Author Impulse 27.5

2023 MountainCross-country Manufacturer page

Fork travel: 100 mm
Wheels: 27.5″
Drivetrain: 3 × 8 24–42t / 12–32t
Gear range: 467%
Weight: 14.2 kg 31.3 lb · Reference configuration not specified
Frame: Aluminum
Brakes: Hydraulic disc

Rider height by size (cm)

Size guide

15" 145–158
17" 155–172
19" 170–185

Components

15 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

alloy 6061 27.5" Not identified

Suspension

1 part

Fork
- RST

Drivetrain

6 parts

Cassette
- Shimano CS-HG200-8 8 speeds
CS-HG200
Chain
- KMC Z8.3 8 speeds
Crankset
- Prowheel
Front derailleur
- Shimano Tourney FD-TY700
FD-TY700
Rear derailleur
- Shimano Altus
Shifters
- Shimano Altus

Brakes

1 part

Brakes
- Tektro HD-M275 / HD-M276
HD-M275HD-M276

Wheels and tires

5 parts

Front hub

QUANDO Disc, 32 holes Not identified
Rear hub

QUANDO Disc, 32 holes Not identified
Rims
- Author
Spokes

black steel Not identified
Tires
- Author

Cockpit and contact points

6 parts

Grips
- Author
Handlebar
- Author
Pedals

resin Not identified
Saddle
- Author
Seatpost
- Author
Stem
- Author

Sizes and geometry

3 sizes Open in the geometry plotter

Enter your height to highlight matching ranges.

Size 17"

Table

Reach 378mm

Stack 602mm

Wheelbase 1076mm

Head angle 69.0°

Seat angle 73.0°

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 3 published sizes

Complete manufacturer geometry by size
Measurement
Reachmm	358	378	401
Stackmm	593	602	607
Top tube lengthmm	570	590	615
Seat tube lengthmm	381	432	483
Head tube lengthmm	115	125	130
Head tube angle	69°	69°	69°
Seat tube angle	73°	73°	73°
Chainstay lengthmm	435	435	435
Wheelbasemm	1050	1076	1101
Front centermm	617	643	668
Bottom bracket dropmm	35	35	35
Bottom bracket heightmm	320	320	320
Fork rakemm	44	44	44
Trailmm	93	89	89
Stack/reach ratio	1.66	1.59	1.51

Not published by the manufacturer: Standover height, Front travel, Rear travel, Crank length, Handlebar width, Stem length, Stem angle, Seatpost length and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Aluminum
Bicycle weight: 14.2 kg

31.3 lb

Suspension

Suspension configuration: Hardtail
Front travel: 100 mm

Drivetrain

Derived by Bikelake

Front chainrings: 3
Smallest chainring: 24
Largest chainring: 42
Rear sprockets: 8
Smallest sprocket: 12
Largest sprocket: 32
Lowest gear: 20.6 in
Highest gear: 96.3 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Hydraulic disc

Fit and controls

Seatpost: Rigid seatpost
Shifting: Mechanical

Additional specifications

Fork spring: Coil
Tire width: 2.1″
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

100 mm

This value is within the central range for this class.

Cohort: Mountain / Cross-country Model year: 2023
Sample: 1,907 bicycles with this information
Coverage: 95.2% of the class

Lowest gear

20.6 gear inches

This value is above the central range for this class.

Cohort: Mountain / Cross-country Model year: 2023
Sample: 1,578 bicycles with this information
Coverage: 78.8% of the class

Highest gear

96.3 gear inches

This value is within the central range for this class.

Cohort: Mountain / Cross-country Model year: 2023
Sample: 1,578 bicycles with this information
Coverage: 78.8% of the class

Shifting

Mechanical

223 of 2,002 bicycles with this information use electronic shifting.

Cohort: Mountain / Cross-country Model year: 2023
Sample: 2,002 bicycles with this information
Coverage: 100.0% of the class

Gearing

Estimated speeds at 80 rpm

Lowest gear: 7.9 km/h
Highest gear: 36.9 km/h

Total gear range 467%

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: 20.6–96.3 gear inches
Class reference (p10–p90): 17.7–101.5 gear inches; The band runs from p10 for the lowest gear to p90 for the highest gear.

Cohort: Mountain / Cross-country Model year: 2023
Lowest gear: 1578 bicycles with this information, 78.8% of the class
Highest gear: 1578 bicycles with this information, 78.8% 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 2023 builds
Specification	This bicycle Author Impulse 27.5	Author Impulse 27.5 ASL	Author Impulse 29	Author Impulse 29 ASL
Frame
Bicycle weight	14.2 kg	13.9 kg	14.9 kg	14.6 kg
Drivetrain
Smallest chainring	24	24	24	22
Largest chainring	42	42	42	40
Lowest gear	20.6 in	20.6 in	21.8 in	19.9 in
Highest gear	96.3 in	96.3 in	101.5 in	96.7 in
Other specifications
Tire width	2.1″	2″	2.1″	2″
Wheel size	27.5″	27.5″	29″	29″