Will gradually add more here. Note that the 'A > B' format can oversimplify relationships between products that have different features.
Road Groupsets
Campagnolo: Super Record > Record > Chorus > Athena > Centaur > Veloce
Shimano: Dura Ace > Ultegra > 105 > Tiagra > Sora > 2200
SRAM: Red > Force > Rival > Apex
Mountain Groupsets
(Downhill/gravity components not listed.)
Shimano: XTR > Deore XT > SLX > Deore > Alivio
SRAM: XX > X0 > X9 > X7 > X5
Disc brakes
Avid (hydraulic): XX > X0 > Elixir CR > Elixir R > Elixir 9 > Elixir 7 > Elixir 5 > Elixir 3 > Juicy 3
Avid (mechanical): BB7 > BB5
Shimano: XTR > Deore XT > SLX > Deore > “Shimano branded”
Road pedals
Look: Keo Blade > Keo 2 Max Carbon > Keo 2 Max > Keo Classic > Keo Easy
Speedplay: Zero (Ti, SS, Cro-Mo) > Light Action (Ti, SS, Cro-Mo)
Mountain pedals
Crank Brothers: Eggbeater/Candy 11 > 3 > 2 > 1
Speedplay: Frog Ti > SS > Cro-Mo
Wheel rims
Mavic (road clincher): Open Pro > Open Sport > A 319 > A 119
Mavic (aero road clincher): CXP 33 > CXP 22
