Hello .... want to ride a new horse ?

[kervelo]

Hello,

Sorry to make such introduction : the topic opened here seem so apart from the other i've read before. So difficult to only start with " Hello and Welcome ".

My background is engineering, and cycling is a daily activity to go to work, for randonnee during holidays or even sometimes for racing if sundays are sunny !

Here, I'm interested in sharing my experience and receiving your advice and comments on a new bicycle type we have built : it can be considered as an "halfway" between an upright bicycle and a recumbent.
It is a front wheel direct drive bicycle using a gearbox in the front wheel with bottom bracket.
It is the first ever built and we are expecting to make the second better with your help !



The riding is easy, safe and fast. As you can see : no chain. So the maintenance is very minimum and it will stay clean !
( more info and pictures can be shared )

Let me know your comments on it.
Thanks for feedback.

Marc

 

[raleighnut]

do you get traction problems on hills.

 

[steveindenmark]

Show us some more photos Marc. I have seen something like this shape before, I will look in my magazines. Can you tell us something more about the hub?

 

[kervelo]

Hello,

Thanks for feedback !

Regarding the traction and the capability to climb :
the position of the pedals axis is lower than the seat in addition to have a strong back rest : this gives more power transfer than a classical "recumbent " design.
There is a "limited" counter reaction at the handle bar when pushing but counter balanced by the pulling on pedals.
Over all, it feels great.
Regarding the hub : Yeah.... that is a piece of good mechanical engineering inspired by car gear box architecture ! It has 18 speeds and covering 600% gear ratio : so good for low speedd/climb and up "high" speed !
The gear selection is done from the handle bar by turning a shifter.

Here is another picture.



Regards
Marc

 

[Shaun]

Welcome to CycleChat Marc.

An interesting design, but one of the limitations of using the pedal driving wheel as the steering wheel it that it is not possible to make sharp / short turns because you cannot sustain the pedal turning momentum or keep your feet on the pedals as the sharpness of the turn increases. This can have a negative impact on handling and either requires a larger and slower turning circle or restricts use of the bike to less winding roads or cycle paths.

Just out of interest, how tight is the turning circle with a rider onboard and do you find it is a limitation of the current design? If it is an issue have you thought about ways to overcome it?

Also, in the demonstration video you appear to be cycling at quite a slow pace. Is this just for the sake of the video? Have you had it up to much higher speeds?

Cheers,
Shaun

 

[steveindenmark]

Which demonstration video?

Can you post it on here?

What does the bike weigh?

 

[Bazzer]

With a tighter turn, do you not find the tyre rubbing against the "outside" leg?

 

[kervelo]

Hi Shaun an all other !

The video is the one from the website is made : www.kervelo-bike.com showing in 2min how the riding is.
I planning to make another video for my next city tour.

Regarding the tight turn : the narrow curves are not made at high speed ( less than 4km/h , walk pace ) and don't require particular effort. As the steering angle is big enough ( not like the Harley Davidson or shopper style ), turing is easy and stable. The legs and pedals need to positioned adequatly to not touch the wheel. It can be managed without problem knowing this aspect ( and yes, a little attention is needed ). In that case, the rider is not at high speed and it will go smoothly will little care.

At a higher speed ( more than 10km/h ) , the curve radius is bigger and therefore the wheel angle won't interfer within the legs.

The version we have built is a "prototype" and its design can be improved on various aspect and on weight specifically : the current frame is made of steel and wheel hub could be lighter. We aim to built a second prototype with a target weight of 15kg compare to this first : 23kg !
The weight is an important criteria ( easy to say ! ), not getting the right value will make the bike not competitive compare to other recumbent or upright bicycle.

 

[ufkacbln]

My immediate thought was how close the loose hub cable is to the pedal arc

My fear would be catching this cable in the pedal and ripping it out

 

[kervelo]

You're right : these ( gear control ) cables are not at their right place : we should position them along the fork instead.
The next revision shall fix this.
Thanks for comment!
Marc