Inner Tube Insights

Here are 7 inner tube tips from Roadbikerider.com.

Protect the valve stem. The edge of the valve stem hole in your wheel can be sharp enough to cut the tube at the base of the stem. After the tube goes flat it’s very difficult or impossible to repair the damage. ┬áTo shield this sharp edge, cut a tiny hole in the center of a small piece of stout cloth (denim works well) and slip this protector over the valve stem during installation.
Fill the rim hole. Similarly, combining a tube with a skinny presta valve stem and a rim that has a large hole for Schrader valves can allow stem movement and damage. For example, you might be upgrading an old bike with new tires and tubes. To convert the large Schrader hole to presta size, use little rubber donuts called rim grommets.
Length matters. When buying a tube, consider valve stem length. This is important nowadays because so many wheels have deep-profile rims. The valve stem must extend enough to accept a pump head. Stem lengths range from about 35 mm to a whopping 80 mm. Measure yours before you go tube shopping or take one of your tubes with you.

Tip: To be able to use a tube with any valve stem length (or help fix a friend’s flat when he doesn’t have the right size) carry a valve extender in your seat bag.

Width matters. Tube sizes can be confusing. There are different diameters, and widths come in ranges. You want a size that’s an easy fit inside your tires. This means a tube that’s slightly narrow (it’ll stretch when inflated).

Start by finding your tire size. You’ll find it on the sidewall or label. For road bikes it’ll likely be 700×23, but the width could be greater (25, 28). 700 is the diameter, which in terms of tube size is the same as 622 and compatible with 27-inch too. So, for ease of installation you want a tube that’s the same diameter but ideally has a slighter smaller width. For example, a 700×20 tube for a 700×23 tire. You would not want a 700×28 tube.

Threaded vs. smooth stems. The valve stems on many tubes are threaded top to bottom. Some are unthreaded. Which is better? It’s personal preference.

Threaded stems allow a knurled nut to be snugged against the rim, keeping the stem perfectly vertical and preventing it from being pushed inward when using a pump. The threads also grip the rubber gasket in the pump head to help hold it on. However, this also makes it harder to get the pump head off, and the threads accelerate wear to the gasket.

Smooth stems avoid these problems, and pump heads with gaskets in good condition usually won’t blow off. Without the knurled nut, you’ll also save several grams of rotating weight per wheel.

Tighten presta cores. Look closely at the top end of your presta valve stems. The core is replaceable on some brands. You can tell because there are wrench flats on either side. If your tubes have these, use pliers or a small adjustable wrench to gently turn the valve core clockwise to make sure it’s tight. Don’t reef on it, just snug it. A loose core can cause a mysterious slow leak.

Lighter is righter. In my experience, thicker, heavier tubes don’t resist flats better or last longer than lightweight tubes. (I’m talking about regular tubes, not the thorn-proof type that makes perfect sense if you ride where thorns and glass are common.) The reason lightweight tubes work equally well is because the tire is the primary flat resistor. Go lighter if you want the improved performance that comes with less rotating weight.
Lighter is righter. In my experience, thicker, heavier tubes don’t resist flats better or last longer than lightweight tubes. (I’m talking about regular tubes, not the thorn-proof type that makes perfect sense if you ride where thorns and glass are common.) The reason lightweight tubes work equally well is because the tire is the primary flat resistor. Go lighter if you want the improved performance that comes with less rotating weight.