Search found 36 matches

by Roger_H
19 Feb 2024, 3:04pm
Forum: Bikes & Bits – Technical section
Topic: Track pump: am I missing something obvious?
Replies: 31
Views: 6417

Re: Track pump: am I missing something obvious?

They are not jamming closed. There is something specific about the valves on Ridenow tubes and if you haven't used them you won't know the solution.
But let me repeat, I have pumped up a tyre or two with lots of different pumps and connectors over many decades so I'm not totally wet behind the ears which I why I am asking has anyone else had this problem.
by Roger_H
19 Feb 2024, 1:33pm
Forum: Bikes & Bits – Technical section
Topic: Track pump: am I missing something obvious?
Replies: 31
Views: 6417

Re: Track pump: am I missing something obvious?

Ridenow valves are plastic and don't have a knurled of any other nut at the base of the valve (next to the rim).

Yes, the valve head was perpendicular to the rim.

There was no problem getting to 50psi or so - but after that there was a massive egress of air with each pump stroke.

I have pumped up tyres for 6 decades without problems but never seen this before.

Has anyone experience this with Ridenow tubes?
by Roger_H
19 Feb 2024, 12:14pm
Forum: Bikes & Bits – Technical section
Topic: Track pump: am I missing something obvious?
Replies: 31
Views: 6417

Re: Track pump: am I missing something obvious?

You wouldn't tell dimensions etc from a photo - but in essence they look similar but I have haven't measured.

But have you had such problems?
by Roger_H
19 Feb 2024, 11:41am
Forum: Bikes & Bits – Technical section
Topic: Track pump: am I missing something obvious?
Replies: 31
Views: 6417

Re: Track pump: am I missing something obvious?

I've just tried some Ridenow TPU tubes.

They both mounted and pumped up fine at first. A day later one had gone soft so replaced but wanted to put a little more air in the other and found my track pump (and other hand pumps) wouldn't connect (again) properly to the valve - every time they got to around 50 psi they just leaked aire when pumping.

Couldn't sort however II tried to position the pump head.

Ended up replacing the TPU tubes with butyls which pumped up without any problems.

So the Q is, has anyone else had similar problems? I suspect the issue is the Ridenow valves aren't made to standard dimensions but haven't properly checked.

Apologies if this has already been covered on an old thread.
by Roger_H
11 Feb 2024, 2:39pm
Forum: Bikes & Bits – Technical section
Topic: Plastic inner tubes.
Replies: 18
Views: 2176

Re: Plastic inner tubes.

I only use CO2 for roadside tube changes so no hardship to let the tube down and pump up with a track pump at home.

But any issues about embrittlement - eg TPU tube failing within a few minutes / miles of inflating with a CO2 inflator?
by Roger_H
11 Feb 2024, 1:24pm
Forum: Bikes & Bits – Technical section
Topic: Plastic inner tubes.
Replies: 18
Views: 2176

Re: Plastic inner tubes.

CO2 inflators?

I've read some very mixed comments about CO2:
- no problem at all (ex Tubulito)
- beware that CO2 leaks out faster than air so consider CO2 just as a get you home solution
- the low temperature from CO2 inflation can cause embrittlement and cracking of the tubes and plastic valve stem.

IE Everything from no problems to your heading for a guaranteed fatal failure!

Any real life experience and, to clarify the picture, was that with any particular brand or metal vs plastic valve?
by Roger_H
27 May 2023, 1:28pm
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

I never remember similar problems with tubs - but of course the tubes were far thinner and the tyres never lasted so long!
by Roger_H
27 May 2023, 11:00am
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

I don't know but I do know something has changed over the years - whether with tyres or tubes. Who knows, perhaps something as simple as higher pressures in 23 and 25 mm 700c tyres...

And one also knows tyre companies have very large R&D budgets.
by Roger_H
27 May 2023, 8:37am
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

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!
by Roger_H
26 May 2023, 10:23am
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

Sadly liberal coating with talc prior to installation doesn't prevent though there clearly is uneven stretching and plastic deformation of the tubes.
by Roger_H
25 May 2023, 7:46pm
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

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.
by Roger_H
25 May 2023, 7:34pm
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

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.
by Roger_H
24 May 2023, 1:26pm
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

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.
by Roger_H
24 May 2023, 7:44am
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

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.
by Roger_H
23 May 2023, 8:52am
Forum: Bikes & Bits – Technical section
Topic: Strange wear pattern on latex tubes
Replies: 34
Views: 3260

Re: Strange wear pattern on latex tubes

Just to also note:
- like the original photo there was a very strong periodicity to the puckering where it appeared on the rim (approx 1/3")
- the puckering was similar on the Michelin and Silca tubes noting the Michelin had been mounted above rim tape and the Silca tubes straight onto the rim bed (one alloy, one carbon).
- I had reverted to Micheli but go clarity.