bernmart

After twenty-five years without a single flat (OK; I've done more miles in the last year than in those 25 years combined), I've gotten four in the last two months. Only one seems to have been caused by a puncture--a thorn I picked up in my driveway. Another was a tear in the tube near the valve; the other two seem to have been malfunctions in the valve itself.

This morning's a case in point: I suddenly found, at the beginning of a group ride, that my front tire was flat. I'd just pumped it up before leaving home. It was a slime tube (boy, am I glad to be rid of that), but there was no puncture for the slime to flow into; the tube simply wouldn't hold air. Again, no thorns, goatheads, or anything in the tire, no holes in the tube. Just a bad valve, apparently.

I'm using good quality tubes; is there something I'm overlooking?

Bernie

mx_599

bernie,
just sounds like a string of bad luck. hang in there. things will get better.

Al1943

Don't guess. Did you hold the tube under water to check the valve for a leak?

SDRider

How does the rim look around the hole where the valve stem goes through? Any rough areas? Do you use a hand pump or a floor pump? I've messed up valves using a hand pump. Floor pumps are better because they isolate the valve stem from the movement of the pump (not to mention that you can pump more air in very quickly).

How old/worn are your tires? Is it primarily the front tire or the rear? I find that I start getting flats more often when a tire is worn and this is a sure sign that you need to replace it.

bernmart

I never thought to examine the valve stem hole in the rim. The next time this happens (!) I'll make a point of checking it out. I do use a floor pump, but in one case it was difficult to disengage the pump head from the valve after inflating, through the life of that tube.

Two flats in front, two in the rear. I didn't submerge the tubes in water, but in one case I could literally feel escaping air from the valve, even when it was screwed shut.

Not to re-start a whole other controversy, but I do use the screw-on washers, snugged up against the rim, to hold the valve in place. Is this a problem? A solution to the problem? Both?

The rear tire has a slight flat worn in it, but there's plenty of tread left. The front tire seems fine.

webist

I consider myself lucky when I discover the flat before the ride. Much better than having one show up on the road. I have one hook in the garage for tubes needing repair and another for those I have already patched. I usually toss 'em if they have more than 4 patches. Flats are a minor irritation. I'd really hate 'em if I took all the measures against 'em like armored tires and tubes and self repairing fluids. I figure I'd just have slightly fewer flats, which were ultimately more expensive and less convenient than what I put up with now.

I also carry a cell phone.

SDRider

If you keep flatting that rear tire I'd replace it. What kind of tires are they? How old are they?

I never use the screw on washers. They get tossed immediately along with the cap.

I've had 1 flat in the last 1,300 miles because of a small piece of glass I picked up in my rear tire. I recently replaced my rear tire because the tread was getting pretty squared off in the center.

Cabrales

Hang in there, this may just be a bout with Murphy. I had a period of time when it seems I was getting flats all the time. Most of the time from glass shards, a couple from nails. Then it stopped. However, if you begin to get flats on the same tire for no apparent reason, look at the inside casing to make sure there aren't little metal pieces sticking out (from the tire belt), or glass embedded from previous flats. And lastly, check the inside of the rim for burrs or other sharp protuberances.

Avalanche325

Check the valve hole, like the other posters are saying. Are you talcing your tubes? I ripped a couple valves off the tube on downhills before I learned that one.

Here is another mystery one I had. On a Mavic Cosmos, I took off the hard plastic strip that comes with them and put on the much revered Velox rim tape. I kept getting flats until I put the hard strip back in. My other rims have always had Velox.

It could be your pump damaging the valves. I have only seen that with hand pumps though.

Put those tubes in water. You will probably find that they have a common problem.

Thrifty1

Check the pump's head for "slime" residue. I had similar problem after slime tubes. The green goo gets everywhere and semi solidifies in the pump head.....during subsequent tire inflation a small "fiber" of the "green goo" was transferred from the pump head in the valve and prevented the valve from seating/sealing properly. I completely disassembled and cleaned the surprising amount of "goo" from my floor pump head, hose, and body.......no problems since.
Hope this helps. Good Luck on your very annnoying dilemna...
BCNU
GARY

bernmart

Gary, I think you're on to something. I've just taken a look at the pump, and there is a lot of green residue in it. I'll take it apart as you sugggest. Those slime tubes are a menace.

Thanks to you, and all the other posters for thoughtful and helpful responses.

Bernie

gmoneyhobbit

hah thats nearly nothing...

when tour de california was in san jose.. me and my buddy went to watch it... we each got 3 flats that day


6 combined in one day.

when tubes are lil over 5 bucks a pop.. thats just no fair

we both ended up getting horny toads in both tires...

came home repaired them .. then went on a ride... where we both ended up getting pinch flats

toolboy

How's 13 flats on one Rockies tour?!! Happened to my friend. Turns out it was the rim tape. Tried masking, electrical. adhesive, duct and Scotch tapes to replace the original rubber but nothing worked until we hit a bike shop in Lake Louise who had a hard plastic one (the yellow kind) When we got home I buffed the inside spoke access holes in her box rim and she has been okay since. Saw a fellow who flatted once because the skewer spring had dropped into his tire and he didn't notice it when he put it back on! Say, you wouldn't have prestas in a Schraeder rim would you?

bernmart

Nope; even I am not that much of a newbie. Given how fragile presta valves have been for me, though, I wonder if Schraeders might be a bettet bet than we give them credit for. This is speculation only; I just spent $ to upgrade to Mavic Ksyriums (despite the ridiculous name), and I'm not about to get rid of them. Still, the theoretical advantage of prestas may not be worth it.

DannoXYZ 

leave the valve-stem nuts off until after you've pumped up the tyre. A lot of people have difficulty fitting the valve-head on the presta stems and they end up pushing and wiggling the thing too much. With the nut off, the force goes into just pushing the stem into the tyre and you know you're messing up. If you've got a locking head, be careful about rocking and tilting the stem as you're flipping the lever. Hold the head AND the stem stationary with one hand while you flip the lever with the other.