Jamis DXT A3 Step-Over Frame

2025 UrbanFitness Manufacturer page

Last known price: $679

Prices shown first for United States
Fork travel: 75 mm
Wheels: 700c
Drivetrain: 3 × 7 28–48t / 12–32t
Gear range: 457%
Weight: 14.4 kg 31.7 lb · Reference configuration not specified
Frame: Aluminum
Brakes: Mechanical disc

Sizes

Size guide

The manufacturer did not publish rider heights for these sizes.

Components

14 of 19 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

Size Specific Design 6061 aluminum with fast back rear triangle, 1 1/8” head tube, internal cable routing, chain stays disc brake mounts, 34.9mm seat tube, kickstand mount, replaceable derailleur hanger, fender/rack eyelets and ring lock mount eyelets. Not identified

Suspension

1 part

Fork
- SR Suntour

Drivetrain

7 parts

Bottom bracket
- VP
Cassette
- Shimano CS-HG200 12–32t
CS-HG200
Chain
- KMC Z7 7 speeds
Crankset

Forged alloy crank with chain guard, 48/38/28T, 170mm Not identified
Front derailleur
- Shimano Tourney FD-TY510
FD-TY510
Rear derailleur
- Shimano Tourney RD-TY300 7 speeds
RD-TY300
Shifters
- Shimano
SL-EF500

Brakes

1 part

Brakes
- Tektro
MD-280

Wheels and tires

2 parts

Cockpit and contact points

7 parts

Grips

ERGO Type Grip Not identified
Handlebar
- Jamis
Headset

Internal Cup, threadless, 1 1/8” Not identified
Pedals

Platform style Not identified
Saddle
- Jamis
Seatpost
- Jamis
Stem
- Jamis

Sizes and geometry

3 sizes Open in the geometry plotter

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

Size 18"

Table

Reach 380mm

Stack 640mm

Wheelbase 1057mm

Head angle 70.5°

Seat angle 74.0°

Every size is drawn to the same scale, in millimeters. Explanatory schematic on an assumed 700c wheel; exact published values are in the table below.

Size Reach Stack

Complete manufacturer geometry table 3 published sizes

Complete manufacturer geometry by size
Measurement
Reachmm	376	380	384
Stackmm	632	640	648
Top tube lengthmm	557	557	570
Seat tube lengthmm	356	457	508
Head tube lengthmm	125	131	135
Head tube angle	70°	70.5°	71.5°
Seat tube angle	73.5°	74°	73.5°
Chainstay lengthmm	440	440	440
Wheelbasemm	1057	1057	1053
Front centermm	624	624	620
Bottom bracket dropmm	60	60	60
Standover heightmm	641	664	662
Fork rakemm	40	40	40
Trailmm	90	88	81
Stack/reach ratio	1.68	1.68	1.69

Not published by the manufacturer: Bottom bracket 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: womens
Frame material: Aluminum
Fork material: Aluminum
Bicycle weight: 14.4 kg

31.7 lb

Suspension

Suspension configuration: Hardtail
Front travel: 75 mm

Drivetrain

Derived by Bikelake

Front chainrings: 3
Smallest chainring: 28
Largest chainring: 48
Rear sprockets: 7
Smallest sprocket: 12
Largest sprocket: 32
Lowest gear: 25.4 in
Highest gear: 116.0 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Mechanical disc

Fit and controls

Seatpost: Rigid seatpost
Shifting: Mechanical

Additional specifications

Fork spring: Coil
Tire width: 42c
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

25.4 gear inches

This value is within the central range for this class.

Cohort: Urban / Fitness Model year: 2025
Sample: 230 bicycles with this information
Coverage: 81.8% of the class

Highest gear

116.0 gear inches

This value is within the central range for this class.

Cohort: Urban / Fitness Model year: 2025
Sample: 230 bicycles with this information
Coverage: 81.8% of the class

Shifting

Mechanical

13 of 281 bicycles with this information use electronic shifting.

Cohort: Urban / Fitness Model year: 2025
Sample: 281 bicycles with this information
Coverage: 100.0% of the class

Gearing

Estimated speeds at 80 rpm

Lowest gear: 9.7 km/h
Highest gear: 44.4 km/h

Total gear range 457%

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: 25.4–116.0 gear inches
Class reference (p10–p90): 21.8–131.8 gear inches; The band runs from p10 for the lowest gear to p90 for the highest gear.

Cohort: Urban / Fitness Model year: 2025
Lowest gear: 230 bicycles with this information, 81.8% of the class
Highest gear: 230 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
Specification	This bicycle Jamis DXT A3 Step-Over Frame	Jamis DXT A1	Jamis DXT A1 Step-Over Frame	Jamis DXT A2	Jamis DXT A2 Step-Over Frame	Jamis DXT A3
Frame
Intended fit	womens	Unisex	womens	Unisex	womens	Unisex
Bicycle weight	14.4 kg	13.61 kg	13.49 kg	14.17 kg	14.06 kg	14.51 kg
Drivetrain
Front chainrings	3	1	1	2	2	3
Smallest chainring	28	32	32	30	30	28
Largest chainring	48	32	32	46	46	48
Rear sprockets	7	9	9	8	8	7
Smallest sprocket	12	11	11	11	11	12
Largest sprocket	32	42	42	34	34	32
Lowest gear	25.4 in	22.1 in	22.1 in	25.6 in	25.6 in	25.4 in
Highest gear	116.0 in	84.4 in	84.4 in	121.3 in	121.3 in	116.0 in
Brakes
Brake type	Mechanical disc	Hydraulic disc	Hydraulic disc	Hydraulic disc	Hydraulic disc	Mechanical disc