Ok..... Remember I'm not trying to survive a stick encounter, just keep the chain from falling off when i rememove the rear wheel.
Chainring sizes http://www.machinehead-software.co.uk/b ... table.html
Gravel (38 - 44) 81 - 93mm
Road (44 - 53) 93 - 111mm
TT (54t - 58t) 113 - 122mm
Brazeon FD hanger - R5 radius on the hanger interior, R7.6 on the exterior. 30mm total with 20mm vert adjustment. It moves in relation to the bike's expected gearing (35mm center above the top of the ring teeth).
Shimano Bracket spec - http://www.peterverdone.com/wiki/index. ... re_Postion
SRAM https://www.servicearchive.sram.com/sit ... 8_road.pdf
Forgive the pics, but between the space I had to hold the camera, the ruler, and interference....
Braze on- mount (trek Emonda) 30mm total with 20mm vert adjustment.
Hanger bolt center to 1x chainring tooth center 20mm
So if you give me a 90mm long device top to bottom, at that bottom comes forward 30mm, then goes out 25mm from the bolt center, and put a hole slightly smaller than 5mm every 10-12mm or so....
Here's a similar unit, that's too solid
(40mm facing to guide leading edge)
(80mm chain top to highest bolt position)
(45mm guide leading edge to vertical rod back)
(20mm chain inside to support frame-side).
The rod on this is 8mm wide with 45deg rounded taper to the 5mm bolt circle.