Bicycle Archive · Specification report

2021 Jamis Portal C4

Velopedia Archive ID 900001529

Overview

Model year	2021
Brand	Jamis
Model	PORTAL C4
Bicycle type	Mountain
Archive ID	900001529
Original MSRP	$4,799.95
Colors	Riptide
Sizes	S/15.5″; M/17″; L/19″; XL/21″
Weight	31.25 lbs

Frameset

Frame construction	Dyad Pro High Modulus Carbon Fiber, 130mm travel 3VO suspension, Enduro¨ Max sealed bearing pivots, 1.5 – 1 1/8Ó tapered head tube, 12x148mm thru-axle, Internal dropper post routing, Custom Jamis upper chainguide mounts, ISCG05 lower chainguide mounts, Fox Float DPS Performance Series EVOL shock w/3-position compression, 10mm shock hardware, replaceable derailleur hanger
Frame material	Carbon
Fork	Fox 34 Rhythm Series Float 29″ w/ sweep adjust compression & lock-out,15x110mm axle, air spring compression, rebound adjust, tapered alloy steerer, 130mm travel, 51mm rake
Fork material	Aluminum
Rear shock	Fox Float DPS Performance Series EVOL shock w/3-position compression

Drivetrain

Component group	Shimano Deore, 12-speed
Shifters	Shimano Deore, 1×12-speed
Rear derailleur	Shimano Deore, 12-speed
Crankset	Race Face Ride, 32T
Bottom bracket	Race Face BSA
Cassette	Shimano M6100, 12-speed, 10-51T
Chain	KMC X12, 12-speed

Brakes

Brakes	Shimano MT420 4-piston hydraulic disc, 180mm front & 160mm rear RT30 rotors

Cockpit & contact points

Headset	FSA Orbit IS Integrated, 8mm cone spacer
Handlebar	Race Face Ride, 760mm x 20mm rise, 35mm diameter
Stem	Race Face Ride, 50mm extension, 35mm clamp diameter
Saddle	WTB Volt
Seatpost	KS Rage Dropper, Southpaw remote

Wheels & tires

Wheels	Stan’s No Tubes Flow D 29″ rims, Shimano MT410 15x110mm front & 12x148mm rear hubs, stainless spokes
Front tire	Vittoria Mazza 29 x 2.4″, TNT tubeless
Rear tire	Vittoria Mazza 29 x 2.4″, TNT tubeless
Wheel size	29

Geometry · S/15.5″

Effective top tube	585 mm
Head tube	105 mm
Head-tube angle	67°
Seat-tube angle	74°
Chainstay / rear center	437 mm
Wheelbase	1148 mm
Reach	418 mm
Stack	606 mm

Geometry · M/17″

Effective top tube	610 mm
Head tube	115 mm
Head-tube angle	67°
Seat-tube angle	74°
Chainstay / rear center	437 mm
Wheelbase	1173 mm
Reach	439 mm
Stack	615 mm

Geometry · L/19″

Effective top tube	635 mm
Head tube	125 mm
Head-tube angle	67°
Seat-tube angle	74°
Chainstay / rear center	437 mm
Wheelbase	1198 mm
Reach	461 mm
Stack	625 mm

Geometry · XL/21″

Effective top tube	660 mm
Head tube	135 mm
Head-tube angle	67°
Seat-tube angle	74°
Chainstay / rear center	437 mm
Wheelbase	1224 mm
Reach	482 mm
Stack	634 mm

Manufacturer-published archive data. Confirm exact standards and dimensions before ordering parts or performing service. Generated by Velopedia on September 14, 2026.