how are you measuring the offset? If it was a motorbike I would use a level/straight edge to continue the angle of the headtube in a straightline down towards the front spindle. Then measure, on the horizontal, from the spindle centre to the level/straightedge which would give me the offset?
Does this sound right?
If its right the offset of the P2's is approx 45mm, which isn't a million miles away from ideal i think?
Basically right, but the offset should be measured normal to the line through the centreline of the headtube, which will give you something more like 41mm offset. I think (although I could be wrong) that those P2's are designed with 38mm offset.
The bike rides nicely at the moment. If the 29" doesn't suit I may stick with how she is now and start saving for a Singular
Well, all this stuff is a bit suck-it-and-see anyway, so the only way to tell if it's for you is to try it, as all this theory (mine and anyone else's) is very subjective. As Dr S says, I wouldn't worry about slackening the angles a degree or two - you can compensate for a lot of that with small saddle position and bar height changes and I've never had any problems with toe overlap on any converted 69er. I don't have big feet, mind.
I personally think that the ultimate handling depends on the combination of head angle and trail - a friend of mine is trying a converted Dialled Bikes Love/Hate (with 440mm P2's) and while it rides well enough, and he finds it an improvement with the 29" wheel, it just doesn't have that certain "je ne sais quoi" that the Hummingbird has (I should be on commission
). The head angle is steeper and it's running with more trail and it feels at the same time more "nervy" and yet less responsive.
Sounds a load of bollox, I know....
You can see from the photograph that the offset seems more noticable with the Singular forks (or maybe not...).
However, I could go on about steering geometry all night, given the slightest encouragement, but it's ok, I'm not going to
I'd stay with decent volume tyres front and rear - I wouldn't compromise tyre choice for what little difference it would make to the geometry.