Tyres, boots, rubbers. Whatever you want to call them, they are the only bit of your bike that should be in contact with the road or trail. If they aren’t, something has gone woefully wrong or you have E.T. as a passenger. Overlooked by many and misunderstood by most, tyre selection is essential to getting the most out of your ride. It means the difference between cornering gracefully and introducing your knees to ‘Mr Asphalt’.
There are a few basics that, whatever style of bike you ride, most tyres follow.
The beading is the ‘rim’ of the tyre running as two hoops down each edge and is the part that secures, or seats, onto the rim of the wheel when inflated. Usually made of steel but Kevlar is becoming more frequent allowing tyres to be folded and stored more easily as well as reducing weight.
Between the two hoops of beading a fabric cloth is woven. Onto this fabric the rubber of the tyre is bonded. Think of the beading and cloth as the skeleton of the tyre. If you can look at your tyres and see this showing through it’s time for some new ones.
The business part of the tyre. Think of it as the muscle on the skeleton. This is the part that grips the road or trail and provides drive and traction.
The odd one out is the tubular tyre beloved of TT riders, trackies and some roadies. This is a cylinder of material with the rubber being built onto it. The tyre is taped or glued to a tubular specific wheel as opposed to a clincher.
Off road riding presents a greater challenge for tyres. Off road is a very broad term and covers a number of disciplines. Cross country, all-mountain and downhill all have differing requirements from a tyre and there are a lot of options to cater for all kind of riding.
Off road Grip
Tread patterns can vary wildly between manufacturers with each one offering its own solution. Generally a cross country tyre will offer a shallower tread and harder rubber than an all mountain or downhill tyre due to greater emphasis on speed rather than sticking to the surface under forces generated by gravity. Like road tyres, off road tyres work on the principle that there is a rolling edge for straight line riding and a biting edge for when the wheel leans in for turning. The rolling edge tread blocks may be shallower or have a chamfered edge in line with the rolling direction to reduce speed resistance whilst biting edge blocks will be deeper with a square edge and possibly softer compounds.
Tyres specifically designed to ride in muddy conditions tend be narrower and have sparsely positioned deep blocks. The slimmer tyre allows for more mud clearance against the bike frame whilst blocks with more open space prevent the mud from clogging up the working surface of the wheel and lose stuck mud once it spins. Mud tyres are typically a soft compound to allow for the blocks to smear onto slippery rocks and roots.
Front and rear
It’s not uncommon to see tyres of the same model have differing tread patterns for front and rear wheels. Some riders will sometimes fit an entirely different model to the rear of even fit a rear tyre backwards. This is because unlike a road bike the wheels of a mountain bike do different things.
A rear wheel needs to provide drive and traction to the rider and for that reason will have a tread pattern that is designed to bite into the surface meaning that when you put power through the pedals it translates to forward motion no matter what surface you are riding on.
A front wheel is used to guide the bike and can have a tread pattern that is more rolling friendly with the emphasis on grip being placed at the side of the tyre surface. The front tyre is less likely to be as clogged with mud and will often give a shallower tread.
Commuting and hybrids
Commuting tyres are durable and tough and offer a car like tread pattern that covers the surface of the tyre without any emphasis on blocks (often called semi-slick). This delivers consistent grip whilst keeping commuting speeds high. Usually tyre sizes are 700 diameter with 35c or 38c width. Hybrid tyres are often the same size as a hybrid tyre with a slight emphasis on grip blocks on the outer edge of the tyre for light off road riding.
My personal record for punctures is six in one journey. Sadly I was riding to work and arrived red faced, swearing and asking why there wasn’t a puncture proof tyre yet.
‘Surely the puncture problem was sorted long ago’ I hear you cry.
Well, no. Not really
There are a range of products out there aimed at reducing impromptu deflation of a pneumatic tyre. The word reducing is very important here. Whilst there are a lot of products out there to minimize the risk of ‘popping air’ there are none that will flat out eliminate it. If you fill a rubber tube with air then run it over a surface made of splintered wood and thorns, sharp gravel and flint or glass then at some point the inevitable will happen. You can cut down how much it happens but never eliminate it.
Unless you get very very lucky.
Slime is a product that comes pre-loaded into a tube or a bottle that can be pumped into a tube. The idea is that when the tube is punctured the slime acts as a coagulant blocking the hole.
Tubeless is a system whereby the inner tube is removed from the equation reducing the weight of the wheel. The wheel rim is sealed preventing air from escaping and the tyre is filled with a solution prior to being fitted to the wheel. Once inflated the solution forms a barrier between the bead and rim preventing deflation. Like slime, when the tyre is punctured the solution coagulates at the hole to stop air escaping. Many manufacturers offer tubeless systems with pre-sealed rims with clincher lips to improve seating between rim and tyre bead.
Definitely worth checking out the video below.
Puncture resistant tyres
There are a number of tyres available (the Schwalbe marathon being one) that contains a puncture protection layer to either prevent sharp objects making their way through the rubber or make the tyre so thick that the offending thorn/glass/flint can’t make it through the tyre surface. For riding in urban environments these are very good at puncture prevention.