Choosing tyres for mixed roads

People come in wanting to make a bike more comfortable and ask about suspension, or a carbon seatpost, or a different saddle. Almost always the answer is tyres, and almost always it is cheaper than what they were about to buy.

A wider tyre at a lower pressure absorbs the small, constant, high frequency buzz that actually tires you out. It does it for forty pounds, with no maintenance, and it makes the bike grip better in the wet as a side effect.

Start with what your frame will take

Before anything else, find out what fits. Measure the gap between the tyre and the frame at the chainstays, the seatstay bridge and the fork crown. You want at least four millimetres of clear space all round on a dry road bike, and more like six if you ride in the wet or run mudguards, because a stone caught between tyre and frame at speed is a serious thing.

If you have mudguards, they eat most of that space, so measure with them fitted.

Frames vary far more than people expect. An older road frame might cap out at 25mm. A modern all road frame will take 45mm. This one measurement decides everything that follows.

Width, and where the gains stop

For mixed surfaces, the useful range is roughly 32mm to 45mm.

• 32 to 35mm if you are mostly on tarmac with occasional rough sections. This is the sweet spot for a commute and it is what we fitted to the bare frame commuter.
• 38 to 42mm if towpaths and rough lanes are a real part of the ride. This is where most mixed surface riders end up, and it is what went on the budget gravel build.
• 45mm and up only if the rough stuff genuinely dominates. Past this the extra weight and rolling resistance on tarmac start to be noticeable.

The gains are large going from 25mm to 35mm, and much smaller going from 40mm to 45mm.

Casing matters more than tread

This is the part that surprises people. On anything short of mud, the tread pattern does very little. What you actually feel is the casing, the fabric the tyre is built on.

A supple, high thread count casing conforms to the surface and rolls better. A stiff cheap casing bounces off bumps and feels dead. Two tyres of identical width and tread can feel completely different because of this, and it is the thing that separates a £25 tyre from a £55 one.

For mixed roads, a light file tread or a smooth centre with a little shoulder texture is all you need. Knobbly tyres on tarmac are slow, loud and no grippier in the wet.

Puncture protection, honestly

A puncture belt costs you some suppleness and some speed. Whether that is a good trade depends entirely on you.

If you commute daily and a puncture means being late for work, fit the protection and accept the slightly duller ride. If you ride for pleasure at weekends and a puncture means fifteen minutes at the roadside, go for the better casing and carry a spare tube.

We fitted heavy protection to the cargo bike without hesitating, because you cannot fix a puncture with two children in the box.

Pressure is half the decision

A wide tyre run hard gives you none of the benefit you paid for. As a rough starting point, for a rider of average weight, 35mm tyres want somewhere around 50 to 60 psi, and 42mm tyres want 35 to 45.

Those are starting points, not rules. Go down in small steps until it feels vague in corners or you start bottoming out on bumps, then come back up a little. Heavier riders and loaded bikes need more.

Most people run twenty psi too high because that is what the sidewall maximum says, and the sidewall maximum is a safety limit, not a recommendation.

Tubeless, or not

Tubeless lets you run lower pressures without pinch flats and seals small thorns as they happen. It is genuinely good on rough surfaces.

It is also messier, needs sealant topping up a few times a year, and a roadside failure is more awkward than swapping a tube. We charge £12 a wheel to set it up and we will happily tell you if we think your riding does not justify it.