Tyres influence every aspect of your riding. Their shape, tread pattern and weight are a factor of rolling resistance and rotational mass, which can increase or lessen fatigue on a long ride. Tread patterns mediate braking inputs and deliver traction, boosting steering confidence when descending.
The best mountain bike tyres can make average brakes and suspension components feel better, while awful tyres can undo the efficacy of even the best four-pot disc brakes. As cycling has split into various disciplines which now include road, mountain bike, gravel and time trial - it’s easy to get lost when trying to understand the jargon and intricacies involved. From high-pressure tubular rubber to tubeless-ready mountain bike tyres, this guide will help point you in the right direction and explain what type of bike tyre is best for you.
Despite the enormous influence they have on your entire riding experience, tyres remain greatly misunderstood by so many. Cycling is highly segmented, with road, off-road and mountain biking and within each of those segments, there are many sub-disciplines, each with its own requirements regarding tyre specification. Product planners and marketing managers in the tyre industry attempt to fill every conceivable niche with new rubber. That creates an enormous portfolio of products, with staggering diversity in sizes, compounds, tread patterns and uses. The potential for confusion is massive. The cycling tyre market has extensive product segmentation. A tyre company that designs, produces and markets slick road bike tyres will also have downhill mountain bike tyres in its portfolio, often weighing twice as much and being nearly three times as wide. But there are general tyre trends and engineering principles that you can follow to empower decision-making on your next set of tyres.
Tyres have the most challenging tasking of any cycling component. Gears need to multiple your power output to forward momentum. Brakes need to slow you down. And on mountain bikes, suspension needs to cushion your ride and enhance control over rough terrain. But tyres are partnered in all those dynamics: acceleration, deceleration, lateral grip and terrain-impact mitigation.
Although road and off-road tyres are very different, reflecting the diversity of terrain they roll across, there are broadly similar performance principles. And the most important of those is tyre pressure – something the tyre industry and riders got very wrong for a long time. For decades all cycling tyres were tubed. Whether journeying on 100-mile Sunday road bike training rides or navigating forest singletrack on a mountain bike, tyres were held in place on rims, with tubes. It was a legacy technology with many weaknesses, especially for off-road cyclists.
Tubes are enormously susceptible to punctures. And any mountain bike trail is littered with surface imperfections – rocks, roots, square-edged ledges – that easily compress a tubed tyre into pinch-flatting. When a point-load terrain impact compresses a mildly inflated tyre, the tube gets pinched against the rim bead, creating a tiny tear and that inevitable loss of air pressure. Hence the name: pinch-flatting.
The risk for road bikers is similar when rolling tubed tyres. The risk of pinch-flatting is high if you strike a pothole at 40mph on a descent - not to mention the reality of road debris, such as glass, nails and building refuse, puncturing your inner tube. Mountain bikers mobilised first, around the late 2000s, adopting tubeless tyre technology as a solution to incessant pinch-flatting. The benefits were evident and tubeless tyres soon became the default. What about tubular tyres? It is a rite of passage for many road riders to acquire the skill of glueing a tubular tyre to the rim, without mess or frustration. Tubular tyres have an inherent safety advantage in the case of sudden puncturing and rapid deflation. Glued to the rim, they should not disengage from your wheel and create a bigger crash risk if there is a sudden and extreme pressure loss.
The broad standardisation of tubeless tyres significantly reduced puncture risk and opened the potential for lower tyre pressures. For road, gravel and mountain biking, tubeless tyres have prevailed as a general design theme. But what about tyre sizes and tread patterns? Tyres size by diameter and volume. When reading a tyre size specification, the first value is diameter and the second corresponds to inflated volume in width. A 29x2.4in mountain bike tyre is shaped for 29-inch diameter rims and will size to 2.4-inches in width when inflated. The array of tyre sizes is dizzying, and they have gotten bigger, with good reason. The relationship between tyre size and low-pressure inflation theory is integral. Larger-volume tyres ride at low pressure with greater confidence and structural stability. Road riders raged against the idea of lower tyre pressures for decades. Outrageously overinflated tyres were the standard. Conventional wisdom and misinformed tradition were finally displaced with robust data.
Engineers realised that the riding surface is imperfect on any ride outside an indoor velodrome. And a bigger tyre, at lower pressure, can shape and conform to those road surface imperfections, delivering a much comfier ride. It is why riders in the Tour de France peloton now ride tyres size 700x25c or even 700x28c. Those are sizes unthinkable in the 2000s when most road pros we unconvinced by any tyre larger than 700x23c.
For off-road riders, the issue of larger tyres is even more critical when wanting to retain control on technical descents. When navigating a mountain bike trail at speed, you need a lot of tyre casing and volume to absorb the impact of ruts, roots and rocks. Nobody enjoys the feeling of nervously skidding tyres when you touch a brake lever or lean the bike when descending. There are abundant tread pattern choices for gravel and mountain bikers. The diversity of tread block sizes and arrangements for off-road riding is many times that of road cycling.
Don’t be confused by all those different-looking off-road tyres. When evaluating a gravel or mountain bike tyre the guiding principles are tread block size and tread spacing. The larger tread blocks are, the more point pressure they can exert on the trail surface, ‘digging’ for grip. But that will make them slower, too. Grip and rolling resistance work in an opposing relationship to each other. The more you have of one – the less you'll have of the other. The bigger your gravel or mountain bike tyre’s tread blocks are, and the further they are spaced apart, the better grip they will have. If you are seeking a faster-rolling tyre, select one with smaller tread blocks stacked in a tighter grouping.
The cycling tyre consensus is beyond debate: you need to ride tubeless. And you should ride at lower pressures than might feel best when you hand-squeeze a tyre. Don’t trust your fingers to be a pressure gauge equivalent. Find inflation values that work for you, memorise them, and keep your tyres inflated accordingly.
Depending on the trails or road conditions you ride, there is without question a tread pattern that will be ideal. Discovering your best tyre set-up is one of the more rewarding personal challenges regarding a rider’s development in terms of technical cycling literacy. You can even mix and match with different tyre widths and tread patterns, front and rear. Off-road riders often use a slightly wider tyre on the front wheel, with large tread blocks. To optimise that low-pressure cushioning effect and enhance grip. When thinking about tyre weight, it is helpful to understand that more grams equal a more robust structure. The lighter you go, the less material there is to resist a rock or root impact scratch, becoming puncture. If you only ride mild fire roads and perfectly manicured singletrack flow trails, lightweight tyres roll faster, with a low risk of puncturing. For riders who enjoy venturing into steeper and more technical trails, with a surface textured with roots and rocks, it's worthwhile edging towards the 1,000g weight range. For your mountain bike tyres. Because nobody wants to spend all that effort climbing, to have a puncture end your descent after only a few yards.
Lance Branquinho is a Namibian-born media professional who graduated to mountain biking after injuries curtailed his fascination with trail running. He has a weakness for British steel hardtails, especially those which only run a single gear. Lance is an award-winning writer who has contributed to myriad piblications all over the world including Cyclingnews, Bike Perfect, MBR, Topgear, TopCar and Car magazine.
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