>>2010305I'd only go for an alloy frame if the entire bike weighs 22 lbs or less otherwise its not worth the buzzy ride quality and galvanically corroded seat post.
for steel bikes chrome moly double butted 0.9 0,7 0,9 main frame triangle is farely normal for a light-ish 28 lb bike
most MTB or touring bikes are a bit thicker than this, desu 33 to 37 lbs is getting a bit porky and 48 lbs is just unreasonable if its not a cargo bike
>>2010383single speed requires more patience and foresight when riding, 70 gear inches is ok for 18 mph, but not so good for taking off from intersections.
3 speed IGH or 8 speed derailleur are a little bit more versatile while not being too obscenely fragile
>>2010384the coasting / free-wheel helps alot, way less problems with chain tension, so cheaper fork ends are fine.
>>2010386ye, some old single speed bikes have a kick back brake but this is hard to control when going down hill or over bumps, also does not work when the chain falls off lol
lots of cheap single speed bikes have single pivot side pull callipers, their performance is a bit variable (proper adjustment and soft brake pads help a bit)
vee brakes or medium profile cantilevers have stronger performance but need more frequent adjustment due to brake pad type and clearance
as for the bike fit that's a nightmare, due to bottom bracket hight and top tube slope
quick hack is to stand next to the bike inline with the chain ring
wrist hight for top tube / stand over
pretty much elbow hight is as high as the seat should go so that you can easily use the pedals to support your weight while getting onto the saddle
with the seat lower than mid fore arm you might have to start pushing the pedals closer to the middle of your foot
>reach and stack being farely random per bikethis is the main problem, its why there are so many types of handle bar
