In hot weather the thing to change is not how much gear you wear, but what it is made of. A mesh jacket with CE armour breathes better than the thin long-sleeve sun shirt most riders default to, and unlike that shirt it has actually been tested for sliding on tarmac. This guide covers how to read a summer jacket label, what to wear on your legs, hands and feet, how to cover the skin UV reaches, and how to spot heat illness before it becomes an emergency.
What tropical heat does to a rider
Table of contents19
Riders coming from the UK, North America or Australia usually arrive in Vietnam prepared for the temperature and unprepared for the humidity. That combination is the part that catches people out. On a bike you take heat from three directions at once: direct sun, radiant heat bouncing off the tarmac, and the engine sitting between your legs in traffic.
The airflow feels like cooling, and to a point it is. But moving air also evaporates sweat faster, which means you lose fluid quickly without your shirt ever feeling wet. In humid air, evaporation slows down and your body loses its most effective way of shedding heat — so the same air temperature is considerably harder on you in Hanoi in July than on a dry summer day in Spain or Arizona.
Dehydration does not drop you off the bike. It does something subtler and more dangerous for someone steering a vehicle: it slows reaction time, narrows attention and degrades judgement in exactly the seconds where good judgement is what keeps you upright.
Signs that mean stop riding now
The US Centers for Disease Control and Prevention, through NIOSH, publishes the standard progression of heat-related illness:
| Condition | Signs | What to do |
|---|---|---|
| Heat cramps | Muscle cramps, pain or spasms in the abdomen, arms or legs | Drink water plus a snack or drink that replaces carbohydrates and electrolytes every 15–20 minutes. Avoid salt tablets. Seek medical help if cramps last more than an hour. |
| Heat syncope | Dizziness, light-headedness, a brief faint — often after standing too long or getting up suddenly | Sit or lie down somewhere cool and sip water slowly. Dehydration and lack of acclimatisation both contribute. |
| Heat exhaustion | Headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, raised body temperature, reduced urine output | Get out of the heat, remove unnecessary clothing, sip cool water, apply cold compresses to head, face and neck. Get a medical evaluation. |
| Heat stroke | Confusion, slurred speech, altered mental status, seizures, loss of consciousness, hot dry skin or profuse sweating, very high body temperature | Call emergency services immediately. This is a medical emergency that can cause permanent disability or death. |
The detail worth memorising from the CDC material: once heat stroke sets in, the sweating mechanism fails and body temperature can rise to 41 °C or higher within 10 to 15 minutes. That is why you do not push on for another few kilometres to reach the stop you had planned.
One common misreading: heat stroke does not always come with dry skin. A rider drenched in sweat can still be in heat stroke. The more reliable warning is a change in mental state — your riding partner answering the wrong question, slurring words, or walking unsteadily after getting off the bike.
A mesh jacket with armour instead of a sun shirt
The thin stretch-fabric sun shirt is the regional uniform, and it does one job well: it blocks sunlight. What it does not do is resist abrasion. Stretch knit tears almost instantly on tarmac, and no standard tests it for that, because it was never designed for it.
The sensible replacement in hot, humid conditions is a mesh jacket with armour: an open-weave body for airflow, abrasion-resistant reinforcement at shoulders, elbows and back, and EN 1621 impact protectors fitted at those points. It runs far cooler than leather or heavy textile, and unlike the sun shirt it has been through real testing.
Reading an EN 17092 label: AAA, AA, A, B and C
EN 17092:2020 is the European standard for motorcycle protective garments, published in six parts. Part 1 describes the test methods; the remaining five set the requirements for the five classes. According to SATRA, a test house for the standard:
| Class | Impact protectors | Abrasion resistance | How it is meant to be used |
|---|---|---|---|
| AAA | Mandatory at shoulder, elbow, knee and hip | Highest level | Touring, higher speeds, long distances |
| AA | Mandatory at shoulder, elbow, knee and hip | Mid level | The usual balance of protection and comfort |
| A | Fitted; hip protectors optional | Entry level | The most common class for summer mesh |
| B | None | Equivalent to Class A | Abrasion protection only, no impact protection |
| C | Protects only where a protector sits | No minimum abrasion protection | To be worn with a Class AAA, AA, A or B garment |
The last two classes are where buyers go wrong, and they go wrong in the direction that leaves them less protected than they believe.
Class B matches Class A for abrasion but carries no armour. Buy a Class B jacket believing you are fully kitted out and you are covered for the slide but have nothing absorbing the impact at your shoulder or elbow.
Class C is the bigger trap, and it is the one that matters most in summer. Those thin mesh armour shirts that look ideal for 35 °C are frequently Class C garments. The standard defines Class C as providing impact protection only for the areas the protectors cover, with no minimum abrasion protection, and states plainly that they are intended to be worn with and to supplement a Class AAA, AA, A or B garment. Wearing a Class C shirt over a t-shirt means your elbows and shoulders have armour and the rest of you is dressed in a t-shirt.
If you take one thing from this article, take that one: a mesh armour shirt worn on its own is not a complete set of protective clothing, CE label or not.
A note for riders shopping at home: EN 17092 is a European standard. A jacket bought in the US or Australia may carry no class marking at all, which does not mean it failed — it may simply never have been submitted for testing. If you want a class on the label, look for it before you buy rather than assuming it is there.
What the abrasion test actually measures
The EN 17092 impact abrasion test simulates a rider of 75 kg and 1.75 m sliding from various starting speeds to a standstill on a real concrete road surface, not on sandpaper. Specimens are mounted in three orientations — warp, weft and at 45 degrees. To pass, there must be no hole 5 mm or larger in any direction in the layer closest to the body.
One detail matters a great deal for summer gear: every removable liner, waterproof or thermal, is taken out before testing, and the weakest material combination is the one tested. The class on the label therefore describes the jacket in its thinnest, airiest configuration — which is exactly how you will be wearing it in the middle of a tropical summer.
Legs, hands and feet in the heat
Upper-body gear gets all the attention, but hips, knees and ankles hit the road too.
- Legs. Shorts are the most popular and the worst choice. Mesh riding trousers with knee armour pockets are the natural counterpart to a mesh jacket. Failing that, heavy jeans are still far better than bare legs — though ordinary jeans will not carry an EN 17092 class unless they have been specifically reinforced.
- Hands. Your hands almost always reach the ground first, and they are also what you need intact to work the brake. In heat, look for mesh gloves with a reinforced palm, light colours and a moisture-wicking lining. How to read an EN 13594 label and test a glove properly is covered in our guide on how to choose motorcycle gloves.
- Feet. Flip-flops are the local default and the local hazard. Tarmac that has been baking all afternoon is a burn waiting to happen, before you even get to the question of sliding. Closed-toe trainers with a grippy sole are the minimum; ventilated riding shoes with ankle protection breathe better than most people expect.
- Helmet. Heat is what tempts riders into an open-face or half helmet. If you make that trade, at least pick one with genuine ventilation and a visor rather than an uncertified shell. The comparison between helmet types and standards is in our guide to motorcycle helmet types and standards.
The governing rule for all summer gear: the best kit is the kit you actually wear. A AAA-rated leather jacket left in the seat compartment because it is unbearable protects you zero per cent of the time. A Class A mesh jacket you keep on all day protects you every kilometre.
Covering neck, face and skin from UV
Ultraviolet exposure has nothing to do with how hot it feels — an overcast, breezy day can still carry a high UV index. The World Health Organization publishes the UV index with this action scale:
- UV 0–2: You can safely be outside; under normal circumstances no protective measures are needed.
- UV 3–7: Seek shade during midday hours, wear a shirt, apply sunscreen, wear a hat.
- UV 8 and above: Avoid being outside during midday hours; shirt, sunscreen and hat are a must.
WHO also makes the timing precise: the maximum daily UV level occurs during the four-hour period around solar noon, and depending on geographical location and whether daylight saving applies, solar noon falls between 12 p.m. and 2 p.m. That is a far more useful planning anchor than vague advice to avoid the midday sun.
On a bike the forgotten patches are the back of the neck, the backs of the hands, the strip of wrist between glove and sleeve, and the tops of the feet in open shoes. A few cheap items solve nearly all of it:
- A neck tube or buff under the helmet, covering the nape. Thin and breathable, not fleece.
- Sunglasses or the helmet visor — UV protection for the eyes plus a shield against dust and insects.
- Sunscreen on exposed face, reapplied after heavy sweating.
- Long sleeves — and this is precisely where a mesh jacket earns its place twice, doing the sun-blocking job and the abrasion job in one layer instead of two.
Are cooling vests worth packing
Evaporative cooling vests work by holding water that evaporates and draws heat from your body. That mechanism is at its best in dry air. Northern Vietnam in summer is humid, and high humidity slows evaporation — so a cooling vest delivers noticeably less here than it would in a dry climate.
Practical conclusion: a cooling vest is not the first purchase. If luggage space is limited, the order is mesh jacket with armour, gloves, closed shoes, and only then a cooling vest. If you do bring one, choose a thin model you can wear under the mesh jacket and set your expectations below the marketing.
Hydration and choosing your riding hours
On a moving bike you will barely register thirst until you are already well down on fluid, because the airflow evaporates sweat as fast as you produce it. A few rules that work:
- Drink to a schedule, not to thirst. Build regular stops into the ride rather than waiting until you feel like drinking.
- Keep water within reach. A bottle buried in the seat compartment is a bottle you will not drink. A hip bag or a bar-mounted holder fixes this.
- If cramps start, the CDC advice is water plus a snack or drink replacing carbohydrates and electrolytes every 15 to 20 minutes — and not salt tablets.
- Rest in shade with the engine off. Sitting on an idling bike in the sun is a fake break; the engine is still radiating heat into your legs.
For riding hours, the workable pattern is to put the long distances in the early morning and late afternoon, and schedule lunch or an indoor sight to coincide with the four-hour window around solar noon that WHO identifies. Check the UV index in your weather app before you set off — if the forecast is 8 or above, treat shade at midday as a requirement rather than an option.
Hot-weather gear checklist
- Certified helmet with real ventilation and a visor
- Mesh jacket with armour — check the EN 17092 class on the label; if it is Class C it must be worn over another garment
- Long trousers; mesh riding trousers with knee armour if you have them
- Light-coloured mesh gloves with a reinforced palm
- Closed-toe shoes with a grippy sole
- Neck tube and sunglasses
- Sunscreen for exposed skin
- Water within reach, plus a snack that replaces electrolytes
- A light rain layer — the hot season in northern Vietnam brings sudden downpours
Packing for a rental bike in Hanoi
If you are flying in and cannot bring a full set of gear, pack in this order of priority: gloves first (light, and they have to fit your hands), then a mesh jacket with armour (it folds down small), then a neck tube. Closed shoes you are already wearing.
Before the trip, ask Mr Tú what comes with the rental bike — helmet, rain gear — so you only pack what is missing. If you want the year-round gear list rather than just the hot-season one, start with our guide to motorcycle safety gear for beginners. And if your trip falls in winter or includes the northern mountains, the problem inverts completely — we cover that in riding a motorcycle in winter.
Frequently asked questions
Is a long-sleeve sun shirt enough for riding in Vietnam?
Not in safety terms. A sun shirt blocks UV well but was never designed or tested for abrasion — stretch knit tears almost immediately on tarmac. A mesh jacket with armour does the sun-blocking job and the abrasion job at once, and in practice it breathes better than most people assume.
Can I wear a thin mesh armour shirt on its own?
It depends on the class printed inside it. If it is Class C under EN 17092, no: the standard defines Class C as providing impact protection only where the protectors sit, with no minimum abrasion protection, and intended to be worn with a Class AAA, AA, A or B garment. Check the label before you decide.
Is protective clothing legally required on a motorbike in Vietnam?
No. Under Article 33 of Law 36/2024/QH15 on road traffic order and safety, what is mandatory is a certified helmet, correctly fastened. Jackets, gloves and closed shoes are safety recommendations, not legal obligations — which is a change of regime if you are used to France or Spain, where gloves are required.
How do I tell heat exhaustion from ordinary tiredness?
The CDC lists heat exhaustion as several signs appearing together: headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating and reduced urine output. If confusion, slurred speech or loss of consciousness appear, that is no longer exhaustion but heat stroke — call emergency services rather than trying to manage it yourself.
What are the best hours to ride to avoid the worst sun?
WHO states that the maximum daily UV level occurs during the four-hour period around solar noon, with solar noon falling between 12 p.m. and 2 p.m. depending on location. The practical pattern is to ride the long legs early morning and late afternoon, and place lunch or a covered sight in the middle of the day.
Do cooling vests work in a humid climate?
They work, but less well than the marketing suggests. Evaporative cooling depends on water leaving the fabric, and high humidity slows that down. With limited luggage, prioritise a mesh jacket with armour, gloves and closed shoes; a cooling vest is the last thing to add.
Should I switch to an open-face helmet when it is hot?
An open-face helmet is legal if it is certified and correctly fastened, but it leaves your chin and face exposed. If you switch for airflow, pick one with real ventilation and a visor rather than a thin uncertified shell. For highway or mountain-pass riding, a three-quarter or full-face helmet remains the safer choice.
Planning a summer ride around Hanoi and northern Vietnam? Message Mr Tú with your route and dates. We will suggest the right bike and tell you exactly what comes with it, so you only have to pack the pieces that are missing.
Comments