Well, fingers crossed, perhaps a bit of scuffing on the drop-outs and/or a new front skewer will give you a more secure wheel? In regard to the skewers, with 22k miles I'd also give those a close look to make sure those end nuts as well as the knurling on the hub's axle end caps are in good shape and cleaned of any embedded crud. Given how often we remove and reinstall from wheels, a front wheel skewer can definitely lose it's bite.
Originally Posted by Cyclesafe
It's amazing how important it is for the hub axle ends & skewer's knurled end-nuts to bite into the drop-outs. Just to underscore how important they can be, here's a little anecdote taken from Update #9 of our Calfee Journal regarding some front wheel hub slippage that we experienced on simply out-of-the-saddle climbing because of a poor interface between a hub axle and fork drop-outs:
Now, I must note we did have one small issue with the Topolinos that initially appeared to be serious but was, in fact, just a minor design issue. More specifically, during hard out of the saddle steep and aggressive climbs we experienced an alarming creaking sound coming from the front of the tandem. Initially it sounded similar to a bearing creak but following the ride everything appeared to be nice and tidy at the hub. On a hunch, I wondered if the titanium skewers that came with the Topolino's might be flexing so I installed a spare set of Salsa skewers with steel axles for our next ride. The creaking was not as pronounced, but was still clearly in evidence and somewhat disconcerting. Once back at home I inspected the hubs more closely and noticed the axle end caps did not have any knurling and were, instead, absolutely smooth. I reinstalled the front wheel in the fork and applied some side loading with my hands and low-and-behold there was the sound: it was a bad case of grip-slip between the front axle and the fork dropouts. Before the next ride I scuffed up the axle end and the fork dropouts and when coupled with the use of the steel skewer the noise was gone. We've since passed along this discovery to the folks at Topolino via our dealer with a recommendation to incorporate knurling for their tandem wheel axle ends as others will no doubt experience this under similar conditions as we're certainly not the strongest, hardest climbing team that will use these wheels.
Update: The response from Topolino regarding the non-knurled end caps has been exceptional. Two new axle sets and very detailed instructions for removal and re-installation arrived just days after a short telephone call to discuss the problem. The next end caps were installed which solved the creaking noise at the fork drop-out.