Originally for the WhiteScar's.
Part 1: Space Marine Scout Bikers:
One of what I consider the “lost children” of the SM Codex. IMHO a under appreciated and used fast attack choice for commander.
To start with they appear to be overly expensive Space Marine Scouts, at 70 points base for 3 bikes and 20 points per additional bike (That's 7 more then baseline scouts). The fact they cannot be taken as a troop choice like their slightly more expensive brothers when paired with a Bike Commander I think this is why they are often dismissed for more “cost effective” units. Well that and their limited upgrade options... However if you look past these points to what they can do (when balanced with other units for similar point values) you might find a home for them in your next army.
Starting here due to how hated they are. Expensive; Only a 4+ Armor save; They cannot switch out either ranged weapon for a CCW making them a bit limited in Close Combat. Pair that with few effective shooting upgrades it makes them more of a orphan finesse unit. Not a Scoring unit. Hydra's eat them alive, ignoring both Turbo-boost and their 4+ armor save.
Combat Squads; Infiltration; Scout move (including turboboosting for a 3++) ; Outflanking threat range of 18 inches; Locator Beacon paired with the Scout move for accurate Deep striking. Risky First turn Assaults. Gimmicky but worthwhile cover denial upgrade. Naked 15 points cheaper, and slightly harder to kill then the Scout/Storm combo.
First, never take just 3, at the minimum I would suggest 5, if you have the points a full unit of 10. A Melta Bomb and Power Weapon are your friends, and for 10 points the Cluster Mines can force the enemy to think twice before entering terrain.
Infiltration anywhere on the board outside of 18 inches from an enemy unit, you can also bubble wrap to limit the scout moves from BA, IG, Grey Knights and other Scout heavy armies. Held in reserve you can (Per the INAT FAQ) combat squad when coming on from reserve and contest objectives.
Placed on the board 1st turn you can scout move for a 3++, and everything behind them will get a 4+ Cover save, including vehicles if positioned properly. Again can be used as bubble wrap for more expensive units (including your main bike squads) preventing assaults and providing a constant 4+ cover save through out the whole game. Every shooting phase your opponent shoots at them it's a another phase your more strategically valuable units stay intact.
The single best justification for using Scout Bikers. With the proliferation of Razorspam / Chimeraspam parking lot armies you can guaranty to give yourself some breathing room as you tie up valuable units with the bikes forcing them to spend time dealing with them.
Verses Longfangs / Devastator, assuming you failed to wound with shooting, your doing 1.5 saveable wounds and 0.75 power weapon wounds the first turn taking 1.4 wounds back either winning or pushing combat for another phase or two.
Verses Vehicles your causing enough hits to get your opponents attention! 2.23 Shaken/Stunned results, 0.84 Weapon Destroyed, 0.84 Immobilized, and 1.12 Wrecked/Explodes. Spreading those over a multiple assault you have a good chance to keep 3 vehicles from shooting primary weapons (S+S+WD) and another vehicle destroyed. Unless eliminated your getting assaults on your opponents turn as well on all the vehicles immobilized or just unable to move out of combat.
Objective based games. In Non-DOW MINE your primary objective. If you camp a squad inside the over the turn the opponent comes to contest and or assault you out of it he/she is taking 2d6 STR 4 hits before anything else happens. Wounds would be treated as a shooting attack so it's possible to rout a unit without doing anything! In DOW Missions mine an objective you don't plan to go to until late in the game, again force the opponent to take risks to just keep in the game.
Requires Khan. Scout move Turboboost stretching the squad back with in 14 inches of your furthest deployment point. Sargent MUST be closest to the enemy. Turn 1, after moving the scout bikers, break Khan off and just move him far enough forward to join him with the Scout Bike Squad. During the assault phase you will loose a couple attacks but gain STR, INIT and most importantly LD 10 and Hit&Run. Assuming you win / stay in combat you will pile in 6” more getting Khan closer for brutal follow up attacks.
One of the most forgotten / missunderstood rules of bikes. They CAN move into cover & they CAN go to ground. You just cannot Turbo-boost in/out of it. Don't be afraid to contest an objective, going to ground for a 3++
Scout bikers can serve a roll in many Space Marine armies, but it requires finesse and skill to make them worth the points you have to sink into them.