Stock fork is 398 a-t-c, low trail conversion fork is 398 a-t-c. Per this calculator the head angle and seat angle shouldn’t increase at all.
I was able to measure the seat angle and confirm it is 74° with the low trail fork. Per this calcultor I am getting a trail of 37mm. I think it’s a little higher since the rear tire is 7mm smaller than the front.
Anyway, the bike is now a low-trail speed machine. It feels really great, I waffle on the existence of planing so let’s just say this bike feels lively and fun to ride even after 3 hours on the road. The fork blades are much thinner than the ones on the Masi Randonneur and since the frame is more than a half pound lighter it’s kinda obvious this bike is going to be a better riding bike.
If you’re looking for a low-trail roadbike that isn’t overbuilt with touring tubing, I think a Soma conversion is the way to go. The Fog Cutter or Double Cross Disc are both great options.
I’ve only done two rides but they’ve both included a little bit of gravel, some singletrack and an hour +3 laps of a training crit. The bike handles well without any load on the front. I’m using a cheap Neco needle bearing headset from eBay and so far I’ve had no shimmy and the handling feels precise and more neutral than expected.
I’m running mis-matched tires because I’m not 100% convinced the Compass tires are to be trusted tubeless. Also the new 1.5mm wider Compass Babyshoe Pass is about the same width as before, right at 40mm. Goddammit Compass why you keep doing this to me. I wish the Hetre came with a tubeless bead.
I’m going to keep using the bike for training crit riding and maybe keep it the way it is before bogging it down with a frame bag or rack and using it as my daily rider.