So when I started, it was on mountain bikes (when I was a kid) and I didn't really have many problems until the tires ran out of the liquid stuff that made it tubeless... but now that I'm on a roadbike, I've been having problems with my tires. Like maybe once a month a tube Is low in pressure or has gone flat and I would check the tube, find nothing, replace it anyway (use the tube without problems as a spare) and get on with it... But I don't think it's normal that I've had to switch out the tubes from (both) tires a total of 4 times (3 times on the front and once on the back) and all the times I've done it, I've checked the tube and used soapy water, checked the tire itself for holes, sand inside, anything and there's been nothing... So do I have faulty tires? Should I just get some new ones from a more reputable company?

Are you pumping up your tires before each ride? Road tires (tubes) lose air quickly and can go flat in a few weeks.
Most folks I know pump up (top off) the tires before each ride.

Rubber is porous and the air molecules escape through the porosity of the tube. Air loss is a natural thing. I think you're making an issue out of a non-issue.
Jon

Yes, I do pump the tires before I go for my ride. Maybe I'll try a higher PSI though...

I mean it's annoying to ride on flat tires... not to mention dangerous. But I would think that it would take longer than that for air to escape... But thanks for the advice and pulling me down to earth.

How are you checking the tube?

Pump the tube up to 2x or 3x its normal size. Then take a bucket of CLEAR water (or a sink full), and slowly rotate the whole tube below the bucket, one bit at a time looking for bubbles. There will be some bubbles from immersion, but make sure you also don't see slowly expanding bubbles on the tube. Also watch the valve.

It is quite possible you're not finding the holes.

Oh, also pay attention to the valve orientation with respect to the tire, so you can go back and find the cause of the flat in the tire. Little pieces of radial tire wire can be nearly invisible, or perhaps a piece of glass embedded in the tire.

Definitely make sure there's nothing stuck in the tire. I had a series of slow leaks and finally found a tiny sliver of glass poking inside the tire, completely undetectable until I took the tire off and flipped it inside out. But, after 3 or 4 days they'll still be pretty low if I don't top them off.

You have to inspect the inside surface of the tire carefully for intrusions of wires, thorns, and the like. Sometimes you can't see it initially but can feel it by running your fingers over the interior. Also you have to inspect your rim strip or tape because during installation of a tire the rim strip or tape will move laterally exposing the tube to a sharp spoke hole edge or nipple. In my experience rim tape works a LOT better than rim strips. Also you should use fine sandpaper or a micro-file to round-over the valve hole edge which is often is sharp enough to cut through the tube eventually. I try to avoid ultra-light inner tubes because in my experience they're a lot more prone to failure. 80-90 gram tubes are better than 60-70 gram tubes. Lastly, some tires puncture a lot more easily than others. People love the Continental GP4000S2 because they resist punctures yet are lightweight. They have a built-in puncture-resistant belt made from Kevlar under the tread. You probably have a combination of all these factors contributing to your frustration.

I've had holes from goatheads so small, that the only way to find the hole was to squeeze the tube underwater-- just holding it underwater wouldn't make bubbles. So it would only leak when under load. Like, 5psi an hour while riding, but lose only 10psi or so when sitting in the stand overnight.

I bike commute 4 days a week. My main bike runs 700x35 road tires. My other two bikes run 26x1.85 and 700x32. I usually top off my tires every other day I ride and find that it has gone from 90psi to 70psi in a couple of days. The other two bikes sit for a couple of weeks at a time and sometimes even a month. In the summer the 700x32 will go from 80 to 50 after a couple of weeks, the 26x1.85 will go from 70psi to 55psi after a couple of weeks.

In the summer I notice the tires loose air more quickly, in the winter they hold their pressure a little longer.

So stop replacing tubes...it's normal for tires to loose pressure over a month. And pumping to a higher pressure will do nothing to change that.

The max PSI or PSI range is shown on the sidewall of the tire. Don't exceed the max PSI.

I'm a bad girl and check my tire pressure roughly every two weeks, I lose 5-10 psi in that time. Losing pressure is completely normal.

Another thing... some people use tubeless sealant (latex, not the green goo) in tubes with good luck. If you're getting slow leaks and pin holes that are difficult to find, I'd imagine the sealant would permanently plug those holes.

However, normally with some care, you can find and patch the holes, as well as determine the cause of the leak.

Like others have said, my road tires loose pressure & I top them off about every 1-3 rides or every 60-80 miles or so.

This is new territory to me.

With automobile tires I don't expect to see any appreciable loss other than summer to winter as a result of reduction in Temperature.

However, I can see that because of the very small amount of Volume, and the very large Surface Area to Volume ratio compared to an Automotive Tire, I can see it.

Just unexpected.

/begin relearning.

It's "normal" for a 700 x 25mm tire to lose up to 5-10% psi in 24 hrs.
I have had tubes that have exceeded this and found that the Presta valve core needed to be "snugged down"...
Nothing is more important than proper tire inflation.
For best results, if possible, top up your tires before every ride.
As a "starting point" - for 25mm tires:
100 psi in the front.
110 in the back.
YRMV.

High pressure road tires lose air a lot more quickly than mtn bike tires. I top mine off before each ride. Mine usually lose about 10 lbs of pressure a week if left alone.

This is far more normal than putting goop into a tyre. Like, it's been that way since the tyre was invented.

I believe it has to do with the size of gas molecules in the air, and the smaller molecules find a way of permeating through the rubber inner tube. I think people who use CO2 to inflate their tubes, have greater issues with deflation over a shorter period than those who use normal air.

Car tyres don't have the same issue to the same extent, mainly because... well, have you seen how thick a car tyre is?

Reference this post in a parallel thread:

https://www.bikeforums.net/19866453-post17.html

If you're airing them up every few days, to a normal road bike pressure range, and the tires are completely flat no that is not normal. Either something in the tire or wheel is pricking a tiny hole, or you or your pump are doing something to the valve stem.

First thing I'd check is the rim tape, replace if it's the thin rubber type that comes stock on some wheels. Check the tubes again, get out the magnifying glasses and cotton to check the tires.

I haven't replaced tubes in our two mountain bikes, ever. My road bikes, which I ride one or the other daily, haven't seen a new tube in a couple of years. Normal air loss on my road bikes, they won't be flat until months have passed.

Also, with an infrequently used tire, if it is completely flat, that is a sign of a problem (hole, bad valve, etc). If it is mostly flat, but still a bit spongy, then it is likely normal air loss due to leakage through the tube.

There may be an air loss curve, so a tire at 120 PSI might lose 10 PSI the first day, but the loss will slow down significantly once it reaches 80 PSI or so. Likely if one is running MTB tires at less than 50 PSI, then the air loss will be much less noticeable.

Car tires do lose air, but at a slower rate. If one leaves the car parked for a couple of years, then better check the air pressure.

I just reread this. How much experience have you had riding with tubes? You've been riding tubeless since you were a kid? Hmmmm.....

Pull the tube out, inflate it to 2x or 3x it's size, and leave it alone for a week. If it's flat, you've got a leak to find and a cause to troubleshoot. Don't forget to check the valve.

OTOH, if it's still inflated after a week, everything's fine.

UNLESS someone put slime in the tube, in which case you'll likely never find a slow leak.

It's not really that much of a stretch-- my nephew rode MTB for years and years, including 4 years on the High School MTB team, and was tubeless the entire time-- he never had to deal with tubes until he got his first road bike. Mind you, he was born in 1996. It's entirely plausible that tubeless bicycle tires predate the OP's cycling career.

Time to go tubeless Road?