Rear tire going down.

[jake42]

I have a question for all the cold weather folks on here.  I've noticed that my rear tire keeps losing pressure while sitting in my garage.  A little info, they're almost new pirellis sport demons that i got back in july so they only have about 500 miles on em.  The bike is up on the center stand and there's no pressure on the tire.  My garage is attached to  my house, but it's pretty cold down there.  It's not quite the same as outside, but you can see your breath, especially when it's this cold outside.

I've checked the whole tire and there's nothing in it, and i can't see any cracks in the sidewalls or divots in the rim or anything.

any help is appreciated.

jake

[pizzleboy]

I could only assume that, similar to car ties, they losse about one pound per month of sitting, and another pound for each ~5degrees the temp drops.

But then, I could just be talking out my ass.

[vtlion]

is it a slow leak?  or a response to the temperature?

A drop from room temperature to freezing corresponds to about a 10% loss in pressure.

[Casimir]

Does the front tire lose pressure too?

If it's only the rear tire, it almost has to be a leak in the tire, the front would respond to the same temperature changes.

How fast it the drop? Did you check the valve stem? Do you have a valve cap? Did you try the soapy water thing? Did you check around the rim to make sure there is a good seal between rim and tire?

I had to get a nail pulled from my car tire this week. The shop immersed the whole wheel in a tank designed for the purpose. Showed them real quick where any leaks were. I don't know if that is doable on our bikes without repacking bearings.

[jake42]

i was thinking leak too because the front doesn't seem to lose any.  I just can't find any real obvious cause like a nail or split or anything.  I"m just bummin because they have very few miles on them.  It seems to be alittle better since i got the back tire off the floor, meaning it doesn't seem to lose as fast. But i filled it up about 2-3 weeks ago and I have noticed that it is down a little bit because i can push the tread in a little bit with my foot while it's on the center stand.  

damn :dunno:

jake

[octane]

If you can't see anything in the tire, it's probably a leaky valve. Pop the wheel off while the bike is in the garage and take it to the shop for a new valve. They should do it for less than 10 bucks - and even that's robbery. The valves only cost a few cents.

[yamahonkawazuki]

if it is not apparent wheel/tire damage, or if the tire passes the soapy water test, id be almost certain, to hazard a guess to the valve-stem

[octane]

Dude! You're peeing on Old Glory man.

[Diderich]

i had new tires put on mine and they leaked like crazy around the rim.  10 PSI a day.  I found the source of the leak by dunking the tire in a 6inch deep large tub of water  and looking for bubbles.  I didn't even have to take the wheel off the bike.  I took the wheel back to the shop and they fiddled with it, until they ripped the tire in their machine.   They ordered a new tire...installed it and no more leaks...magic.

I'm pretty lucky that nothing bad happened, because as soon as i got the tire put on, i verified the tire pressure and i took it out for a hundred mile break in ride.   Two days later I went on another 50 miler to the coast and it felt funny.  I thought i was just getting used to the new tire..which never felt right to begin with, but I got back and the tire had 5 psi in it!  Good thing i was riding with my cruiser buddies that time and not my sport bike buddies.

[Mat]

i agree with just about everybody saying the valve stem.  Mix up a bottle of "snoop"(soapy water as i  and some others and i have come to to call it).  used this for a lot of things... tires, dry suits, compressed air systems.  used to work at a tire shop and a scuba dive shop.  snoops good stuff. give it a whirl and see what you find.