I can't stop obsessing about crank length

531Aussie said:

Maybe I just don't have the flexibility for the longer reach....I dunno.....or maybe I'm simply not tall enough for 180

I just don't see how this infatuation with long cranks could possibly be healthy. Maybe you should talk to a therapist. 😉

Its not just cranks alone, you may need to refit the bike, bring the seat forward, a longer stem, or a bike with a longer top tube and steeper seat tube.

I have a 4'10" friend with 71cm inseam, when we put her on 155mm cranks, she had to go down a frame size and her stem is now 85mm.

thanks for the replies.

So, I put some of my old 175s on today, and I felt like I was flying!! It probably had something to do with having 4 days of easy spinning, and that I've lost 2kg, but it's safe to say I'm definitely not slower on 175s.

You've really gotta stop obsessing about length Oz. 😄

Ody 😉

flipper said:

You've really gotta stop obsessing about length Oz.

too right, Flipp, especially since I'm only a size 43 shoe 🙂

531Aussie said:

I think I just want someone to remind me that the whole issue is overblown

I’m 6ft, with longish legs (~89.5cm inseam), and over the years I've used all the typical crank lengths for someone my height: 165 (track bike), 170, 172.5, 175, but for just over a year, I’ve been using 180s, and I still can’t get the position right!!!

eh....I dunno

🙁

Why doesn't this thread surprise me?........you've got to much time on your hands, get a haircut & get a real job!....or go see some bloke called Kennedy!....either way, you'll be over it! 😄

Hitchy

Hitchy said:

Why doesn't this thread surprise me?

OMG!! Hitchyoh lives!! 🙂 Yesterday was your first post here in 7 months!!

Know anyone one who wants some cheap Dura-Ace 180s? :p

531Aussie said:

Know anyone one who wants some cheap Dura-Ace 180s? :p

DA, you didn't!! :eek:
When playing with crank lengths, Sugino rules. 😄

gclark8 said:

DA, you didn't!! :eek:
When playing with crank lengths, Sugino rules. 😄

maaaaaate, I bought 2 pairs :p.......but I got 'em kinda cheap

Some saddle height formulas like Lemond,Hinault, etc. are measured from the center of the BB and don't change the height with a change in crank length. That effectively settles the crank length debate because the dimensions of your feet and legs will make it impossible to pedal well or without reaching if you go past a certain crank length.

If you lower the seat it alters the pedaling mechanics in a non-symetrical way and doubles the mechanical disadvantage at top of the stroke. I have no idea what the supposed justification is in thinking that is a good idea or thinking maintaining the relationship at the bottom of the stroke should take precedence over what's going on at every other point in the stroke.

mises said:

Some saddle height formulas like Lemond,Hinault, etc. are measured from the center of the BB and don't change the height with a change in crank length. That effectively settles the crank length debate because the dimensions of your feet and legs will make it impossible to pedal well or without reaching if you go past a certain crank length.

If you lower the seat it alters the pedaling mechanics in a non-symetrical way and doubles the mechanical disadvantage at top of the stroke. I have no idea what the supposed justification is in thinking that is a good idea or thinking maintaining the relationship at the bottom of the stroke should take precedence over what's going on at every other point in the stroke.

I've got a 78.5cm inseam and am currently using 175mm cranks. I believe it's part of the reason why my feet bother me. I'll be switching to 170's next month and that'll mean moving the saddle forward and/or seatpost down; most likely a saddle reposition is all that's needed.

bbattle said:

I've got a 78.5cm inseam and am currently using 175mm cranks. I believe it's part of the reason why my feet bother me. I'll be switching to 170's next month and that'll mean moving the saddle forward and/or seatpost down; most likely a saddle reposition is all that's needed.

usually when the cranks are shorter, the seat goes up and sometimes back, too

531Aussie said:

usually when the cranks are shorter, the seat goes up and sometimes back, too

Thanks for catching that; for some reason I was considering the distance when the pedal is at the top, not the bottom, which is what counts.

My feet have been going numb on me; starting at the toes after just 5-6 miles. I've had 3 different fittings, new shoes, and now orthotics and a third pair of shoes. I've only had two rides since the orthotics and while the feet did go a little numb, it was only after 24 miles and the numbness was very general, suggesting my feet are getting used to the new shoes/orthotics. The last fitter was skeptical of the 175mm cranks, and I've noticed that nobody my size has reported using cranks that large.

So, next month it's new cranks. FSA Gossamer compact

531Aussie said:

maaaaaate, I bought 2 pairs :p.......but I got 'em kinda cheap

Where did you get 180mm DA cranks for cheap? I have been looking all over for a good deal on them, new or used. 😉

I am 6'7' and my pants inseam is 91.44. The difference between 175 and 180 is substantial for me (in a good way).

Ron

ronsmithjunior said:

Where did you get 180mm DA cranks for cheap? I

they weren't super cheap.

Bicycle Recycle's normal price is about $510, not including the bottom bracket. I got mine a bit cheaper than that because I've spent over $10,000 there in the last 5 years

Cecil Walker sell them for $537
http://www.cecilwalker.com.au/category249_1.htm