By Alex Evans

Published: Friday, 20 May 2022 at 12:00 am


Cotic’s RocketMAX Gen4 29in-wheeled enduro bike is now offered in five sizes under Cotic’s C-Sizing structure, where the change in reach between each size is just 19mm. The C5 – equivalent to the old XL size – has a 5mm increase in reach.

Staying true to Cotic’s long-standing relationship with steel, the new RocketMAX’s front triangle is made from Renyolds 853 tubing that’s exclusive to the brand, in a bid to increase strength.

Maximum compatible front-wheel travel has been increased from 160mm to 170mm, with some geometry changes to accommodate the tweak.

Out back, Cotic still uses its Droplink suspension with a progressive kinematic offering of between 150mm and 160mm of travel depending on the stroke of the shock fitted.

Prices start at £3,999 for a RocketMAX Silver SLX build and increase to £6,499 for the Platinum SRAM GX AXS build.

Cotic RocketMAX Gen4 frame

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The RocketMAX is Cotic’s longest-travel, hardest-riding bike.
Ian Linton / Cotic Bikes

The headline update to the RocketMAX Gen4’s frame is its new Reynolds 853 Ovalform down tube, chosen to increase strength and stiffness. However, thanks to its steel construction, Cotic claims its frame is “compliant and naturally ground moulding”, something we want in spades, please.

To boot, the front triangle is manufactured in the UK – a factor only a few brands of Cotic’s size can boast of.

The Taiwan-made 6066-T6 aluminium swingarm has a Boost 12x148mm rear axle and clearance for 29×2.5in tyres.

Other visible changes include the addition of a small brace tube between the down and seat tubes.

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A new brace between down and seat tubes has been added to the Gen4 bike.
Ian Linton / Cotic Bikes

On the underside of the top tube are water bottle mounts, where there’s space for a 625ml bottle. There are secondary mounts on the underside of the down tube, and Cotic sells frame bags to fit the RocketMAX for onboard storage.

Cables are externally routed from front to back, except the gear cable, which passes through the seatstay to reduce noise and give the frame clean lines.

The rear brake mount and chainstay and seatstay pivot use the same bolt, which is an interesting touch.

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Cotic’s custom-specced Reynolds 853 tubing is used on the bike.
Ian Linton / Cotic Bikes

It uses a standard 44mm head tube with an external lower cup and integrated upper. This design means the bike can be run with 29in or 27.5in rear wheels, because the angleset evens out the geometry change created by the 27.5in or mullet rear-wheel setup.

The Gen4 is now compatible with 170mm-travel front forks, up from 160mm on the previous bike, where the maximum permitted axle-to-crown length is 586mm. A 170mm-travel 29in Fox 38 measures 583.7mm and a 170mm 29in ZEB 586mm.

Cotic RocketMAX Gen4 suspension

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The Droplink suspension design is claimed to be massively progressive.
Ian Linton / Cotic Bikes

Cotic’s Droplink suspension is a single-pivot design with a linkage-driven rear shock that’s used to tune the bike’s kinematics.

The linkage on the Gen4 RocketMAX uses an all-new keyed design, where the linkage and axle can only be assembled one way. The keyed – or flat – sections, Cotic claims, help reduce twisting and flexing through the linkage.

Travel sits at 160mm with a standard 65mm stroke shock, but this can be reduced to 155mm or 150mm with a shorter stroke.

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Rather than welding the shock mount to the down tube, it’s bolted.
Ian Linton / Cotic Bikes

The revised link also has a reduced leverage ratio compared to the Gen3 bike, but retains its super-progressive feel to provide support and bottom-out resistance, while being supple at the start of its travel.

This also means it’s compatible with both coil and air shocks, although Cotic only recommends using Cane Creek’s Kitsuma coil with the RocketMAX.

Cotic RocketMAX Gen4 geometry

Cotic’s departure from the often-used size names (small to extra-large, for example) to its new C-Sizing structure not only results in an additional frame size, upping the number of RocketMAX variations to five from four, but also helps remove the stigma or entrenched conviction that a rider is any given size.

This is accompanied by 15mm reach increases between sizes and, Cotic hopes, Goldilocks reach figures in each of its C designations.

The C1 bike is recommended for riders between 162 and 172cm, while the C5 ups that to 184cm to 192cm, hopefully catering for a wide range of body types and riding styles. Each size designation has an overlap for its recommended rider, too.

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The sizes are now denoted from C1 to C5.
Ian Linton / Cotic Bikes

Cotic says for its C3, C4 and C5 sizes, the seat tube angle has been steepened to compensate for the increase in seat height usually associated with bigger riders on those bikes.

The geometry of the bike is typical of Cotic, with a long reach, wheelbase and chainstays paired with a slack head angle.

Cotic RocketMAX geometrty chart 170mm fork, 29in wheels
SizeC1C2C3C4C5
Seat tube (mm)390417444471496
Top tube (mm)599621639660679
Head angle (degrees)63.563.563.563.563.5
Seat tube angle (815mm seat height) (degrees)75.575.576.276.276.2
Chainstay length (mm)448448448448448
BB drop (mm)2323232323
Head tube length (mm)100110120130130
Reach (mm)444462482501520
Stack (mm)630639648657657
Wheelbase (mm)1,2441,2681,2901,3141,333
Recommended rider height (cm)162-172170-178176-184182-190184-192

Headline figures include a slack 63.5-degree head angle, a fairly steep 76-degree seat tube angle, long 448mm chainstays across the sizes and reach figures that span from 444mm to 520mm.

Compatibility with mullet wheels and 160mm-travel forks adjust the geometry from the stock 29in-wheel, 170mm-travel fork setup.

Cotic hopes that a customer is more likely to find their perfect fit with this new sizing structure.

Cotic RocketMAX Gen4 specs and prices

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Cotic’s steel frames have become legendary.
Ian Linton / Cotic Bikes

Sticking to Cotic’s Silver, Gold and Platinum build range, prices for RocketMAX Gen4 full bikes range from £3,999 to £6,499.

Each of the models is entirely customisable by the consumer, too, so it’s possible to up- or down-spec any bike in the range.

Cotic has been smart with its spec choices, however, offering higher-performing parts in key areas. For example, even its most affordable RocketMAX Silver SLX build features RockShox’s Lyrik Ultimate fork, SLX M7100 drivetrain and Deore M6100 brakes.

Cotic’s focus on price and performance is impressive. At the top end, the Fox 38 and Float X2 Factory-equipped Platinum build also has SRAM’s GX Eagle AXS drivetrain and is built with Hunt’s Trail Wide 29 v2 wheels.

 

Cotic RocketMAX Gen4 Silver SLX

  • Frame: RocketMAX Gen4 (155mm travel)
  • Shock: RockShox Deluxe Select Plus (230×62.5mm)
  • Fork: RockShox Lyrik Ultimate (160mm travel)
  • DrivetrainShimano SLX M7100
  • Brakes: Shimano Deore M6120
  • Wheels / tyres: Shimano MT620 / WTB Verdict 2.5 Slashguard (f), WTB Trail Boss Tough Casing (r)
  • Bar / stem: Cotic Calver / Cotic Shorterstem
  • Seatpost: BikeYoke Devine
  • Price: £3,999

Cotic RocketMAX Gen4 Gold XT

  • Frame: RocketMAX Gen4 (160mm travel)
  • Shock: Cane Creek Kitsuma Air (230x65mm)
  • Fork: RockShox ZEB Ultimate (170mm travel)
  • DrivetrainShimano XT M8100
  • Brakes: Shimano XT M8120
  • Wheels / tyres: Hunt Trail Wide v2 / WTB Verdict 2.5 Light Casing Slashguard (f), WTB Trail Boss Light Casing Slashguard (r)
  • Bar / stem: Cotic Calver / Cotic Shorterstem
  • Seatpost: BikeYoke Devine
  • Price: £4,999

Cotic RocketMAX Gen4 Gold SRAM GX Eagle

  • Frame: RocketMAX Gen4 (160mm travel)
  • Shock: Cane Creek Kitsuma Air (230x65mm)
  • Fork: RockShox ZEB Ultimate (170mm travel)
  • DrivetrainSRAM GX Eagle
  • Brakes: SRAM Guide G2 RSC
  • Wheels / tyres: Hunt Trail Wide v2 / WTB Verdict 2.5 Light Casing Slashguard (f), WTB Trail Boss Light Casing Slashguard (r)
  • Bar / stem: Cotic Calver / Cotic Shorterstem
  • Seatpost: BikeYoke Devine
  • Price: £5,149

Cotic RocketMAX Gen4 Gold SRAM GX Eagle AXS

  • Frame: RocketMAX Gen4 (160mm travel)
  • Shock: Cane Creek Kitsuma Air (230x65mm)
  • Fork: RockShox ZEB Ultimate (170mm travel)
  • DrivetrainSRAM GX Eagle AXS
  • Brakes: SRAM Guide G2 RSC
  • Wheels / tyres: Hunt Trail Wide v2 / WTB Verdict 2.5 Light Casing Slashguard (f), WTB Trail Boss Light Casing Slashguard (r)
  • Bar / stem: Cotic Calver / Cotic Shorterstem
  • Seatpost: BikeYoke Devine
  • Price: £5,749

Cotic RocketMAX Gen4 Platinum SRAM GX Eagle AXS

  • Frame: RocketMAX Gen4 (160mm travel)
  • Shock: Fox Float X2 Factory (230x65mm)
  • Fork: Fox 38 Factory (170mm travel)
  • DrivetrainSRAM GX Eagle AXS
  • Brakes: SRAM Guide G2 RSC
  • Wheels / tyres: Hunt Trail Wide v2 / WTB Verdict 2.5 Light Casing Slashguard (f), WTB Trail Boss Light Casing Slashguard (r)
  • Bar / stem: Hope Carbon Bar / Hope AM 35mm
  • Seatpost: BikeYoke Devine
  • Price: £6,499

Cotic RocketMAX Gen4 rolling chassis

  • Frame: RocketMAX Gen4 (155mm travel)
  • Shock: RockShox Deluxe Select Plus (230×62.5mm)
  • Fork: RockShox ZEB Ultimate (170mm travel)
  • Wheels: Shimano MT620
  • Seat clamp: Hope
  • Price: £3,249