Your board has side bite boxes. You have side bites in a drawer somewhere. The question everyone asks and nobody answers clearly: should you put them in?
Here's the actual answer.
What Side Bites Do
A single fin generates all its hold and drive from one point. When you turn, you load the fin, it flexes, and releases. The whole board pivots around that one fin.
Side bites add two more contact points near the rails. When you put the board on rail, the side bite on that side engages the water and pushes back. More hold. More drive through the turn. Less slide.
That's it. They're not magic. They add grip when the board is on rail.
What They Don't Do
They don't make your board faster. They add drag—two more fins in the water is two more sources of resistance. On a clean, open face where you're trimming, side bites slow you down.
They don't make your board easier to turn. They do the opposite. More fins gripping the water means more resistance to direction changes. Your board becomes stiffer through transitions.
They don't fix a bad fin setup. If your center fin is wrong for your board, adding side bites just adds more wrong.
When to Put Them In
Your wave is steep and you're losing hold. This is the original reason side bites exist. When the wave gets steep, a single fin can lose grip—the tail slides, you lose your line, you eat it on the drop. Side bites give you rail-to-rail stability in steeper surf. If you're surfing overhead waves on a mid-length and the tail keeps washing out on your bottom turn, try side bites before you try a bigger center fin.
You want to surf your longboard more aggressively. If you're doing performance longboarding—real turns off the tail, not just trimming and noserides—a 2+1 setup lets you push harder into turns without the tail releasing. The side bites catch you when you'd otherwise slide out. This is why every competitive longboarder runs a 2+1.
Your board was designed for it. Some boards are shaped specifically for a 2+1 setup: more rocker, harder rails at the tail, concave through the bottom. The shaper built the board expecting three fins to be in the water. Running it as a single fin will feel loose and underpowered because the board's outline was designed to work with side bites.
When to Leave Them Out
You're noseriding. Side bites add drag at the tail, which changes the balance point of the board. For dedicated noseriding on a classic log, a single fin keeps the tail clean and lets you walk to the nose without fighting extra resistance behind you. The whole point of a good noserider single fin (big pivot fin, lots of area) is that it holds the tail down so the nose lifts. Side bites mess with that equation.
You're on a classic log or hull. These boards are designed around the single fin. The smooth, flowing, drawn-out turn of a log comes from loading one fin and releasing. Adding side bites stiffens the turn, shortens the arc, and kills the glide. A hull is even more specific—the bottom contour channels water into the center fin. Side bites disrupt that flow.
You want speed on a clean face. If you're surfing small, clean waves and the goal is trim speed and flow, every extra fin is drag you don't need. One fin, less resistance, more glide. This is physics, not opinion.
You can't feel the difference. This is the honest one. If you've been surfing with and without side bites and you genuinely can't tell, leave them out. Less drag, simpler setup, nothing to lose. The people who benefit from side bites know immediately because the hold difference is obvious. If it's not obvious, you don't need them.
The 2+1 Setup: Getting the Sizes Right
This is where most people get it wrong. You can't just throw your 9" single fin in the center box and add side bites. That's too much total fin area—the board will track like a train and refuse to turn.
The rule: when you add side bites, drop your center fin.
If you ride a 9" single fin on your 9' board, drop to a 7"–7.5" center fin when you add side bites. The side bites (usually 3"–4") make up the difference in total area, but redistribute it to the rails.
True Ames has a straightforward sizing approach:
For a 9' board as a single fin, you'd typically ride a 9" fin—something like the Greenough 4A in 9". Switch to a 2+1 and you drop to a 7"–7.5" center fin paired with 3.7" side bites or 3.25" side bites.
For an 8' board as a single fin, you'd ride 7.5"–8" center. In a 2+1, drop to 6"–6.5" center with 3.25" or 2.6" side bites.
The center fin template matters too. A cutaway fin (narrow base, less area) is designed to work as a 2+1 center. A big pivot fin is designed to work alone. Don't put a 7" pivot fin in a 2+1—the base is too wide relative to the side bites and the board will fight itself.
Side Bite Sizing
We carry True Ames side bites from 2.6" up through 4.35" in both FCS and Futures. Here's how to think about sizing:
Small (2.6"–3.25"): Subtle addition. Adds hold without dramatically changing the single fin character. Good for mid-lengths and boards where you want just a bit more grip on rail. The 2.6" is barely there—a safety net for single fin purists. The 3.25" is the sweet spot for most mid-length 2+1 setups.
Medium (3.7"): The most popular size for longboard 2+1 setups. The 3.7" side bites add meaningful hold and drive without overpowering the center fin. This is where most people should start.
Large (4.0"–4.35"): Aggressive hold. The 4.0" and 4.35" turn your board into a performance 2+1 that starts to feel thruster-adjacent. Good for bigger logs in steeper waves where you want maximum rail grip. The CI-template side bites (3.6" CI and 4.0" CI) have a slightly different foil that some riders prefer for performance longboarding.
Specialty Side Bites
Beyond the standard True Ames sizes, we stock shaper-specific side bite templates that pair with particular boards and surfing styles:
The Brothers Marshall side bites and Skip Frye side bites are designed for specific board families—if you're riding one of those shapers' boards, these are the intended match.
Wayne Rich side bites come in 3.4" and 4.0" and are built for aggressive performance 2+1 riding. The Wild Things Fitz side bites come in 3.66" and 4.33".
Fin Cluster Spacing
If your board has adjustable side bite placement (most FCS and Futures boxes are fixed, but some are adjustable), the distance between the side bites and center fin changes the feel:
Closer together: Faster turns, more responsive, board pivots quicker. Feels more like a shortboard thruster. Good for performance longboarding.
Further apart: More stability, wider turning arc, board holds its line better. Feels more like a single fin with training wheels. Good for bigger surf where you want hold without twitchiness.
Box position of center fin: Same rules as a single fin. Forward = looser, back = more hold. With side bites in, you can usually push the center fin a little further forward than you would as a single, because the side bites provide the hold you're giving up.
Nubsters, Canards, and Other Small Weird Fins
Nubsters (also called guitar picks or 5th fins): Tiny center trailer fins used behind a quad or twin setup. About 1"–1.5" tall. They add a pivot point and prevent the tail from sliding on steeper waves. If you're riding a twin or quad and it feels too loose or skatey in bigger surf, a nubster tightens it up without turning it into a thruster. Kelly Slater made these famous. They're subtle—don't expect a dramatic change.
Canards: Small front fins used in a Twinzer setup. They sit forward of and outside the main twin fins, close to the rail. They break the water tension before it hits the main fins, creating lift and reducing drag. We carry canards from Lovelace, Lovelace FM, Derrick Disney RDM, Derrick Disney DST, Mandala, Pavel, True Ames, and Valaric. A Twinzer (canards + twins) feels like a twin with more bite and control—somewhere between a twin and a quad. These are specific to Twinzer boards. Don't just stick canards in random boxes hoping for improvement.
Bonzer side fins: Half-moon shaped fins with heavy cant, set close to the center fin on either side. These are part of the Bonzer system designed by the Campbell brothers. They channel water into the center fin, increasing its effectiveness. The Campbell Brothers Alpha Omega twin set works with the Bonzer system. A Bonzer surfs like a single fin with thruster-level drive. You need a Bonzer bottom (double concave channels) for these to work. They're not interchangeable with regular side bites. We also carry the 2.37" Bonzer side bites and 2.75" Bonzer side bites for proper Bonzer setups.
The Call
Put in the side bites if: steep waves, performance longboarding, your board was shaped for 2+1, you want more hold and drive and are willing to trade speed and flow.
Leave them in the drawer if: you're noseriding, riding a classic log or hull, surfing clean small waves, or you honestly can't feel the difference.
If you're not sure: try them for a few sessions, then take them out. The difference is immediate. You'll know which you prefer within one wave.
We stock side bites from True Ames in multiple sizes and templates. Come by the shop and we'll match them to your center fin and board.