DOH! Persistent rear flat

[rideswaves]

hello all!

i was wondering if anyone knew any likely causes of a consistently rear flat tire. a new tube is only lasting 2 rides.

would i need a new rim? tire? i really have no clue (doh!).

thanks for your thoughts
/christina

[johnnyt]

Be sure you are not pinching the new tube when you install it. Add a little air to it before you pull the side of the tire on.
Also, there could be something in there...What you should do is remove the tire and tube. Wipe out the inside of the tire with a wet rag and do the same to the tire then let them dry by hanging them (be sure nothing gets in or on them. It might be a good idea to replace the rim tape as well (about $1). Then check the rim to be sure there are no burs on the inside.
If you are using a CO2 cartridge, tires do seem to lose air after a few days. Pump that new tube up with a good ole pump the first time.
Good luck. - JT

[CouchingTiger]

Could be one or more of a few things. First, whenever you get a flat, check the inside of the tire for thorns/protrusions. Throw a new tube into a tire w/ a thorn and you've got a new flat.

If the tire is good, check the rim. Thin rim strips are flat prone as they allow the pressurized tube to push in on the inside spoke eyelets toward the nipple heads. Both surfaces can have burs and can cause flats. I use Velox or the like, heavy cloth rim strips ONLY. The other inside surfaces of the rim should be smooth and free of burs and such as well.

Beyond that, there is the obvious, maybe you're running inadequate pressure for the terrain or maybe you are hitting rocks and such with too much force. I tend to live by the rule that more pressure is better. I run big tires and I run them hard. I don't like to flat.

If you are getting lots of snake-bite pinch flats (2 holes in the tube caused by pinching/cutting tthe tube between the rim and the surface you smacked into), then it's likely an issue of technique and pressure. When you hit something, or see yourself about to hit a rock/root/log, you should stand up and try to de-weight the bike. Absorb the impact with your legs and arms rather then with the tire. Also try running a little more pressure in the tires.

-Couch

[AA]

OK so your tire is flat after 2 rides, does it go flat gradually? If so the culprit it probably a thorn or other hard to see sharp object stuck in your tire.

If this is the case you can try the following;

*take your wheel off your bike
*remove one side of the tire from the rim
*pull the tube out of the tire but leave the valve stuck in the rim so you know where the tube has been sitting in the tire
*pump up the tube enough so its got some decent pressure in it
*try and detect any small holes in the tube by holding the tube close to your face or with the back of your hand. You will be surprised at how small a hole can be detected with this method.
*Once you find a hole trace it back to the area of the tire the tube came from (this is why you leave the valve in the rim)
*Inspect the tire for thorns, glass, small nails etc. If the tire is repeatedly going flat you usually find something.

Good luck

AA

[gungywump]

Christina,
1. Check inside of tire for thorns or anything that may be puncturing tire.
2. Check tire to see if there are any tears or holes. Especially along the bead where brakepads can wear through.
3. Check rim to make sure there are no sharp edges.
4. Check rim tape to make sure there are no spokes poking through.

If everything checks out it may be related to tire pressure and/or riding style. Is there something you are doing that is causing flats?

[rideswaves]

> Is there something you are doing that is causing flats?

you mean beyond the bed of nails trick??? ;D

many thanks all. i'll check all of it out!