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Old 05-23-12, 09:34 PM
  #5  
chucky
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Join Date: Aug 2009
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Bikes: Self-designed carbon fiber highracer, BikesDirect Kilo WT5, Pacific Cycles Carryme, Dahon Boardwalk with custom Sturmey Archer wheelset

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Originally Posted by gregf83
I'm sceptical you're getting 'spoke flats". Tubes don't normally explode. I suspect it's related to how you are mounting the tires. Are you using tire irons to get the tires on?
I'm just using my hands to get the tires on and they go on very easily without any struggle. Also what I'm calling a "spoke flat" is just a single pinhole directly above the spoke hole (on the inner circumference of the tube).

I'm very careful about mounting my tires after noticing how crooked they can be when mounted carelessly (I've mostly observed this crooked mounting on new/display bikes)...also one time I had a bump in my tire (on another bike) due to the bulky part of the tube (over the valve stem) being seated too close to the tire bead and since then I'm extra extra careful. For example, I never pump up the tire all at once, but rather I pump to:
-40 psi then let the air out.
-80 psi then let the air out.
-and finally to 100 psi.
...that way I make sure the tube doesn't get pinched.

Originally Posted by Homebrew01
What the heck does that have to do with flat tires ? "trimmed" rims ???

Anyway, "exploding" tubes usually points to user error ... either pinching the tube under the bead of the tire, or not seating the tire evenly around the rim. Nothing wrong with tire irons when used correctly.

For #7, the spoke is coming through the tape ? Or the spoke hole is exposed ?
What size & type of rims & tires. What psi are you using ?
Neither spoke nor spoke hole is coming through the tape or exposed....if I had to guess I'd say the inflated tube is flexing the tape and expanding into the spoke hole where it gets punctured, but why would it suddenly be able to do that with good cloth rim tape or after thousands of miles of successful riding (with 3 layers of strapping tape)?

The rim is an Araya RB-17 (ISO 406) with an Intense MicroKnobby folding bead tire (20x2.0" wide). Tire is rated for 110 psi and I usually pump them to 100 psi...but the explosions/punctures have been happening around 60 psi.

Also this wheel has never been trued...nothing changed since the day I built it.

Last edited by chucky; 05-23-12 at 09:51 PM.
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