Countdown
The countdown is the period at the start of each race before the timer starts, where the player only has limited control over the vehicle.
Overview
The countdown lasts for the first 239 frames of the race. During the countdown, max speed is set to 0; additionally, bikes are put into a "slow fall" state, where they move downwards at a constant 1.3 u/f instead of being affected by gravity's constant 1.3 u/f² acceleration.
Controls are limited during the countdown. Pressing A only affects the start boost charge, while pressing B has no effect. Stick inputs allow bikes to move by leaning, and have no effect otherwise. Bikes are also allowed to wheelie by pressing up; wheelies are automatically cancelled after 15 frames since IV is 0. Wheelies can also cause the bike to go airborne, depending on the length of the bike.
Start boost
As soon as the countdown ends, the vehicle can receive a boost or burn out (hitstun animation lasting 120 frames) according to the start boost charge value. It is clamped between 0 and 1, and is updated every frame according to the state of the A button. If A is pressed, the charge is set to [0.02 + 0.982 * (previous value)]. If A is not pressed, it is set to [0.96 * (previous value)]. These recursive equations can be rewritten as such:
If A is pressed,
If A is not pressed,
where is the number of frames the button is held or released.
The start boost increases max speed by 20%, grants an IV acceleration of 3 u/f², and lasts for a variable number of frames depending on the start boost charge. The possible start boost lengths are listed in the table below.
| Start boost charge | Boost duration (frames) |
|---|---|
| 0 - 0.85 | 0 |
| 0.85 - 0.88 | 10 |
| 0.88 - 0.905 | 20 |
| 0.905 - 0.925 | 30 |
| 0.925 - 0.94 | 45 |
| 0.94 - 0.95 | 70 |
| 0.95 - 1 | 0 (burnout) |
Start slide
Using the ability to wheelie and lean, bikes are able to move forwards a small amount during the countdown. The general strategy for start slides to the right is as follows; rotate counter-clockwise with a wheelie, lean to the right to slide sideways (and partially forwards), then (optionally) rotate clockwise with a wheelie to adjust rotation.
All bikes can wiggle sideways by alternating leaning and neutral inputs. Some bikes are also able to slide much more efficiently by going airborne when performing a double wheelie (e.g. doing a second wheelie immediately after the cooldown from the first expires). This strategy works because while the bike is airborne, wheel EV decay does not apply, so the leaning EV lasts a long time. The ability of bikes to double wheelie is correlated with the distance between the bike's origin and its bike tire; the greater the distance, the greater the airtime from a double wheelie, while short bikes can't gain airtime from double wheelies at all.
Depending on the length of the bike, there are three main types of start slides.
- Short bikes: Standard Bike S, Bullet Bike, Bit Bike, Quacker, Magikruiser, Dolphin Dasher, Standard Bike L, Shooting Star. They are unable to gain airtime during the countdown. As such, the optimal strategy is to wiggle sideways a short distance, following the optimal leaning pattern for |IV| < 5 u/f. These vehicles share the same optimal slide inputs, as the leaning pattern is the same for both IDBs and ODBs; however, they all slide a slightly different amount, as wheel EV dissipation varies slightly by vehicle.[1] Dolphin Dasher slides the furthest (by a small amount).
- Medium-length bikes: Jet Bubble, Standard Bike M, Mach Bike, Sugarscoot, Zip Zip, Flame Runner. These bikes can gain a small amount of airtime (12-15 frames) by performing a double wheelie, but only while A is not held. (Holding A increases grip to the ground.) As such, these bikes perform one small double wheelie, then wiggle or perform single wheelies for the rest of the countdown. In theory, each bike should have its own unique optimal slide, but slides have only been made for Flame Runner,[2], Mach Bike,[3] and Zip Zip.[4]
- Long bikes: Sneakster, Wario Bike, Spear, Phantom. These bikes can go airborne at will by performing both single (12-15 frames), and double wheelies (20+ frames). For each bike, the optimal strategy is to perform one single wheelie to rotate and move a small amount, then two double wheelies to slide very far. An optimal strat slide has been made for each long bike. Spear slides the furthest,[5] followed by Sneakster,[6] Wario Bike,[7] and Phantom.[8]
On all bikes, performing a wheelie shortly before the end of the countdown causes the bike's pitch to quickly decrease during the start boost, due to the acceleration. With the right inputs during the slide, the bike can get airtime pockets during the boost, as late as during the boost deceleration. These airtime pockets can be used for a slipdrift, known as a start slip, or a slipchain.
Start curve
After performing a start slide, the optimal strategy is to turn in the same direction to realign, known as a start curve. Start curves actually save a few milliseconds over realigning and driving in a straight line, due to EV to IV conversion causing the bike to gain a small amount of extra speed. To optimize start curves, it is better to keep turning in the direction of the slide and delay the wheelie as much as possible, then turn in the opposite direction to realign, even if this leads to a suboptimal driving line. This ensures the increased IV due to EV conversion is preserved as long as possible during the acceleration.
On slippery road, EV to IV conversion works differently, allowing bikes to gain slightly more IV during the start curve. As such, there are different optimal start slides for regular and slippery road; for the latter, sacrificing a bit of distance for more rotation saves time during the start curve.[9] On slippery road only, the traction stat has a very small effect on the movement of start slides; it is the only character stat to affect start slides.