Thanks for the link. I don’t fully understand it, though. I mean, the
calculations are straightforward enough, but what is the context;
e.g., what does “Speed” mean? Is it the maximum that Roger ever
achieved personally? Strange then that he achieved greater footspeed
(i.e. MUCH greater angular velocity) when the cranks get smaller.
I don’t think it’s Rogers maximums and the highest ‘foot speed’ is 2.99 m/s with the largest crank size, 170, on a 26” wheel. I took it that it was just acquired data so you could do some comparisons and draw your own conclusions, I could be wrong.
The figures are not my maximum on those size of wheel (I don’t have 170mm on
any unicycle!) I set it up for people to play with, you put in your crank
size and your speed and it gives you the foot speed, m/s and Cadence. I
know I can achieve 14mph on a 26" with 150 cranks which gives 2.85, my max
on a Coker is 24 (no don’t do it, it was scary and I am not doing it again)
and that would give 2.65. I think the difference for the speeds is the
“other factors” like weight of unit and wind resistance (it can not be the
crank size that is reducing the foot speed because look at the 20" speeds).
As an additional piece of additional data to this puzzle when I change my
rim to the new lighter rim my top speed increased. For what I thought was
sub 20mph was in fact 22mph. The rolling weight for the new wheel is a lot
lighter than the old one and it obviously does make a difference.
50mm cranks on a Coker… yes Miark put them on my Coker at red Bull and
didn’t tell me. I jumped on and rode a 100m or so on them, very fast very
hard very silly, very don’t try hills! (yes I did realise… well not until I
was on it! it was a morning!).
Roger
The UK’s Unicycle Source
----- Original Message -----
From: “Klaas Bil” <klaasbil_remove_the_spamkiller_@xs4all.nl>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Thursday, September 12, 2002 11:58 PM
Subject: Re: crank length versus cadence? (PING Roger)
> On Wed, 11 Sep 2002 18:04:29 -0500, unicus
> <unicus.au9ba@timelimit.unicyclist.com> wrote:
>
> >http://www.unicycle.uk.com/cranklength.xls
>
> Thanks for the link. I don’t fully understand it, though. I mean, the
> calculations are straightforward enough, but what is the context;
> e.g., what does “Speed” mean? Is it the maximum that Roger ever
> achieved personally? Strange then that he achieved greater footspeed
> (i.e. MUCH greater angular velocity) when the cranks get smaller.
>
> Roger could you please chime in?
>
> Klaas Bil
>
> If you had this signature, I have forged it.
>
>oops sorry I was asleep there…
That’s OK I should have slept at that time as well. I usually look
only once a day anyway (in r.s.u. I mean).
>I can achieve 14mph on a 26" with 150 cranks which gives 2.85, my max
>on a Coker is 24 (no don’t do it, it was scary and I am not doing it again)
>and that would give 2.65. I think the difference for the speeds is the
>“other factors” like weight of unit and wind resistance (it can not be the
>crank size that is reducing the foot speed because look at the 20" speeds).
Are you implying that as a first approach, foot speed should remain
constant through various crank lengths? If that is the case, it
answers my original question. But why don’t I try it out myself?
Yes I am implying that the foot speed is the critical factor when looking at
unicycles (but not the whole story!). I think the theory appears reasonably
consistent within a certain range of cranks length and speed.
Roger
The UK’s Unicycle Source
----- Original Message -----
From: “Klaas Bil” <klaasbil_remove_the_spamkiller_@xs4all.nl>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Friday, September 13, 2002 11:19 PM
Subject: Re: crank length versus cadence? (PING Roger)
> On Fri, 13 Sep 2002 08:13:22 +0100, “Roger Davies”
> <Roger.Davies@octacon.co.uk> wrote:
>
> >oops sorry I was asleep there…
> That’s OK I should have slept at that time as well. I usually look
> only once a day anyway (in r.s.u. I mean).
>
> >I can achieve 14mph on a 26" with 150 cranks which gives 2.85, my max
> >on a Coker is 24 (no don’t do it, it was scary and I am not doing it
again)
> >and that would give 2.65. I think the difference for the speeds is the
> >“other factors” like weight of unit and wind resistance (it can not be
the
> >crank size that is reducing the foot speed because look at the 20"
speeds).
> Are you implying that as a first approach, foot speed should remain
> constant through various crank lengths? If that is the case, it
> answers my original question. But why don’t I try it out myself?
>
> Klaas Bil
>
> If you had this signature, I have forged it.
>