[python] Re: Evolution Bike
- From: Jaculus <jaculusbent@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Wed, 27 Mar 2013 14:14:47 +0100
The optimum for aerodynamics is a BB well above seat hight so that the
heel in it's lowest position is at seat hight.
The optimum for preformance of the human poweroutput (max watts) is a
straight body. For recumbents this means the higher the BB goes, the
flatter the seat should be.
These two optima don't take handling into account. For the python
handling is a major issue. The more upright the seat is the easier
handling usually is.
Jaculus
2013/3/27 Tihamer Juhasz <balamber@xxxxxxxxx>:
> Hi Jürgen,
>
> I see. So optimum BB height is somewhere around seat height. As your say,
> too low should be bad indeed for aerodynamics and pushing the rider up in
> the seat.
>
> Thanks.
>
> Tiha
>
>
>
>
> On Wed, Mar 27, 2013 at 1:32 PM, Jürgen Mages <jmages@xxxxxx> wrote:
>>
>> Hi Tiha,
>>
>> first argument pro high BB is better aerodynamics and second is better
>> force input.
>>
>> I once rode the airbike which has a low BB. Especially when climbing, the
>> applied pedalling force is pushing my body up from the seat.
>>
>> Jürgen.
>>
>>
>> On 27.03.2013 12:14, Tihamer Juhasz wrote:
>>>
>>> Hi,
>>>
>>> Please enlighten me. Why is a low BB compared to the seat a problem?
>>> Until
>>> now I thought that a BB should go as low as possible, as long as the
>>> heels
>>> don't hit the wheel or the ground when turning. A low BB has the
>>> advantages
>>> that pushing down from the higher seat is easier especially for climbing
>>> compared to pushing upwards.
>>> Furthermore when the BB is low, the angle between the steering axis and
>>> imaginary line between the BB and the seat (the line along which you push
>>> the pedal) is shallower and thus the pedal induced steering effect is
>>> weaker.
>>> These are two advantages of the low BB I know of. What are the
>>> disadvantages?
>>>
>>> I think that this steering angle will not work good in practice indeed.
>>>
>>> Best, Tiha
>>>
>>>
>>>
>>> On Wed, Mar 27, 2013 at 1:04 PM, Jürgen Mages <jmages@xxxxxx> wrote:
>>>
>>>> Design is indeed nice and clean. Performance would be not so good. BB is
>>>> too low compared to the seat and even worse: the steering angle is too
>>>> small which causes the front wheel to flop in curves.
>>>>
>>>> Jürgen.
>>>>
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