can a frame cause a flat?
 

my friend has been having a curious -- and devastating problem -- on his bike.

he's had 5 flats the last ten times he's rode it, on different wheels and tires and tubes. last night, he got a brand new pair of IRO singlespeed wheels, had the rimtape, tube and tire professionally mounted at a reputable local bike shop, and on his 1 mile ride already had experienced a flat.

the brake rims aren't doing it, nothing is touching the wheel/rim/tire. so, extraordinarily bad luck or something withe frame? he's not a heavy guy and the bike is his size (its a little small, but just a little)

thanks
bikey

What is the bike?

Hey, I'm said friend. The bike is an old steel road bike of unknown origin, as it's been painted over its original paint job. I can take a picture and post tonight.

If it is not a pinch from the rim, or junk embedded in the tire, it could be excessive/inadequate pressure, riding surface or style (don't jump curbs or drains)...but it could just be bad luck; I assume you guys ride in the city (NY?). I had three flat tires on my car within two months, all were unique and unavoidable situations.

Or it could be sabotage by you lbs...

I dont think it can be the frame, unless there is actual contact with the tire somehow. Are the roads you ride on clear of debris?

+1

Yeah, we're in NYC. I was riding a well paved road in almost every case, perhaps a small pothole but nothing major. The back tire just keeps going flat. There is not contact with the frame. It's hard for me to fathom such bad luck--there have been no incisions in the tires in any circumstance--I just wonder if the physics of the frame might in some weird way cause undue weight/pressure on the back tire.

Does anyone have suggestions for good (yet affordable) road tires to buy that might offer more protection? I have IRO 700c's.

My guess is that you have a defect/hole in your inner tube. also could be that the presta valve is not closed all the way (assuming you have presta). If you've screwed the valve down proper and the tire still goes flat, take the tire off and inspect it inside and out for embedded stuff. All it takes is a staple, really. Inflate the inner tube and listen/feel for escaping air. Re-inspect the rimtape and rim before you put the tire back on.

no way could any extra pressure you could put on the back tire cause a flat all by itself (i.e.: panniers) if the tire is inflated up to spec.

I like these a lot.http://slime.com/images/products/SL-f1_b.jpg

Does it tend to flat in the same place? If it flats at the stem, round off the hole in the rim for the stem.

Feed us more facts. Following up on San Rensho's question: when you inspect the flatted tubes, what do you find and where do you find it? That can provide an important clue to what might be going on. Is there a single hole or a "snake bite" (2 holes)? On the inside of the tube or the outisde? At the valve? In the same spot along the circumference of the tube, or different places? Have you checked the inside of the tire for tiny objects that might be causing your problem? What is the recommended air pressure for those tires, and what pressure do you run? And so on....

In the realm of goofy tire problems, might I suggest that you carefully check the rim tape and wheel for burrs? I had a wheel that drove me crazy with metal burr that came loose. Had flats all the time and they seemed to move. Sometimes they would be on the inside part of the tube like a snake bite and sometimes on the outside of the tube. Finally narrowed it down to the burr when it got embedded in the rim tape.

Be careful looking for it. Burrs can be small, sharp and painful!

+1 on the burrs. Especially with the old rims, this is quite a common but annoying problem.

It sounds like you kept the *same* tire and tube when you replaced the wheelset. Is that correct? Is it possible that there are small bits of glass or metal embedded in the inside surface of the tire? Check for those carefully, shine a flashlight around the inside and outside of the tire and look for anything that glitters a bit.

http://www.nashbar.com/profile.cfm?c...=672&pagename=

If you can fit the 700c x 35's on your bike, these are excellent tires, and they've got a kevlar belt beneath the tread for flat protection, and a kevlar bead. It's a killer deal for $11.95. If you need a narrower tire, Nashbar has the other sizes in the same tire for $19.95, I believe.

The wheels, rim tape, tires, and tube were all brand new for last night's flat...They are very small 23c michelin tires.

I've got these Kevlar-belted IRC tires: http://www.nashbar.com/profile.cfm?c...eid=&pagename=
They're cheap and really tough.

I've run those IRC's, too. But the Panaracer's are a much superior tire, in my opinion..........but since the OP says the current tires are 23's, he may want to go with something else.

Make sure your pump isn't damaging the valve stems when you pump up the tires.

Good to know about those Panaracers! I see they've got a folding bead, which is nice. But do they ever have 28 mm's in stock?

Yeah, I really like them. And I think I've had maybe one flat in the almost 3000 miles I've put on them, so they seem pretty flat resistant.............It seems that while Nashbar is running the big tire sale on certain tires, they may have taken the more popular sizes of the Panaracers down off the website. Normally, they've got all sizes, from about 700c x 28 on up, and two sizes of 27's, for $19.95 each. But for anybody who can use the 700c x 35's or the 27's, $11.95 is a great deal on them for now-

And just what would the point of this be? So the shop could give away a free tube? This was brought up once before when someone found a nail in side the tire.
A shop is not going to "rig" a tire to flat because they would then get to install another tube for free.

Find the hole in the tube then relate that to the valve hole in the rim and its position realitive to the tire(This is why you line the tire label up with the valve hole) Now you have narrowed your search area.

So where exactly are the holes in the inner tubes? Locating them will provide a big clue toward solving your friend's frequent flat tire problem.

I will identify the hole(s) tonight and report back...thank you all for this advice. Sheldon Brown's article was particularly illuminating.