Archive: Rocket Gen4

Cotic Rocket Gen4 in Gloss Metal

Discontinued. This page is kept as an archive record for owners and for anyone researching an older Cotic Rocket.

Years of production: 2020-2023

The Cotic Rocket Gen4 was our rough and tough, race proven steel full suspension enduro bike for 27.5" wheels. 165mm rear travel, up to a 170mm fork. See the Rocket archive for the other generations.

Finishes: Gloss Metal and Sunny Yellow.

The Rocket is wild and fast and just so much fun, designed to get you down the rowdiest trails with an infectious grin on your face. 165mm of trail eating travel and the subtly supple Reynolds 853 steel frame gives you ground moulding traction in the corners, and keeps you trucking through the chunkiest rock gardens and most sketchy chutes you can find. droplink still lets you skip and pop down the trail, seeking out gaps and jumps, and lets you scramble back to the top like a mountain goat.

Our signature Longshot geometry, with its slack head angle, short stem and low standover, gets a steeper seat angle and longer reach over the previous model for improved climbing, keeping your weight central over the bike. It balances quick handling from the nimble 27.5" wheels with a swaggering "bring it on" attitude that needs no encouragement to go blisteringly fast. Developed on tough Peak District trails, the Rocket was ready for anything you could throw at it.

What's new in Gen4

Travel up to 165mm, out of a longer stroke shock. That reduces the leverage for a smoother, plusher feel while keeping the signature interactive Cotic ride
A new Cotic exclusive Reynolds 853 HD tubeset increases stiffness, strength and life of the front end to keep up with rowdy situations
The latest iteration of Longshot geometry brings idealised sizing, longer reach and steeper seat angles. A long frame, matched with a responsive 30-45mm stem, combines with a slacker head angle for a controlled and exciting ride. Longer reach and steeper seat angles give a better seated climbing position, and a longer wheelbase gives more stability

Reviews

Watch the off.road.cc first ride video review:

off.road.cc also published a full review after three months with the bike. They said the fourth generation Rocket "builds on a solid foundation" with handling that flatters the timid and encourages the confident, and gave it 4.5 stars out of 5. Read the full review.

Features and benefits

Longshot geometry. Radical Longshot geometry keeps the bike stable through the rough stuff, planted in the corners and pinpoint accurate in the steep tech. Couple a super short stem to the optimised head angle and the bike really pushes you on, looking for every stump to boost off, rock to gap and berm to rail, keeping you connected to the trail with incredible poise and composure.

Reynolds 853. Reynolds 853 builds a light, lively and fantastically robust front end, and includes our custom ride tuned Ovalform top tube, which delivers sublime trail damping and that signature Cotic feel. The steel construction is compliant and naturally ground moulding, extracting grip and feedback from the trail where you thought there was none.

27.5" wheels. The Rocket is designed around the latest 27.5 x 2.6" wide trail tyres, with clearance to spare. 27.5" wheels are lighter, livelier and easier to accelerate than 29" or 27.5Plus wheels, with a more interactive feel, at the expense of slightly less stability and easy rollover on rockier terrain. They also package into a small frame more easily, so the proportions suit shorter riders.

droplink. Cotic droplink suspension is supportive and progressive, keeping the Rocket's 165mm of travel feeling lively and interactive, with grip to spare on the descents and support and traction on the climbs.

Frame details

Longshot geometry designed for short stems (30-45mm), giving incredible steering responsiveness combined with confidence inspiring capability at speed
Reynolds 853 Ovalform and DZB tubed front end brings precision, beautiful ride feel, durability and strength
44mm standard head tube designed with an external bottom cup for taper steerer compatibility and a zero stack top cup for minimal stack height
Custom Cotic designed 35mm heat treated cromoly seat tube for super stiff support for the main suspension pivots
31.6mm seatpost size is dropper seatpost compatible, with internal "Stealth" dropper post remote routing
Regular threaded bottom bracket for reliability and ease of maintenance
Rear mech cable routed internally through the steel seat stay for clean lines and low noise
Dedicated 1x drivetrain design: maximum width swingarm pivot, low drop, forged construction swingarm heads with an integrated top chain guide, combined with ISCG05 lower tabs for maximum drivetrain reliability and security
6066-T6 aluminium swingarm with Syntace X-12 Boost 148 x 12 rear axle for maximum wheel stiffness and mud clearance
15mm main and seat tube pivots and a droplink thru axle style linkage clamp keep the frame solid front to rear
One bottle mount
Clearance for the latest generation 27.5 x 2.6" tyres
Optimised around 160mm forks for a great balance of speed and precision, with a 170mm fork option for bigger hits
165mm of Cotic droplink suspension via a strong progression rate on the linkage driven single pivot layout
Sizes: Small (390mm), Medium (425mm), Large (460mm) and XL (495mm)
Weight: Gold spec bike 30.7 lbs without pedals

Geometry

The chart is a guide to frame size. Longshot geometry means the frames are low and long, with plenty of standover room. We recommend the size suggested for your height, to get all the benefits of a super short, responsive stem. If you upsize you might not be able to fit a longer dropper, because the collar hits the seat tube top or the dropper bottoms out on the droplink pivot. All measurements are static.

Frame Size	Small	Medium	Large	XL
Seat Tube (centre-top)	390mm	425mm	460mm	495mm
Chainstay Length	437mm	437mm	437mm	437mm
Head Tube Length	100mm	110mm	120mm	130mm
Usual Height Range	165-172cm	169-180cm	178-188cm	186-195cm
Stem Length	30-45mm	30-45mm	30-45mm	30-45mm
Frame Wheel Travel	165mm	165mm	165mm	165mm
Max Tyre Size	27.5 x 2.6"	27.5 x 2.6"	27.5 x 2.6"	27.5 x 2.6"
Max Seatpost Insertion (incl. actuator)	178mm	213mm	248mm	283mm

Seatpost maximum insertion is guidance based on leaving 25mm clear below the actuator for any hose or cable to route through the frame. Your post may need less or more, and an externally routed dropper won't need this margin at all.

160mm travel fork: head angle 64.5°, actual seat angle 74.9° (at 720mm BB-to-saddle height) or 74.7° (at 815mm), BB drop -10mm.

160mm fork	Small	Medium	Large	XL
Top Tube (effective)	600mm	626mm	651mm	679mm
Reach	444mm	467mm	490mm	515mm
Stack	589.5mm	598.5mm	607.5mm	616.5mm
Wheelbase	1208.1mm	1236.2mm	1263.0mm	1292.0mm

170mm travel fork: head angle 64.0°, actual seat angle 74.4° (at 720mm) or 74.2° (at 815mm), BB drop -7mm.

170mm fork	Small	Medium	Large	XL
Top Tube (effective)	601.0mm	627.3mm	652.7mm	680.2mm
Reach	439.6mm	463.2mm	485.9mm	510.7mm
Stack	593.0mm	602.0mm	611.0mm	620.0mm
Wheelbase	1212.4mm	1240.5mm	1267.3mm	1296.2mm

Component sizes

Seatpost diameter: 31.6mm (380mm long minimum)
Front mech: not applicable: 1x drivetrains only
Fork: minimum 160mm, maximum 170mm travel, 563mm axle to crown (without sag)
Bottom bracket: 73mm, conventional English/BSA thread
Chainline: 52mm Shimano or 53mm Boost chainline for up to a 32t round or 30t oval chainring; 55mm Shimano chainline for up to a 36t round or 34t oval chainring
Chain guide mounting: ISCG05 bottom two tabs, plus the integrated Cotic x OneUp Components top guide (included with frame or bike)
Headset: 44mm for taper steerer forks: Hope 2H, Cane Creek ZS44 top/EC44 bottom, Chris King Inset I7
Rear hub: Boost 148 x 12 bolt through
Rear axle: Syntace X-12
Rear mech hanger: Syntace X-12 Type 1 (conventional or Shimano Direct Mount)
Shock: 215 x 63, AIR SHOCK ONLY, with 15.75 x M8 fittings at the down tube end and 24.0 x M8 at the seat stay end
Dropper post routing: Stealth via the down tube
Rear brake mounting: I.S., compatible with rotors up to 203mm

Origin: UK and Taiwan

Cotic frames are designed, developed, engineered and tested entirely by us at our base in the Peak District, near Sheffield. Our founder, Cy Turner, is the lead designer and engineer, and our frames are rigorously ride tested by everyone at Cotic and chosen test riders and ambassadors. They are fully certified and lab tested in excess of the requirements of ISO4210 safety standards.

For this frame the majority of the production process happened in the UK. Five Land Bikes in Scotland manufactured the Reynolds 853 front triangle in small batches to their exacting standards. It was married to our proven rear ends from our suppliers in Taiwan, as found across the droplink range, and much of the remaining machined parts were made by Unite Components and Bear Frame Supplies.

All the major parts of the frame were dip coated in manganese phosphate to prevent corrosion, then painted with tough, durable automotive spec paint by Five Land. After their hand finishing and rigorous QC, the parts underwent further checks by us before assembly at our HQ in the Peak District. All our made in Britain frames were Datatag'd from the factory. As always, complete bikes were built to order by us, to the exact spec of your choice.

Set-up guide: Rocket Gen4

droplink works best with 25-30% of the travel as sag, with 30% our preferred starting point. The Rocket Gen4 has a 63mm stroke shock, so aim for 17-19mm of shock sag, 32-40mm of sag on a 160mm fork and 34-42mm on a 170mm fork. A good starting point is 18mm at the rear and 36mm (160mm fork) or 38mm (170mm fork) at the front. Always set up by measuring sag, not by a generic pressure. The full step-by-step sag measurement procedure and the rebound and compression advice for the shock and fork are the same as in the Rocket Gen2 set-up guide.

Cane Creek base settings (relative to fully open):

DB Air CS: 1 large volume spacer, 1.0 turns high speed compression, 4 clicks low speed compression, 1.0 turns high speed rebound, 2 clicks low speed rebound
DB Air IL: 1 large volume spacer, 0.5 turns high speed compression, 6 clicks low speed compression, 1.0 turns high speed rebound, 4 clicks low speed rebound

For other shocks, start with rebound 3 clicks from fully open and compression or pedal platform off. Cotic base settings run on the lively, fast rebound side. The Cane Creek Field Tuning Guide covers fine tuning.

Owner's manual: download the droplink Longshot user manual, 2021 (PDF).