Latex tube and quick air leaking

[xmashx]

Hi,
I haven't used a latex tube with clinchers for couple of years but I have an experience with latex in tubular.
I used a brand new Vittoria Competition Latex 19-23/622 with a Conti GP5000 23mm on a brand new rims for a velodrome outdor session.

I pumped up to 7.5 bar and after 1 hour of bike transportation I was rather suprised to have only about 7.1 bar left (in an hour!). I pumped back to 7.5 and go for some fast rolling. An air temperature was between 35-40 degrees Celsius and bike was exposed on direct sun during break periods. I was rather sure to get some "free" pressure due to high temperature and direct sun (the reason why I kept 1 bar to the maximum of tire pressure just in case). Nothing like this. After 3 hours of the session, I ended up with about 6.9-7.0 bar.

Isn't a bit to quick for leaking? The leaking is rather constant, both wheels loose the same amount of air in the same time.
For latex tubulars I would say they keep pressure for at least 3-4 hours and with riding it doesn't loose at all. Maybe I haven't verified it much on road and it's only my impression?

[mattr]

Where are you measuring?
If you are using the gauge on the pump, you are losing air to the hose every time you connect it.

Other than that, check valve cores are tight. Loose ones tend to come in batches for some reason.

[1415chris]

0.4bar it is around 6psi, well too much for an hour of air loss.
Having experiance with different latex tubes I'd say the air loss over 24h is around 15-20psi.

[xmashx]

Where are you measuring?
If you are using the gauge on the pump, you are losing air to the hose every time you connect it.

I use a Topeak Smartgauge D2, it's a digital gauge. I have been using it for years, so I understand the problem you are talking here but it's not a problem here.

Other than that, check valve cores are tight. Loose ones tend to come in batches for some reason.

Right, will check. Good tip! Especially that my LBS added valve extenders (for no reason imho) while preparing the wheelset.

0.4bar it is around 6psi, well too much for an hour of air loss.
Having experiance with different latex tubes I'd say the air loss over 24h is around 15-20psi.

Yeah, so my suspicions were correct.


Anything else that can cause the problem? Like wrong tube installation or something?

[mattr]

If the valve extenders aren't needed, get rid.

If you have some plumbers tape to hand, maybe add a wrap of that to the thread.
Could also be used to improve the seal on the extenders. If they are needed.

[1415chris]

You coud have a very tiny puncture causing a slow leak. Couple of weeks ago I had such one in Vredestein tube. I couldn't locate the spot, even checking under water. In these cases I simply add sealant into tube.

[xmashx]

You coud have a very tiny puncture causing a slow leak. Couple of weeks ago I had such one in Vredestein tube. I couldn't locate the spot, even checking under water. In these cases I simply add sealant into tube.

The trick is that amout of air leaking is exactly the same in both both wheels. It's pretty hard to make two similar punctures but who knows. A sealant is no go for track purposes though.

I will play with valves..

[alcatraz]

The tubes might belong to a batch with defects.

Are you pumping CO2?

[IvanZg]

I am using Vredestein Race Latex tubes. Yesterday I pumped front tire to 5,9 bar and rear to 6,4 bar. Measurement was taken with Topeak SmartGauge D2. I did a 2h10min ride with avg temp (as per wahoo element) of 18C. Bike was then stored in the house with avg temp of around 24C. 24h later I went for a ride once more and measured pressure before pumping it and rear tire lost 1,1 bar and front 1 bar. I do not track pressure drop on a regular bases but pump it before every ride to what I require. I did many rides with avg temp above 30C and 3h+ and never felt like it lost any significant amount of pressure that I would notice while riding. I am using this tubes for last 2500km.

[pdlpsher1]

Unlike butyl, latex is a material that is difficult to manufacture consistently. So you may have 10 tubes and each tube expands differently and have different air loss rates. And over time those inconsistencies get bigger as the tube stretches. It’s not the fault of the manufacturers but rather the finicky nature of the material itself. Latex in a tubular doesn't suffer from issues as much as clinchers because in the tubular the tube expands into a perfectly round space. If you choose to use latex in a clincher the best advice is to choose a thicker, heavier tube. You will less likely to run into issues with a thicker tube.


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[wheelsONfire]

I have latex tubes in my tubulars. I think Vittoria is the worst. They drop pressure while out biking which is crap.

[xmashx]

I tried to make all threads tight on the valve but it didn't help much.
Pump up to 8.5 bar. 30 minutes of storage. 1 hour of riding on rollers. 30 minutes. 7.8 bar.

Not the best result. I pump with a floor pump, don't use CO2 - I know latex don't like it as much as butyl.
Well, I can live with it. Basically on track I can easilly do a 4-5 hours session without necessarity of pump it up. However, forgot to check after the pressure after a session.

This is indeed on Vittoria tubes. I have also a pair of Vredestein latex tubes. I will leave it as it is for now. Howver while changing tires, I will try to remove the extenders and maybe put the Vredestein too. The rims height is 30mm while the Vittoria's valve height is 45mm. I don't see a bottom line of the extender, it's somewhere inside a rim. Pretty weird as 15mm shouldn't be enough I guess.