Was very close again today, but managed to make it home. Was on a group ride near my house (I had ridden to the start) and I had a front flat at about 17 miles. No problem, I had two spare tubes. After checking the inside of the tire with my fingers and finding nothing, I put a spare tube in, but it wouldn't even start to inflate. I checked my frame pump and it was working fine. I took the spare tube back out and tried pumping it up, and sure enough, it wouldn't hold any air. I did another tactile inspection of the inside of the tire and again didn't feel anything so I got out my second spare tube and first pumped it up a bit before putting it in. It held air so I put it in, pumped up the tire which held, and we continued riding. But after about 8 miles, the front started to slowly go flat. Since it was a slow leak, I convinced the rest of the group to continue and I headed toward home. But the tube held air only for another mile or so and would not hold any more when I tried to pump it up. So I tried to put all three flat tubes into my front tire but I just couldn't squeeze all three in there. I did get two in, but I'm not sure that made any difference. I rode about 8 miles at about 8-10 mph on the flat front tire to get home. It wasn't as bad as I thought it would be.

After a shower and a beer, I brought the wheel down to my basement shop and did another tactile inspection but still didn't feel anything. Then I did a thorough visual inspection with good lighting and found the very thin steel wire that was protruding into the tire.