Advantage on a short arm crankset?



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Ole Carlsen

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Hi! Will there be any advantages in using a short arm crankset? I'm using a 170mm noname today, but
will I gain anything apart from a lower periphery speed?
--
Ole
 
> Will there be any advantages in using a short arm crankset?

A number of us are answering this question for ourselves. There has been a number of posts on the
topic recently. Perhaps a search using "155 mm" or "150 mm" etc would yield information. I dropped
down to a 155mm Dotech crank set and dropped several *minutes* off my best commute time. Traveling
is simply easier now. I am a 5'9" mezomorph, muscular legs, somewhat rotund, 52 yo male. I ride a
SWB USS Vision
R40. Been 'bent for a year.
 
Ole, It is impossible to answer that question without knowing what you are riding and how much knee
flex you have at the closest position (pedal closest to you). Do a search. This topic has been
thoroughly discussed including places to buy shorter cranks.

The big concern with too long cranks is knee soreness and damage. Higher BB bikes seem to
exaggerate the effect. Riders switching to shorter cranks have reported NO loss in power. They have
generally been very positive regarding the switch. If your cranks are too long your stroke is not
effective because your leg becomes too compressed and you are not in your power zone. Your knees
and RPMs will suffer. Please do a search. There is a lot of information already on this forum
regarding crank length.

Good luck, Don

Ole Carlsen <carloingendåsekø[email protected]> wrote in message
news:<[email protected]>...
> Hi! Will there be any advantages in using a short arm crankset? I'm using a 170mm noname today,
> but will I gain anything apart from a lower periphery speed?
 
>> Will there be any advantages in using a short arm crankset?

>GeoB at [email protected] wrote: A number of us are answering this question for ourselves. There has
>been a number of posts on the topic recently. Perhaps a search using "155 mm" or "150 mm" etc would
>yield information. I dropped down to a 155mm Dotech crank set and dropped several *minutes* off my
>best commute time. Traveling is simply easier now. I am a 5'9" mezomorph, muscular legs, somewhat
>rotund, 52 yo male. I ride a SWB USS Vision
> R40. Been 'bent for a year.

I switched to 150mm cranks and love it! Much better for spinning like a hummingbird! I am sized like
an elf with a 28 1/2 inch inseam.

Jay <-- the happy elf-like triker
 
"Don" <[email protected]> wrote in message news:[email protected]...
> Ole, It is impossible to answer that question without knowing what you are riding and how much
> knee flex you have at the closest position (pedal closest to you). Do a search. This topic has
> been thoroughly discussed including places to buy shorter cranks.
>
> The big concern with too long cranks is knee soreness and damage. Higher BB bikes seem to
> exaggerate the effect. Riders switching to shorter cranks have reported NO loss in power. They
> have generally been very positive regarding the switch. If your cranks are too long your stroke is
> not effective because your leg becomes too compressed and you are not in your power zone. Your
> knees and RPMs will suffer. Please do a search. There is a lot of information already on this
> forum regarding crank length.
>
> Good luck, Don

Then again, I normally spin away at a cadence af 90-100 on my 175mm dotek's. I'm 1950mm myself -
normal proportions. http://www.hpv-klub.dk/Arrangementer/03-05-10_rulletest/images/torben_side.jpg

I have allway's (err, well since my ~1850mm) used 170 or 175mm cranks. Only exception was the 20"
bongo bike, the shorter cranks, the faster you go.

Torben
 
Great Site!!!

Thanks for the heads up.

Personally, all I know is: Knees used to get sore with 170's. Knees don't get sore with 155's. I can
note no decrease in speed.

--
Miles of Smiles,

Tom Blum Winter Haven, Florida Homebuilts: SWB Tour Easy Clone Speed Machine Clone

www.gate.net/~teblum
 
> Will there be any advantages in using a short arm crankset?

I went to: http://www.cranklength.info/cranks.htm

Then "Crank length -- The debate" choice.

And did some reading. Very fascinating. this guy has done a lot of work on this very informational
site. In one place he sums up his opinions in a chart he has constructed (search for the string
"Here's a visual representation of my crank-length scheme:"). Using this chart, as well as the
others shown that attempt to correlate leg size and geometry to crank length, I find that I should
be using a 150-155mm crank arms. Note that I switched from 170mm to 155mm and found a very favorable
result in efficiency and comfort.

This may be an interesting site for many of us to explore.

Other posts said "This topic has been thoroughly discussed". I don't agree with that. Yes, we had
shared experiences and ignorance, but there remains much to be explained/wondered at. This site
delves deeply where we have previously skimmed.
 
I have just started riding my new Giro Supreme with 150mm Thorn cranks
(26/36/46T rings). I have ridden for four years with a 170mm Campy Racing triple (26/40/50T rings)
on my Haluzak Leprechaun Hybrid/Race.

I do not miss the 170 at all. My knees feel better and I am riding faster and climbing better. Of
course, I confounded the experiment by buying a new bike. I do not feel like the 150s are too short.
I am loving them and think it was a great decision on my part. The rings seem to be working out well
also. If I start to spin out too often, I will get bigger rings. It was all kind of a
guess/experiment that is working.

FYI, I am 5/3" with long torso and short legs if that helps anyone evaluate the viability of shorter
cranks for themselves. My cadence is in the low 80s. Other factors to consider are BB elevation
relative to the seat and femur length. Good luck. Don
 
GeoB wrote:
> I went to: http://www.cranklength.info/cranks.htm (...)Using this chart, as well as the others
> shown that attempt to correlate leg size and geometry to crank length, I find that I should be
> using a 150-155mm crank arms.

Interesting. Can anyone guide me to a source for the 190 mm cranks I should be looking for...

/Torsten
 
"Torsten Lif" <[email protected]> wrote in message news:[email protected]...
>
>
> GeoB wrote:
> > I went to: http://www.cranklength.info/cranks.htm (...)Using this chart, as well as the others
> > shown that attempt to correlate leg size and geometry to crank length, I find that I should be
> > using a 150-155mm crank arms.
>
> Interesting. Can anyone guide me to a source for the 190 mm cranks I should be looking for...

Turn a crank shortener around? ;-)
 
> Interesting. Can anyone guide me to a source for the 190 mm cranks I should be looking for...

Do a search. There is a lot of information already on this forum regarding crank length. I remember
seeing a number of sources listed.
 
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