Opus Fortitude 105

Name: Opus Fortitude 105
Brand: Opus

2025 RoadEndurance Manufacturer page

Suspension: Rigid
Wheels: 700c
Drivetrain: 2 × 12 34–50t / 11–34t
Gear range: 455%
Weight: 9.4 kg 20.7 lb · Reference configuration not specified
Frame: Aluminum
Brakes: Hydraulic disc

Sizes

Size guide

The manufacturer did not publish rider heights for these sizes.

Components

18 of 20 identified

Parts found in a manufacturer catalog show their brand, model and key numbers, and the steps show how precisely they are identified: brand, series, model, or the exact product. The info button has every detail and the text the manufacturer published.

Frame and fork

1 part

Frame

Aluminum Not identified

Suspension

1 part

Fork

Full Carbon Tapered 1-1/2 to 1-1/8 in Not identified

Drivetrain

7 parts

Bottom bracket
- Shimano
Cassette
- Shimano 11–34t
Chain
- Shimano SLX CN-M7100
CN-M7100
Crankset
- Shimano 105 FC-R7100 12 speeds
FC-R7100
Front derailleur
- Shimano 105 FD-R7100 2 speeds
FD-R7100
Rear derailleur
- Shimano 105 RD-R7100 12 speeds
RD-R7100
Shifters
- Shimano 105

Brakes

2 parts

Brake levers
- Shimano
Brakes
- Shimano

Wheels and tires

4 parts

Cockpit and contact points

6 parts

Sizes and geometry

6 sizes Open in the geometry plotter

Complete rider-height ranges are not published for these sizes. You can still explore the geometry below.

Size SM

Table

Geometry diagram unavailable

The drawing needs wheelbase, which the manufacturer did not publish. Available facts remain in the table.

Size Reach Stack

Complete manufacturer geometry table 6 published sizes

Complete manufacturer geometry by size
Measurement
Frame
Reachmm	362	370	378	387	396	405
Stackmm	522	540	560	580	600	620
Top tube lengthmm	507	525	544	564	585	607
Seat tube lengthmm	440	480	520	540	560	580
Head tube lengthmm	100	120	138	157	178	199
Head tube angle	70.5°	71.25°	72°	72.5°	72.5°	73°
Seat tube angle	74.5°	74°	73.5°	73°	72.5°	72°
Chainstay lengthmm	416	416	419	419	422	422
Bottom bracket dropmm	79	76	76	76	76	74
Bottom bracket heightmm	257	260	260	260	260	262
Standover heightmm	709	736	772	790	810	830
Stack/reach ratio	1.44	1.46	1.48	1.50	1.52	1.53
Suspension and parts
Crank lengthmm	165	170	172.5	172.5	172.5	175
Handlebar widthmm	380	400	420	420	440	460
Stem lengthmm	70	80	90	100	110	120

Not published by the manufacturer: Wheelbase, Front center, Fork rake, Trail, Front travel, Rear travel, Stem angle, Seatpost length and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Aluminum
Fork material: Carbon
Bicycle weight: 9.4 kg

20.7 lb

Suspension

Suspension configuration: Rigid

Drivetrain

Derived by Bikelake

Front chainrings: 2
Smallest chainring: 34
Largest chainring: 50
Rear sprockets: 12
Smallest sprocket: 11
Largest sprocket: 34
Lowest gear: 29.0 in
Highest gear: 131.8 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Hydraulic disc

Fit and controls

Seatpost: Rigid seatpost
Shifting: Mechanical

Additional specifications

Tire clearance: Maximum tire width: 35c
Tire width: 32c
Wheel material: Aluminum
Wheel size: 700c

Technical analysis

3 measures

How these figures sit among bicycles of the same class and model year. Context, not a ranking.

Lowest gear

29.0 gear inches

This value is within the central range for this class.

Cohort: Road / Endurance Model year: 2025
Sample: 546 bicycles with this information
Coverage: 81.8% of the class

Highest gear

131.8 gear inches

This value is within the central range for this class.

Cohort: Road / Endurance Model year: 2025
Sample: 546 bicycles with this information
Coverage: 81.8% of the class

Shifting

Mechanical

356 of 663 bicycles with this information use electronic shifting.

Cohort: Road / Endurance Model year: 2025
Sample: 663 bicycles with this information
Coverage: 99.4% of the class

Gearing

Estimated speeds at 80 rpm

Lowest gear: 11.1 km/h
Highest gear: 50.5 km/h

Total gear range 455%

Technical details and class reference

These speeds describe the gearing at the selected cadence, not how fast you can ride.
Calculated from published gear-inch values and their wheel-size assumptions.
These gearing values describe the bicycle, not a selected frame size.
A 100% range means one ratio; 500% means the highest ratio is five times the lowest.
For e-bikes, motor assistance cutoff is not represented.

Gear-inch range

Lower gear-inch values travel less distance per pedal revolution; higher values travel farther.

This bicycle: 29.0–131.8 gear inches
Class reference (p10–p90): 26.6–139.2 gear inches; The band runs from p10 for the lowest gear to p90 for the highest gear.

Cohort: Road / Endurance Model year: 2025
Lowest gear: 546 bicycles with this information, 81.8% of the class
Highest gear: 546 bicycles with this information, 81.8% of the class

Lineup changes

The published facts that differ across this family's builds and from the same model a year earlier. Missing information never counts as zero.

Differences across 2025 builds

Differences across 2025 builds
Specification	This bicycle Opus Fortitude 105	Opus Fortitude Claris	Opus Fortitude FB Tiagra	Opus Fortitude Tiagra
Frame
Fork material	Carbon	Aluminum	Carbon	Carbon
Bicycle weight	9.4 kg	9.7 kg	Not informed	9.5 kg
Drivetrain
Smallest chainring	34	32	30	34
Largest chainring	50	48	46	50
Rear sprockets	12	8	10	10
Largest sprocket	34	32	32	34
Lowest gear	29.0 in	29.0 in	27.2 in	29.0 in
Highest gear	131.8 in	126.6 in	121.3 in	131.8 in
Brakes
Brake type	Hydraulic disc	Rim brake	Hydraulic disc	Hydraulic disc
Other specifications
Tire clearance	Maximum tire width: 35c	Not informed	Maximum tire width: 35c	Maximum tire width: 35c
Tire width	32c	28c	35c	32c