Veloflex pressure loss

[LegendRider]

My Veloflex Carbons seems to lose approx 35 psi per day (120 => 85 psi overnight). In a 7 hr Tour stage or Classic, a rider could lose 10 lbs of pressure. Do you think any riders notice or care?

[Matt Barkley]

Just curious if this is isolated to one of your tires maybe...How many of these tires have you owned? Both of your do this? Latex tubes do loose air quickly... - are you using valve extenders not tefloned? 10 lbs of pressure over 7 hrs.... Hmmmm.... Good luck :beer: - Matt

[Tom Kellogg]

I don't know, sounds about right to me. My CX EVOs go down about 2-3 bar overnight. That is about 25 to 40 psi.

[Grant McLean]

In a 7 hr Tour stage or Classic, a rider could lose 10 lbs of pressure. Do you think any riders notice or care?

They likely lose a few pounds themselves when it's hot.


g

[Xyzzy]

When I bought my truck the dealership made a big deal about the fact they filled the tires with nitrogen. Maybe that would have less air loss?

I know CO2 doesn't last long.

My Veloflex Black tires and Michelin A1 latex tubes lost about 40 pounds overnight. They lose less the following nights if I don't ride and refill them, so the loss is not linear, probably related to pressure.

I love this combo. All my friends tell me a good set of tubulars will blow my socks off but I can't imagine it being better than this.

[sspielman]

When I bought my truck the dealership made a big deal about the fact they filled the tires with nitrogen.

Since the composition of the atmosphere is 78% nitrogen, if they used a regular air compressor (as I suspect they did), they are essentially correct....

[Xyzzy]

Filling your tires with nitrogen mainly does two things: it eliminates moisture, and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls.
http://www.straightdope.com/columns/070216.html

[Mud]

I have Corsa CXs on our bikes and thought my gauge was broken. They seem to lose 30 or so lbs every night. Surprised me since the Contis and the Tufos (long gone) lost very little.

[Too Tall]

+1. That's about right. Infact on Furnace Creek 508, RAAM and other sim. events we check tyre pressure every shift change. It's a real prob. at PBP. I tried to grab a floor pump every time I could.

[chrisroph]

latex tubes. that is why track racers are always pumping up their tires.

[J.Greene]

Has anyone measure the drop over a 6-7 hour ride?

JG

[Jack Brunk]

Has anyone measure the drop over a 6-7 hour ride?

JG
I average between 10-20 lbs of air loss during a double century.

[Xyzzy]

I average between 10-20 lbs of air loss during a double century.
Perhaps that is a feature and not a bug in the system. After 200 miles, you probably want a softer ride. Just pump them up a little extra at the start, eh?

[BdaGhisallo]

I believe that Continental, and maybe Tufo too, use butyl tubes in their tubulars. Butyl tubes are far less porous than latex tubes and therefore lose far less air than the latex tubes do.

[LegendRider]

I believe that Continental, and maybe Tufo too, use butyl tubes in their tubulars. Butyl tubes are far less porous than latex tubes and therefore lose far less air than the latex tubes do.

It's my understanding that Tufo's don't have inner tubes at all.

[Lanternrouge]

I believe that Continental, and maybe Tufo too, use butyl tubes in their tubulars. Butyl tubes are far less porous than latex tubes and therefore lose far less air than the latex tubes do.

The Conti tubulars seem to hold air for a very long time and at least as well as clinchers. I think I've only had one Tufo tubular and it also held air really well.