moosehead

i'm 260lbs and on my Specialized Expedition Sport my front tire depresses a little once i get on the bike and start riding. I had taken it out of the bike shop after putting stuff on the bike, they had the tires aired just right they said. it was only a day or two later that I start to notice the depression. The depression doesn't seem to be getting worse, but i do think about it, since its visable from up above. i did not invest $40 in a bike pump i know soon I will have to.

thanks

Tom Stormcrowe

Yeah, bike tires lose air faster than car tires do. Thinner tube walls leak air faster by osmosis, it's the nature of the beast, I'm afraid.

idig

Airing up should become part of your pre-ride ritual. My Ritchey Tom Slicks loose 5-10psi on a typical 2-hour spin.

st0ut

racing slick tires pump up every day. heck even sometimes twice a day.

my other bikes every other day, or or when it indicates it needs air which ever come sooner.

Wogster

It's supposed to squish a little, if it doesn't then there would be no difference between a pneumatic tire and a solid one. Best is to get an inexpensive foot pump, that you keep at home, and a tire gauge ( the pencil type are most accurate ) some pumps have a gauge built in, the dial type are not that accurate though. If the shop has a pencil type, then air up with your new pump until you have the right amount of air by the dial gauge, then check with the pencil gauge, and adjust as needed, note the level on the dial that corresponds with the right amount of air, and use the dial to get to that point. May not be 100% but should be close enough....

DieselDan

Keep the tire pressures up and don't try to defy the Laws of Gravity, Physics, and Chemistry. A tire will NEVER be perfectly round on a bicycle, car, truck, or airplane.

deraltekluge

What do you mean by "pencil type"? If you're referring to those where a rod comes out the end, and the amount it extends indicates pressure...


then you are wrong. Those are next to worthless. Get a dial gauge or an electronic gauge if you want any degree of accuracy at all. Note: Being a dial or electronic gauge doesn't automatically guarantee accuracy...but "pencil" virtually guarantees inaccuracy.

The rate at which a tire's pressure drops depends on the tube material and its thickness, the size of the tube, and the pressure. A smaller, higher pressure tube (like on a road bike) will lose pressure faster than a larger, lower pressure tube (like on a mountain bike). Higher pressure means faster air loss, and smaller size means less air to lose. You might end up pumping up the tires on a road bike every day or every other day, and those on a mountain bike once or twice a week. By contrast, a car tire, with its lower pressure and much larger size, would last weeks or even months, and still be close to the desired pressure.

Wogster

The pencil type, depend on how accurate the engraving on the rod is, typically it doesn't change much as it ages, whether it's a week old or 5 years old, it will have the same accuracy. I've seen dial type where you check a tire 3 times, and each is different, most pump gauges are this way. I had an electronic one where it only read 10PSI, and was designed so that in trying to check a tire, it would leak out most of the air, until you only had about 10PSI. I finally chucked it in the trash..... You used to be able to get decent ones of all types, now of course, most of them are cheap crap made in the worlds larges slave labour camp (China), even better ones.....

As for car tires, they should be checked about once a week, a 1PSI drop is worth something like 3MPG, with todays gas prices..... Bike tires need to be checked at least once a day.

10 Wheels

Pump mine up everyday. 120 psi
Low pressure can cause a pinch flat.