kg/cm² to psi

Your Bike's Placard Says kg/cm², Your Gauge Says psi

Lift the seat of a scooter sold in Vietnam, India, Thailand or Indonesia and the inflation label on the frame or swingarm is printed in kilograms per square centimetre. Roll up to a workshop compressor or reach for a pencil gauge, and the scale is in psi. The two figures look nothing alike — 2.25 on the label, 32 on the dial — yet they describe the same amount of air.

Multiply by 14.2233433 to go from kg/cm² to psi. The rear-tyre figure on a typical 125 cc automatic scooter, 2.25 kg/cm², works out at 32.00 psi — the round number you would have guessed, which is exactly why the factory picked it.

What the Label Is Actually Telling You

A figure per wheel, not per bike

Front and rear carry different shares of the weight, so the label always lists them apart. On most small machines the rear sits a quarter to half a kg/cm² above the front.

A second column for two-up

Asian-market labels usually add a "with passenger" or "2 persons" row. It lifts the rear figure, and occasionally the front too, because the extra load is not shared evenly.

Cold, always

Label values assume the tyre has not been ridden. A warm tyre after 20 km of town traffic can read 0.15–0.25 kg/cm² higher, which is 2–3.5 psi of heat rather than air.

A recommendation, not a ceiling

The tyre sidewall carries its own maximum, stamped by the tyre maker. That figure belongs to the tyre; the label figure belongs to the motorcycle it was fitted to.

Getting From Label to Gauge in Four Moves

Do this once per wheel and note the psi values in your phone — the label will not change until you change tyre size.

Copy the front figure off the label

Put it in the left box — 1.75, 2.00, whatever is printed there. The psi equivalent fills in while you type. If the sticker uses a comma, as many Asian and European labels do, type the comma; it is read as a decimal point.

Repeat for the rear, then the two-up row

Overwrite the same box instead of opening another tab. Three or four values take seconds, and you finish with the whole set your machine needs rather than one lucky number.

Lift the plain number for your notes

Each field carries its own copy button, and it hands over digits only — no unit, no spacing — so the value drops straight into a notes app or a service log. Pressing Ctrl + C with the cursor in a field does the same.

Go the other way at the air pump

Plenty of garage inflators offer only psi and bar. Tap the swap arrows (↔) to run psi → kg/cm² and check what the pump just put in: the reverse multiplier is 0.07030696, so 30 psi lands at 2.109 kg/cm².

Never bleed a hot tyre down to the label figure. Doing so leaves it under-inflated once it cools. Set pressures in the morning before you ride, or accept that the reading is high and re-check later.

Placard Pressures by Class of Machine

Representative cold pressures from Asian-market inflation labels, shown in the kg/cm² the sticker prints and the psi your gauge reads. Your own label always wins — this table is for judging whether a figure you found online is plausible.

Machine	Wheel / load	Placard (kg/cm²)	Gauge (psi)
Automatic scooter, 110–125 cc	Front, rider only	1.75	24.89
Automatic scooter, 110–125 cc	Rear, rider only	2.25	32.00
Automatic scooter, 110–125 cc	Rear, with passenger	2.50	35.56
Underbone / step-through	Front, rider only	1.75	24.89
Underbone / step-through	Rear, rider only	2.00	28.45
Small sport, 150–250 cc	Front	2.00	28.45
Small sport, 150–250 cc	Rear	2.25	32.00
Large sport / naked	Front	2.50	35.56
Large sport / naked	Rear	2.90	41.25

Notice how narrow the useful band is. The whole two-wheeler world lives between roughly 1.5 and 3.0 kg/cm², or 21 to 43 psi. A quarter of a kg/cm² — three and a half psi — separates a scooter set up for the rider alone from one loaded with a passenger and a week of shopping.

What Helps While You Are Standing at the Compressor

One box changes, both stay live

Neither field is locked, so front, rear and two-up figures can be run back to back, each psi value appearing as the last digit lands.

Flip it for the garage inflator

The arrows reverse the pair, so a psi reading taken off a workshop hose comes back as the kg/cm² figure your label is written in.

kPa and bar sit one dropdown away

Searchable unit lists on both sides hold all 26 pressure units, so the same label value also converts to the kPa on a digital gauge or the bar on a European pump.

Clean digits for the service log

Results carry up to eight decimals when a value needs them, with thousands spaced for legibility, and copying strips everything except the number itself.

Questions Riders Ask About the Sticker

My label lists a solo and a two-up rear pressure. Which do I set if I ride both ways?

Set whichever load you carry most, and top up before the trips that carry more. Of the two, sitting on the higher two-up figure is the safer compromise: a slightly firm rear costs a little comfort, while a rear left 0.25 kg/cm² (about 3.5 psi) short under a passenger runs hot and squirms in corners. What you should not do is set the solo number and forget it before a loaded ride.

Why is the rear always higher than the front on a scooter?

Because the rear wheel carries far more of the load. On a step-through or automatic scooter the rider sits almost over the rear axle, the engine and transmission hang off the swingarm, and the top box is behind that again. A 0.50 kg/cm² split — 1.75 front against 2.25 rear, or 24.89 against 32.00 psi — reflects that weight bias, not any difference between the two tyres.

My sticker prints three sets of numbers side by side — which one do I read?

One factory builds machines for markets that use different gauges, so a single label carries kPa, kg/cm² and psi — for instance 220 kPa / 2.25 kg/cm² / 32 psi. Those are three spellings of one pressure, not three options. Read the column that matches the gauge in your hand. Where the rounding differs slightly between columns, that is the label being tidy, not the tyres asking for something different.

How cold does a "cold tyre" actually have to be?

Cold means the machine has stood for a few hours, or has covered no more than a kilometre or two gently, and the tyre sits at ambient temperature. Direct sun on one side of a parked bike is enough to skew a reading. Checking at the petrol station on the corner is fine; checking after a 40-minute commute is not, because that reading contains several psi of heat that will be gone by morning.

My tyre is tube-type and the sidewall shows a different figure to the label. Now what?

The sidewall number is the tyre's own maximum cold pressure, tied to its maximum load rating, and it usually sits well above what your machine asks for. Follow the label unless you have fitted a tyre outside the sizes it covers, in which case the tyre maker's fitment chart becomes the right reference. Tube-type tyres are no different on pressure, but they tend to lose air faster around the valve stem and rim, so check them more often.