Martin Motors · MM520 · kPa
Martin Motors MM520 tyre pressure in kPa
- Drivetrain
- front-wheel drive
- Body
- passenger car
- PSI F / R
- 32-35 / 32-35
- Bar F / R
- 2.2-2.4 / 2.2-2.4
kPa
231 / 231
2.31 / 2.31 bar · 32-35 / 32-35 psi
32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa
Kilopascals show up on some Asian stickers and ISO sheets. 231 kPa front and 231 kPa rear is the Martin Motors MM520 midpoint (100 kPa = 1 bar). Size estimates on this page include 275/35R18, 255/35R18 and 275/30R19 — interpolated from the catalogue midpoint, not a second factory sticker.
kPa, bar and PSI
kPa-led conversions. 220 kPa is 2.2 bar and about 32 psi — handy if this MM520 sticker uses SI units.
| kPa | Bar | PSI |
|---|---|---|
| 207 | 2.07 | 30 |
| 221 | 2.21 | 32 |
| 228 | 2.28 | 33 |
| 231 | 2.31 | 33.5 |
| 241 | 2.41 | 35 |
| 248 | 2.48 | 36 |
| 262 | 2.62 | 38 |
| 276 | 2.76 | 40 |
| 303 | 3.03 | 44 |
| 345 | 3.45 | 50 |
| 414 | 4.14 | 60 |
Estimated pressure by tyre size (275/35R18 and others)
If your Martin Motors MM520 no longer wears the OEM diameter, start at the row nearest 275/35R18 or 255/35R18 and confirm with the tyre maker’s load table.
| Tyre size | Front PSI | Rear PSI | Front bar | Rear bar | Front kPa | Rear kPa | Note |
|---|---|---|---|---|---|---|---|
| 275/35R18 | 36 | 37 | 2.48 | 2.55 | 248 | 255 | Wide rear |
| 255/35R18 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Rear stagger 18-inch |
| 275/30R19 | 36 | 37 | 2.48 | 2.55 | 248 | 255 | Rear 19-inch |
| 255/40R17 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Rear stagger 17-inch |
| 225/45R17 | 34 | 35 | 2.34 | 2.41 | 234 | 241 | Front sport size |
| 225/40R18 | 35 | 35 | 2.41 | 2.41 | 241 | 241 | Front 18-inch |
| 245/40R18 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Square-ish sport |
| 235/35R19 | 36 | 36 | 2.48 | 2.48 | 248 | 248 | Front 19-inch |
Martin Motors MM520 placard versus sidewall
Sidewall PSI is a carcass maximum. Recommended operating pressure for this MM520 is the pillar sticker, near 34/34 psi.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 34 psi as a 20 °C baseline for this MM520.
| Ambient | Gauge (front mid) | Bar | kPa | Note |
|---|---|---|---|---|
| −5 °C (hard frost) | 31 psi | 2.14 bar | 214 kPa | Gauge reads low; do not overfill once warm |
| 0 °C | 32 psi | 2.21 bar | 221 kPa | Gauge reads low; do not overfill once warm |
| 8 °C (UK winter morning) | 33 psi | 2.28 bar | 228 kPa | Gauge reads low; do not overfill once warm |
| 20 °C (set cold here) | 34 psi | 2.34 bar | 234 kPa | Baseline |
| 30 °C | 36 psi | 2.48 bar | 248 kPa | Do not bleed a hot tyre |
| 38 °C (heatwave tarmac) | 37 psi | 2.55 bar | 255 kPa | Do not bleed a hot tyre |
How to set the MM520
- Measure before the school run, not after the M25.
- Write LF / RF / RR / RL. Do not keep MM520 numbers in your head.
- Add air in short bursts toward 34 psi (2.31 bar) front and 34 psi rear.
- If one corner is 4 psi down, hunt for a nail before you blame the weather.
- Log date, ambient temperature and the four readings.
Load notes
Load moves the rear of a passenger car first. If the factory placard already has a “laden” column, use that instead of these sketches.
| Condition | Front (est.) | Rear (est.) |
|---|---|---|
| Driver only | 34 psi / 2.34 bar | 34 psi / 2.34 bar |
| Full occupancy | 34 psi / 2.34 bar | 35 psi / 2.41 bar |
| Motorway + luggage | 35 psi / 2.41 bar | 38 psi / 2.62 bar |
Martin Motors notes
No special Martin Motors exception: the MM520 uses the door-pillar placard. Size estimates on this page only help if you have left the original load index behind.
Spare and inflator kit
A matching full-size spare on the Martin Motors MM520 usually follows the higher axle (often the rear, near 32-35 psi). A space-saver is commonly 60 psi / 4.1 bar — read that tyre’s own sidewall. An inflator kit is not a spare; check the sealant date.
If the Martin Motors sticker and this page disagree, the sticker wins.
Other Martin Motors models
Questions about this MM520
What is that in bar and kPa for the MM520?
Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.
Front versus rear on the Martin Motors MM520?
This row is 32-35 F / 32-35 R. Even when they match, a laden rear can justify a higher number if the sticker prints one.
How often should I check a MM520?
Monthly, before a long trip, and after a 10 °C weather swing. Include a full-size spare.
Should I bleed pressure after a motorway run?
No. Heat raises the gauge. Set cold only. Bleeding a hot tyre leaves it low the next morning.
What tyre pressure should a Martin Motors MM520 use?
Catalogue reference is 32-35 psi front and 32-35 psi rear (2.2-2.4 / 2.2-2.4 bar), cold. Confirm on the door-pillar placard.
Handbook: placard · bar vs PSI · front vs rear · cold inflation