Strange wear pattern on latex tubes

[Roger_H]

Me neither. I've never used tyre used tyre levers to fit a tyre; I was taught years ago that if you do you'll be sing them a few minutes later to take the tyre off again! And I always check for any pinches right round the circumference before I inflate to a working pressure.

But to recap, quite a few people have seen the same failure pattern and:
- the tubes have been correctly sized,
- the tubes have come from Michelin, Silca and Challenge (ie no just one label),
- the tubes have, in many cases been liberally dusted with talc,
- the installation has been good in other aspects (ie no tyre levers, checking for no pinches before inflating),
- the failures have been seen many months after initial installation,
- the failures appear to have been on the base (ie centre of the rim bed and not near the bead interface) and seen on taped rims as well as un-taped aluminium and carbon rims.

I find it hard to believe that someone from the manufacturers is not aware of the causes. It's clearly a well documented effect and not just something that I alone am finding. Inasmuch as I don't recall any such failures with latex tubes years ago, my suspicion is the chemistry of the tubes has been changed over the years increasing the tendency of the tube to stick to tyre and rim and this is behind the failures - but that's just a suspicion of course.

But not knowing just how long this puckering failure takes to occur and knowing that it can lead to a total (ie flat), it's very much tipping me to just using butyl on safety grounds.

[axel_knutt]

It looks to me like there's a seam running round the tube along the line of the puckering. If for any reason the seam is more prone to creep than the rest of the tube, then when the tube is deflated the part that hasn't crept wil compress the part that has, and cause it to pucker up.

[TheBomber]

Roger - your summary points sound fair to me. Maybe next time I have a tube in that state I'll take a photo and send it to Challenge. They were approachable and helpful when I contacted them with a question about their tyres previously.

To give a bit of balance about using latex tubes generally: if you already have nice supple tyres then latex tubes can further enhance the quality of the ride you get. They appear to be more puncture resistant than butyl (ie foreign objects are less likely to pierce them) but they are prone to other types of failure. They also do not last as long as butyl before some sort of distortion brings them to their end of life. This is part of the cost of their ownership. I don't have experience of tubeless to rate them against that, but if you are looking for improvements over butyl and don't want to go tubeless then they do offer you an alternative.

[Roger_H]

I'm not sure how much difference I can feel between butyl and latex tubes; imho the big differences come from tyre pressure, sidewall construction and tyre type (ie fine cotton/silk open tubular vs nylon carcass with moulded tread) and tyre width.
But my original materials science/Chartered Engineer training makes me interested in why the latex tubes are failing - but mainly it makes me worry that there is a failure mechanism which others are clearly finding and I have no idea how quickly it is happening. That gives me a serious safety worry; are latex tubes only good for X riding hours or to change every so many months etc.
Overall, it's pushing me to abandon latex and move to lightweight butyl tubes.

[TheBomber]

I agree that the tyre construction is more important - so switching from low tpi nylon carcass to a high tpi polyester one, and ditching vulcanised construction in favour of open tubulars will bring greater benefits. But if you want more and for whatever reason don't want to go tubeless, they are an option.

I first tried latex tubes in my current tyres when the Conti lightweight butyl ones I had been using were withdrawn. Schwalbe have since introduced some nice ones in a 700x35 size which are almost as good as the latex, and come without the issues that we've been discussing here. Obviously there are good butyl ones to be had in the 700x25 sizes Roger is after too.

[Roger_H]

I think I might have answered my own Q in terms of the mechanism causing the puckering.

I changed out a latex tube for a lightweight butyl today - because of safety concerns.

The latex tube wasn't punctured but I noticed two faint lines all the way around the base of the tube - which I believe corresponded to the tyre's two beads in the rim's well.

Nearly all the tube was totally free of any puckering but there was a very small section (about 2cm) where there was the start of some puckering - and it was contained within the lines.

So what I think is happening is the stresses from braking are causing very small shear movements between the trye and the rim and the tube - which is effectively adhered to the cover and the rim is responding to the micro movements by showing the ladder puckering.

It would be really interesting if anyone has experience of latex tubes and disc brake wheels inasmuch as you wouldn't then expect to see any puckering.

[brucelee]

Had exactly the same experience 25mm GP5000/Michelin latex tubes. I always fit tyre/tube the same way : A little pressure in the tube to give it shape then push it into the rim then fit the free bead. This has always worked for me with butyl tubes but last time (with the latex ones) I double checked and went round the rim on both sides checking for pinches - and there they were... Maybe double check if your using this setup.

[Roger_H]

In my case I've always gone round the rim to check for any pinches before putting and pressure (ie beyond that to give a little shape to the tube); and the fact that latex tubes are normally green or pink makes it really easy to check there are no pinches.

[TheBomber]

Roger, unfortunately I don’t think I understand your theory of what might be going in with these tubes. You do seem to be asking if anyone is using them with disk brakes though - I am and I have seen the puckering distortions in my latex tubes.

[rogerzilla]

They all do it. A deflated balloon is the same once it's been inflated for a few days. Latex creeps a bit. Nothing to worry about.

[Norman H]

It's probably unrelated to the puckering, but others have recommended using talc or baby powder with latex tubes. It should be noted that perfumed talcum powders or baby powders contain essential oils which can degrade latex rubber. Back in the day when I was using talc on the latex wrist and neck seals of my diving suit I ordered 2Kg of French Chalk from my local chemist, enough to last a life time.

[Vorpal]

In my opinion, the answer is in 531colin's post:

Dust the latex tube and inside the tyre liberally with French chalk/talc. This should stop the tube sticking to the inside of the tyre, so that the only bit free to move and expand is the bit next to the rim tape. That might be what is causing this strange localised stretching of the tube.

The tube is sticking to the tyre, so that it is inflating unevenly & stretching around the stuck points. Using chalk/talc will prevent the weird stretching & greatly reduce the likelihood of slow leaks.

NB: cross posted with Norman H who makes a good point.

[Roger_H]

Sadly liberal coating with talc prior to installation doesn't prevent though there clearly is uneven stretching and plastic deformation of the tubes.

[TheBomber]

It should be noted that perfumed talcum powders or baby powders contain essential oils which can degrade latex rubber.

This had never occurred to me but sounds plausible. Norman, do you actually know this, perhaps from some professional expertise position? I see that french chalk is widely available online and not expensive, so I might switch anyway.

[Roger_H]

Personally, I had never heard this before and I would have thought that the concentrations in baby powder would have be very low because of allergy concerns (even if there) in terms of causing an impact on the latex.
But all the puckering I have seen has been on the rim bed area - ie whatever chemical effects there are, they would be across the whole of the tube whereas the puckering is purely in the rim bed area.
I did notice one latex tube I removed recently (a Silca from a Vittoria Corsa SC cover had stuck to the cover despite liberal dusting when originally mounted. This tends to imply the talc is being "lost" and, couple with the observation that I don't ever recall this type of puckering failure years ago, makes me think something has changed in the latex tube production process/chemistry so we are seeing a mix of chemical and mechanical effects.
The silence over the years from latex tube makers has been noticeably deafening!