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


Go Back   > >

Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-02-06, 02:17 PM   #1
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
cranks, bent spindle; what the...?

So I'm looking over at my fixed bike today and I noticed that the crank arms are not exactly 180 degrees opposite of eachother. The left arm is rotated foward by degree or so. I suppose I've bent (twisted) the spindle. Funny I didn't notice it while riding, but now its going to drive me nuts until I replace it. Thats never happened to me before, even in years of BMX jumping, acid drops, wall rides, etc. I skip-stop frequently, but I've never crashed or acid dropped my fixie or anything. I can't imagine that skipping causes enough torque to bend the crank spindle. In fact I mostly skip with my left foot back, which would torque the spindle in the opposite direction. I'm just wondering how the hell I torqued my spindle so hard that it bent, or is it possible that its just a poorly made spindle and that the crank arms have never been properly lined up?
mihlbach is offline   Reply With Quote
Old 05-02-06, 02:20 PM   #2
Pat Eisenhauer
Senior Member
 
Join Date: Aug 2004
Location: Brooklyn
Bikes:
Posts: 177
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The crank not the spindle most likely. Do not ride until it is replaced.
Pat Eisenhauer is offline   Reply With Quote
Old 05-02-06, 02:35 PM   #3
muftek
awesome
 
muftek's Avatar
 
Join Date: Feb 2006
Location: urbana / chicago
Bikes:
Posts: 198
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
yeah, you may have rounded out your taper a little bit...
muftek is offline   Reply With Quote
Old 05-02-06, 02:59 PM   #4
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by muftek
yeah, you may have rounded out your taper a little bit...
When I get home tonight, I'll pull off the crank and have a looksee.
mihlbach is offline   Reply With Quote
Old 05-02-06, 03:03 PM   #5
mattface
Senior Member
 
mattface's Avatar
 
Join Date: Sep 2005
Location: Montpeculiar, VT
Bikes: Soma Rush, Fuji Cross, Raleigh Technium Mtn Bike, Ross 10 speed with Shimano 600.
Posts: 3,951
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
if I hadda guess I would blame a good hard pedal strike. Check your undies for other signs of something like that having occurred recently.
mattface is offline   Reply With Quote
Old 05-02-06, 04:17 PM   #6
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
OK, so I pulled the crank arms off and I've concluded that its definately the spindle thats bent-twisted.

The crank arms and taper part of the spindle are in good shape. I put a spare set of crank arms on the spindle, and the same thing...the left one is rotated forward, so it must be the spindle, not the crank arms. Next, I put my crank arms on another bottom bracket spindle that I'm not using and they are perfectly straight. So I must conclude that the spindle currently on my fixie is twisted-bent.

Hard pedal strike, crash, or random acts of violence are out of the question...haven't had anything like this happen, and I don;t park my bike outside, so vandalism is ruled out as well. Several weeks ago, I took apart the BB and lubed the bearings (its a cup and cone) and everything looks fine. I bought this bike used (old Bianchi road conversion), so I suspect it was bent all along and I just now noticed it. Nothing else looks damaged however; possibly the current spindle is not the stock spindle.

Last edited by mihlbach; 05-02-06 at 04:43 PM.
mihlbach is offline   Reply With Quote
Old 05-02-06, 04:55 PM   #7
baxtefer
Cornucopia of Awesomeness
 
baxtefer's Avatar
 
Join Date: Oct 2004
Location: not where i used to be
Bikes:
Posts: 4,847
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
i find it hard to believe that you twisted a solid half inch bar of steel using only your legs
baxtefer is offline   Reply With Quote
Old 05-02-06, 05:59 PM   #8
sers
Senior Member
 
sers's Avatar
 
Join Date: Oct 2005
Location: Salem, MA
Bikes: Land Shark, Level Professional, Tsunami singlespeed, Giant Reign 1
Posts: 2,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by baxtefer
i find it hard to believe that you twisted a solid half inch bar of steel using only your legs
sers is offline   Reply With Quote
Old 05-02-06, 06:06 PM   #9
na975
Guest
 
Bikes:
Posts: n/a
Mentioned: Post(s)
Tagged: Thread(s)
Quoted: Post(s)
^^^^ yeah, me too!
  Reply With Quote
Old 05-02-06, 06:17 PM   #10
sers
Senior Member
 
sers's Avatar
 
Join Date: Oct 2005
Location: Salem, MA
Bikes: Land Shark, Level Professional, Tsunami singlespeed, Giant Reign 1
Posts: 2,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
is it possible that the cartridge slipped out of/broke the fixing cup on the other side, and now is diagonal?
sers is offline   Reply With Quote
Old 05-02-06, 07:09 PM   #11
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by baxtefer
i find it hard to believe that you twisted a solid half inch bar of steel using only your legs
Well, so do I. I'm a strong cyclist but not that strong; thats why I'm perplexed.
mihlbach is offline   Reply With Quote
Old 05-02-06, 07:16 PM   #12
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by sers
is it possible that the cartridge slipped out of/broke the fixing cup on the other side, and now is diagonal?
Nice suggestion...but, no, the spindle is not diagonal. I inspected the BB and BB shell for damage and theres nothing wrong with it. It spins straight and smooth; the bottom bracket is undamaged, installed correctly, etc. The crank arms are simply not perfectly 180 degrees opposite from eachother. As noted above the crank arms and square tapir part of the spindle are in good shape, not rounded...all I can figure is that the spindle is twisted.
mihlbach is offline   Reply With Quote
Old 05-02-06, 07:17 PM   #13
baxtefer
Cornucopia of Awesomeness
 
baxtefer's Avatar
 
Join Date: Oct 2004
Location: not where i used to be
Bikes:
Posts: 4,847
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've seen people collapse crank spiders sprinting out of a trackstand, but bending a BB spindle would be waaaaay past that.
baxtefer is offline   Reply With Quote
Old 05-02-06, 07:20 PM   #14
Hellseeker
Murder Face Crew
 
Hellseeker's Avatar
 
Join Date: Apr 2006
Bikes:
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
....and people tell me having a beer and gazing at my bike serves no purpose.
Hellseeker is offline   Reply With Quote
Old 05-02-06, 07:20 PM   #15
dutret
Banned
 
Join Date: May 2005
Location: GA
Bikes:
Posts: 5,317
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I snapped one off once. Noone at the bike shop would believe me till I brought it in to show them.
dutret is offline   Reply With Quote
Old 05-02-06, 07:21 PM   #16
transplant
this portrait of karma
 
transplant's Avatar
 
Join Date: Aug 2005
Location: chicago
Bikes:
Posts: 1,238
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by sers
we train together

transplant is offline   Reply With Quote
Old 05-02-06, 07:22 PM   #17
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by baxtefer
I've seen people collapse crank spiders sprinting out of a trackstand, but bending a BB spindle would be waaaaay past that.

The right crank doesn't really torque the spindle when pedaling..the force goes directly to the spider into the chainring. The left on the other hand, torques the spindle. So its really only possible to twist the spindle with the left arm..but I agree, the cranks or frame are probably more likely to break before the spindle twist/bends.
mihlbach is offline   Reply With Quote
Old 05-02-06, 07:26 PM   #18
baxtefer
Cornucopia of Awesomeness
 
baxtefer's Avatar
 
Join Date: Oct 2004
Location: not where i used to be
Bikes:
Posts: 4,847
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
granted, it was one of those flimsy Kooka CNC jobbies...



bent frame maybe?
baxtefer is offline   Reply With Quote
Old 05-02-06, 07:30 PM   #19
mihlbach
Senior Member
Thread Starter
 
mihlbach's Avatar
 
Join Date: Dec 2005
Location: Long Island, NY
Bikes:
Posts: 6,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by baxtefer
granted, it was one of those flimsy Kooka CNC jobbies...



bent frame maybe?

dude, you should change that..you might throw your chain. I hope you are using brakes!
mihlbach is offline   Reply With Quote
Old 05-02-06, 08:00 PM   #20
Sin-A-Matic
Senior Member
 
Join Date: Oct 2005
Location: Seattle, WA
Bikes:
Posts: 479
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by baxtefer
granted, it was one of those flimsy Kooka CNC jobbies...



bent frame maybe?

Is that one of those biopace chainrings?
Sin-A-Matic is offline   Reply With Quote
Old 05-02-06, 08:52 PM   #21
sers
Senior Member
 
sers's Avatar
 
Join Date: Oct 2005
Location: Salem, MA
Bikes: Land Shark, Level Professional, Tsunami singlespeed, Giant Reign 1
Posts: 2,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by transplant
we train together

gnarly! what kind of crank was that
sers is offline   Reply With Quote
Old 05-02-06, 10:26 PM   #22
Brad M
nub
 
Brad M's Avatar
 
Join Date: Apr 2005
Location: The Hammer, Ontario
Bikes:
Posts: 264
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by transplant
we train together

(A little OT)

Is it safe to mount your chainring on the back of the spider like that, or will my crank arms explode too? It might be an easy way to fix my wonky chainline.
Brad M is offline   Reply With Quote
Old 05-02-06, 10:31 PM   #23
thurstonboise
Senior Member
 
Join Date: Feb 2006
Location: Boise, Idyho
Bikes: '04 fisher 29er, NYC Bikes CityFixed
Posts: 676
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Brad M
(A little OT)

Is it safe to mount your chainring on the back of the spider like that, or will my crank arms explode too? It might be an easy way to fix my wonky chainline.
They'll explode. It happens to roadies all the time riding on the little ring.
thurstonboise is offline   Reply With Quote
Old 05-02-06, 10:52 PM   #24
legalize_it
legalize bikes
 
Join Date: May 2003
Location: bucks county, PA
Bikes: too damn many
Posts: 1,250
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
spindles can and do twist after a long time of fatigue. its very common in heavily used old cottered cranks. ive seen it plenty of times before on cottered, but never on a square taper. unless its super old id guess it to be a manufacturing defect.
legalize_it 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 08:33 AM.