Whether braking in a curve, on wet cobblestones, or on gravel: grip determines whether you're safe on the road – or whether you lose control. Grip isn't a matter of chance. It results from the interplay of tire compound, tread pattern, width, and air pressure. Understanding these four factors allows you to tailor your tires to any surface.
What grip actually means
Grip describes a tire's ability to interlock with a surface and absorb lateral forces. It arises from two mechanisms: mechanical interlocking (tread lugs dig into the surface) and molecular adhesion (the soft rubber compound conforms to the surface). On asphalt, adhesion dominates, while on loose surfaces, interlocking is more important.
Grip is particularly relevant for e-bike riders: The higher weight of the bike and the stronger acceleration from the motor put more strain on the tire than on a classic bike – especially when starting and braking.
The four influencing factors
1. Tire compound
The rubber compound is the most important factor. Soft compounds (often recognizable by additions like "Soft" or "Grip" in the product name) offer more adhesion and therefore more grip – but wear out faster. Hard compounds roll more easily and last longer, but grip less securely, especially in wet conditions.
Many tires combine both: a harder center tread for efficient rolling resistance on straightaways, and softer shoulders for grip in corners. These so-called dual-compound tires are a good choice for mixed terrain.
2. Tire tread
The tread pattern determines how the tire interacts with the surface:
- Slick and semi-slick tires – with minimal or flat tread, ideal for asphalt. A large contact patch ensures maximum adhesion on hard surfaces.
- Mixed tread pattern – fine center, pronounced side knobs. For gravel roads and compacted forest tracks.
- Aggressive MTB tread pattern – deep, widely spaced knobs. Grips firmly in soil, on roots, and in wet leaves. For trails and off-road use.
On asphalt, a coarse tread pattern offers no grip advantage – on the contrary: it reduces the contact area and increases rolling resistance.
3. Tire width
Wider tires have a larger contact patch and distribute the rider's weight (and, in the case of e-bikes, the bike's own weight) over more rubber. This means more grip at the same tire pressure. Typical guidelines:
- 23–28 mm – Road bike, asphalt, efficiency
- 35–50 mm – Gravel, paved farm roads, mixed tours
- 2.0–2.6 inches – E-MTB and E-SUV, trail and off-road
Those who use their e-MTB on trails should not skimp on tire width – here, volume directly translates into control and safety.
4. Air pressure
Tire pressure is the simplest and quickest adjustment. Lower pressure equals more tire deformation, which means a larger contact patch and therefore more grip. However, too little pressure leads to snakebite and increased rolling resistance.
Guideline values as a starting point (always also consider the driver's weight):
| Tires | asphalt | Gravel / Trail |
|---|
| 28 mm road tires | 5.5–7 bar | – |
| 40 mm gravel | 2.5–4 bar | 2.0–3.0 bar |
| 2.4 inch MTB | 1.8–2.4 bar | 1.4–1.8 bar |
A digital tire pressure gauge is worthwhile – the built-in thumb check is too inaccurate for reproducible results.
Grip on various surfaces
Wet asphalt is the most common grip killer in everyday driving. The following can help: a soft compound, slightly reduced tire pressure, and a light semi-slick tread pattern that channels water away to the sides. Avoid jerky steering and braking movements.
Gravel and pebbles require a pronounced sidewall tread and lower tire pressure. The tire must be able to grip the loose material – too high a pressure will cause it to slide over it.
Roots and wet leaves are considered particularly treacherous because friction is extremely low. Wider tires with a soft compound and the lowest possible pressure (even lower with tubeless tires) help delay loss of contact.
Sand resists almost any traction. Width is the most important factor here: a wide tire with low pressure floats on top, while a narrow one digs in and gets stuck.
Special features of e-bikes
E-bikes put more weight on the road – this increases the contact pressure and therefore the traction. At the same time, the motor transmits more torque to the rear wheel when starting, which can lead to slippage on poor surfaces. A grippy rear tire with a soft shoulder is therefore particularly important for e-SUVs and e-MTBs.
Conclusion
Maximum grip isn't a matter of chance – it comes from the right combination of compound, tread pattern, width, and pressure, tailored to the specific surface. Those who regularly switch between asphalt and gravel will find a dual-compound tire with a mixed tread pattern to be the most versatile. Those who primarily ride on trails should opt for wide tires with a soft compound and the lowest possible pressure.
