2023 CHIRU Alpin Base

Design
Drop Bar, Rigid, suspension corrected
Frame
Titanium
Fork
Titanium
Features
Disc brake
Average stack and reachvs category
Somewhat aggressive stack and reachvs category
Somewhat aggressive stack and reachvs category

Geometry

S
M
L
Stack
576mm
587mm
615mm
Reach
401mm
431mm
443.8mm
Stack to Reach Ratio
1.44:1
1.36:1
1.39:1
Seat Tube Length, C-T
420mm
450mm
475mm
Top Tube Length, Effective/Horizontal Center
545mm
575mm
600mm
Top Tube Slope
18.5deg
15.6deg
15.4deg
Head Tube Angle
67.7deg
68deg
68.3deg
Seat Tube Angle
74.5deg
74.5deg
74.1deg
Head Tube Length
135mm
150mm
180mm
Bottom Bracket Drop
74mm
70mm
68mm
Bottom Bracket Height
287mm
291mm
293mm
Chainstay Length
428mm
430mm
435mm
Chainstay Length Horizontal
421.6mm
424.3mm
429.7mm
Front-Center
668.6mm
697.3mm
718.6mm
Front-Center Horizontal
664.5mm
693.7mm
715.4mm
Wheelbase
1086mm
1118mm
1145mm
Fork Offset/Rake
50mm
50mm
50mm
Fork Length (Axle-To-Crown)
427mm
427mm
427mm
Trail
94mm
very high
91.9mm
very high
89.9mm
very high
Mechanical Trail
87mm
85.2mm
83.5mm
Wheel Flop
33mm
31.9mm
30.9mm
Tire to Pedal Spindle
137.6mm
170 mm cranks
166.3mm
170 mm cranks
187.6mm
170 mm cranks
Pedal Spindle to Ground Clearance
117mm
170 mm cranks
121mm
170 mm cranks
123mm
170 mm cranks

Base Build

S
M
L
Wheel Size
700C/29 in
622 mm BSD
700C/29 in
622 mm BSD
700C/29 in
622 mm BSD
Tire Width
50mm
50mm
50mm
Tire Width Max
55mm
55mm
55mm
Tire Outer Diameter
722mm
722mm
722mm
Bike Length with Tires
1808mm
1840mm
1867mm

Stack and Reach vs. Category Trend

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.

Learn more about the Upright/Aggressive Scale
Category Trend
Progressive Gravel
Source:https://www.chirubikes.com/en/kit-cadre/alpin/