Reddit reviews Shimano UN55 BB Square Taper Bottom Bracket (68x113mm)

This is what you're looking for.

Or the UN26 you mentioned, which is just a less expensive version.

LHT Frame - $520 after tax

Chukker Wheels - $85 x 2

Tires Schwalbe Marathon Plus RLX 700 x 45 C Bicycle Tire - $54 x 2

Alloy Headset Spacers - $7.89 x 2

Shift Levers - $60

Chain - $10

Brake Cables - $10

Brakes - $15 x 2

Extra Long Shift Cables - $6

Derailleur - $24

Cassette - $17

Crankset - $40

Spindle - $24

Headset - $45

Seatpost - $20

Brooks Saddle - $145

Rack - $35

Brooks Panniers - $150 x 2

Brooks Bar Tape - $65

Tools

Saw Guide - $41.36

Starnut Setter - $22

https://www.amazon.com/gp/aw/d/B005DTIKQE/ref=mp_s_a_1_1?ie=UTF8&qid=1486739389&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=bottom+bracket&dpPl=1&dpID=414eo6f6tjL&ref=plSrch

This is what I used.

I bought most of my tools off amazon, treefortbikes, and Performance bike.

From what I can tell from the product page for that bike, it does look like a sealed cartridge BB so it probably is a square taper. You need to find out the spindle length so that you can preserve the chainline. After you get the BB out, it should be stamped on there, it should say something like 68x___mm. Once you've got that measurement, buy one of these, they're solid.

For a square taper you're going to need a crank puller, a bottom bracket tool, and a socket wrench. There are a bunch of guides out there, I know park tool has some decent ones so check on their site.