Originally Posted by
unterhausen
It really depends on if you are ever going to put a front load on it. If not, it really doesn't matter. Except your geometry is going to be a little annoying while standing on hills.
Your proposed head angle makes it so a 55mm rake fork would be mid-trail, I think. If you look at production bikes, they definitely lean towards high trail. It makes sense, most production bikes don't get ridden, and most of the ones that do get ridden are ridden without a front load. People don't like steering they have to get used to, and low trail takes a bit of adaptation. Unladen high trail bikes do not. So production bikes are made to feel stable during a 10 minute test ride.
I have a bike with 73mm hta and 55mm rake, and it takes me approximately one hill to get used to the steering if I have been riding something higher trail. The one with 73hta and 65mm rake takes two hills to get used to, but since it always has a front randonneur bag on it, it feels perfectly normal all the time. Even if the bag is mostly empty.
You just had to open up that can again....
The trail of my design should be around 59 (HTA 71.5, 559 x 2.0, 50mm rake). I was surprised to discover that my Voyaguer was 62, as that seemed a bit low relative to the other touring bikes I was seeing. I also found that the Fuji S10S (a darling of the 650b/low trail conversions) shipped with a trail of 40 (HTA73, 27", 65mm rake), with the 650b conversion going to 33mm and being "fixed" with a bag (this sounds like your second bike from above?).
At this point, I sort of gave up worrying about it at this point, as it seems to put "low trail" at around 30mm, "standard touring trail" around 67, and I have no idea about high-trail. So my thinking was that 8mm +/- (20% towards low trail) won't be something I can detect, or register enough to complain to the builder about.
I always found the bag idea confusing, as it doesn't sound like big loads (lunch and a patch kit), as you suggested. So is 2# really changing behaviour that much? It seems like fit items - handle bar reach, slope of the terrain, would move that way more (i.e. a 200# rider shifting 1% by changing posture would offset that).
But, I do agree that in the end one can adapt very quickly and happily. Sort of like toe clips - after a flop or two it is completely second nature, even under panic situations.