alank2

I've got one of these:
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I weight around 195 pounds and have been filling the tires to 75 psi, but it seems like it doesn't take a lot of time for them (both) to lose pressure. How much pressure loss is normal?

alcjphil

How long does it take exactly? It is not the tire that holds the air, but the inner tube. Lightweight inner tubes allow air to diffuse faster than heavier, thicker tubes, so there is no set amount of time that it takes for pressure to drop

Iride01 

On my 622x25 mm tires I'll loose about a pound of PSI every other day. These things have pretty thin tubes. If that bothers you, then maybe a thicker puncture resistant tube might last longer, but the ride will likely be terrible.

If it's been more than one day since my last ride, I'm putting air in my tires. It's normal.

HillRider

I fill my road (700-23) tires every other day. For larger, lower pressure tires I would top them up every three or four days.

alank2

Thanks guys - I had no idea - I figured they would keep pressure for a month or two.

HillRider

Nope. These aren't car tires which have a much greater air volume, thicker rubber and lower pressure. Bike tires lose pressure rather quickly.

jon c. 

I probably lose about a pound a day. But I'm not that fussy so I will pump them to 115 psi and sometimes not fill them again for a couple of weeks.

KJK

I usually ride my 28's at 70psi and it takes about a week for them to leak down to 60psi where they will then stay for quite a while.

79pmooney

This is dependent on 1) the pressure, 2) both the thickness and material of the tube, and 3) the tube size relative to the tire.

1) is obvious. Twice the pressure, loses twice the psi per day. 2) Tube thickness vary a lot. There are very thick tubes that lose little pressure in months. Very thin ones can lose several psi a day. Materials also vary. The black butyl tubes are the norm and hold air quite well (depending on thnckness). Then there are other materials that lose air far faster, A thin latex tube can lose half its pressure overnight. And 3) if you run a small tube jn a big tire, that stretches the tube a lot, both making it thinner and making it effectively more porous.

This brings us to the ride. Almost all of those factors that make for more air lose also make the tube thinner and more elastic adding up to a ride that feels better on rough roads, rolls faster and has more grip for corners. (Most of these also make the tube lighter, saving weight where you feel it the most. I used to race on those 1/2-the-pressure-lost-ovenight tubes. Wonderful, fast ride!)

shelbyfv

I always pump my tires before each ride. Never thought to do otherwise.

steve sumner

the higher the pressure the quicker the air loss. as simple as that. the 35 lbs. in my cruiser will feel the same for monthes.
the 120 that I use in my race bike has to be pumped up every time I use it (daily)

Pratt

Different strokes for different tires. Skinny road tires, I pumped before every ride. Fifty mm tires kept their pressure (40-55psi) all summer

fujidon

I fill my tires to 100 PSI (700 X 25). I usually top them off about once a week and the pressure has dropped about 5 to 7 pounds.

Riding at 95 PSI is fine with me so I don't bother topping them off every day.

LazyMike

Yep, my 25mm tire gets aired up every other day, fatter, lower pressure tires last longer.

rydabent

Really dont make much difference to me. Before each ride, generally every other day, I always check and pump up my tires. That way if one is a lot lower I check for what is causing the low pressure. Easier to fix a flat at home than out on the trail.

Also when you ride on tires that are low on pressure, you can get snake bite flats.

cxwrench

Slightly off topic, but

steve sumner

why off topic? I run tubulars at 120 min.The one time I was lucky enough to afford silks
I pumped them up to 150

Iride01 

I think he meant his comment was off topic. His eyes will really pop when he sees my 25mm rear tire at 125 psi.


What size are those tubulars that you used 150psi once? On a road or velodrome track?

steve sumner

they were Clement Criterium Seta on the road ( didn't last long) but 195gr tires on
Super Champion Medaille 'd Ore 260gr rims means I got to feel something most riders
never will (it's all downhill from here) part of the reason I'll never ride clinchers no matter
what the marketing people say.the physics say that clinchers will NEVER have the same sidewall
flex as tubulars no matter how high tech the materials are. I still prefer cotton over any
man made sidewall material because you can feel (if you're in tune with your bike) the difference
in sidewall movement (more comfortable while giving more grip in cornering. a win-win
in my book oh the size was approx.23mm

Amber1988

Check the PSI before the ride. The temperature also affects tire pressure.

KC8QVO

I pump tires/check pressure every ride. I don't ride every day, though. The few times I don't is if I am going a short distance or if I worked on the bike the day before. If I know I am going to ride the next day I go an extra 5psi above my riding pressure. I like to run around 70psi (700c x 38's) and they are rated for 85. So even at 75 or 80psi I'm still under max and by the time I ride the next day the pressure has faded off a bit more. Mostly, though, by a long shot, I inflate to riding pressure every ride.

djb

Get thee to a nunnery and buy yourself a gauge, you'll then know the specific answer.
A floor pump with a gauge is a nice thing to own, for a bunch of reasons but this is one of them.

alank2

I tried to do that on Tuesday - harbor freight had a tall floor pump with gauge for $15, but too bad they didn't have it in stock after I drove over there.

djb

if you plan to bike often, a good quality floor pump is one of those things that you'll never go wrong getting.

fooferdoggie 

it varies so much its crazy. one of my bike the back looses 10 psi a week the front 1/2 that my other bike its just the opposite.