[Sparticus]

Guys,
Been thinking about the crank length issue and got it figured out.
Optimum bicycle crank length is 2 inches. So I'm having some custom 50mm cranks made.
Also a custom 12 tooth chainring to go with. Gonna run one of those 9-46t cassettes.
You losers running 150mm+ cranks are doing it wrong.
Think of the advantages of a 50mm crank. You see? Yeah, thot so.
If short is good, shorter is better and shortest is best.
Who's with me?
=sParty

P.S. Considering going even shorter... maybe 30mm?

 

[J.B. Weld]

As long as it has a front derailleur and quad rings I'm in.

 

[Cerberus75]

I'll beta test it for the short leg research. But I'll probably go back to 160mm lol.

 

[BadgerOne]

Market them under the name 'Corgi Crank'. You're welcome, invite me for a pint when you hit your first million.

 

[BrianU]

Sounds like just the thing for a fully rigid bike.

 

[Sparticus]

Sounds like just the thing for a fully rigid bike.

You mean one with no rear fork, right?
=sParty

 

[noapathy]

I could only see this working on one of those new 36ers as long as the bottom bracket isn't too low.

 

[stripes]

Market them under the name 'Corgi Crank'. You're welcome, invite me for a pint when you hit your first million.

Lol i was thinking sausage dog.

Sent from my iPhone using Tapatalk

 

[rockcrusher]

Guys,
Been thinking about the crank length issue and got it figured out.
Optimum bicycle crank length is 2 inches. So I'm having some custom 50mm cranks made.
Also a custom 12 tooth chainring to go with. Gonna run one of those 9-46t cassettes.
You losers running 150mm+ cranks are doing it wrong.
Think of the advantages of a 50mm crank. You see? Yeah, thot so.
If short is good, shorter is better and shortest is best.
Who's with me?
=sParty

P.S. Considering going even shorter... maybe 30mm?

I have jumped on my kids bikes occasionally and found I really appreciated the short cranks. When standing it is almost just like standing and shuffling my feet, which is nice. When seated it is like sitting and just moving my feet to get them comfortable. It is the best of all worlds honestly. I think you are on to something for sure.

Bonus is that you can get a really low BB for that in the bike feel. Way in the bike.

 

[Sparticus]

Way in the bike.

WAY in the bike!

 

[slapheadmofo]

Think of all the rotating weight you'll save.
Some dork with a scale and spreadsheet will be all over these things!

 

[Sparticus]

Think of all the rotating weight you'll save.
Some dork with a scale and spreadsheet will be all over these things!

Precisely.
Now here's a thought -- if short cranks are so awesome, consider for a moment smaller diameter wheels.
I'm thinking, you know, like 26" or maybe even 20".
Can you say, "improvement!"?
=sParty

 

[J.B. Weld]

Aside from poking fun at people who like shorter crankarns, is there a point to this thread?

 

[Sparticus]

Aside from poking fun at people who like shorter crankarns, is there a point to this thread?

No.
Well, maybe.
No -- yes.
In my mind the intentionally humorous nature of my post might initiate a serious question in peoples' minds, this question being: "At what point does shortening crank length (aka leverage) cross the good/bad line?"
Perhaps I haven't worded that question ideally but I think you know what I mean.
Personal mobility/immobility issues aside...
Does this point in question between positive and negative remain constant? Is it one specific length?
Does this point change with individual rider's leg lengths?
Exactly where is it? How can it be derived?
I wonder why children's wheeled toys (tricycles, bicycles) have such short cranks unless optimum crank length is leg length dependent.
Despite all the experiential research I've done with various length cranks, I feel like I've got more questions than I have answers.
The biggest question that remains in my mind is, "Why is everyone rushing toward shorter cranks these days when 10-15 years ago the trend was rushing toward longer cranks?"
Have we actually learned something or is the short crank trend just another fad?
Was the rush to shorter cranks instigated by the bike industry's lowering of BBs such that people wanted to avoid pedal strikes?
Or did they actually see a benefit to shorter cranks with regard to human power development / performance?
Or comfort / bike control?
Something else?
I don't know the answers. As for the nature of this thread, I prefer to employ irreverence whenever possible to ferret responses.
=sParty

 

[noapathy]

Surely one of those engineers could come up with a science-based answer for this almost question. (if they don't preface their statement with "as an engineer", all such suggestions should immediately be dismissed, of course)

 

[006_007]

I have holes drilled into my crankarms with a moveable threaded insert for the pedals that I can adjust the length as desired. Added bonus of setup variety is they are lighter.

 

[Mike Aswell]

In my mind the intentionally humorous nature of my post might initiate a serious question in peoples' minds, this question being: "At what point does shortening crank length (aka leverage) cross the good/bad line?"

=sParty

I know you already know this but the answer is that it depends. If there was some algorithm for perfect crank length we would all already be running it.

When I was running a Cascade link on my HT2 I tried 165 cranks to help deal with the lower BB causing some increase in pedal strikes but in the end preferred my 170 crank and went back. If I could bike blindfolded I would have tried that because for weeks I was convinced I was just imagining my preference for the 170 crank. But in the end it was undeniable. The reduction in strikes was not worth the shorter crank. That being said, eventually I went back to the stock link because I realized that objectively I preferred it over the Cascade link. So maybe I'm just weird.

 

[Hexsense]

Well, from 165mm to 50mm here you have only about 30% the leverage at the crank and only 30% circumference. So, your gearing seems messed up.
To make things equal you'd have to reduce gear ratio down to 30% of what you had before.
Say. 30t front ring to 9t front ring. Then you can spin 3.3x faster because the circumference is so small that 3.3x cadence put you at the same linear foot speed as 3.3x slower cadence on normal 165mm crank.
In other words, 198rpm cadence on 50mm crank feel as fast (same linear foot speed) as 60rpm on 165mm crank.
Now, the problem is, how do we even get gearing small enough for this fast natural cadence?

 

[VegasSingleSpeed]

What if you just run one crankarm that's 160mm long? That averages out to 80mm per side, plus one leg never gets tired. I think that's a reasonable compromise for 50mm cranks.

 

[iliketexmex]

There is a lot of outside the box thinking going on here.