|Inner Tube Vending Machine (Photo credit: Planetgordon.com)|
Your brain is probably full of useful information after reading the first part. Show of hands, how many of you attempted to purchase a tire for your bicycle after reading the previous post? Did you feel confident? Was the bike shop employee impressed by your vast knowledge of tire sizes? If he/she wasn’t, don’t worry, they’re not an easily impressible lot.
I touched on tubes a bit near the end of the first post. To reiterate, the sizing convention is the same for tubes as they are for tires. If you know the tire size, you know the tube size. The only difference is that tubes fit a range of different tire sizes. Here’s an example:
You have a 26″ x 1.95″ tire. The shop has a tube that fits 26″ x 1.75-1.95″ tires. That would be the appropriate tube because your tire is in the range of that tube. If your tire was, say, a 26″ x 2.25″, the tube would not be a good fit for your tire.
Depending on the person selling the tube, some will tell you the skinnier 1.95″ wide tube will fit the wider 2.25″ tire. As a mechanic, I will tell you it will. What happens is that the tube will stretch to fill that space, even though it’s wider. It does stretch the tube material a bit thinner, but for all intents and purposes, it is negligible. I’m sure someone is going to read this and raise holy heck about this, but I have done it for years with no ill effects. I didn’t get more flat tires or anything.
Now, believe it or not, there are a variety of tubes you can get for your bicycle. First, I’ll go over the different types. Secondly, we’ll look at valves. I know, the suspense is killing me too. After the break, all shall be revealed.
Bicycle Inner Tubes
Tubes are typically made of butyl rubber. That’s the familiar black rubber we all know and love. Natural rubber is mixed with additives to make it stronger and more stable as it ages. These are typically the least expensive tubes you can buy.
There are butyl rubber tubes that have a higher natural rubber content, or use what is referred to as “virgin rubber.” Get your head out of the gutter. This basically means that the rubber used to make the tube isn’t recycled. Making tubes produces scrap material and most manufacturers will reintroduce the scraps into the process to use as much material as they can. Virgin rubber tubes don’t contain those scraps. According to the manufacturer, this makes for a more supple tube which in turn reduces friction between the tube and the inside of the tire. Thereby it reduces rolling resistance. Another benefit is that the more supple tube conforms to foreign objects more readily, making it more puncture resistant. This isn’t me saying this. This is the marketing material from Continental Tires. I’ve been running Continental tires for as long as I’ve been riding, but as for their tubes, I haven’t really used them.
What I have used is the polyurethane or latex tube. These tubes use either a flexible polyurethane material, or latex rubber for the tube material. These tubes, in addition to being more supple and conforming like virgin rubber tubes (I hear you giggling), are lighter in weight than their butyl rubber cousins. I can attest to the faster feeling and more supple ride that these tubes produce. However, they do come at a premium, usually around $18 a tube.
So take you pick. I still use the inexpensive butyl rubber tube because even as a bike shop employee, the lightweight tubes are still expensive. Though I do run the lightweights in my road bike because I do like the ride quality they give.
Bicycle Inner Tube Valves
Next up, valves. Oh the silly valves. There are three, yes three, different valves:
Schrader, or the valves you see on your car tires and most bikes.
Presta, A.K.A. French valves which you tend to see on the more expensive bikes. Or what people like to refer to as “racing bikes.” I mean really, you can race any bike.
Dunlop, an older tire valve which is popular in Asian countries but sometimes finds it way to the states.
|The Holy Trinity of Bicycle Valves as Illustrated by Yours Truly|
Refer to the picture to see the differences. When buying a tube, this is typically the second question a bicycle shop employee will ask after getting the size. You also need to know what valves you have so that your spare tube matches.
Trade secret: A presta valve tube will work in a wheel drilled out for Schrader because it is narrower. Some presta valves come with a valve nut that allows you to tighten down, holding the valve in place. If it doesn’t have one, it still works. I do recommend replacing the tube with the appropriate Schrader valved tube as soon as possible. Unfortunately, this doesn’t work the other way as Schrader valves are a larger diameter than Presta.
Now those pesky Dunlop valves. Those valves were around when the Wright brothers had their shop. It’s sort of a combination between the presta and Schrader I guess. There are adapters out there that allow you to inflate a Dunlop valve with your, hopefully universal as I recommended, bicycle pump. In a pinch, I have use a Presta specific pump to inflate one, though it is a bit frustrating.
Why the different valves? Well, that’s another post. For right now, know which one(s) you have on your bicycle.