just got my 6th flat within the last month, this sucks. i got a new rear wheel (dp18) and since then none stop flats all puncturing the tube from beneath. i have had two LBS look at it but am still getting flats. i checked the rim, rim tape (as did they) and there is nothing unusual. i pump to 110psi. wtf.

WoundedKnee had this same trouble with his DP18s. Hopefully he'll chime in.

I had the same problem. I went to the hardware store and got some black grip tape for tools/ hockey stick etc. (it looks like electrical tape.) I made 2 passes with that and haven't had a single problem since.

SRTboy, was this with a DP18 too?

Yeah it was. I don't know why this set gave me so many problems. My other set was just fine.

sounds like a defect, i just can not figure out where or what it is. 100% sure it is the wheel though.

I cannot imagine this being anything other than a rim tape issue.

tomorrow i'll get some new rim tape (cheap enough), although all spoke holes are cover.

Make sure you get the thick-ish cloth kind, not the electrical tape-looking crap. It might be $4 for a roll instead of $2.

While you've got the old rim tape off, take 36 seconds and run your finger around the inside of each nipple hole. If your finger is bleeding when you finish, there's probably some burrs you need to work on with some sandpaper or a file.

Yep, likely a tiny burr around a spoke hole that is pushing through the rim tape, and causing your issue. Strip the original tape, run over the inside of the rim with a maroon Scotchbrite pad, or some 220 wet-or-dry sandpaper. Pay particular attention to the spoke holes. Clean/degrease with some alcohol on a rag, and apply new Velox (thick cotton) rim tape. That stuff has been made for eons, and simply works.

Have all the tubes gotten holes in similar locations? Keep track of where the holes are vs. where it was on the rim, might be able to find your culprit. Worked for me for a piece of glass embedded in my tire that took me 3 tubes to finally find...

Yeah, take out the rim tape and do a very thorough cleaning out of the rim. Replace with new rim tape (or a couple layers of electrical tape—I've never had a problem with this) and reinstall tire.

The inside of your rim needs to be absolutely pristine. Consider investing in a cleanroom.

:::Update:::

Took my bike to my LBS today. Dude was kind of a jerk, refused to look into it but did however offer my money back for the DP18 (he was the one who built it for me and offers a 1 year mechanics guarantee). I declined being the nice guy I am and asked him to install some new rim tape and see if there was a burr underneath. He basically said no. Long story short I went to a different bike shop and bought some new rim tape. Came home, took off old tape, lightly sanded rim, there were a few rough spots for sure....

I then wiped down the rim with a wet cotton ball, followed by a dry one, followed by a fine wool scarf (my girlfriend knitted this for me, ha). I put two layers of electric tape followed by the new rim tape. Installed new tube, pumped to 110 psi and rode 20 miles today without a problem. I do not want to start singing too soon though. After I put 200 miles on it without a rear wheel rim side puncture I will gain some trust again and consider the problem "fixed".

Long story short I am sick of my LBS's and really feel that I need to have the tools and ability to maintenance every aspect of my simple fixed gear myself.

Not a single mechanic at my LBS thought new rim tape was a good idea after multiple flats (bottom of the tube) on a new rear wheel in one month. They did however sell me a new tire and tubes.

Thanks to the posters here for directing me to the possible and likely cause and solution (hopefully).

:::crosses fingers and rides bicycle:::

Yeah I don't get the laziness and snobbery at a lot of LBSs. Getting the tools and learning to DIY is very liberating...and much more cost effective.

For sure.