Walked out to a flat tire this morning, but can't find leak

Got home at 3am last night and bike felt "wobble" on the way home. I had a passenger most of the night, so I just thought it might have been from riding single.
Walked out today to a flat, rear tire.
Can't see any nails/holes in the tire. I sprayed it with soap/water to see any air bubbles, but didn't really see any. Rims don't seem to be dented.
Only thing I can think of is I put on these things:
http://cgi.ebay.com/ebaymotors/ws/eBayI ... &viewitem=


I was messing around with them last night and I'm thinking I put it on too tight and broke the stem seal or something. The stem piece did turn a few times, and I dont think they're suppose to.

Any ideas how to fix? I used a hand pump and put 37lbs of air into the tire and gonna go check in 2 hours to see how much is still in there.

 

Might be the centre peice is depressing the stem centre, therefor slow leak?

 

Exactly, I had that happen with something like those.

BTW - they are not DOT/legal. Most likely won't get caught with them, but any lights other than headlight, taillight, 'accessory lights' (and only one pair, basic term fog lights) and blinkers are legal.

Obviously people cover their vehicles with lights, but if you stay away from colors other than white/red/yellow depending on their locations, you are ok.

I had two 20LED yellow strips under the edge of my seat on my old bike, added a glow to the side of the bike, and it was yellow so it 'looked' like marker lights basically.

If the tire's flat when you go outside, put a regular cover on the stem.
That doesn't work - get a valve repair kit at a local auto place (~$5) and take the valve out, clean the threads with the included tool, and drop a new stem in. See if that solves it.

 

Re: Walked out to a flat tire this morning, but can't find l

no their not

 

It's been about 3 hours and it's down to 33 or 34 lbs. I switched the caps to the normal cap now though so hopefully that fixes it.

How do I do the valve repair kit? Do I have to take the whole tire off? Seems like it'd be kinda of a pain to do, but hopefully not.

 

is there a nut or two holding the stem to the rim? put some tighten to it
check it with bubbles

 

the bottom has a cover so I can see really. Should I cut the cover off?
I sprayed some soap onto it and took the pressure. Air came out the bottom of it when I took a pressure read. Guessing thats not normal. I'll get one fo those valve kits tomorrow, its getting dark and starting to rain now so I'll worry about this tomorrow. At least I'm only losing about 1lb every 90 min so it's still rideable around town in the mean time.

 

Oh the actual stem piece in the center was bent a little so don't know if that's having an effect.

 

The entire valve can be removed and replaced - but most of them I do believe have to have the tire taken off, should be installed from inside the tire.

If it's just the valve core (leaking from INSIDE the stem) you can repair it with what I said earlier, valve repair kit.

Inside the stem is a one check valve, the pin you push in with an air compressor opens the valve, the spring inside it (along with the air pressure) hold it shut.

Where did the air come out? At the base of the stem? That's not normal. Could be some dirt or crud, or more than likely when it went FLAT and then you filled it up, it was seated wrong.

a) if your leak is from INSIDE the stem, meaning under the cap, you need to replace the valve CORE.

b) If the leak is around the base of the stem, by the rim, you need to fix it there. If you have a nut around the stem, try tightening it. If not, it's more a pressure fit from the inside and you need to let the tire go FLAT, clean around the stem area with a q-tip and straighten the whole stem out as your pressurize the tire. If it still leaks from the base of the stem, you'll need a new one to be put in for you.

 

Went and check again and I'm pretty sure its at the bottom of the stem thats the problem. The covering of the stem seems to be a pressure holder/blocker so I don't want to cut it off to see underneath. I can twist the whole stem like a screw and I'm not sure if these are suppose to do that. I "unscrewed" it 10+ turns and "tightened" 20+ turns.
I DO have 2 spare rims w/ tires and maybe I could take the stem from one of those tires and put it on this one?

 

Re: Walked out to a flat tire this morning, but can't find l

As far as I know there are 2 types of stems:

1 - brass with a nut that tightens against the rim and you could try to tighten.

2 - rubber body that is pulled through the hole and is essentially a press fit. There is no "pressure holder/blocker" and if you cut it it'll just leak faster.

Tire valves are cheap. Don't move a used one.

 

guessing its the 2nd one you said then. I'm going to a tire place tomorrow and hopefully they can fix it easy.
Hopefully I dont need to take off the tire to fix it, cause I'm just going to a car tire place ^^

 

Re: Walked out to a flat tire this morning, but can't find l

I doubt a car tire place will have the valve you need. Most (maybe all) automobile wheels take a larger diameter valve.

The tire doesn't need to come off, but the bead needs to be broken on one side to get the valve in.

 

Yep. But - did you flatten it first?

Could be set in there wrong. What happens is when the tire goes flat, the pressure that USED to hold it there ISN'T THERE anymore.

Thus, the valve falls in, twists, sits sideways, something isn't sitting right.

My guess - when you put those blue covers on, it hit the pin and released the air. When you refilled - the valve wasn't straight and it's leaking. Not a tight seal.

Either that or when you twisted real hard, you cracked it or broke the seal...

Anyway - try letting all the air out, and pull up on the stem and hold it straight as you fill the tire.

And no, I don't think they'll have that valve at a car place.

 

well it's been over two hours now and I left it with 37ish lbs of air. It now had 35-36 lbs and I'm hoping that was just from the temperature drop. I'm hoping it turns into one of those things that just "fix itself" haha.
Either way, it's not a bad leak and definitely manageable until I get it fully solved.
When riding, would that cause the leak to go faster or slower?

 

It honestly could - the pressure would help reseat the valve if that was the problem.

The pressure loss also could be the pressure gauge you are using - like the fork air pressure, it's a low pressure system, low pressure gauge. Every time you TAKE the gauge off -you lose ~4PSI. Shouldn't be as much loss in the higher pressure tire, closes the seal faster. But still - 1-2 PSI loss is nothing to bark at for sure.

 

If you use a digital gauge the loss should be a lot less.