Chaos Bike Tactica
The size of the squad appears to be in direct relation with the purpose you want it to fulfill. According to your recommendations, Tank Hunting squads should be at minimum size and assault oriented squad should include at least six models. Also, marked units should be favoured as we will see later.
Purposes of the squad
Tank Hunting is one of the most common uses of bikes as they are fast and can be equipped with anti-tank weaponry and veteran skills. As stated before, there is no need to have more than three bikes: two with assault weapons and one Aspiring Champion (AC).
Daemon Summoning Mobile Beacon (DSMB) (Also more commonly known as the Daemon Bomb) is another common tactics, in which turbo boosting plays an essential part. You move forward to the enemy and summon all you can on turns 2 and 3. This tactic will allow your daemons to flank the enemy instead of charging upfront, usually against units that are not meant to be assaulted. Again, you don’t need a big squad to accomplish this goal, you mainly need the invulnerable save provided by the turbo-boosted move.
Variation : Mobile Teleport Homer (MTH). As the name imply, you can use your bike, by equipping your AC with a Teleport Homer, to position your terminator exactly where you want them to arrive. They may then act as support for your biker squad or fight on their own. This alternative can be combined with any of the other alternative presented on this post.
The third technique is to Hunt Fragile or Fast units (HFF). Based on my own understanding of the game, middle-sized squads should be enough to accomplish this task. The objective is to target elusive targets and to empty all your magazines on them before assaulting. Assault weapons are recommended and your AC should be kitted with power weapons and spiky bits as all your attacks will count (smaller squad, need more punch). By fragile or fast units, I mean Havocs, Devastators, Land Speeders, Tau Battle suits, Dark Reaper, Bright Lance Squad, Raiders transport vehicles, etc.
The fourth tactic is to use them is Assault. I, personally, would not recommend this in games under 1500 points as bikers are a big point sink and this technique requires more models. From what I’ve heard and read, bike assault squad should be bigger than five models. Also, they should use whatever marks you can give them (we’ll cover this later). This squad’s purpose is to run into enemy line and kill as much as they can. Because they move fast, you’ll need to send support quickly to avoid all opposing units to concentrate on this sole target and flush your 300+ point unit on turn 2. Having 2 of such squads could be nice, especially in a Night Lords army.
The last tactic is to use them as Melee Support unit in a stand and shoot army. Playing against horde army with a stand and shoot configuration usualy imply that you will eventually be assaulted. Now, as the game goes on, you will see that your line will show some weakness, unnoticed during deployment. This is where your bikes come in an handy. Use them to support assaulted squad that needs more hands. If deployed in the middle, they can travel 24″ a turn in any direction. No matter what, you can use them as regular firing squad in shooting phase.
Bikes are made to move fast so they don’t need a Line of Sight (LOS) at the start of the first turn. Therefore, the best place to deploy them is behind cover. I would suggest that unless you plan to send them straight up the enemy front lines that they be deployed on sides of the board. If you choose to use them as melee support, deploy them in the middle of your army, behind the front line.
Where to strike
To this question, most answers goes to Flank and Rear, never front. I would agree, unless your objective is to create anarchy in the enemy front lines. As the bikes allow you to easily flank your enemy, you should always tank hunt the side or rear armour of vehicles.
Remember that daemons are summoned before you can move. This means that you should end your previous movement exactly where you want the summoning to occur. Be sure to allow for some scatter, as daemons rarely land exactly where you want them to.
Marked bikes squads are an excellent option. There are only two marks other than the Mark of Chaos Undivided (MoCU) that can be applied to biker squads:
Khorne is excellent for two reasons: The favoured number of Khorne is perfectly suited to the Assault Purpose detailed earlier due to the extra attack bonus, and it gives a Khorne army a controllable element to their armies that they would usually otherwise lack. You can all figure the outcome of a melee including eight Khorne ‘Bikezerkers’.
Slaanesh is also very good with the possibility to upgrade your Twin-Linked bolters to Sonics Blasters at a low point cost. The fact that they count as a stable platform means they’ll usually triple their fire power in the 13 to 24 inch range.
How to dress your AC for the occasion
Huge Assault oriented squad and Tank Hunters: Power Fist, Spiky bits.
Small DSMB: Whatever you like, the squad will mainly be used to summon. Best to outfit for some assault so that they have a purpose after summoning is finished.
Melee Support: Power Weapon or lightning claw (1).
HFF : Kai Gun; Power Weapon and Daemonic Strength or lightning claw (1) as you want to inflict a lot of damage fast.