I put a 29er wheel on my rigid monocog. It had steep angles to begin with, and a very low (in terms of ride height) fork. The 29er wheel made a huge difference in head angle, and i had some trouble with toe overlap. If your talking about a 29er suspension fork, and a 29er wheel, expect a huge slackening of your geometry. I would recommend a rigid 26" fork with a 29er wheel on it. If you go this route, you'll need a disc brake up front because the brake bosses won't line up. Even with my already steep geometry and low rigid fork, i still felt like the front wheel was wandering on climbes and that it had a tendency to flop over. However, it carved downhills like a pair of parabolic skis and rolled over just about everything. i was pretty happy with it and am now thinking about getting a 29er (maybe 1X9?). If you ask more specifc questions, maybe i can contribute a bit more. Hope this helped. In short, your handling will change no matter what, and if you go for a 29er suspension fork it will change drastically.