in a post in this forum. I still use the same tubes but went to goodyear with a Flight Custom III on one wheel (right main) and a Flight Special II on the other. Both performed well with no evidence of unusual wear. Unlike your tire, both of mine had spot wear all the way through the tire cord.

Also consider that the failure may have occurred on takeoff instead of the landing. One of my failures occurred after the race at Llano in 2012. There was a strategic advantage in getting to maximum altitude after takeoff before crossing the start line. Photographer Jo Hunter took a photo where I rotated at the earliest possible time with max power and RPM and right rudder and probably some right brake. Her photo shows me settling back on with a small puff of smoke from the right tire. I finished the race refueled and took off for home only to realize I still had the fresh air vents covered. I landed at Hamilton to remove them or die and the right main went flat. Probably just another uninteresting story but consider that incident that caused the failure may not be the point in time when the failure occurred.

Bob Axsom

In case Carl doesn't see that his thread was resurrected, he had another flat after this with the same markings on the tube. We examined the inside of the tire carefully and found a matching "rough spot" on the sidewall - a perfect match. That was his issue in this case - it just took a good tactile examination.

Paul

I just put together a new nosewheel for the 10 with a tube that came in a finish kit 2 months ago. It had the same problem Paul Dye posted about. It was folded up and had a stress mark in the rubber from the threaded end of the brass tube. I stuck a small tire patch over it. I'll whine to Vans on my next order.

Wear on R Main tire

The outside of my R main tire on my RV-6A has worn bald, like me, I'd say. No problem with a flat but the outside 3/4" has worn down. L main is fine. I have about 150 hours and over that in landings.