Saturday, July 21, 2007


So, I've been battling a ridiculously slow leak after patching my rear tire back on the 12th. I'm talking going from 100 PSI to 70 PSI overnight or while I'm at work. Enough to where I can pump it up before my commute and get home with the rear tire starting to get teeny bit squishy.

So yesterday, I tried to find the leak. Impossible. I had the whole tube under water at about 20 PSI (bulging) without a single bubble. It's that slow. I rolled it up and switched it out for the brand new 700x18-25mm tube that I had in my seat bag. I figure this slow leaking tube would make a great "limp it home" spare.

When I aired up the new tire, I noticed that it had a narrow area near the valve stem. I deflated it and examined it, and it looks pretty strange. I aired it up again and thought to myself that it might be okay.

Right after I made my last post, I found a really low tire. The trip to the PHP user's group meeting was the first time I'd ridden on the new tube. I definitely wasn't going to make it home. With a total of 4 CO2 cartridges and a spare (slow leaky) tube, I decided to see how far I'd get by filling the current tire up. It bought me about 20 minutes, which got me within a mile or so of home. I was losing about 2 PSI per minute, by my estimates. I had some CO2 left from that cartridge and finished it off. I decided I would go past home by about 2 miles to hit Turner Cyclery for some decent tubes. I ended up burning another cartridge on the way there. When I got there, they topped off the tire once more and told me to hurry. I was losing about 5-7 PSI per minute now, and it didn't have much left by the time I rode the 2 miles back to my apartment.

Thank goodness I bought that cheap 25 pack of cartridges, eh? Remind me to never buy 18-25mm tubes again. I bought two 28-32mm tubes for my 25mm tires. I know it sounds bad, but the one I installed tonight seems to be a perfect fit. I don't think it's any worse than the 1.75" tube that's in the 1.25" tire on the back of my hybrid. That's held solid for over 400 miles.

I put the other new tube in the seat bag, and stuffed the slow-leaking spare into the pouch I keep in my panniers that contains some extra tools and my first-aid kit.


Ed W said...

On your slowly leaking tube, try putting it underwater again and work the valve stem back and forth. Sometime the valve leaks at higher pressure, but it's OK at a couple of psi,

Sirrus Rider said...

Also, avoid long valve stems. Sun & Ski here in Houston only seem to want to cater to the Deep Vee/Aero rim crowd the tubes the sell have presta valves like an African bushwoman's nipples... Very long! Especially when mounted in conventional rims. The problem with this is that as the valve is manipulated for pumping and while at pressure it will separate from the tube causing either an immediate or slow leak depending on how hard it had been pulled upon.

Privacy Policy

This site is driven by software that uses third-party cookies from Google (Blogger, AdSense, Feedburner and their associates.) Cookies are small pieces of non-executable data stored by your web browser, often for the purpose of storing preferences or data from previous visits to a site. No individual user is directly tracked by this or any other means, but I do use the aggregate data for statistics purposes.

By leaving a link or e-mail address in my comments (including your blogger profile or website URL), you acknowledge that the published comment and associated links will be available to the public and that they will likely be clicked on.