All-road/Gravel bike custom geometry help

[snguyen268]

Hi all,

I am designing a custom all-road/gravel Ti bike and would love some of your opinions on a couple things.

1. Which of the 2 attached geometries is more in-line with what I need? My intention for the design is to have it optimized for road/rough road/maintained dirt road, do well on rough gravel/fire roads, and somewhat capable of getting me through some single-track. In other words, toward a road bike with wide tire as opposed to a drop-bar MTB. What I am trying to achieve here is a geometry that will not feel sluggish on road, especially on climbs while still give me confidence off-road. My question is wheelbase length or steering more important for "stability", especially for off-road? I understand stability is achieved by a combination of those factors and more but I am just trying to decouple their effect. Also, is there a sweet spot of trail figure I should aim for? Currently thinking 59-65mm. I am planning to run 35-38mm on a regular basis (currently trail figures are calculated based on 38mm) but do plan to go up as terrain requires (frame is designed to clear 700c x 45mm or 650b x 53).

2. T47 vs. BSA BB? I am running Di2, which precludes the ability to use 30mm BSA BBs (not enough room for cable routing according to my understanding). Should I go for T47 to have maximum versatility? Any other downsides besides slightly heavier BB and not as common as BSA? I am getting a new crankset for this build as well (my fitter recommends going down to 165mm) and there seems too be more options for 30mm cranks so maybe it's a good idea to not limit myself to 24mm spindle? Are 30mm cranks like Rotor ALDHU worth the extra $$$ over 24mm cranks like Ultegra 8100?

Thanks all for taking your time!