Some days ago, I’ve invited everyone to see my homebuilt unicycle at my
webpage. A special answer was gave by Klaas Bil. You’ve said that my
unicycle has a high Q factor, because the “S” cranks I’ve used.
After a long search in my city, I’ve found a pair of cottered cranks
absolutely straight. I’ll mount the “new” cranks (to tell the truth, the
cranks was took from an old children bike…), but I have a doubt… These
are 4 1/2" cranks and I took notice that the best majority of 20" unicycles
uses 5" cranks…
Now the question: These 1/2" each crank will be significant? What will be
5 inches roughly = 125 mm
4 1/2 inches roughly equals 112 mm.
It will be like putting 110 mm cranks on instead of 125s, more or less.
Theoretically, the uni should go about 13% faster - that’s top speed and average cruising speed. The exact figure doesn’t matter, but you will notice a small difference.
You will have around 12% less leverage, which will have a small effect on hill climbing and idling.
In practice, it won’t make any huge difference.
I ride a 20 inch with 110mm cranks, a 24 with 102s, a 26 with 150s and a 28 with 110s - all are controllable and idleable. Don’t worry, the pros and cons will more or less balance out. On the whole, I prefer shorter cranks. Not everyone does.
I think your’ll be fine with the shorter cranks, Some people prefer them as you can see, I however do not. I like longer cranks (140’s) on my 20" this is probably because I do more trails stuff than freestyle though.
----- Original Message -----
From: “Klaas Bil” <firstname.lastname@example.org>
Sent: Saturday, November 23, 2002 10:50 PM
Subject: Re: Crank Length…
> Have you tried your new cranks already? Did you notice less wobbling
> or any other difference related to the cranks being straight?
> Klaas Bil
> The average person falls asleep in seven minutes.