The main triangle is dead space on most bikes, and it's the ideal place to carry heavy, dense items: a U-lock, your tool kit, a spare charger. Because the weight sits low and centered, a loaded frame bag barely changes how the bike handles — unlike a heavy basket or rear load.
Full-frame bags maximize space but may crowd a bottle cage; half-frame and top-tube 'bolt-on' bags leave room for bottles and are easier to fit around a downtube battery. Measure your triangle (many e-bike downtubes are fat) and check whether your bag straps on or bolts to cage mounts.
Where to buy
Two paths — match your spend to the bike. Quality picks last longer and protect resale; affordable picks get you riding safely today.
Quality picks
Affordable picks
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Pro tips from our test team
- Carry your heaviest items here — low, centered weight handles best.
- A fat e-bike downtube can shrink the triangle; measure before buying.
- Keep straps clear of your knee path so they don't rub while you pedal.
