2026 Dartmoor Bikes Thunderbird FR Pro Gx

	Small	Medium	Large
Stack	652mm	652mm	652mm
Reach	445mm	470mm	490mm
Stack to Reach Ratio	1.47:1	1.39:1	1.33:1
Seat Tube Length, C-T	410mm	430mm	450mm
Top Tube Length, Effective/Horizontal HT Top	545mm	570mm	590mm
Head Tube Angle	63.5deg	63.5deg	63.5deg
Effective Seat Tube Angle, ETT HT Top	81deg	81deg	81deg
Head Tube Length	110mm	110mm	110mm
Bottom Bracket Drop	34mm	34mm	34mm
Bottom Bracket Height	321mm	321mm	321mm
Chainstay Length	430mm	430mm	430mm
Chainstay Length Horizontal	428.7mm	428.7mm	428.7mm
Front-Center	809.1mm	834mm	854mm
Front-Center Horizontal	808.4mm	833.4mm	853.4mm
Wheelbase	1237mm	1262mm	1282mm
Fork Offset/Rake	44mm	44mm	44mm
Fork Length (Axle-To-Crown)	606mm	606mm	606mm
Trail	127.8mm very high	127.8mm very high	127.8mm very high
Mechanical Trail	114.4mm	114.4mm	114.4mm
Wheel Flop	51.1mm	51.1mm	51.1mm
Standover Height	795mm	795mm	795mm
Tire to Pedal Spindle	284.1mm 170 mm cranks	309mm 170 mm cranks	329mm 170 mm cranks
Pedal Spindle to Ground Clearance	151mm 170 mm cranks	151mm 170 mm cranks	151mm 170 mm cranks

Very Upright

Somewhat Upright

Average

Somewhat Aggressive

Very Aggressive

The Bike Insights Upright/Aggressive scale is based on analysis of a bike’s proportions relative to similar sized bikes in the same category.

Category Trend

Source:https://dartmoor-bikes.com/hardware/freeridejib/thunderbird-fr-pro-gx

Geometry