Specialized Stumpjumper ST Alloy 27.5

Name: Specialized Stumpjumper ST Alloy 27.5
Brand: Specialized

2020 MountainTrail Manufacturer page

Last known price: $2,010

Prices shown first for United States
Travel: 130 / 130 mm Fork / rear shock
Wheels: 27.5″
Drivetrain: 1 × 12 32t / 11–50t
Gear range: 455%
Frame: Aluminum
Brakes: Hydraulic disc

Rider height by size (cm)

Size guide

XS 156–166
SM 163–174
MD 171–182
LG 179–189
XL 185–195

Components

14 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

M5 alloy chassis and rear end, asymmetrical design, 27.5 Trail Geometry, threaded BB, fully enclosed internal cable routing, 12x148mm dropouts, sealed cartridge bearing pivots, replaceable derailleur hanger, 130mm of travel Not identified

Suspension

2 parts

Drivetrain

6 parts

Brakes

1 part

Brakes
- Tektro Gemini

Wheels and tires

5 parts

Front hub
- Specialized
Rear hub
- Specialized
Rims

Double-wall alloy, 27mm internal width Not identified
Spokes

Stainless, 14g Not identified
Tires

Front: Purgatory, GRID casing, GRIPTON® compound, 2Bliss Ready, 27.5 x 2.3", Rear: Purgatory, GRID casing, GRIPTON® compound, 2Bliss Ready, 27.5 x 2.3" Not identified

Cockpit and contact points

5 parts

Grips
- Specialized
Handlebar
- Specialized
Saddle

Body Geometry Myth:155 XS/S, Body Geometry Henge:143 M/L/XL, steel rails Not identified
Seatpost

TransX dropper, 34.9mm, XS: 100mm, S: 125mm, ML/XL: 150mm Travel Not identified
Stem
- Specialized

Sizes and geometry

5 sizes Open in the geometry plotter

Enter your height to highlight matching ranges.

Size MD

Table

Reach 435mm

Stack 596mm

Wheelbase 1179mm

Head angle 65.5°

Seat angle 75.0°

Every size is drawn to the same scale, in millimeters. Explanatory schematic on an assumed 27.5″ wheel; exact published values are in the table below.

Size Reported by the manufacturer

Complete manufacturer geometry table 5 published sizes

Complete manufacturer geometry by size
Measurement
Frame
Reachmm	405	415	435	455	480
Stackmm	581	592	596	623	637
Top tube lengthmm	544	570	595	627	660
Seat tube lengthmm	380	380	410	455	505
Head tube lengthmm	100	105	110	140	155
Head tube angle	66.5°	65.5°	65.5°	65.5°	65.5°
Seat tube angle	76.5°	75.3°	75°	74.6°	74.2°
Chainstay lengthmm	432	432	432	432	432
Wheelbasemm	1127	1157	1179	1212	1243
Front centermm	696	726	748	780	812
Bottom bracket dropmm	28	21	21	21	21
Bottom bracket heightmm	325	336	336	336	336
Standover heightmm	742	752	757	769	770
Fork rakemm	46	46	46	46	46
Trailmm	103	112	112	112	112
Stack/reach ratio	1.44	1.43	1.37	1.37	1.33
Suspension and parts
Crank lengthmm	170	170	170	170	170
Handlebar widthmm	780	780	780	780	780
Stem lengthmm	50	50	50	50	50
Seatpost lengthmm	356	406	456	456	456

Not published by the manufacturer: Front travel, Rear travel, Stem angle and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Aluminum

Suspension

Suspension configuration: Full suspension
Front travel: 130 mm
Rear travel: 130 mm

Drivetrain

Derived by Bikelake

Front chainrings: 1
Smallest chainring: 32
Largest chainring: 32
Rear sprockets: 12
Smallest sprocket: 11
Largest sprocket: 50
Lowest gear: 17.6 in
Highest gear: 80.0 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Hydraulic disc

Fit and controls

Seatpost: Dropper seatpost
Shifting: Mechanical

Additional specifications

Bottom bracket standard: BSA
Tire width: 2.3″
Wheel material: Aluminum
Wheel size: 27.5″

Technical analysis

4 measures

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

Front travel

130 mm

This value is within the central range for this class.

Cohort: Mountain / Trail Model year: 2020
Sample: 1,339 bicycles with this information
Coverage: 93.7% of the class

Lowest gear

17.6 gear inches

This value is within the central range for this class.

Cohort: Mountain / Trail Model year: 2020
Sample: 1,217 bicycles with this information
Coverage: 85.2% of the class

Highest gear

80.0 gear inches

This value is below the central range for this class.

Cohort: Mountain / Trail Model year: 2020
Sample: 1,217 bicycles with this information
Coverage: 85.2% of the class

Shifting

Mechanical

55 of 1,428 bicycles with this information use electronic shifting.

Cohort: Mountain / Trail Model year: 2020
Sample: 1,428 bicycles with this information
Coverage: 100.0% of the class

Gearing

Estimated speeds at 80 rpm

Lowest gear: 6.7 km/h
Highest gear: 30.6 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: 17.6–80.0 gear inches
Class reference (p10–p90): 17.1–98.6 gear inches; The band runs from p10 for the lowest gear to p90 for the highest gear.

Cohort: Mountain / Trail Model year: 2020
Lowest gear: 1217 bicycles with this information, 85.2% of the class
Highest gear: 1217 bicycles with this information, 85.2% 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 2020 builds

Differences across 2020 builds
Specification	This bicycle Specialized Stumpjumper ST Alloy 27.5	Specialized Men's Stumpjumper Comp Alloy 27.5 12-speed	Specialized Men's Stumpjumper Comp Alloy 29 12-speed	Specialized Men's Stumpjumper Comp Carbon 27.5 12-speed	Specialized Men's Stumpjumper Comp Carbon 29 12-speed	Specialized Men's Stumpjumper Pro 29
Frame
Frame material	Aluminum	Aluminum	Aluminum	Carbon	Carbon	Carbon
Fork material	Not informed	Aluminum	Aluminum	Aluminum	Aluminum	Not informed
Suspension
Front travel	130 mm	150 mm	150 mm	150 mm	150 mm	150 mm
Rear travel	130 mm	150 mm	140 mm	150 mm	140 mm	140 mm
Drivetrain
Smallest chainring	32	32	30	32	30	30
Largest chainring	32	32	30	32	30	30
Smallest sprocket	11	11	11	11	11	10
Lowest gear	17.6 in	17.6 in	17.4 in	18.6 in	17.4 in	17.4 in
Highest gear	80.0 in	80.0 in	79.1 in	84.4 in	79.1 in	87.0 in
Other specifications
Tire width	2.3″	2.6″	2.6″	2.6″	2.6″	2.6″
Wheel material	Aluminum	Aluminum	Aluminum	Aluminum	Aluminum	Carbon
Wheel size	27.5″	27.5″	29″	29″	29″	29″
Fork spring	Not informed	Air	Air	Air	Air	Air