Tyre pressure is one of those things most riders set at home, check occasionally, and don’t think about much beyond that. A number that works in your local conditions, on familiar roads, in familiar temperatures — and you leave it there.
Then you arrive somewhere like Phuket, and your familiar number stops being the right number.
Here’s what changes, and how to dial it in properly.
Heat increases pressure. More than you’d think.
As ambient temperature rises, the air inside your tyre expands. Every 10 degrees Celsius increase adds roughly 2% to your tyre pressure — which doesn’t sound like much until you consider that you might be going from a 15-degree morning in the UK to 34-degree tarmac in Thailand, where road surface temperatures in direct sun can hit 55-60 degrees.
That’s not a small change. A tyre inflated to 90 psi before a Phuket ride could be running well above 100 psi by midday. On rough or uneven road surfaces — and there are plenty of those — that’s a much harsher, skittish ride, with reduced grip and a higher chance of a pinch flat from impact.
The practical upshot: inflate your tyres a few psi lower than you normally would, check them in the morning when temperatures are at their coolest, and know that what you set at 7am will be different by 10am.
Lower pressure isn’t a weakness
There’s a tendency among cyclists — particularly those who’ve come up riding road bikes with narrow tyres — to associate lower pressure with rolling resistance and slower speed. And for very narrow tyres on perfectly smooth tarmac, that’s not entirely wrong.
But on the roads you’ll encounter in Phuket — a mix of good tarmac, patchy surfaces, rippled sections from heat expansion and heavy vehicle traffic — a tyre with a little give in it grips better, absorbs small vibrations that would otherwise go straight through the bike, and handles the heat-expansion issue built in rather than fighting against it.
Unless you’re on a perfectly smooth course in controlled conditions, the fastest tyre is rarely the hardest tyre. It’s the one that stays in contact with the road.
What to actually run
This depends on your tyre width, your weight, your bike, and how rough the roads are that day — but as a rough framework for a road ride in Phuket’s climate:
For 25mm tyres, consider starting around 85-88 psi rather than the 90-95 you might run at home. For 28mm or wider, 75-80 psi gives you good compliance without sacrificing too much rolling efficiency. These are morning numbers, before the heat builds.
If you’re on a more mixed-surface or gravel-oriented ride, go lower still. More tyre volume, more compliance, better grip on anything that isn’t smooth tarmac.
And if you’re running tubeless — which is increasingly common and makes excellent sense for this kind of trip — you can afford to go lower again, without the pinch flat risk that limits clincher pressures.
Check every morning. Not every few days.
At home, many riders will check pressure once at the start of a trip and leave it. In the heat, do it every morning before you ride. Temperature fluctuations between night and day are enough to make yesterday’s perfect pressure feel wrong today, and in humid conditions, valves and seals can lose air faster than in dry environments.
Sixty seconds with a pump. It’s the simplest mechanical job of the day and one of the highest-return ones.
One practical note on pumps and gauges
The gauge on a lot of portable pumps is not particularly accurate at the best of times, and accuracy matters more when you’re making deliberate adjustments for conditions rather than just pumping until it feels hard.
If tyre pressure is something you take seriously — and on a trip where the conditions are working against you, it should be — bring a small, good quality gauge rather than relying entirely on the pump readout. A digital gauge weighs almost nothing and takes the guesswork out.
Your tyres are the only thing between you and the road. Spend sixty seconds on them each morning and they’ll look after you for the rest of the day.