Full speed | 100rpm shifting under full load

WHAT? 

⦿ This is our HiT Transmission.  It is a prototype Gearbox based on unique hinged ring-clusters for changing gears all while under load. 

⦿ The HiT Gear Box has been an R&D “Skunk Works” project at our Santa Cruz, California office.

⦿ Ring segments swing on a hinge in and out from the loaded chain which sets the gearing. These hinged rings allow the transmission to stay compact and keep a constant chain line across all the gears. (The chain does NOT move laterally)

HIT GEAR BOX
GB DE CALIPER
RyanSoldering
HIT CHAIN 2 SQ
GB Install SQ

WHY? 

⦿ We believe a GearBox is the way forward for the majority of bicycles.  The HiT can be applied to a variety of different types of bicycles such as DH, mountain, pavement and cargo.  We have been riding and testing both MTN and Pavement versions of it for the past couple of years.

⦿ Design, Build, Ride and Repeat; that's what we've been doing. In fact, we have been out on the trails riding versions of HiT for the past two years giving it a real world beat down.  With the conversations about Gearboxes getting louder and louder we thought it's time to share our prototype, how it works and its potential.

⦿ Praxis is mostly known for our cranks, chainrings, and bottom brackets, but behind the scenes we continued innovating in new drivetrain areas.

⦿ As an engineering-driven company committed to advancing the bicycle, we developed the HiT GearBox to showcase its unique functionality and look at possibilities for riders.  

Screenshot
Screenshot
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PatentRyanCAD
Screenshot

HOW? 

⦿ We are still exploring the options as the next step in the development is combining it with an eBike motor.

⦿ We are looking for the right partner to help develop the HiT beyond our current capabilities.  This includes potentially finding partners for manufacturing, service, and/or licensing agreement.

⦿ Currently, we are talking to multiple brands about partnership/potential projects using the HiT Gear Box.  

HiT MTN

HIGHLIGHTS

⦿ Shifts under full load!

⦿ Chain driven transmission

⦿ Can be designed as 4sp to 16sp

⦿ Optimized internal chainline

⦿ Electronic shifting

⦿ Programmable/Auto shifting

⦿ Direct Shift (One touch Sweep/Dump)

⦿ Designed for serviceability

Can be made as Concentric or NonConcentric

Pavement Concentric

MTN NonConcentric

(High Pivot MTN)

GOAL : eBike

We have already built, ridden and tested the HiT gear box on mountain and pavement bikes.  However to fully realize the potential, our next step is integrating it with an eBike mid-motor.

Watch the ring segments in Slow Motion...

GB EXPLODED LABELS.1

CALFEE CONCEPT BIKE

 4sp HiT with Mahle eHub Motor for a Super-Commuter

FAQ - DEEP DIVE

What is HiT?

This is our HiT GearBox Prototype. 

It is a bicycle transmission based on unique hinged clusters for changing gears.

Gear segments swing on a hinge in and out from the loaded chain which sets the gearing. This hinged gearing allows the transmission to stay compact and a constant chain line across all the gears.

The HiT Gear Box has been a “Skunk Works” engineering project at Praxis for a while and it’s simply time to share this R&D project, how it works and its potential.

Why is Praxis showing this?

Known for our cranks, chainrings, and bottom brackets, we are also innovating behind the scenes in new drivetrain areas.

Design, Build, Ride and Repeat; that's what we've been doing. In fact, we have been out on the trails riding versions of HiT for the past two years giving it a real world beat down.  With the conversations about Gearboxes getting louder and louder we thought it's time to share our prototype, how it works and its potential.

We believe a GearBox is the way forward for bicycles…and the HiT can be applied to many different types of bicycles such as DH, mountain, commute and cargo.

 

What kind of bike is this for?

HiT Gear Box is for any type of Bicycle really.   Part of us showing it off is explaining how it can be modular/scaled/geared for different Bikes.

Our Concept Bike is a 4sp GB connected to a Mahle eHub as a commuter style Bike.    We liked the concept of 4 ‘Gears’ but connected to a popular eHub.     

It can be made into an 8sp Downhill/Gearing, a 12sp Enduro/Gearing or even Cargo Bike etc.    

Basically the HiT GB internals can be built for a variety of Bicycle types.

How are you moving forward?

We are exploring the next steps.

Currently, we are talking to multiple brands about partnership/potential projects using the HiT Gear Box.

As a small company, we’re looking for the right relationship to help develop the HiT beyond our current capabilities. 

This includes potentially finding partners for integration into eMotors, manufacturing, service, and/or licensing agreements.

 

What is the goal of the HiT Gear Box?

We have already built, ridden and tested a few different bikes with our analog HiT gear box.  

To fully realize the potential, our next step and main goal is combining it with an eBike mid-motor.    

 

SIZE | It is kind of big, can it be made smaller?

This is an early prototype.

Our size analysis looks like it can get a great deal smaller.  It is all dependent on the size of the internal chains and how many gears are wanted in a bike.

ELECTRONIC | Is it electric or cable actuated?

YES, It's electronic shifting only.

The internal shifting ‘Hinges’ of the HiT are wired electronic currently. 

In future we foresee Hit to be wireless electronic.

MOUNTING - Does this use the Pinion or other mounting?

No.  Because of the unique design, it will require proprietary mounting dimensions.    

BELT - Does this use belts?

For now the Hit Gear Box is an internal chain system.

However the external drive of the bicycle can be chain or belt...that's up to the bike design/spec.      

WEIGHT - What is the weight?

Depends on the final gearing/build.  

4sp… 8sp… 12sp etc.  

We are shooting for a final version that is comparable to a high level full group-set.

    

GEARING - What are the gear count possibilities?

Virtually unlimited gear range.  

A HiT can be made as a 4sp (like our concept bike here) all the way to 16sp.   We can configure multiple gear clusters inside the box.   

    

COMPARISON | vs a conventional bicycle drivetrain...

Early calculations estimate 92-96% efficiency. 

This is based on the fact that it is simply 2 chain driven drivetrains with no cross chaining (always perfect chain line)

As we are a relatively small company with limited resources, we have not had the ability to do mechanical lab testing.  We hope to be able to do this in the near future.

Other systems (these are averages across all gears assuming perfectly clean and lubricated):

  • 94-96% for derailleur based 12 speed (typical)
  • 97% for single speed (typical)
  • 91% for Pinion 18-speed (average across all ratios)
  • 84% for Enviolo (NuVinci) CVT (average across all ratios)

Some third party testing summaries here : 

COMPARISON | vs the other Gear Box seen like Pinion
  • Exceptionally smooth shifting 
  • Shifting under load up to 1000+ Watts 
  • Sequential or non-sequential shifting, equally smooth.  Basically you can go from any one gear to another in one click. 
  • Drive gear flexibility - Can be made also as Non-Concentric output (for High Pivot MTN)
  • Virtually unlimited gear range. Can be built to whatever a specific bicycle needs.
  • Automatic shifting possible - Programmable in software.
COMPARISON | Is this similar to the Honda old GearBox?

Not really. 

The Honda design is basically an enclosed derailleur/cassette type system. 

Other than being chain driven, ours is completely different as there is no derailleur.

SERVICE | What is the serviceability like?

Serviceability is a major design criteria we always talk about and keep in focus as we rev the prototype. 

Right now as a working/rideable prototype, it's very serviceable.  We are constantly breaking it down and building it back up swapping out ring segments and other parts. 

So we'd like to keep a good amount of it serviceable... however we just don't know yet if that means shop level or consumer level servicing.   

PATENTS - Any relations to other systems?

Yes, we acquired the Vyro patent as it was necessary for the realization of our design.

Our system, in the most basic way, uses the fundamentals of the Vyro design.  Otherwise, it is completely different as we have 10+ separate patents granted (with more on the way) that make the HiT completely unique and what you see today.

    

BIKE | Is Praxis or other brand producing a bicycle with this?

We are not.

This is an R&D prototype bicycle showing off the HiT GearBox and how it works.   

We are just unveiling/displaying it in this concept form to explain and show how it works and how it can be integrated into a bicycle. 

However, we are talking to multiple bike brands about partnership/potential projects using the HiT Gear Box.

INTERESTED IN HiT?

We are looking to collaborate and partner with industry Brands. If interested in HiT and learning more about partnership please contact us here.

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