robertj298 

Seems if I haven't ridden a bike in a week or so the tire pressure drops from 100 psi down to about 60 psi.
Is this normal? Not just one particular bike but all 5 that I own.

Mr. 66

That sounds fast. Slow leaks could be a number of things from a bad stem or a thorn in the tread.

alcjphil

What size tire? The narrower the tire, the less air inside thus faster pressure loss

Juan Foote

My road bike needs the air topped every subsequent daily ride. I try to be very specific about the pressure in those tires, as well as the comment above cause wise.
My city bike I have often just "finger pinch" check and go for a week or so because I am (mostly) not as concerned about it on that bike and MUCH larger tires.

Lemond1985

I like to think by keeping my tires aired up to nice high pressures, I can avoid a lot of flats. IMO, soft tires tend to pick up more debris, have a larger contact patch, and have more "give" if poked with something sharp, which invites sharp objects to get a foothold. Which is yet another reason I'm not a huge fan of the whole "run your 120 lb rated tires at 60 PSI" fad.

T-Mar

I find that the ability to hold pressure will vary with the tube. It can occur even within a brand/model. One will hold air well, while another will lose pressure relatively quickly, yet there are no leaks to be found during a submersion test. I put it down to poor quality control during the manufacturing process. Then, of course, there's also some natural variation due to thickness and compounds. It was amazing how many upset customers would come into the shop because they thought they shouldn't have to pump up their tyres more than once a year! When I started riding tubulars, back in the early 1970s, it was standard procedure to top them off, daily.

SJX426 

@robertj298 - Yes

Interesting you would ask about how fast a tire looses air (pressure) instead of how long a tire should hold pressure.

I check and pump before every ride.

Velo Mule

The higher the pressure, the faster the loss.

tiger1964 

+1

I've stepped down form 145PSI 23's to 120PSI 25's last year, and am now experimenting with 110PSI. No change, every day need a top-off of a few PSI regardless.

nlerner

That's why the good people at Park Tool sell pumps.

canklecat

Depends on the tubes. I like latex and the very thin butyl Continental Race 28 Lite, both of which lose pressure more quickly. Latex tubes need to be checked every day and it's not unusual for those to lose 20 psi overnight. With thinner sidewall tires it's easier to get snakebite pinch flats.

My hybrids have heavier tubes and I might check them once a week. Even if they're a little low it doesn't matter much because I'm using 700x32 up to 700x40 tires, with more rigid sidewalls so they're a bit more resistant to snakebite flats.

Cyclist0108

In defense of the fad, which is harder to pop, a fully-inflated balloon or a somewhat under-inflated, flaccid balloon?

davester

That was exactly my thought. It's pretty obvious to me that while tires at high pressure are more resistant to pinch flats, they are less resistant to being punctured by an object on the road. Not to mention the lower rolling resistance, greater comfort and cornering ability of those lower pressure, wider tires.

In answer to the OP and as alluded to by several, the air-loss properties depend on tube type (fastest to slowest loss would be latex, ultralight, regular, heavy duty), and pressure (high pressure loses faster). On my most commonly used bike, running 32 mm tires, ultralight tubes and about 70 psi, I only need to pump it up about once every two weeks.

tiger1964 

I am not certain that that analogy, ahem, holds air.

Cyclist0108

I don't know how I managed to mangle the spelling of balloon twice, but it is a bit more than an analogy.

Low-pressure tires, especially supple ones like Rene Herse, measurably deform around objects that more highly-inflated tires ping off of (or get stabbed by).

When I first started riding them, I assumed they would be a nightmare in terms of puncture resistance, since they don't have kevlar belts and stuff that I previously thought was a necessity for riding the streets of America. But I hardly ever get punctures (and the two I did get were pinch-flats). It really does work.

RobbieTunes

It is normal for a man your age.
It happens to many of us.
Don’t worry about it.

robertj298 

But I'm still just a rookie at this at 66 years. I never rode a geared
bicycle until I was 60 .

nlerner

Shrinkage happens!

BFisher

I've heard the Swedes make pumps for that.

Kabuki12

I check and usually add whenever I ride because i have more than one bike and rotate with reckless abandon. I can't remember which one I rode last unless I check my Strava. So sometimes a bike may have been siting for 2 weeks without riding. I routinely check the tires before I take off for a ride for thorns or damage. Better to find it on the stand than out in the middle of nowhere sweating and changing a tube.

iab

That's not mine baby.

MntnMan62

Mine also will lose some pressure between rides. I always check my tires before a ride. Both road and mountain. But I'm religious about checking my road tires. Not as festidious with my mtb tires, but still check them regularly, at least every other ride. And I find I have to top them off each time.