What wide tyres are
Tyre widths have grown over the past years. Road bikes that once used very narrow tyres now often use wider ones, gravel bikes sit in the middle and mountain bikes use wider tyres still. Some bikes use so-called plus-size tyres, wider than a typical mountain bike tyre, and fat bikes use very wide ones built for sand, snow and soft ground. “Wide” is relative, so what feels wide to a road rider might be normal for a mountain biker.
This article describes general effects. Your bike and its parts have limits, so check the frame, fork and rim manufacturer’s information on the largest tyre and the right pressure range, and ask a shop if you are unsure. Our fat bike handling article covers the extreme end of the range.
Grip and comfort
A wider tyre generally has more air volume, and it can run at a lower pressure than a narrower tyre while still holding its shape. The lower pressure lets the tyre deform around bumps, which often improves comfort and helps the tyre keep contact with uneven ground. More contact and more flexibility generally means more grip on loose or rough surfaces. This is why wider tyres are popular off road and increasingly on rough roads.
There are trade-offs, and they vary with the tyre and the surface. Wider tyres can weigh more, and they can feel less lively on smooth tarmac. Drag and rolling resistance depend on many things, including tread, construction and pressure, so it is not safe to assume wider is always slower or faster. Tyre tread and grip are covered in a separate article, and the answer in practice is that the right tyre depends on your surface.
Pressure
Pressure is where wide tyres need the most care. They are usually run lower than narrow ones, and getting it wrong can cause problems.
- Too low. The tyre may squirm in corners, feel vague, and the rim can strike the ground over bumps, which can damage the rim or tyre and cause a pinch flat on a tube setup. The tyre may also come off the rim in some setups.
- Too high. The tyre will feel hard and bouncy and lose some of the comfort and grip you chose it for.
Use a pressure gauge, because feel alone is unreliable at the low pressures wide tyres use. Follow the tyre and rim manufacturers’ pressure ranges, and start in the middle of the range, adjusting in small steps. Rider weight, load, surface and whether the tyres are tubeless all change the best pressure, so there is no universal number. Check the pressure often, since low-pressure tyres can lose air without any obvious sign. A tyre inspection before a ride, covered in its own article, should include looking for cuts and embedded debris.
Steering feel
A wide tyre has a broader, rounder contact area, and a bigger tyre adds weight at the edge of the wheel. Together these can change the steering in a few ways.
Slower, heavier feel. Many riders find that the steering feels a little slower and more deliberate on wide tyres, particularly at low speed. The bike may take more effort to initiate a turn.
Self-steer and flop. At low pressure, a wide tyre may feel as if it wants to turn itself when you lean or at slow speed. The front wheel can flop to one side in tight, slow turns, particularly when the tyre is soft or the tread is rounded. Some riders call this self-steer. It varies between tyre designs and is often reduced by adjusting the pressure, by choosing a tyre with a different profile or by being smoother with your inputs.
Squirm in corners. If the pressure is too low, the sidewalls can flex under cornering load and the tyre can feel unsteady. Raise the pressure slightly in small steps to test.
Tips for handling wide tyres
- Start with a gentle test ride. Choose a quiet, flat, safe place and ride slowly, doing gentle turns and stops before heading into traffic or onto tricky ground.
- Look ahead and be smooth. Wide tyres respond well to smooth steering. Avoid sudden movements, especially on loose surfaces.
- Lean the bike and keep your weight low. In corners, press into the outside pedal and let the bike lean. Our articles on the cornering line and mountain bike cornering expand on this.
- Brake before the corner. Wide tyres have a larger contact patch, but grip still has limits. Brake in a straight line where you can, and see our article on traction while braking for the basics.
- Pick lines carefully. A low-pressure tyre can handle small bumps but still suffers on sharp edges. Avoid big hits to the rim, because rim strikes can damage the wheel.
- Adjust pressure for the day. If you are riding on a different surface or carrying a load, check whether the pressure still suits.
Wet roads, gravel and mud all change grip. Our article on wet road traction covers rain, and the pieces on mixed surfaces and riding in sand look at looser ground. Wide tyres do not make a bike immune to slipping.
Avoiding rim strikes and damage
A rim strike happens when the tyre is compressed fully and the rim hits the obstacle. It can dent or crack a rim and can pinch a tube between the rim and the obstacle. To lower the risk:
- Keep to the recommended pressure range for your tyre and rim.
- Look for obstacles and avoid them or roll over them gently.
- Do not ride fast over sharp-edged bumps or potholes.
- Check the rims and tyres regularly for dents, cuts and bulges, and see a shop if you see any.
- If you use tubeless tyres, follow the manufacturer’s instructions on the sealant and setup.
Fitting and compatibility
Not every bike can take a wide tyre. Frames and forks have limits on clearance, and mudguards, brakes and drivetrain parts can also limit the size. A tyre that rubs the frame, fork or brake is unsafe. Wheels also have a recommended range of tyre widths, and the wrong match can affect how the tyre sits on the rim. Check the manufacturers’ information and ask a shop to fit new tyres if you are not experienced. After any change, check that the wheel spins freely, the brakes work and nothing rubs.
A sensible approach
Wide tyres can make a bike more comfortable and more capable, but they are not a magic fix. Change one thing at a time, watch your pressure, give yourself time to adapt and keep your riding smooth. Wear a helmet, and check your bike before every ride. If something feels unstable, slow down and make sure your tyres, pressure and fit are right.