crank length experiment

[eddief]

Over the past few years I have tried a couple of different crank lengths. Had three Shimano triple bikes with 172.5. When I went to the Yellow Jersey Compact doubles on two bikes I chose to go to 175 since Sugino does not make 172.5. After a number of thousand miles at 175 I just did not feel comfortable and was getting some knee pain. Today I substituted 170 arms onto one of the Sugino cranks. I immediately felt comfortable. Not like some adjustments where you say oh sh*t why did I try that? Pedal stroke felt more efficient and knees felt good. This is the first attempt at 170, and I immediately liked it. Could be novelty, could be exactly the right length for my legs. And only 3plus years of experiments to get to this point.

[dbrk]

A bit shorter is better than a bit too long. I'm best with 172.5, I think, but I ride 170s one a few bikes. Every attempt at 175 has felt waaay wrong. But here's my gripe, as it were. Why is it that 172.5 mtn bike cranks are so, so hard to find? I'm not fond of triples but I'm more fond of 46/36 than I am of anything/38, so I like the 110BCD on the five armers. Go figure. Finding a 110BCD is, god forbid, silver is like finding a lugged steel bike in the peloton.

dbrk
not interested in what the peloton rides...except as a sporting curiosity

[Louis]

Gents,

Given your crank lengths, what is your floor-to-PBH measurement?

Louis

[eddief]

for me pbh is about 85. Today after the experiment, I felt the concept of femur length for the first time. I don't know what the definition of short or long is as it relates to femurs, but I felt with the 170's that I was getting really good leverage without over extending/bending my knees.

[Louis]

My PBH is around 89. I've been using 170 cranks on my road bikes for ages and recently have gone up to 172.5 I've been debating whether or not I should try 175. The various rules-of-thumb I've come across suggest that for my PBH at least a 175 would be best, but I have yet to try.

Louis

[Ahneida Ride]

I'm 6"4 and riding 172.5. Yes they are short. Conventional wisdom has
me on 180 or 177.5 at least. And at times, I can feel that a longer crank
would offer more power. I could introduce a bit more Umph into the
pedal stroke..

BUT ......

The 172.5 forces me to spin. I like that .... AND I have NO KNEE PAIN.
If I lower my seat just a bit, my knees kill me after 10 miles. So...
I'm quite terrified of jumping to 175's. There is no happy medium.
It's either no knee pain or lots of it. I'll take no knee pain.

On thoses 20% grades. I just shift into 22/29 spin and smile.

Long live the TA Zephyr. Oh yea, they discontinued it !
The TA Zephyr allows one to also introduce a 20,22 or 24 granny.

DBRK is right. For touring the hills of New York, Vermont and New
Hampshire, a 46/36 up front is a happy combination.

Less is more.

[William]

I was surprised when AR told he was riding 172.5's. :confused: But, if they work for him, more power to you my friend. I have two inches on him height wise and I run 180's. I started on 175's and never had a problem on them, but when the opportunity became available for me to try some 180's, I never looked back. I certainly felt that I could apply more power with them, but I can also spin them. Just like anyone riding smaller cranks, climbing a hill is about staying on top of the gear, and with the 180's, I have no problem doing so with a 53x39 up front.

My PBH (pretty bad haggis) measurement is 100%. I can't take the stuff. :rolleyes:

William

[jerk]

the jerk has become so lazy the 177.5 have been traded in of late for 180s.....god its easy to just musseuw everyone off your wheel with those big mothers on our flat eastern massachusetts roads....(ogf course the spin has suffered and if the jerk wants any chance in a sprint against anyone worth their salt the wind-up better start 3 km from the town line....but hey, mashing a big gear gets the jerk all the chicks.)
jerk