Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 04-06-10, 05:41 AM   #1
jroyero
Junior Member
Thread Starter
 
Join Date: Jan 2010
Bikes:
Posts: 22
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Crank Arm!!

I need some help guys. Anybody who is 5'8" or close what length do you have on your crank arm??..i just bought myself a shimano 105 for just $120 and the length is supposedly my length which is 172.5, but i want to be sure.
jroyero is offline   Reply With Quote
Old 04-06-10, 06:16 AM   #2
Metzinger
Primate
 
Metzinger's Avatar
 
Join Date: Jan 2006
Location: gone
Bikes: Concorde Columbus SL, Rocky Mountain Edge, Sparta stadfiets
Posts: 2,582
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There are many length calculators that you can google.
Your selection may be right or a bit long, depending on your inseam measurement.
But everyone's different, and the only true test is experience with different lengths to compare them.
Metzinger is offline   Reply With Quote
Old 04-06-10, 07:26 AM   #3
Bianchigirll 
Bianchi Goddess
 
Bianchigirll's Avatar
 
Join Date: Apr 2009
Location: Camp Hill, PA
Bikes: Too many to list here check my signature.
Posts: 22,422
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
I am a bit statuesque at 5'11" and I perfer a 172.5, I am not a good spinner and the 172s always felt better. wheter it is the "correct" crank length for my height and leg length I have no Idea, I just tried a set and I seem to be more comfortable on them.

but I agree with Metzinger there are several methods to caculate this.
__________________
Bianchis '87 Sport SX, '90 Proto, '90 Campione del Fausto Giamondi Specialisma Italiano Mundo, '91 Boarala 'cross, '93 Project 3, '86 Volpe, '97 Ti Megatube, , '90 something Vento 603,

Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '09 Motobecane SOLD, '?? Jane Doe (still on the drawing board), '90ish Haro Escape
Bianchigirll is offline   Reply With Quote
Old 04-06-10, 07:54 AM   #4
nymtber
Senior Member
 
Join Date: Mar 2005
Location: NY state
Bikes: See Signature...
Posts: 1,293
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'm 5'8, 30" inseam, and I have a 175mm on my mtb, and my Specialized Sirrus came with 170mm cranks. I sure as heck think there is a difference, but might just be me. The Allez I used to own had 175mm as well, and I feel the 175mm was easier to pedal?

172.5 should be fine.
nymtber is offline   Reply With Quote
Old 04-06-10, 09:30 AM   #5
Mr. Beanz
Banned.
 
Mr. Beanz's Avatar
 
Join Date: Dec 2005
Location: Upland Ca
Bikes: Lemond Chambery/Cannondale R-900/Trek 8000 MTB/Burley Duet tandem
Posts: 20,030
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
6'1 with different setups, 175 and 172.5. Over 60,000 miles, 35 or so centuries and I stil can't tell a difference in crank length.

1 mm = .039...so 2.5 X .039 = .097 of an inch which is less that 1/10 of an inch. If that affects your pedal stroke, you are very sensitive. That's less of a difference than inserting and insole which many riders do.

It would make a differnce in lenght if it were a dude 6'7 and 180 cranks vs a 5'2 with 172.5. Then you are talking a difference, but other than that.....Pfft!

I've read one statement that said a 172.5 corners better than a 175. Sure, if you're dumb enough to take a sharp turn and lay the bike down on it's side with the pedal down!
Mr. Beanz is offline   Reply With Quote
Old 04-06-10, 09:42 AM   #6
Loose Chain
Senior Member
 
Loose Chain's Avatar
 
Join Date: Sep 2009
Location: USA
Bikes: 84 Pinarello Trevisio, 86 Guerciotti SLX, 96 Specialized Stumpjumper, 2010 Surly Cross Check, 88 Centurion Prestige, 73 Raleigh Sports
Posts: 1,484
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
I prefer a 170, I am a spinner and prefer the smaller diameter as it is easier for me to turn high rpm smoothly. That said, two of my four bikes have 175s on them. Near 5-11 and 86cm PBH. Go figure.
Loose Chain is offline   Reply With Quote
Old 04-06-10, 10:14 AM   #7
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,488
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
175, 172.5, 170. You're only talking about around 1/4" difference on the outside. I doubt very many people of average size (5,8" is roughly average) will notice a difference. I know I can't.

When I bought the compact crankset for my road bike I worried endlessy because I cound get 175 mm immediately and 172.5 was going to be an indefinate wait. I bought the 175 and couldn't tell any difference.
Retro Grouch is offline   Reply With Quote
Old 04-07-10, 09:40 AM   #8
Big_Red
Senior Member
 
Big_Red's Avatar
 
Join Date: Dec 2009
Location: Aurora, CO USA
Bikes:
Posts: 160
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I think you will be OK. Might be a bit long for you, might be just right. Besides, since you already bought it you might as well give it a try.
Big_Red is offline   Reply With Quote
Old 04-07-10, 10:31 AM   #9
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 16,355
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 54 Post(s)
Quote:
Originally Posted by jroyero View Post
I need some help guys. Anybody who is 5'8" or close what length do you have on your crank arm??..i just bought myself a shimano 105 for just $120 and the length is supposedly my length which is 172.5, but i want to be sure.
I use 170s on my geared bikes and 165s on my fixed bikes.
JohnDThompson is offline   Reply With Quote
Old 04-07-10, 10:32 AM   #10
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 16,355
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 54 Post(s)
Quote:
Originally Posted by Mr. Beanz View Post
I've read one statement that said a 172.5 corners better than a 175. Sure, if you're dumb enough to take a sharp turn and lay the bike down on it's side with the pedal down!
If you're riding fixed gear you may not have a choice. That's why I use 165s.
JohnDThompson is offline   Reply With Quote
Old 04-07-10, 11:02 AM   #11
Mr. Beanz
Banned.
 
Mr. Beanz's Avatar
 
Join Date: Dec 2005
Location: Upland Ca
Bikes: Lemond Chambery/Cannondale R-900/Trek 8000 MTB/Burley Duet tandem
Posts: 20,030
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by JohnDThompson View Post
If you're riding fixed gear you may not have a choice. That's why I use 165s.
That's true! But the sharp turns I had in mind were 35-40 mph swithcbacks on mtn descents, aint happening on a fixie!

I do know that some flip flop wheels may have a freecoasting side (?) so if a fixie were to do sharp turns on the ride I describe, they have the ability to keep the pedal up in the turn.

We've had some excellent fixie riders do 5,000 ft climbs with us. They are fine on the way up but never do they keep up on the way down. Even with the freecoasting (?) side, gear isn't big enough to keep our speeds. I imagine they could put a larger gear in the rear, but still...... Plus "most" fixie riders don't do these climbs.
Mr. Beanz is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:21 PM.