Todzilla

Rode a 20 mile trip last Thursday. all fine. Put bike away in garage. Next morning rear tire flat as pancake.

Changed the inner tube carefully, checking for anything on inside of tire. Found nothing, finished installing new tube. Inflated tire.

Rode same 20 miles this Monday. all fine. Put bike away in garage. This morning rear tire flat as pancake.\

Obviously, I'm doing something boneheaded. I'd rather not run to my LBS every time there's a problem.

What do I need to double triple check?

Thanks in Advance!

le mans

maybe theres a sharp spot in the rim, spoke nipple, the rubber rim tape might have something sharp on there



before you take the tyre off, pump air in the tyre and try to locate what section of the rim where its leaking. you might be able to listen for it, if not, take the tyre off and leave the tube there, then pump it up a bit, squirt a bit of soapy water over the tube.

Canker

Did you check the rim tape? If it shifts over and exposes part of one of the holes it can keep wearing a hole in the tube.

johnny99

Remove the tube from the tire, then pump it up. Look for a hole in it somewhere. There almost always will be one. See if the old tube has a hole in the same place. Look for whatever is causing the hole in your rim or your tire. Small pieces of glass in your tire can be hard to find unless you know exactly where to look.

Lonesome rider

Check the rim tape, check the rim walls, check the tyre even more carefully, check if spoke doesn't stick. I had two punctures in two days. The culprit was the small metal needle that stuck through the tyre. It was so small that even upon close inspection I couldn't notice it.

10 Wheels

These wires can hide inside your tire.

Mauriceloridans

If you always use new tubes you probably are not getting location data you need. First you need to know if the leak is on the inner or outer part of the tube to know what to look for. Then you see how far from the valve the leak is. This helps focus your search.

I noticed one of my tires kept getting leaks in the same zone because all the tubes had patches in the same place. I found a minor slit on the tire surface in the area and probed into it and found a sharp tiny glass shard that had given me multiple flats.

dsbrantjr

If you always mount your tire in the same orientation relative to the valve (I put mine directly opposite) you will be able to know where to look once you find the hole in the tube.

You may need to turn the tire inside-out to put tension on the inner surface to open up any tiny holes which can hide sharp objects. Running a cotton ball around the inside may also help locate an object by snagging on it. A strong light and/or a magnifier may help spot tiny objects more easily.

Todzilla

Thanks folks! These are all good suggestions.

I did check the spoke nipple tape, all seemed fine, but I will fine tooth comb it all this weekend.

mconlonx

With what OP describes, 9/10 times, this is what it is. Shard from a radial tire asploding.

Once you pump up the tube and find where the leak is, as Johnny99 advised, feel around in the tire in the corresponding area. It will feel like a grain of sand or something, so do it carefully. You could also use a cotton ball -- note where it snags. You'll need a decent pair of needlenose pliers or tweezers to get it out.

HvPnyrs

I feel your pain.
Having TWO consecutive flats can Truly Suck. EVEN SUCKIER is even more repeat flats (Don't. ... Ask. ... )

THE GREAT NEWS IS, you NOW have 2 inner tubes With Holes in them (you did save them right? ...Right? Again... don't. ask.).
Assuming that you did In Fact KEEP the Punctured TUBES, THEY will be EXCELLENT TROUBLESHOOTING Tools to help PINPOINT the cause of the flats (or at least narrow it down substantially).

digibud

Pump up the tube before you remove it or the tire from the wheel, after pulling all but the valve out while the valve is still inside the tire or at least make sure you keep the tire/tube in the same orientation so you can know exactly where on the tire the tube is being punctured. If you remove the tire and lose track of the orientation you have to search the entire tire. Noting whether the hole is on the inner or outer section of the tube is also instructive if it might be the rim tape out of place. I just had the exact thing happen to me the other day when I changed a tube on the road and didn't catch the tiny embedded shard that looked exactly like the piece shown in this thread!

Todzilla

Found the problem!

A small crack/hole in the tire sidewall - just enough to let a small bulge (the size of a BB) of tube protrude. New tire time. It was worn out anyway, after 6 months of my new bike.

Thanks to all!