Odd Shaped Hole in Radial Tube

[RDVAARK]

I have worked with many different rubber compounds, plastics,and unusual materials in injection molding,extrusion,and casting processes,usually in a PITA Milspec situation. That blemish is typical of flow patterns in the uncured material coming together in a shaping operation and not curing evenly-likely all the way through that cross section in that location,like two little pancakes making one big one. This may have been the first tube of a batch- the first few are usually scrap until tool temps, material temps and flow turbulence are 'normalized'. Likely repeated in others areas of that one tube and the one made before or after before the run was 'dialled in'. On something relatively cheap and mass produced there probably won't be any tracking or even caring about a few bad tubes. I've called Coker in the past,usually on radial tubes made "away', and they basically say "Hmmm, really. Sorry about that . Well, we'll send you a new one. Throw it out." And they did several times. Manufacturing defect, occurring long ago and far, far away even after I'd mounted and driven on them.

More common are surface blems that look like that, or an amoeba shape on a surface with a clear border. These are from drops of water, spit, snot, beverages or whatever splashing on a hot surface. Usually not structural or indicative of a faulty product.

Information gathered during long boring factory shifts with the help of self-defensive machine operators and an OCD gov't inspector with a chip on its shoulder. Life experiences of a mechanical engineer, earning a living, when mountains and molehills are closely examined (see recent post about career choices).

[katy]

Send the picture(s) to the vendor you bought them from and ask for an explanation and a new replacement tube.

[shew01]

Originally Posted by Oldbluoval

My recollection is that tubes with metal stems had the stems installed aftermarket. Most (all?) tubes were made with rubber stems. Rubber stems removed,hole patched and metal stems installed.
Likely the patch of rubber stems??
Could be wrong…been awhile since dealing with tires!

You are correct, this is an aftermarket metal stem. My first thought was that the valve stem core might be leaking. So, I replaced that a few days ago, and it didn’t make any difference. That’s when I broke down the tire and tube.

Under water in my “test tank,” the metal stem was not leaking at all. The only spot leaking was on the sidewall of the tube.


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[Oldbluoval]

Katy
I doubt there’s a guarantee or such on tubes. If so looks like he’s over a year (assuming last summer, it’s still this summer??).
I’d just put another patch and see if it leaks

Then replace it!!

[shew01]

I think tube was only $18 or so, probably not worth the hassle of trying to get a replacement. The tube cost is overshadowed by the nuisance of having to dismount, patch, and remount it.

I patched it last night, mostly just to see if my first-time patch works. I was a bit surprised that the tire mostly held air overnight. (I’m not sure I got a good tire pressure reading last night.)

I took it for a test drive today and will recheck the air pressure after the tires cool. If it still leaks, I plan to replace it.


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[lrf]

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I just bought four inner tubes from Bratton's, $30 each, new 100% butyl rubber, made for standard and radial tires. Great quality and IN STOCK! I'm tired of changing flats the next day after a tour and then trying to repair 10 year old tubes.

[shew01]

Originally Posted by lrf

I just bought four inner tubes from Bratton's, $30 each, new 100% butyl rubber, made for standard and radial tires. Great quality and IN STOCK! I'm tired of changing flats the next day after a tour and then trying to repair 10 year old tubes.

I checked my records, and I bought this tube, along with 4 others from Snyder’s in August of last year. They were $18.50 a piece, and they came with a package insert that said confirmed the tubes were compatible with radial tires.


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[shew01]

I checked the tire pressure this morning, and the patch seems to be holding air. If the tube starts losing air again, I plan to replace it.


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[denniskliesen]

I have the same blemish on at least 2 tubes and started to leak air either a day after mounted or several days. These tubes have radial molded on the stem and I seriously doubt they are radial tubes. Recently I had a tire on the front that started loosing air slowly. I had one replacement tube that actually looks like it could be a true radial tube. The molding is circular instead of what looks to be like a bias ply tube. I doubt it’s a pinched tube problem as every tire I’ve mounted have never had this problem until I mounted the set of American Classic radials. Getting new tubes has been a problem, vendors claim they are sold out on tubes, same as with certain brands tires.

[Synchro909]

Originally Posted by burner31

Sounds right, quality control/manufacturing issue, and I think it's safe to say not Made in the USA

My most recent tubes have "CHINA" moulded in them. I've worn out 2 sets of tyres with them and still no issues and all at a fraction of the price of US made ones.
IMO, Just because US made is generally good, doesn't mean others are not.

Back to the OP. That looks to me to be a flaw from the manufacturing process but chasing warrantee claim is probably not worth the hassle. I'd replace it and drive on.

[denniskliesen]

Here’s 1 of those blemished tubes that was loosing air a few days ago. It would lose about 5 lbs a day. I decided after needing air after the first fill it has something wrong. I suspected tube and sure enough …

[aermotor]

Originally Posted by denniskliesen

Here’s 1 of those blemished tubes that was loosing air a few days ago. It would lose about 5 lbs a day. I decided after needing air after the first fill it has something wrong. I suspected tube and sure enough …

If that was a slow leak I wonder how long a blow out would last?

[Synchro909]

Originally Posted by denniskliesen

Here’s 1 of those blemished tubes that was loosing air a few days ago. It would lose about 5 lbs a day. I decided after needing air after the first fill it has something wrong. I suspected tube and sure enough …

That is typical of tubes that were available about 10 years ago. Is it that old? If so, I am amazed it lasted that long. I had one tear all the way around the side except for about a foot after travelling only a few hundred metres. That went flat quickly!

[Jeff/Illinois]

Originally Posted by lrf

I just bought four inner tubes from Bratton's, $30 each, new 100% butyl rubber, made for standard and radial tires. Great quality and IN STOCK! I'm tired of changing flats the next day after a tour and then trying to repair 10 year old tubes.

I just bought 5 new tubes from Bratton's.

I'm happy with them, good quality!

[denniskliesen]

Originally Posted by Synchro909

That is typical of tubes that were available about 10 years ago. Is it that old? If so, I am amazed it lasted that long. I had one tear all the way around the side except for about a foot after travelling only a few hundred metres. That went flat quickly!

It was a new tube about 7 months ago.

[Synchro909]

Originally Posted by denniskliesen

It was a new tube about 7 months ago.

Those dud tubes from 10 years ago were made from recycled materials. Maybe someone has just had the same great idea!

[ETAModel]

When I worked with earth moving equipment I spent many a rainy day patching tubes and tires for 3/4 ton trucks to 6X6 tires on split rims, Semi 2 piece rims up to Cat loaders, which were always fun. I was the apprentice, Johnny would spray ether in the tire and "burn in" the patch, and use lots more in a tubeless tire to seat it. I think he liked blowing things up. I almost always used the cage or a chain on 2 piece rims, Johnny called me a sissy, but I'm still here.

I always used a hand scraper to rough up the tube/tire. Johnny used an air buffer, but I saw him cut to the core more than once. He just laughed and threw it in the junk pile. We rarely had talcum, just cleaned it up good, sprayed some ether on it and let it dry, then lots of glue, give it another minute to get tacky, patch it and rolled it good.

The boss had bought a warehouse full of old GI tires. I hated them because they were soooo thick and stiff. I don't miss THAT job.

[CT Jack]

It looks like a quick and dirty repair was made during manufacture. More than likely it came from Vietnam or China. I know nothing about the different types of rubber used in the manufacture of tubes but apparently there is a durability difference between 100% butyl and other compounds. I also think it is important to keep radial tire pressure higher than bias ply tires. Too low of pressure might cause more flexing or rubbing between the tube and the tire, just a guess. I just installed 4 new American made radials with new tubes made in Vietnam and set the pressure at 40psi.

[jimvette59]

Manufacture bad batch of rubber. Where did you buy them ? Where were they made ?

[shew01]

Originally Posted by jimvette59

Manufacture bad batch of rubber. Where did you buy them ? Where were they made ?

I bought them from Snyder’s, who got them from Coker, I think. I had a hard time finding tubes a year ago when I purchased them. So, the tubes should be a little over a year old. The other 4 tubes are working fine.


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