Martin Motors · MM520 · Recommended
Recommended tyre pressure for a Martin Motors MM520
- 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
psi
34 / 34
Catalogue mid-points, front / rear · 2.2-2.4 / 2.2-2.4 bar
32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa
Recommended pressure means the vehicle placard, not the tyre sidewall. For a Martin Motors MM520 the catalogue proxy is 32-35/32-35 psi (2.2-2.4/2.2-2.4 bar). TPMS typically warns near 25 psi (about 25% below target). That is already a soft tyre, not a fill target.
How to set the MM520
- Park the Martin Motors MM520 for at least three hours (cold tyres).
- Use a calibrated gauge, not the only meter on a forecourt hose.
- Set the placard for that axle — about 32-35 psi / 2.2-2.4 bar front and 32-35 psi / 2.2-2.4 bar rear on this catalogue row.
- Recheck all four. A 2 psi miss on a front-wheel drive MM520 is enough to feel a pull.
- Refit valve caps and reset TPMS if the handbook asks for a relearn.
Martin Motors MM520 placard versus sidewall
The tyre-information placard on a Martin Motors MM520 sits on the driver’s door pillar (sometimes the fuel-filler flap). Catalogue figures here are a general band: 32-35 / 32-35 psi.
Estimated pressure by tyre size (225/40R18 and others)
225/40R18 is the first planning size here. 235/35R19 is usually the plus-size or LT step. Keep load index at or above original equipment.
| Tyre size | Front PSI | Rear PSI | Front bar | Rear bar | Front kPa | Rear kPa | Note |
|---|---|---|---|---|---|---|---|
| 225/40R18 | 35 | 35 | 2.41 | 2.41 | 241 | 241 | Front 18-inch |
| 225/45R17 | 34 | 35 | 2.34 | 2.41 | 234 | 241 | Front sport size |
| 235/35R19 | 36 | 36 | 2.48 | 2.48 | 248 | 248 | Front 19-inch |
| 275/30R19 | 36 | 37 | 2.48 | 2.55 | 248 | 255 | Rear 19-inch |
| 275/35R18 | 36 | 37 | 2.48 | 2.55 | 248 | 255 | Wide rear |
| 255/40R17 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Rear stagger 17-inch |
| 245/40R18 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Square-ish sport |
| 255/35R18 | 35 | 36 | 2.41 | 2.48 | 241 | 248 | Rear stagger 18-inch |
PSI, bar and kPa
PSI-led conversions for the Martin Motors MM520 band (32-35 / 32-35).
| PSI | Bar | kPa |
|---|---|---|
| 30 | 2.07 | 207 |
| 32 | 2.21 | 221 |
| 33 | 2.28 | 228 |
| 33.5 | 2.31 | 231 |
| 35 | 2.41 | 241 |
| 36 | 2.48 | 248 |
| 38 | 2.62 | 262 |
| 40 | 2.76 | 276 |
| 44 | 3.03 | 303 |
| 50 | 3.45 | 345 |
| 60 | 4.14 | 414 |
Pressure against load
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 | 37 psi / 2.55 bar |
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 |
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.
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.
When does TPMS warn on a Martin Motors MM520?
Direct TPMS typically flags about 25% below placard — near 25 psi on this row. Fill to the sticker, not to the lamp.
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