Cycling UK Forum

I just bought these for my Trek Madone today but they are to big

I thought they were all the same size.
Here are my wheels with the current valve plus extension in.

I want spare extension as when I last had a puncher I couldn’t get the extension off the old tube.



I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

What's the question?

Why not buy inner tubes with long valves?

mjr wrote:What's the question?

Why not buy inner tubes with long valves?

are there different size pretzels valves???
Neil

ndwgolf wrote:

mjr wrote:What's the question?

Why not buy inner tubes with long valves?

are there different size pretzels valves???
Neil

Specialized do tubes with 48, 60, 80mm valve stems - its likely the original tube has a fixed stem. Generally valve extenders are only needed on the really deep aero rims and disc wheels.

Of course other brands do similar options.

This is the tubes I’m using that have a 45mm stem

I will have a look on Lazada and see if they have any longer


I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

These would be ideal except my tires are 28mm


Neil


I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

Continental are available in 28mm width with the choice of 42, 60 and 80mm valve lengths .... https://www.evanscycles.com/continental ... e-EV270746

What's the problem? Is the drilled hole in the rim too small so the extension won't fit through?.. if it's marginal use a rat's tail file to open up the hole a fraction.

there are three ways of getting long valves;

a) use tubes with long valves
b) use tubes with removable valve cores together with an internal-fit extension
c) use tubes without removable cores together with an external-fit extension

IMHO this is in order of preference too, (although long valve stems are usually brass and are often so heavy they can throw a wheel out of balance)


internal fit extension for tube with removable core


external fit extension; (some have dustcap threads, others don't). These remove using an allen key

The problem with external-fit extensions is that in order for them to end up 6.00mm external diameter (and therefore pass through any presta rim drilling), the wall thickness can't be any more than 0.4mm above the dustcap threads (which are 5.2mm). Often they end up a bit wider than 6.00mm. In addition the valve core locknut can only be tightened if the extension is removed and refitted every time the tyre is inflated.

The problem with internal fit extensions is that they only fit tubes with removable valve cores; these are made by Continental, Schwalbe, Vittoria and one or two others. This arguably defeats the main object of using an extension, which is to be able to use more widely available tubes. However, armed with as many extensions as spare tubes, you are reasonably assured of getting home without a lot of hassle; the extensions will usually pass through any rim drilling.

BTW it is not without risk to open up the rim drilling; the valve should be supported by a small ridge at the base of the valve stem (and if it isn't the valve stems can be torn out of the tubes). This ridge is only a little over 6.5mm diameter, so if you open up the rim drilling appreciably then the valve stem probably won't be supported properly any more.

cheers

Extensions such as those red ones can be very fussy about the pump head. I have a Zipp (supposedly a premium brand ) on my 55mm deep TT wheel. Thevlip at the top, as pictured, makes pump removal nearly impossible without much force. I took the lip off with a file. Perfect now. Bit of PTFE tape on the join helps. The is with expensive tubs already owned. With tubes I'd just buy new ones.

I just ordered 10 tubes with 80mm valve stems and also a new set of tires also 700 x 28 from Evans Cycles and will have them shipped to my daughters house in Scotland as she is coming to Phuket next month for a holiday.........
Happy days

Neil