Playbooks · The bike flip · updated September 19, 2026
Trek FX 3
The FX 3 is the fitness hybrid every bike shop sells and every commuter buys: carbon fork, hydraulic disc brakes since 2020, sizes for everyone. It is the used bike that sells within a week in spring and sits in November. Sizes and model years decide the price; stolen units are the risk.
This week in Salt Lake City · from the desk, not a writer
The ceiling is for exactly this: Trek FX 3, as listed. Priced the way the app prices a target you add yourself: from eBay comps (17) on Sep 19; sells-for is 90% of the eBay median, the ceiling leaves 25–30% after you sell. eBay fees 13.6% + $0.40 + ~$20 shipping.
Is it the right one?
- Model name on the down tube; the serial stamped under the bottom bracket (WTU…). Model year from the serial and the paint scheme (Trek's archive site lists them).
- FX 3 Disc (2020+): hydraulic disc brakes, 1×/2× Shimano drivetrain, carbon fork. Older FX 3 has rim brakes and prices lower.
- Frame size is on a sticker on the seat tube or measured (S 15", M 17.5", L 20", XL 22.5"). The ceiling is for the size you entered; a size that does not fit your buyers sits.
Before you drive
- Ask for the serial (stamped under the bottom bracket) and check it on Bike Index and the local police stolen-bike registry before you drive. Ask the frame size and the model year.
- Frame first: sight along the top tube and down tube for dents, ripples behind the head tube (a crash), cracks at every weld; on carbon, tap around the frame with a coin and listen for dull spots.
- Drivetrain on a stand or lifted: shift through every gear both ways, chain stretch with the checker, cassette teeth not hooked; brakes bite with a firm lever; wheels spin true; headset no knock; bottom bracket no play.
- Ride it around the block. Pay after.
Bring
- A tape measure (frame size matters more than the seller thinks)
- A chain checker ($10) and a multitool
- A pump
- Cash
What to check in person
- Serial on Bike Index and the local stolen registry before you drive; no serial photo, no deal.
- Frame: ripples behind the head tube (a crash), cracks at the welds, a bent derailleur hanger; the carbon fork tapped with a coin for dull spots.
- Drivetrain: every gear both ways on a stand, chain stretch under 0.75%, cassette teeth not hooked, brake pads with life, rotors true, levers firm.
- Wheels true and hubs quiet; tires not cracked; headset and bottom bracket without play.
- Ride it around the block: shifting under load, brakes, no creaks.
- Included: pedals (often removed), rack, fenders, lights add $20–60.
The desk's own checklist for this unit
- Serial number under the bottom bracket: run it on Bike Index for stolen reports; no serial or a ground-off one is a walk.
- Frame: sight down the top tube for cracks at the welds and the head tube; carbon frames need a coin-tap test for delamination.
- Drivetrain: shift through every gear on a stand; chain stretch with a checker; worn cassette teeth look like shark fins.
- Wheels true, hubs quiet, brakes bite (hydraulic levers firm, no sponge); tyres not cracked.
- Match the model year and groupset to the listing; the ceiling is for the spec as sold.
- Ceiling comes from current eBay asks, not sold prices. Treat it as a starting point and tighten it with your own sales.
What goes wrong
- Stolen
- The most common problem in used bikes. No serial photo, ground-off serial, a $2,000 bike for $300, "my brother's bike", meeting at night: walk. Registries exist for a reason; use them.
- Crashed frame
- A ripple or a paint crack behind the head tube, a bent derailleur hanger, a fork that does not match. Frames do not come back from that.
- Wrong size, wrong year
- A 54 cm and a 58 cm are different bikes for different buyers; the model year decides the groupset. The seller often does not know; you have to.
- E-bike batteries
- A dead or swollen battery is $400–800. Ask for the charge cycle count in the app or a video of it charging to full and holding.
The message
What the app writes for you, one tap, never above the ceiling. If the ask is under $415 you meet the ask; if it's over, you offer the ceiling.
Hi! Is the Trek FX still available? I can pick up today with cash near Salt Lake City. Would you take $415?
Then, before you drive: "Could you send a quick video of it powering on and working? Then I'll head straight over with cash."
Where it sells
- Local cash is the whole market: bikes do not ship well. Photograph it clean, drive side, in daylight, with the size and the groupset in the title ("Trek FX 3 · size L · 2022 · Shimano Acera").
- A $30 tune (cables, lube, true the wheels) returns $100. New tires on a road bike return their cost.
- Spring sells; November does not. Buy in the fall, sell in April.
"Trek FX 3 Disc · 2021 · size L · fresh tune" with a drive-side photo in daylight. List it the first warm week of spring.
Why this one
The widest buyer pool of any bike, a price that holds, and sellers who list in the fall when demand is gone. Buy in October, sell in April.
In the app