Aluminium Pursuit Frame
A 6061 T6 aluminium frame with a round down tube that flattens towards the bottom bracket.
Unknown PS1
Green
Fixed Gear / Single Speed Bike
The Unknown PS1 is built around a 6061 T6 aluminium pursuit frame and a carbon fork, with bullhorn handlebars, front and rear brakes and a flip-flop rear hub.
This version has a bright green frame with black Unknown graphics, a black carbon fork, black wheels and black bar tape.
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6061 T6 Aluminium
Signature pursuit frame
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Carbon Fork
Aluminium steerer, 30 mm rake
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Bullhorn Bars
Supplied as standard, 90 mm stem
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48T × 17T
165 mm cranks, 130 BCD
Key Features
Carbon Fork & Bullhorns
A carbon fork with an aluminium steerer (30 mm rake, 1 1/8"), with taped bullhorn bars on a 90 mm stem.
48T × 17T Drivetrain
165 mm cranks with a 48T chainring, KMC Z510 chain and a 17T cog on a flip-flop rear hub.
Saddle & Seatpost
An Unknown saddle on a 27.2 mm, 300 mm seatpost.
A Pursuit Frame for the Street
The PS1 takes its shape from pursuit track frames. The down tube starts round at the head tube and gradually flattens as it runs down to the bottom bracket, giving the 6061 T6 aluminium frame its distinctive profile.
A carbon fork with an aluminium steerer and taped bullhorn bars complete the front end. The drivetrain runs a 48T chainring and a 17T cog on a flip-flop rear hub, so the same bike can be ridden fixed or with the included single-speed freewheel.
What's Included
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Pedals + Foot Straps
Included with the bike
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Single-Speed Freewheel
For the threaded side of the flip-flop hub
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Front & Rear Brakes
Fitted as standard
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90% Pre-Assembled
Final assembly and safety checks required before riding
Specifications
| Frame | Unknown PS1, 6061 T6 aluminium |
|---|---|
| Fork | Carbon, aluminium steerer, 30 mm rake, 1 1/8" |
| Handlebars | Unknown bullhorn bars, taped |
| Chainring | Unknown 48T, 130 BCD |
| Rear cog | 17T fixed |
| Rear hub | Unknown flip-flop (fix/free) |
| Brakes | Front and rear, fitted |
| Tyres | Slick tyres |
Show all specifications
| Headset | Integrated, 45 × 45, 1 1/8" |
|---|---|
| Stem | Unknown 90 mm |
| Crank arms | Unknown 165 mm, 130 BCD |
| Chain | KMC Z510, 1/2" × 1/8" |
| Freewheel | Single speed, included |
| Rims | Unknown 28H |
| Rear axle | Nutted (track nuts) |
| Seatpost | Unknown 27.2 mm, 300 mm |
| Saddle | Unknown |
| Bottom bracket | 68 × 103 mm, BSA, square taper |
Frame Geometry
| Size | Top tube | Seat tube | Chainstay | HT° | ST° |
|---|---|---|---|---|---|
| 52 | 508 | 520 | 387 | 73° | 77° |
| 54 | 523 | 540 | 390 | 74° | 76° |
| 57 | 541 | 570 | 390 | 74° | 76° |
| 59 | 553 | 590 | 390 | 74° | 76° |
| 62 | 568 | 620 | 390 | 74° | 76° |
PS1 frame geometry. Lengths in mm; HT° and ST° are the head tube and seat tube angles. Compare the top tube and seat tube with a bike that fits you, or contact us for sizing help.
Fixed Gear & Single Speed
The PS1 has a flip-flop rear hub: a 17T fixed cog on one side, and a threaded side for the single-speed freewheel, which is included. Turn the rear wheel round to switch between riding fixed and freewheeling. See all PS1 colours or other fixed gear bikes.
Frequently Asked Questions
Is the Unknown PS1 fixed gear or single speed?
Both. The flip-flop rear hub has a 17T fixed cog on one side. A single-speed freewheel is included for the other side.
Which handlebars does the PS1 come with?
The PS1 is supplied with taped bullhorn handlebars on a 90 mm stem.
How much assembly is needed?
The PS1 arrives 90% pre-assembled. Final assembly and safety checks are required before riding, and front and rear brakes are already fitted.
Which PS1 size do I need?
Use the frame geometry above and compare the top tube and seat tube with a bike that fits you. If you are unsure, contact us before ordering.
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Free Standard Shipping
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5-Year Frame Warranty
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