Continental 42mm Presta Valve Tube (2-Pack, 20 x 1-1/8-1-1/4cc) Slim

These tubes, for my recumbent front wheel, are harder to find sometimes. Thanks.

I am slowly trying to do my own conversion to a more "serious" bike, and this was my first attempt at moving from tubes with a schraeder valve to tubes with a presta valve. These were easy to install, even on a wheel that seems more cut out for anything but a presta valve. While the valve didn't exactly seat itself into the rim as well as it could have, due to the v-shape, it did work out. I also got a presta air attachment so I could use my compressor. My old tubes and tires would continuously leak air. I would have to add about 20 pounds each time out to get to 65 psi. These, with the tires, only go up to 45-50, but I am not finding that I need to keep checking prior to every time I go our on a ride as I did before with the old tube/tire combination.I'm buying two more today just to keep as spares, although I don't expect to have any trouble. I just like to have spares on hand.

Although the factory packaging and the actual tube itself is labeled as suitable for both 406 and 451 wheels, I found that there is excess material when installing on 406 wheels. I used a lot of talc on the tubes so hopefully they will self-center and distribute the excess evenly but who knows what's actually going on inside there. I'm assuming that Continental knows what they're doing and this will be OK. I couldn't detect any lumps or unevenness after the install or after pumping up to pressure so again I'm assuming they know more than I do but in my opinion it's a less than ideal solution. Probably a cost savings move on their part but next time I'll go with Schwalbe if they're still making 406-specific tubes in the future. Not cool!!

Who knew that in the bicycling world 20 inches is not equal to 20 inches? I had no idea that two tubes identically marked as 20 inches could be so different in size. I guess it is a guy thing, where 9 inches is no where close to being 9 inches. I finally found a good reference about ISO sizes and ordered that way. Finally got tubes that fit and they arrived quickly. So I need to ask guys about their ISO size?

These hold air so much longer and better than the standard tubes bikes come with! Took me buying several ones to find these. The valve is perfect. Which was an issue. The threads and length perfect for the Schrader valve adapter!

Bought this for me recumbent bike 451 front wheel. I had a flat today for my century ride and the tube was so small I had to stretch it around the rim to fit and it was hugging my rim so much that is I tried to inflate it it would have caused a pinch flat. Lucky I was able to patch my old tube because this one didn't fit as advertised! This was definitely a 406 tube! Now it's past the 30 day return period and I'm stuck with these useless tubes.

One thing to note: these conti tubes come with one piece removable presta valves. If you want to add a sealant (like Slime) to them, there is no need of the myriad "hacks" to do so. Just remove the valve, add sealant, and reinstall. This is reason enough to choose them. Besides, I like having a spare valve (from an old tube) in my bike bag. I've never had a valve go bad, but hey - if I do I can change it without replacing the tube. Since I've cycled in the Yucatan, Central America, and North Africa, I like the idea.

It holds air like a bike tube should.