All-road/Gravel bike custom geometry help

[snguyen268]

Originally Posted by Spoker

I'm in the lower BB drop category.
Since you're running 165 mm cranks you can already go lower by 5 mm.
Design for the road tire, and when you go to rough terrain the bigger tire will raise it.

That makes sense! I will definitely consider that.

Originally Posted by .RJ

I dont see T47 going away and will future proof against just about any crankset that you'd ever want to use. If you want to run a rear brake cable internally you will need a T47 BB to get the clearance you need.

BSA may restrict your choices in the future. How? Who knows. I went T47 on a custom steel road frame, and I wish I'd done BSA - the internal routing has not proved really necessary and aesthetically the BSA would have looked better and I didnt consider that when making my choices.

I actually will not be running hydraulic hose through BB but around it externally. One thing I am safeguarding against is the ability to run di2 + 30mm crank, which seems to be too tight with BSA and makes me leaning toward T47. Of course, shimano might go completely wireless in the future and I am going to run SRAM for now, so that might be a moot point and I am just overthinking?

Originally Posted by Wunder

46/10 is a HUGE gear, are you sure you need that much? My gravel bike runs SRAM 11 speed with a 42T and 10-42, that yields 27-114 gear inches on 35mm tires (even higher if using 42 or 50mm). I've considered dropping the ring to a 38 or 36 if I was riding a very hilly course.

I personally like BSA, it's been around a long time and works well. Tons of crank options.

Thanks for the insights! I agree with you as I don't need that 46/10 combo. Reason I am thinking 46 is not really because of the 46/10 combo but because I am still going to be doing a lot of road riding and 46 gets me the closest to the 3 heavily used gear ratios on my current setup( which is 50/34 + 11-34). If I end up needing lower gears, it should be simple enough to get a smaller chainring and swap out (at least that is my current thinking). Not sure if that rationale makese sense? Or I should be thinking about it differently?