Montague FIT (Custom)
We had a couple of new (circa 2015) Montague frame sets left and decided to indulge some ideas (and actually document them).
For the FIT 21" frame, we installed a Box Three Prime 9 X-wide transmission which boasts an 11-50t in just 9 speeds or 455%! This is rare in a 9 speed and incidentally the same range you'd get if you maxed out a Tiagra 2x10 group set (50/34 x 11-34t) - and most of those are assembled with 11-25 or 11-28 rears. So it just became a case of picking the size of the front chainring. We opted for a 44t front which gives the rider a 4 ratio on the top gear and a 0.88 low gear.
We settled on a 650b x 42mm gravel tire which is a fair bit wider than the standard 700c x 28mm tires normally installed...and with a few more teeth. Definitely a much wider range of terrain.
The brake set are mechanical Avid BB5s with 160mm rotors and FR-5 levers. No fuss. Fully competent. We ride these on our own bikes.
And for comfort we also installed a 28" alloy bar with a 2" rise, a Brooks Standard B17 saddle, and MKS FD-7 alloy folding pedals (that spin beautifully).
All together, it's a simple yet able and convenient package. Grab your backpack, go ride wherever and then fold it into the train, your car, plane, boat, or closet.
See this link for more details: https://www.beaglebicycles.com/product-page/montague-fit-pc-650b-box9x