paulhoneybadger

I got a broken bike. My car was stolen and need it to get around.
Mongoose, Excursion, 24", 17 speed... beat to hell.

The front rim had an inner tube, cut and wrapped around it.
I bought a new one, Slime, .. but after putting it on... the air leaked from the steam.
I don't know what is wrong.

Please help.

Homebrew01

Where are you located. Is there a bike coop near you to help ?
Or watch some videos about fixing a flat / replacing tube.

davei1980

Leaking OUT of the end of the valve stem or from the base? It's possible the base became "cut" during install, which would cause the stem to leak close to the tube. Not sure why it would leak from the top of the valve stem unless it has something stuck in it. I have never had good luck with Slime stuff so I suggest getting a garden-variety tube, not one pre-treated with fix a flat sealant.

+1 to finding a co-op and LOTS of vids on YouTube showing you how to correctly change tires but here's a brief summary:

- Slide ONE bead of the tire on the rim so it's 1/2 on (should be able to do by hand)
- Pump JUST enough air in to the tube so that it vaguely takes shape, you can let a little air out if you overdo it
- Place the valve stem through the hole on the rim, replace the cap (so that it doesn't back out )
- Place the tube in the void in the inside of the tire
- Work the rest of the bead on the rim, working in opposite directions away from the valve stem and ending on the side opposite the valve stem. You can do this by hand until you get very close to the end, try to get it on by hand and if you can't, you may need tire levers to pry the bead on. I am guessing you don't have these so a handle of a spoon works, just be careful.
- Pump enough air in to get the bead to set and inspect, if the bead is set up all the way, then pump up to spec and you're good to go.

If you're serious about working on your bike going forward, you should read all the sticky threads here and bookmark SheldonBrown.com - an encyclopedia of practical knowledge (geared toward us, not lycra-clad elite racers)

Leisesturm

Mongoose Excursion 24". Juvenile market MTB. Top rider size 5'6". Beat to hell? Seriously. I wouldn't bother. The co-op's in my area sell ready to roll refurbished bikes for riders in exactly the o.p.'s situation starting at $29.00. And they will teach you how to work on it free of charge. If you read that as me being in agreement with the other two posts that mention bike co-op's you would be correct. FWIW.

Iride01 

If air leaks from around where the stem exits the rim, then you busted the tube while installing it. If air leaks from the stem itself, then you got a bad valve core or you gunked it up when you added slime and maybe some trash is stuck in the slime right at the valve keeping it open.

The piece of rubber wrapped around the rim you mentioned might have been the rim strip that protects the tube from the spokes or spoke holes. You replaced that with a new rim strip or rim tape?

davei1980

^ Also yes.