Latex and TPU Inner Tubes

In the earlier post on the Specialized Aethos, I introduced the Dura-Ace C36 wheelset, which is lighter in weight than the Dura-Ace C50 wheelset. This time, I still chose a normal clincher type of tire, which means that an inner tube is required. The Continental GP5000 tire is available in both tubeless and tubed type depending on the rider's preference.

The C36 wheelset is tubeless ready, with rim tape already installed. This setup can be used for both tubed and tubeless tires. Since I am using a tubed setup, I would need to select inner tubes for this wheelset.

Previously I have been using normal butyl inner tubes, such as those from Schwalbe. They work well, however there are now alternatives that has some advantages over normal butyl tires.

Butyl inner tubes are cheap and relatively durable, but have more rolling resistance and weigh more. The air retention is good compared to other types. It is the safe but boring option.

Latex inner tubes are a bit more expensive, and are rather fragile. The rolling resistance is very low, about the same as using a tubeless setup. The weight is about 30% less than butyl, while the folded size is about the same as butyl. Biggest disadvantage of latex inner tubes is the poor air retention, as the air pressure can drop drastically over a day. It is usually necessary to pump the tires just before going for a ride.

TPU inner tubes are relatively new, but they have the potential to become an excellent option. They are the most expensive type for now, although they are also more durable than latex tubes. Rolling resistance is also low, although not as low as latex tubes. Weight can be 1/3 that of butyl, while the folded size is reduced by half. Air retention is acceptable as it can last a few days before needing a top up.

From left to right, TPU vs Latex vs Butyl inner tubes.

TPU tube is about half the size of the other two types, which makes it ideal for packing as a spare.

Weight of butyl inner tube (60 mm valve) is 113 grams, which is an average weight for this spec. 

This spec is for 700C tires that are 28 mm wide.

Vittoria latex inner tube for 25-28 mm wide 700C tires, with a plastic 48 mm valve.

Latex tube weighs 81 grams, which is 32 grams less than the butyl type.

TPU inner tube, compatible for 18 to 28 mm wide, 700C tires.

Very lightweight at just 37 grams, which is 1/3 the weight of the butyl type.

Lightweight plastic valve is bonded to the TPU tube. Failure point is usually the bonding area on the TPU surface.

Joint on the TPU tube, one of the common failure points.

If you are a weight weenie, you would definitely choose the TPU inner tube, as it can save about 150 grams per bike (2 wheels), at a reasonable cost. One of the easiest and most affordable way to reduce weight on the bike.

What you need to take note, when using the TPU inner tube, is to inflate it only slightly during installation, just enough to give it some shape. Without the tire to maintain the shape, the TPU tube will stretch and bulge even if you just lightly exceed the atmospheric pressure.

Other than that, the TPU tube air retention is pretty OK, as I only need to pump it every 2-3 days even if I ride every day. For the butyl tubes, it will last at least 1 week without needing to pump.

The butyl inner tube has been tried and tested for a long time, and is in use on the C50 wheelset that is on the Focus Paralane. As for this new C36 wheelset on the Specialized Aethos, I will try both the latex inner tubes and the TPU inner tubes to see which is more suitable.