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the story & tech behind the Menace frame

Menace 145

Dirtlab cycles and the Menace 145 design thesis:

A New Brand Dirtlab and a new Bike the Menace or as known in the prototype stage the C2. With this all new in-house design, we are evolving in terms of Design, Features, Geometry (G-volve) and Kinematics (K-Volve) in order to keep up with the big brands.

Bikelab Inc. the owner and developer of the brands FATlab, Roadlab and Sandman bikes and run by bike industry veteran and former mtb racer enthusiast Marvin Besselink, designed the C1 full suspension platform in 120 and 150mm in 2014 and for 2020 we introduce our C2 a completely new frame with superb kinematics and an updated gravity centered geometry.

The C1 was a project where we designed the bikes and they were produced by a carbon factory that paid for the tooling in order to have it sold under a few brands worldwide so we could make enough quantity to justify the cost of the project.

The project was discussed and soon agreed upon that the new bike should be top of the line in terms of geometry, kinematics looks, durability, safety and features.

The C1 was built around old school short reach geometry that puts the rider in a rear centered position and puts a lot of weight on the rear suspension causing it to compress faster than needed, the C2 is more gravity centered in order to keep the rider balance over the center of the bike instead of the rear.

The design phase took us 1 year and we had several alloy prototypes welded in order to have riders test the new forward geometry in relation to the kinematics and we made several changes along the way.

The C2 was born which is based on 145mm rear travel (29x2.4/2.6 tires) paired with a 150mm fork (561ac) yet it was also designed with bigger travel forks up to 170/180mm in mind depending on the rider’s choice and combined with adjustable rear travel lengths. In order to make sure we could adjust the geometry we fitted the frame with a regular press fit headtube in favor of an integrated cup version and we stay away from the modern features such as  reach adjust as this has too many issues with creaky noises etc. Reach can be adjusted with stems and bars and stem height or by using different forks and by changing wheel sizes or adding a different press fit lower cup with added height or simply a few spacers more or less. In order to make this work we are using low headtube stack heights in the original model allowing you to change headset stack build up, stem/bar height and few spacers if really needed to adjust reach stack and your position on the bike.

The rear suspension has a flip yoke that ensures a bb lower shock mount area without walls in order to avoid water build up under the shock mount. The flip yoke makes sure that we can modify the bb height and chain stay length of the bike while maintaining the (almost) same geometry and ride the bike with 27.5x2.6/2.8 tires or 29x2.4 (design base) and even 29x2.6 tires.

Our former C1 was based of 27.5x3.0 yet as the market progresses and 29x2.4/2.6 are the future tires we redesigned the C2 around the 29r wheels whilst staying compatible with 27.5x2.8 (27.5x2.6 are possible by using different flip yoke plates)

Geometry C1 compared to C2 G-Volve:

 The head angle on the C1 was 65.5 which has proven to be a sweet spot, C2 is 65.5 as well why change something that obviously works. The seat tube angle was 73 and on the new frame we moved the rider more forward and have a 76.5-degree seat tube angle.

The new seat tube angle serves a gravity centered positioning purpose that basically moves the rider forward by 25 to 40mm depending on frame size. (formula for that distance is sinus X seat tube length at 73 degrees / 76.5)

By creating a steeper seat tube, we could also make shorter chain stays then on the old C1 yet where we started out with 430mm (27.5”) and 435mm (29”) chain stays we opted for 435mm for 27.5” wheels and 440mm for 29” wheels in the end to ensure better bike stability at high speeds and maintaining superb climbing traction whilst being more gravity centered then before.

 

Sizing and Top Tube lengths where short on the C1 yet we know if the riders weight is at the rear center of the bike the front end is more loose and tends to loose it’s ground tracing effect which is an essential part of the bikes handling. We tested several lengths on M sized bikes with several test riders in different regions such as Taiwan (where bikelab Inc. is situated), Japan with test rider Kazuo Chikamochi and in Ireland with test rider Jonathan Maunsell and our partner Transalpes tested in Switzerland and Italy. The testing criteria where to develop a geometry and suspension system that would be useable with 3 frame sizes to fit small to XXL people while maintaining a superb geometry kinematics and the lowest possible stand over heights.

 The 3 sizes are designed to be ridden with 35-60mm stems depending on rider preference and ride styles and can be used with low to high riser bars. All sizes are 150-180mm dropper post compatible, and the dropper cable is ran completely internal and easy to install adjust and remove. Rear derailleur and rear brake housing are also internal and exit behind the seat tube and then enter the chain stay just below the main pivot, this creates stress free installation and easy maintenance and maximum water shielding and optimizes shift and brake performance compared to differently routed frames.

 

Geometry

Kinematics

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DIRTlab Menace 145 frame

Menace 145 geometry

menace 145 kinematics