tube being pinched by the tyre irons when replacing the tube , even when the tube is slightly inflated to help with installation . Working carefully will most likely prevent this however there is another consideration . A too large a tube can often fold on itself creating a weak point as the rubber moves or flexes under normal use creating excess heat or even a weak spot that will eventually fail – think of it as bending a piece of plastic back and forth , it will eventually break .
Whilst using a tube that is too large does have downsides it can likely be a saviour when needing to make an emergency replacement . A front tyre tube is a better option to replace a rear if the correct size isn ’ t available as opposed to the other way around . A too small tube will fail and generally quite quickly .
A tube that is too small will need to be over inflated weakening the performance of the tubes rubber , rendering it susceptible to damage , and while in an emergency , fitting a tube that is too small can get you by it isn ’ t recommended . Too small means too tight , it can also be a nightmare to fit .
The tube plays a huge part in the performance of a tyre , the way it flexes , the way feels , the way it provides consistency . While the tube must fit the diameter of the tyre and wheel it should also be compatible with the width of the tyre . The tube should always fit snuggly against the rim as well as the tyre side and tread walls ( carcass ). Any area where there is not a snug fit can mean a feeling of mushiness and excess heat generation , one will cause an uneasy feeling when riding the other will cause eventual failure .
How does heat affect a tyre or tubes performance ? Racers , both two and four wheeled , are forever talking of heat generation of a tyre . Too low , too high , both have an impact . Inflating to the recommended pressure by both the tyre and motorcycle manufacturer is advised however , in some instances a different approach is needed . Regardless of the pressures you run always try to inflate when the tyre is cold as pressures will increase as the temperature does , over inflating without even realising can by a problem . Too low with the tyre pressures will cause heat build up through the sidewall as it pushes against the road surface . This will bring tyre pressures up slightly however , it will more than likely cause the tyre sidewall construction to delaminate and fail . Conversely an over inflated tyre will cause the tread to ‘ bulge ’ meaning reduced contact with the road , this too will cause overheating , generally through the tread which in turn can also cause overheating and delamination however through the tread .
Tubes do add weight to the overall motorcycle , and generally where it ’ s not wanted , as unsprung weight … we won ’ t go into the physics of weight , suspension , and handling . Two tubes can easily mean the addition of 2.5 kilograms to your bikes weight , more if you carry spares . Heavier duty tubes can even be as much 4 kilograms for the two tubes . This comes down to the thickness of the tube .
Common regular tubes are generally around 1.5 to 1.75 millimetres thick , whilst ultra-heavy-duty tubes can be as much as 4mm . Motorcycle manufacturers want to save weight as well as money so will always fit the thinnest tube possible , generally not a problem , these tubes will last as long as the tyre , more than likely longer however thicker tubes offer a level of confidence that they will be up to the job of riding tougher more demanding conditions . That doesn ’ t mean they won ’ t fail and when they do , replacing can often be a challenge due to the thicker , lesser malleable rubber .
The properties of the rubber that make up a tube also have an impact on performance . Construction is often a mix of synthetic and natural rubber . Cheap tubes often have a higher content of synthetic rubber , sometimes all , and while fine in most instances synthetic rubber has less propensity to form to the tyre and can be more susceptible to damage and flats . Tubes with a higher concentrate of natural rubber , are much more pliable and therefore offer greater resistance to punctures .
Finding the right tube for your needs comes down to choice , there ’ s no right , there ’ s no wrong , it ’ s simply what works best for you at a cost that meets your budget . However , regardless of the quality , size , or construction of the tube there are several ways to ensure you maximise the tubes life and operational ability .
When fitting a tube , a little baby powder goes a long way . We all hate the friction generated when out on run or spirited walk and so do your tubes and tyres as they work together . A small amount of baby powder will help reduce the friction or chaffing , don ’ t over do it , just a light dusting before installing the tube is enough . When installing a tube , it ’ s also a good idea to inflate it slightly to form its shape and help prevent pinch punctures . A point to consider when removing or replacing a tyre or tube is that whilst the rubber becomes more malleable when heated ( i . e . working in the sun ) it also shrinks . So , although soft and supple it might also become too tight to easily work .
When refitting the tube check the tyre and rim for contamination . Grit , water or even the slightest rough patch can cause a tube to be weakened through wear and eventually fail , a few extra minutes can save you the angst of a puncture or worse . And always check the valve stem . Generally , this is the weakest part of the tube and often the most neglected . Never excessively tighten the valve stem nut to the rim , allow a degree of movement as this is needed when running lower pressures . Just
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