Yup, here's to Mario S for helping to make our competitors slower!

Amazing how much misinformation shows up on a public message board, even a moderated one like ST.

Latex likes to expand into a round shape, especially a shape where the surface making contact with the tube is smooth and free of irregularities. This is why latex tubes are used for racing tubulars as the tubular tire provides a consistent and smooth 'container' for the tube. Latex in a clincher tire is more problematic, due to the non-tubular shape of the tire/rim and also the irregularities found inside a wheel. Latex has a ability to find the smallest crevice and expand into the crevice. Rim tape is especially vulnerable. This also explains why many spontaneous latex failures are found on the rim side and not the tire side. Years ago I used latex and many tubes exploded without explanation. This was a time when rims were metallic and very narrow, like 13C and 15C, and used Velox cotton rim tapes. Think of the Mavic Reflex and Open Pro rims. Cotton rim tape is the worst tape for latex because they are too thick, and can lift up resulting in crevices. Fast forward to the present. I'm using latex now because my wheels (Campy Boras) don't have spoke holes, hence no need for rim tape. The wheel is also wider (17C) which means I can run at lower pressures. Higher pressure creates problems with latex especially in a clincher. The higher the pressure, the more likely latex will expand into the smallest crevices. So if one does elect to use latex the safest wheel is the one without spoke holes. A wider rim also helps as latex does't like high pressures. Any pressure over 90psi will be too high.

And right on cue, another one above!

At least this is relatively harmless misinformation. Unlike some of the COVID-19 stuff out there.

"This was a time when rims were metallic and very narrow, like 13C and 15C"


What does the C stand for?

ETRTO standard for the internal width of the rim.
https://en.wikipedia.org/wiki/ISO_5775

The link that you provided says that the C means "crochet type" rim.

New question......

If I do have lasting concerns about this (not knowing if my front wheel got taken out in a sprint OR if I had a front latex tube go)...................is there ANY logic in running latex ONLY in the rear tire? And butyl in the front? Rear gets more weight, more CRR resistance. Front has the more "tragic" possibility of failure in terms of bodily injury in a bad situation.

Been running latex tubes exclusively for over 10 years... >60k miles. They don't "spontaneously fail" if you install them correctly, and they are much more resistant to pinch flats and punctures. I'd never use a butyl tube for "piece of mind"... just learn how to install them?

Generally the above is true. However, I did get a 'bad' batch of vittoria tubes in January. All 4 went where the black valve 'skirt' glues to the pink main tube. And all 4 in the same location of that skirt. Made for a relatively stressed race morning as was changing tubes pre race as they had installed OK initially, but then when I went to re-inflate after the bike had been in over night, that caused the first two to go.

Fair play to the local importer though, they sent me a courier label for me to return the tubes and sent me 4 new ones from a different batch. And the two I've used got me through Ironman with no issues at all.

Interesting...some of the first Vittoria latex tubes I used a LONG time ago (~10 years ago?) had a similar "batch" failure. Sounds like whatever the fixed in the process back then may have come back to the fore...

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Tom - or the tubes I got had been on the shelf that long! The new ones come in a grey box, the old ones in black.

I had the same thing happen with a batch appx 3 years ago. Used for years before that and then again after with no problems at all. But one season, I think it was 2018, using tubes bought in 17 I had like 3 or 4 failures same spot.

I had a few failures in tubes I had used successfully for months. Sometimes it was really hard to find the hole,because of the sealant, but I did figure out that the rim strip will dimple at the spoke holes and it seems like the repeated stretching of the rube in that location causes an eventual failure or leak. An extra layer of good rim tape seems to have fixed that issue permanently. Don't use rim strips.

I had a one too. I thought everything was fine, but then 9 months later....😂

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http://www.TriScottsdale.org

I've noticed that the "newer" Vittoria latex tubes have a round skirt on the valve stem - the "older" ones had a larger and more substantial oval skirt. IMHO, the newer ones are not as strong - this one suffered immediate failure in the red circled area.

I've ordered Challenge latex tubes that hopefully will still have the larger oval skirt.

I'll also say this - latex tubes and GP5000's produce a gorgeous ride. However, probably due to the different construction of the plies in the tread area, IMHO once it's punctured, latex tubes are far more likely to herniate through a 5000 vs a 4000.

I'm picking this up because I had a failure in the same region on a recently purchased Vittoria tube. For about a week, my front tube had been losing pressure overnight faster than the rear. It wasn't noticeable while riding, just overnight. Then yesterday, I was pumping up my front tire, and I heard a hiss.



You can't see, but there's a small hole on the left of the stem, and there's a small abrasion that hasn't punctured the tube to the right of the stem. There's also some dimpling of the tube around the stem. There wasn't any debris between the tube and rim strip. I haven't had issues with the rim strip before, and it didn't look like it was damaged. I'll check the other tube, but it hasn't been losing pressure abnormally.

The rim strip is the one Boyd supplies stock with its wheels. I didn't think there should be any issues. However, does anyone know differently? I'm perfectly willing to get some good tubeless tape if it would resolve this.

https://www.amazon.com/...601649234&sr=8-1

I have raced on latex inners a few times and like the ride feel, but after two failures, in exactly the same manner, while pumping the tires in transition, on race morning, I lost confidence in them. While I'm sure the time difference made little or no change in my race result (place) it was a pain to be changing an inner right before a race.

I learned later that the problem may have been caused by me, as I never used the nut to hold the valve in place. Apparently pushing on the latex valve, when you are pumping with a hand held pump, can cause that joint to fail as the latex has no support when you pump. Using the nut keeps the tube stable. Perhaps a floor pump wouldn't do that, but I have tended to use a hand pump. I haven't tested that theory mainly because I'm cheap.

I've seen this issue numerous times and it comes up here once in a while. It's not the rim strip and it's not a defect in the tube. The problem is that you need to seat the valve by pulling on it gently as you add air that first time (and any time the pressure in the tube is close to zero). If you don't, the valve can get stuck in the wrong place when you first fill it, leaving a gap inside. Latex is not good at filling spaces so the gap will eventually (sometimes right away) lead to a tube failure in that spot.

You are correct... except I think you meant it is *very* good at filling spaces. If it isn't seated properly the tube will fold over itself and stretch to fill that space rather than push the valve out.

Dude, yes. This is how I screwed up in the post I just made. Same exact failure.

With a disc I was pushing instead of pulling because it is hard to get your fingers in there.

I had made a custom chuck attachment to screw my frame pump hose onto the valve instead of pushing a chuck on. I stopped using it because I got my press on disc chuck working after tightening the o-ring down.

I never had this problem with my screw-on solution.

Problem solved, pull........don't press. I'll go back to my little custom chuck/hose thing I made though as that was foolproof is not a bit more time consuming!

So, you and lanierb think we need to not push too hard (or at all?) on the valve when seating a pump? How am I supposed not to push on the valve? And these being Vittoria tubes, there are no threads on the valve, so I can't use a valve stem nut.

Press lightly on the tire where the valve is when you start pumping to keep it pressed against the valve hole. Obviously you'll need some force to get the pump head on but when you're holding it from the back it's like not pushing at all.

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Attach pump, then use your fingers to pull down on the valve as you pump. If your pump doesn't attach then you'll need to push on the tire opposite the valve to acheive the same thing. That can be tricky, but you normally only need to do it for one squirt of the pump.

I also have gone to using an old tube as my hole punch for rim tape. Tubeless tape. I’ll heat the old valve stem and push thru the tape. Creates a very snug fit around the stem which helps hold the valve in place and prevents any sneaky latex slipping by if it does get pushed on first pump.

I agree tho - try not to push even if you do that extra step with the rim tape.