July 17th, 2012
Over the years I have spent many hours at community centres, schools and workplaces providing a Dr Bike service. Possibly the easiest and often one of the most beneficial ‘quick fixes’ that I perform during my bike fettling sessions is to inflate a bike tyre to the correct pressure.
More often than not I will see commuters in their lunch break complaining that riding to work is getting harder rather than easier and usually the cause for this sluggish feeling is running tyres too soft for the conditions and rider.
How do I choose the correct pressure?
The correct pressure that your tyres will need to be depends on several variables and these include the type of riding you are doing, wheel size and weight of rider. Usually you will find the manufacturer’s recommendations detailed on the side of the tyre.
This can be a fairly wide range, sometimes varying by as much as 40psi and this is when we take into account the variables mentioned earlier.
Hybrid, commuter and touring bikes
My commuting bike is fairly typical in that it spends time on a variety of surfaces from smooth ribbons of road linking the more scenic but often rougher and less forgiving bridleways on the journey to work. For this reason I use a relaxed geometry touring bike and run what is referred to as a semi slick tyre that features a smooth centre grove with a series of knobs on the edge of the tyre to aid with cornering on loose surfaces.
With this in mind I need a pressure that works on smooth road surfaces and aids my journey by providing me the minimal in rolling resistance but also the grip that is associated with a softer tyre.
The good folk at Maxxis recommend I run somewhere between 80 and 120psi and given that I want to find some grip on looser surfaces I tend to hover around the 100psi mark. If I was a lighter rider then I may find an advantage in running a lower pressure thus seeing improvements in comfort and grip.
Generally, something around 100-120psi will make a considerable difference if you’ve been riding on 85psi for the past few months without knowing it. If you’ve got tubeless tyres you can pump them up as high as 200psi – depending on the tyre – without damaging it. However this won’t necessarily make you faster: rolling resistance will increase because the tyre has no chance to deform.
Moving over to the world of MTB the same rules apply but at much lower pressures. Whereas a road bike will run efficiently at around 100psi a mountain bike would typically have its tyres inflated to somewhere around the 30psi mark. As the conditions can vary so greatly in the world of off road cycling it is very important to get the pressure of your tyres in line with the conditions just right. You will often hear professional mountain bike riders talk about dropping just 1psi out of there tyre to find that extra bit of grip.
All this can be a bit of a minefield but the key to finding a pressure that works for you is spending some time riding a few different setups and being aware that with different pressures there will be changes in how the bike reacts.
One last thing to remember is that even without getting a puncture your bike will lose air over time so it’s worth checking your tyres every week or so. Otherwise I may see you at my next Dr Bike session.