Double Choc

A wide operating window, by design

Rather than committing the Double Choc to a single category, we designed it as a platform with range.

With adjustable suspension configurations, the bike can be built from a capable trail setup to a more aggressive all‑mountain configuration. Running 140/136 mm gives a balanced, efficient trail bike that pedals willingly and stays composed on long rides. Pushing it to 160/148 mm shifts the focus toward steeper, rougher terrain while retaining control and predictability.

This versatility isn’t about indecision – it’s about acknowledging that riding styles, terrain and priorities change. The frame supports those choices without losing its character.

Steel where feel matters, aluminum where precision counts

The Double Choc combines a steel front triangle with an aluminum rear end, because each material contributes differently to how the bike behaves.

Steel up front adds durability and a ride feel that remains calm over sustained rough terrain. It provides subtle feedback rather than filtering everything out – something that matters on long days and repeated impacts. The aluminum rear triangle brings stiffness and precision where suspension performance and tracking are critical, keeping the bike sharp when loading the rear end through berms and compressions. Together, the materials form a system that feels controlled rather than overbuilt.

A steel full‑suspension mountain bike, built with intent – adaptable, composed and ready for commitment.

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A suspension layout chosen with intent

The Double Choc uses a Horst‑link four‑bar suspension design. This layout allows pedaling forces, braking behavior and bump absorption to be tuned independently.

The result is a suspension platform that remains efficient under power while staying active over uneven terrain. Anti‑squat characteristics support climbing and acceleration, while anti‑rise behavior keeps the bike stable under braking on steep descents. Instead of feeling isolated from the trail, the suspension encourages momentum and consistency.

We chose commonly available bearings, hardware and threads to keep long‑term maintenance straightforward. Serviceability isn’t a secondary concern here – it’s part of the design brief.

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Geometry for commitment, not correction

The geometry of the Double Choc is progressive, but measured.

It’s built to reward commitment rather than constant correction. Stable at speed, predictable when pushed hard and balanced when terrain gets steep or loose. The bike invites big moves, but keeps enough composure to stay manageable when fatigue sets in.

Rather than chasing numbers for their own sake, the geometry reflects how the bike is actually ridden: hard descents followed by real climbs, repeated over long days.

Developed over time, not rushed

The Double Choc is the result of several years of development.

From early ideas to multiple prototypes, the platform matured through riding, testing and refinement. Changes were introduced when they added clarity – not novelty. The result is a bike that feels settled, not experimental.

This development process shaped a frame that encourages confidence rather than demanding it.

Built by hand, built to be used

Every Double Choc frame is built by hand in our workshop in Saxony.

Designing and building under the same roof keeps decisions grounded. Tube selection, gussets, reinforcements and alignment are considered as part of the complete structure, not as afterthoughts. The frame is built to tolerate repeated hard use, not just perfect conditions.

This is a bike intended to be ridden often and pushed hard.

Go big, ride home

The Double Choc is for riders who want to go further into terrain, ride bigger lines and still pedal back out with control.

It’s not about owning multiple bikes for different moods. It’s about having one bike that makes sense across a wide range of riding – because it was designed that way from the start.

Geometry

Geometry	M	L	XL
ST Length (mm)	390	440	480
TT Length (mm)	602	627	663
Reach (mm)	470	495	526
Stack (mm)	634	634	656
HT Angle (°)	64,5	64,5	64,5
HT Length (mm)	110	110	135
ST Angle (°)	77	77	77
CS Length (mm)	438	444	444
BB Drop (mm)	32	32	32
Wheelbase (mm)	1239	1272	1311

How we see Steel

At Sour, steel is not a stylistic choice.
It’s a design decision.

We use steel because it allows us to define frame behavior precisely — under load, over time, and across a wide range of riding conditions. Material choice, tube selection and heat treatment directly influence how a frame transfers forces, responds to repeated stress and ages through use.

This is Sour Bicycles – Made in Germany

Our manufacturing represents the culmination of plans, chats with friends while out riding, and many late nights writing ideas down. Our on-shoring process, the project we started to make all our frames right here in Germany, one-by-one, by hand, in our own facilities is our biggest adventure yet.

It is by far the biggest step we’ve ever made as a company: moving 100% of our production to Saxony. We are so proud to be Made in Germany and will continue to grow the project in the coming years.

By the numbers:

Headtube: ZS44/ZS56 tapered headtube
Bottom bracket: 73mm BSA bottom bracket
Axle: 12mm x 148mm thru axle (Syntace X-12)
Seat post: 31.6mm
Brake standard: PM180 Direct. More info here.
Fork travel: 140-160mm
Wheel size: M/L/XL 29″
Tire clearance: up to 2,5″
Tubing: Custom drawn, multiple butted, partly heat treated SOUR 4130 CrMo (we love steel)

Bonus facts and features:

SRAM UDH derailleur hanger and Transmission-ready
Recommended tire size 2,2″ – 2,4″
External downtube cable routing
One water bottle braze-on, one tool holder braze-on (top tube)
Optional second bottle braze-on and top tube bag braze-on
Low standover height
CNC’d bottom bracket for better power transfer (go fast)
CNC’d and welded rocker for control (don’t crash)
Maximum chainring size: 34t

It’s all in the details

We’ve tried to make all the details of the Double Choc as straight forward as possible so know you what you’re getting into. Still not sure? Just drop us an email!

Suspension Design	Horst Link
Headset/Headtube	EC44/ZS56
Seat Post	31.6mm
Seat Clamp	Integrated
Eye to Eye length	210mm
Stroke	55mm / 50mm (136mm)
Fork Compatibility	140-160mm
Fork Offset	44mm
Brake Mount	PM 180mm
BB Shell	73mm Threaded
Max Tire Size	2.5″
Max Chainring Size	34t
Water Bottle Mounts	1 + 1 Tool Box
Shock Mounting Bushing Top	22,2×8
Shock Mounting Bushing Bottom	21,84×8

Below is the sample weight of a size medium Double Choc. This weight does not include powdercoating, but please keep in mind that your chose powdercoat may be heavier than the average coating we use. Fades, gradients, and metallic colours can weigh more than single solid colour. If you are interested the final weight, please get in touch. We apply an inside wax coating before shipping the frame to your door that will add additional weight.

Frames

A Sour Double Choc frameset weighs 3.8 kg in size medium with all it’s small parts and suspension pivots, bearings, and bolts installed. This weight is excluding powdercoat which will add between 50g and 200g depending on your color choice.

Included with your frame

Included with your Double Choc frame or frameset are all small parts, cable guides and bolts to build your bike. You get a rear thru-axle of course, and if you’re ordering a frameset, you get a front axle with your fork as well. Headsets are only included if you add one to your order.

We are currently working on more options for the Cowboy Cookie, but currently we offer some amazing options from Fox and Manitou that work perfectly with our suspension design. If you have any questions about tuning or clearance, feel free to drop us an email.

You can add a rear shock and other parts at check out.

Check out the next drop-down for all the suspension characteristics, you kinematics-sniffer!