Inspection
Frame condition
Inspect the frame, fork, welds, and high-stress areas for cracks, dents, or prior repairs.
Diamondback
2021 Diamondback Union 2
Value Guide market data · 2021 Diamondback Union 2
12-month trend
13%
Direction and magnitude, not judgment
vs. category average
— %
No category comparison available
Price over time - 2021 Diamondback Union 2
Values based on actual sales data. Enter your bike's specifics to get a precise valuation.
All Union model years
2021 Union 2 lineup
Overview
About this bike
2021 Diamondback Union 2 value depends on condition, original build, frame material, service history, and current buyer demand.
Specifications
Drivetrain
- Groupset
- 2021 Diamondback Union 2
- Shifters
- Shimano Deore SL-M6000, 10 Speed
Brakes
- Brake Levers
- Shimano MT420, 2 Finger Lever
- Brakes
- Shimano MT420, 4 Piston Front 180mm Rotor, 2 Piston Rear 160mm Rotor
Cockpit
- Tape/Grips
- Ergo Comfort Control
Wheels & Tires
- Hubs
- Front: Formula, Sealed Bearing, Thru Axle<br>Rear: Formula, Sealed Bearing, Thru Axle
- Rims
- Aluminum 27.5", Black Anodized, 25mm ID, Disc Specific, 32 Hole
Pedals
- Pedals
- Shoe Friendly Urban Design, Resin Body
Accessories
- Accessories & Extras
- Aluminum Structural Extrusion Fenders with Integrated Rear Rack, Lezyne Headlight & Taillight, Rear Mounted Kickstand
Frame sizing
XS4'10"-5'2"
S5'2"-5'6"
M5'6"-5'10"
L5'10"-6'2"
XL6'2"-6'6"
M highlighted as most common resale size. Sourced from catalog metadata.
Geometry
- Stack
- Varies by size
- Reach
- Varies by size
- Wheelbase
- Varies by size
Industry standard. Sourced from catalog metadata.
What to check when buying used
Inspection
Drivetrain wear
Check chain stretch, cassette teeth, chainrings, and shifting under load before negotiating price.
Inspection
Wheel condition
Inspect rims, hubs, spokes, and bearing play; ask about the tire age and any prior wheel rebuilds.
Inspection
Service history
Ask for service records covering bearings, brakes, drivetrain, and any frame or fork warranty work.
Inspection
Battery health
Request battery cycle count and any diagnostic report; older packs lose range and capacity.
Inspection
Motor warranty
Verify motor warranty status and any firmware updates from the manufacturer dealer.