Tag Archives: 29er

A case of study: 29er inner tubes

Not long ago bike shops struggled to source specific 29er tubes (700x54mm). A widespread practise was to overinflate the classic 26″ size or 700x35c inners with the risk of sudden blow ups, decreased rolling eficiency and more punctures. Only some beefy tubes behaved well with no surprises for this purpose.

Foto 1 Nikki Gudex tubes

Tubes are within the most iconic bicycle components

Now the market is full of 29 inches tubes. For around £4-5, 6-7€ or 7-8$ you can afford good quality spares. Maxxis (Taiwan) and Schwalbe (Germany) are remarkable brands that produce tubes in many different sizes.

After damaging the original “unlabelled” tubes that came with my bike (probably made by CST, Vee or any other asian bulk manufacturer), I picked the Maxxis Welterweight (4,24€) and Schwalbe Extra Light (6,60€), both in online stores, to give them a go.

A thousand kilometers after testing the tubes with new tyres, the Maxxis tube has result in an amazing and absolute quality product. A bargain for the price (now over 5€).

Maxxis tubes are always true to the word of the company. Since the moment you open the box they meet the announced weight in the worst scenario, and sometimes a lot less.

The Welterweight is not a weight weenie product unlike the intended use of the Schwalbe Extra Light. Officially 205g. versus 140g. Note that the thickness of the butyl wall and tube dimensions will determine its final weight. The valve type, porosity and overall rubber quality have a negligible impact on it.

Foto 2

Maxxis tubes are made in Taiwan while Schwalbe units come from Indonesia

The good thing of the Maxxis is the fact that it is a real 29er inner tube. The Extra Light tube width doesn´t meet the requirements to fit securely a 2.4 tyre despite it is recommended for this size. It is clear when you put them close together that something is wrong in the Extra Light product. It looks like a 700x35c spare.

But what is even more shocking is reading the compatibility printed in the cardbox. It suits also 650b/584mm/27.5 wheels! Wouldn´t have been any wiser to make a compatible 650c/26″/559mm and 584mm tube while producing separately the specific 29er size? The discrepancy of the 29er size (622mm) with the 584mm standard is more than the 559mm measure has instead.

Foto 3

A nonsense of tyre matching specifications that even claims 700b compatibility (635mm)

The result is that the Schwalbe model is not a proper 29er tube and nor a 650b one. You have to slightly overinflate them on 2.2 Continental Mountain King tyres for example. It’s tricky to slide equally the tube inside the tyre bulging it on many ocassions unless you use an air compressor.

What’s more I got quite a few flats. None with the Maxxis. I reckon even the rolling eficiency is compromised with such a tight fitting. A hassle.

The final blow came when checking the weights. The taiwaneses are only 40 grams on average heavier than the germans, instead of the expected 65g.

Average weights

Average weights. Less than 40 grams average discrepancy between models

Cheaper, easier installation, more reliable and keeping the pressure for longer my vote is on the Welterweights. It’s great that Maxxis produces almost each single size of bicycle inner tubes. Meanwhile the design of the Extra Light tube is all messed up.


Bicis de montaña con ruedas 650B

Esta medida de ruedas se sitúa a medio camino entre las convencionales de 26″ y la nueva moda de 29″, es decir, unas 27,5″ (en realidad un poco menos). Desde hace un par de años hay usuarios que están montando en cuadros específicos para 26″ ruedas un poco más grandes. La ventaja es su mayor inercia y que pasan por los obstáculos más fácilmente. Lógicamente, no todos los cuadros ni horquillas las aceptan.

Tienen décadas de existencia. En muchas bicis de paseo del norte de Europa son muy comunes. Su futuro en el MTB es del todo incierto pues hay pocos fabricantes de aros, cubiertas y horquillas, además de que las 29er se están haciendo con el mercado de las ruedas “grandes”. Algunas marcas han realizado diseños específicos para explotar todas las ventajas de las ruedas de mayor tamaño. La idea principal es bajar la altura del pedalier respecto a los ejes de rueda consiguiendo una bici mucho más difícil de volcar aumentando la sensación de estar metido en la bici y no sobre ella.

Ahora mismo es el tipo de bici que más me llama la atención pues, entre otras cosas, apenas aumenta la longitud de las vainas respecto a las tradicionales de 26″ y no tienen tanto slooping ni los tubos horizontales extralargos tan frecuentes de las 29er.

Independient Fabrication 650B acero

Vicious Cycles Mambo Sun Ti

Vicious Cycles Mambo Sun acero

Kish 650B