Hilary and Brandon have hit the mark. I have a 86cm inseam and just have
never FELT COMFORTABLE on cranks longer than 170mm. I have 172.5mm on my De
Rosa and it just does not FEEL right to ME. I'm giving serious consideration
to 165mm , I have a few sets around here , TA and Campy Pista. I'm going to
give them a try.
Sterling Peters
San Diego
> This issue of crank length is a subject very close to my heart - but what
> the pros use is not necessarily a good guide to what is ideal. They ride
> what they are given.
>
> Having worked with kids for the past five years or so and having designed
> frames for short and tall riders for the past 17 years I generally
recommend
> about 20 to 21% of your inside leg length. Foot length is another factor
to
> affect crank length as is pedalling style. This particular formula results
> for me in 162.5mm cranks - my son is at present on 150mms. On the correct
> crank length pedalling is far smoother - I do not think power output is
> necessarily badly affected by slightly too long or too short but comfort
is.
> However seriously too short or long cranks I am sure will seriously affect
> pwer. Correct crank lengths also make the design of small frames far
easier
> - toeclip overlap (foot overlap when using clipless pedals) is far less of
a
> problem. The bottom bracket can also be lowered which is particularly of
> benefit on a touring frame or one used mostly in the city.
>
> In Britain the standard crank length for many years was 165mm (6 1/2in)
> which I suspect was about right. A lot of experimentation with crank
length
> was carried out at the beginning of the 20th century in England - cranks
as
> long as 9in were used but the standard length eventually arrived at was
> 165mm.
>
> Hilary Stone, Bristol, England
>
>
> Sterling Peters wrote:
> > Jan Heine made some interesting comments about crank length in Vintage
Bicycle
> > Quarterly ( A 400K Brevet ). He commented about the fact that with
shorter
> > crank arms you can lower the Bottom bracket height , get a better
cornering
> > more stable bike and have the additional advantage of being able to
continue
> > pedaling thru the corners without fear of kissing the pavement , not to
> > mention you also save your knees from the stress of longer cranks. I
remeber
> > reading somewhere that in the 50's the Randoneurs typically used crank
lengths
> > of about 165mm and smaller gear ratios.
> > I can also recall that this long crank thing has been tried before by
the
> > Professional racers again I think it was in the 50's or 60's and they
moved
> > back to more knee forgiving lenghts after a few years. What does anyone
know
> > about this?