Retrospec Harper Plus

Fixed-Gear / Single-Speed Bike


The Harper Plus is Retrospec’s premium fixie/single-speed. Quick response dual braking, sealed-bearing hubs, and dripping with style, Mantra is your go-to for your every commuting, cruising, zipping, coasting, and speeding need.

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Buy peace of mind: All of our bikes are built by professionals and come with a free 90-day tune-up!



Hand Built tig-welded high-tensile steel, “UrbanComfort” design, forged horizontal rear dropouts with integrated chain tensioners, bar-spin clearance with no toe overlap

Unicrown, Threadless, 28.6mm, fender-eyelet

Internal rear brake cable routings

2 sets water bottle braze-ons

Rear rack braze-ons

Decals protected by clear-coat


Crank: Mantra Forged Aluminum Alloy 170mm x 46T x1/8″

Chain: KMC C1 1/2 x 1/8″

BB: Sealed Cartridge

Freewheel: 16T x 1/8″


Retrospec aluminum double-wall 32H, 40mm deep-V section, precision machined brake tracks

Hubs: Retrospec large-flange aluminum alloy, sealed cartridge bearings, 32H, rear flip-flop, bolt-on

Spokes: 14G Stainless steel

Retrospec 700 x 28C all-season, P/V valves


Headset: 1 1/8″ (28.6mm) steel, Threadless

Brakes: Aluminum alloy dual-pivot side-pull calipers & aluminum brake levers

Handlebars: Aluminum Alloy 520mm Wide x 30mm Rise, 25.4

Grips: Retrospec UrbanComfort Kraton 125mm length

Stem: Aluminum alloy 4-bolt Threadless, 80mm extension x 7⁰ rise x 36mm rise, 25.4 handlebar clamp, 28.6 steerer

Saddle: Retrospec Urban2

Seatpost: Aluminum Alloy Seat Post 25.4 x 300mm with Micro Adjust head

Seatpost Clamp: Aluminum alloy CNC precision 28.6mm

Pedals: Low-Profile Platform, Reinforced Nylon resin, 9/16″