How long should a road tyre hold its pressure?

Inflating daily might be a bit more work than necessary. Inflate them before every ride. From my experience with 700x25c tires at 115 PSI, I find they lose about 5 PSI after 24 hours, just due to the natural properties of the rubber.

I ride a few times a week, and it's part of my standard pre-ride checklist to give each tire about 3-4 strokes on the floor pump, or whatever it takes to get them back up to 115.

My recommendation is that road bikes get inflated before the first ride of each day. With lower pressure mountain bike tires I find that the pressure is acceptable if I've inflated them within the last 7 days.

With 700x28 tires @ 110psi, I only inflate them about once every two weeks (if I remember), or right before a major ride. I always give the tires a quick squeeze before every ride just to make sure neither has developed a slow leak.

Daily inflation, or before every ride seems like overkill to me. When you connect a pump or gauge to measure your tire pressure, you're probably losing up to 5psi just from air used to fill the pump/gauge (plus any leakage while getting them lined up right). This gets worse the smaller your tires are.

the figures you'd quoted seem to be normal, i check and pump mine at least once every 3 days when i used to ride regularly. unlike car tyres the bike tubes have much lower material density but the pressure held inside is 3x higher than your typical city car tyres ... if you are really paranoid, get some commuter grade tubes which have thicker walls hopefully they hold the air longer, another possibility is that you have a crooked valve, in that case you need to replace the tube too.

Another thing is that it is highly worthwhile investing in a good track pump (known as floor pump elsewhere in the world). Here in Australia you can get a reasonable one for around 70-80 AUD. With a track pump it takes only a minute or two to top up the tyres and check their pressure.

With 23s at 100psi you may need to inflate daily. My 35s run at 100psi and I need to inflate every 3-4 days, and relative leakage rate increases as tire width decreases.

But two things:

• Use decent quality tubes, and beware of some brands. Some "racing" tubes are very thin and leak very rapidly. Ask the guy at your LBS which brands they get complaints about and stay away from them.
• Don't over-tighten the valve. There is a rubber gasket in the valve that can be damaged by over-tightening. Air pressure is sufficient to hold the valve closed, and the nut is there just to secure the valve on bumps, etc.

I use 700x23c tires with 120 psi recommended. In my experience my tires lost about 5-10 psi in a day with riding and slightly more if I don't ride for a day or two. I check the pressure and fill it to recommended before every ride.

Avoid pinch flats, and damage to wheel-set, check and fill tires to right pressure before each ride.

You don't need to inflate them daily, unless using lightweight and/or latex tubes.

You don't need to inflate them before every ride, unless using lightweight and/or latex tubes.

A 28mm road bike tire with the heaviest 622 - 28/47 butyl inner tube you can find, inflated to 7 bar / 100 psi with air, will hold acceptable pressure for at least two weeks. By acceptable, I mean more than 5 bar / 70 psi.

If inflated with carbon dioxide, it will lose pressure faster. Yet another reason to not use carbon dioxide inflation and instead prefer air pumps.

Of course some ridiculously narrow tire such as 23mm tire might need so high pressures and the inflation margin between pressure needed to prevent pinch flats and maximum pressure might be so low that inflation more often is necessary. You need not use such tires. A 28mm tire besides has a lower rolling resistance than an otherwise identical 23mm tire.