Inner tubes

The rule is simple: the valve must protrude from the rim by at least 30 mm to allow connection of the pump or pressure gauge. For rims with a 25–30 mm profile, a 40–48 mm valve is sufficient. For rims with a 35–50 mm profile (aero or mid-section carbon), use 60 mm valves. For rims with a 50–80 mm profile and above, 80–90 mm valves are required. If the valve is too short, add a valve extension (Zipp, Silca) which screws onto the Presta valve stem. Please note: non-removable Presta valves do not allow the use of a standard extension.

Yes. Inner tubes have a tolerance: a 700x23-25 mm inner tube can often fit up to 28 mm, as latex or butyl stretches. The information on the packaging indicates the compatibility range: a 700x20-28 inner tube covers all standard road tyre sizes. However, fitting an inner tube designed for 25 mm onto a 32 mm tyre or larger creates a risk of weakening due to overstretching. Always check the ETRTO range indicated on the sidewall or packaging of the inner tube. If in doubt, choose the inner tube with a range covering the target tyre width.

Pinching is the leading cause of punctures immediately after fitting. The technique: slightly inflate the inner tube to give it its shape before inserting it into the tyre, then fit the tyre by hand without a metal tyre lever (use plastic tools or the strength of your thumbs), check all the way round the rim that the inner tube is not trapped between the tyre sidewall and the rim before inflating. A latex inner tube is particularly vulnerable to this error. A little talcum powder on the inner tube makes fitting easier and reduces the risk of pinching.

No, this is a known and documented incompatibility. Rim brakes on carbon rims generate significant heat during descents, which can reach 180–250°C on the braking surface. Latex melts at a much lower temperature than butyl and can burst under the effect of this heat. On carbon rims with rim brakes, butyl is mandatory, or better still, a high-temperature TPU inner tube. Latex is compatible with disc brakes (the rim does not heat up) or on aluminium rims with rim brakes on reasonable descents.

Under normal use, a butyl inner tube can last between 3,000 and 10,000 km depending on conditions. Poor road surfaces, sharp objects embedded in the tyre that haven’t been removed, and incorrect tyre pressure cause premature wear. Signs of wear: cracks on the sidewalls or near the valve (ageing of the rubber), increasing porosity (losing too much pressure between rides). Latex inner tubes last around 1,500 to 2,000 km in competitive use and must be stored away from light and heat. A well-maintained TPU inner tube can last over 5,000 km.

Yes, absolutely. Tubeless tyres do not make the bike invulnerable: a deep or sidewall puncture cannot be sealed by the sealant alone. Carrying a spare inner tube of the correct size (700x25-32 or 700x20-28 depending on your setup) remains essential for any self-sufficient cyclist. The TPU inner tube is ideal for tubeless repairs: it’s smaller than a credit card, weighs 40 g and fits in a jersey pocket. Don’t forget to bring a strap or tape to act as a temporary rim strip if the tubeless valve needs to be replaced with the inner tube’s valve.

Yes, TPU inner tubes (Tubolito, Pirelli SmarTUBE, etc. ) are compatible with CO2 cartridges, unlike latex inner tubes, which can be damaged by CO2. The only point to note: after inflating with CO2, switch back to compressed air as soon as possible (CO2 diffuses through TPU faster than air, so the pressure drops more quickly). In an emergency on the road, CO2 + TPU works perfectly. For butyl inner tubes, CO2 is also compatible, but the final pressure may slightly exceed 8 bar if you are not careful with the cartridge.

The size is marked on the tyre sidewall in two formats: ISO/ETRTO (e.g. 25-622 for a 700x25 tyre) and in inches (e.g. 700x25C). The inner tube must cover this section within its compatibility range. A 700x18-25 inner tube is suitable for tyres from 18 to 25 mm. A 700x25-32 inner tube is suitable for tyres from 25 to 32 mm. If in doubt, an inner tube slightly larger than the tyre is preferable to one that is too small: butyl stretches safely, whereas an inner tube that is too small creates localised stress that weakens the material near the valve.

Yes, this is the standard repair procedure if the sealant fails or the puncture is too large. First, wipe the inside of the tyre to remove as much sealant as possible (it is sticky and can pinch the inner tube), insert the inner tube as normal, then inflate carefully. The tubeless valve must be removed so that the inner tube’s valve can be inserted into the rim hole. Your repair kit should include: a lightweight butyl or TPU inner tube of the correct size, and a standard Presta valve compatible with the rim’s valve hole (often 6.5 mm on road bikes).