Tyre pressure affects a motorcycle's handling, braking distance, steering feel and tyre life all at once. On two wheels, moreover, the margin for error is much smaller than in a car. The good news: finding the right value and measuring it are both easy. In this guide we explain where the value is written, converting bar and psi, why you should measure when the tyres are cold, and how to adjust the pressure for a passenger or load.
Where is the right value written?
The right pressure is written in your motorcycle's owner's manual, usually in the "Specifications" section; on many models there is also a tyre label on the motorcycle itself. The value is always given separately for front and rear, and most manuals have two separate lines, for riding solo and for riding with a passenger or load. The "max" value on the tyre sidewall, however, is the highest pressure the tyre can withstand, not the pressure recommended for your motorcycle; do not use it.
A concrete example: the values in the Turkish owner's manual for Honda's CB125F (SC74 type) are as follows.
| Use | Front | Rear |
|---|---|---|
| Rider only | 175 kPa (1.75 bar, 25 psi) | 200 kPa (2.00 bar, 29 psi) |
| Rider and passenger | 175 kPa (1.75 bar, 25 psi) | 225 kPa (2.25 bar, 33 psi) |
As you can see, only the rear pressure rises with a passenger. These values are set for that model's original tyre size; do not apply another motorcycle's values to yours. We explained how to read the tyre size in the tyre size guide.
Bar, psi, kPa: conversion table
Manuals usually give kPa and psi, while petrol station compressors often show bar or psi. 1 bar = 100 kPa ≈ 14.5 psi.
| bar | kPa | psi (approx.) |
|---|---|---|
| 1.75 | 175 | 25 |
| 2.00 | 200 | 29 |
| 2.25 | 225 | 33 |
| 2.50 | 250 | 36 |
| 2.80 | 280 | 41 |
| 2.90 | 290 | 42 |
Why measure when cold?
While you ride, the air inside the tyre heats up and the pressure rises. Michelin states that in a tyre warmed by riding, the pressure can rise by 4–6 psi or more. The values in the manual are for a cold tyre. So:
- Measure when the motorcycle has not been used for at least two hours, or after riding no more than a few kilometres at low speed.
- Do not let air out to bring a pressure you read as high after a long ride down to the cold value. When the tyre cools, the pressure will be below the recommended value.
- If you have come a long way to the petrol station, the value you measure will read high. The most accurate measurement is the one you make at home with your own pressure gauge in the morning before setting off.
Air temperature also affects pressure. By the gas law, pressure falls as the air cools; on a tyre at around 2 bar, every 10 °C fall means roughly a 0.1 bar (about 1.5 psi) loss. Check the pressure more often when the seasons change, especially in autumn. We explained how tyres behave in cold weather in the winter tyre guide.
How often should you check?
The Honda CB125F manual recommends checking with a pressure gauge at least once a month and whenever you suspect the tyre has gone down. Michelin recommends checking every two weeks and before every long trip. A practical rule: every two weeks, and before every long trip and before loading a passenger or luggage.
Adjusting pressure for a passenger and load
When you add a passenger or luggage, the load on the tyre increases and you need to use the manual's loaded value. This value is usually higher on the rear tyre. If no loaded value is given in the manual, consult an authorised service centre or the tyre manufacturer; do not decide on a value on your own. We explained the other adjustments for riding with a passenger in the carrying a passenger guide.
Symptoms of low pressure
- The steering becomes heavy and the motorcycle is reluctant to turn into bends.
- Mid-corner the motorcycle feels like it is "floating" or wallowing.
- The tyre overheats; at high speed and under load this is dangerous.
- The shoulders of the tyre wear quickly.
- Fuel consumption may rise.
Symptoms of high pressure
- The ride becomes harsh and you feel road imperfections more.
- The tyre's contact patch with the ground shrinks; grip falls, especially on wet ground.
- The centre of the tyre wears quickly.
For wear patterns and when to replace the tyre, see the tyre replacement guide.
Track and off-road values are not used on the road
Tyre manufacturers publish separate pressure recommendations for track days and off-road use; Michelin also has separate guides for track and off-road. On a track the tyre heats up far more, so the cold pressure is set differently, and off-road the pressure can be lowered for grip. Do not carry these values over to everyday road use: riding on tarmac at low pressure overheats the tyre and leaves the rim exposed to impacts. After an off-road trip, bring the pressure back to the road value before returning to tarmac.
If a tyre loses air on the road
With a sudden loss of pressure the motorcycle weaves from side to side, especially with a rear tyre, and with a front tyre the steering becomes heavy. Do not brake hard and do not try to correct the handlebar with sudden movements. Close the throttle slowly, slow down keeping the motorcycle upright and pull over somewhere safe. If a nail is lodged in the tyre, mark where it is; leaving it in place may leak less air than removing it. After a repair with a repair kit, go to the nearest tyre shop at low speed.
Tips for accurate measurement
- Get your own pressure gauge. Petrol station gauges can show different values; measuring with the same device gives consistency.
- Fit the valve cap. The cap protects the valve from dust and moisture.
- Inspect the tyre as you measure. As the Honda manual suggests, look for cuts, splits, cracks, lodged nails and bulges in the sidewall.
- If it keeps losing air, find the cause. It could be a lodged nail, a damaged rim or valve. For roadside tyre repair tyre repair kits do the job, but for a lasting fix call in at a tyre shop.
- Check by hand even if you have TPMS. The pressure sensor gives a warning, but you still need a gauge to set the right value.
Conclusion
The right pressure is written in the manual or on your motorcycle's tyre label; not the "max" value on the tyre. Measure when cold, do not let air out of a hot tyre, and check every two weeks and before every long trip. If there is a passenger or load, apply the loaded value in the manual. For example, on the Honda CB125F the rear is 2.00 bar solo and 2.25 bar with a passenger.
Frequently asked questions
How many psi should be put in a motorcycle tyre?
It varies by model and is written in the manual. For example, on the Honda CB125F solo it is 25 psi front and 29 psi rear; with a passenger 33 psi rear.
What happens if tyre pressure is too high?
The contact patch shrinks and grip falls, the ride becomes harsh and the centre of the tyre wears quickly. The effect is more noticeable on wet ground.
Where is the tyre pressure written?
In the specifications section of the owner's manual and, on many models, on the tyre label on the motorcycle. The "max" value on the tyre sidewall is not the recommended pressure.
Is it right to measure at a petrol station straight after riding?
A warmed tyre reads high. If possible, measure when cold with your own gauge; if you do measure at the petrol station, know that the value is hot and do not let air out.