I haven't searched for answers to this problem; my apologies but I'm on the road and have little internet time, and need ideas. Hope you can help.

I'm in mid bike tour and had a problem develop in the last few days with a slight wobble in my front wheel; it's only really noticable when I'm descending a hill and get up above 20 or 25 miles an hour, and then it feels like the front tire is shaking sideways back and forth.

My bike is a new Surly Long Haul Trucker. I bought it a month ago and I'm 700 miles into a tour. It's been fine so far; I noticed this problem a few days ago. The frame is 54 cm and the tires are 26 inch. I'm fully loaded with four panniers and a handlebar bag and a sleeping bag; the bike is quite heavy.

I took it to a bike shop today; the guy trued the wheel (it was pretty true already), but noticed the wheel still had a bit of a wobble. Kind of like a small bulge in the tire. When the wheel spins and the bulge reaches the fork, the wheel moves laterally very slightly; it does not appear to move up and down at all. This matches the feeling I was getting on the bike (lateral movement).

We replaced the tube and the tire but it did not fix the problem. I did not trust this mechanic but he's the only one around. He was baffled, so I called my local bike shop who I do trust, and they said if the wheel is true and the problem persists with a new tube and a new tire, then they have no idea what the problem could be. He had me check to see if the tire was seated properly, but it looked fine. Also no apparant problems with the tape on the inside of the rim.

Having no other options at the moment I'm continuing my tour and will try to limit my speed on the downhills. I'll get to another bike shop in a few days (in Arcata, Ca I think). What should I do when I get there? Maybe the guy today didn't true it properly? (I watched him do it and it looked fine). What else could be causing the problem?