Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

PSA: Chainwheels are nasty

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

PSA: Chainwheels are nasty

Old 06-01-19, 12:53 PM
  #1  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
PSA: Chainwheels are nasty

This is what happens when you get impatient removing a crankset.



In the ER awaiting my 5 stitches. Hastily bandaged at home so as not to bleed all over my car. Also, don't go back and finish the job before the lidocaine wears off. When they tell you not to use the hand, don't use the hand. Now I have nice, new chainrings on a bike I can't ride.
BobFishell is offline  
Old 06-01-19, 12:54 PM
  #2  
Bill Kapaun
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,824

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1774 Post(s)
Liked 1,231 Times in 852 Posts
have you tried the head in the vise trick?
Bill Kapaun is offline  
Old 06-01-19, 01:13 PM
  #3  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
Originally Posted by Bill Kapaun
have you tried the head in the vise trick?
Not since I retired. Saved a sh&%load of money on Advil.
BobFishell is offline  
Old 06-01-19, 01:53 PM
  #4  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,003

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4172 Post(s)
Liked 3,793 Times in 2,272 Posts
Did you see bone? When I did it gave me a sick feeling. Mine came when tightening a Stronglight 99 crank with it's 16mm arm bolt. needless to say I think about that every time I touch a wrench to a crank arm retaining bolt. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Likes For Andrew R Stewart:
Old 06-01-19, 01:58 PM
  #5  
Cyclist0108
Occam's Rotor
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Sorry about the wound. I hope it heals rapidly and fully.

Wrap the chain around the (big) ring.
Cyclist0108 is offline  
Likes For Cyclist0108:
Old 06-01-19, 02:22 PM
  #6  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times in 723 Posts
And put a rag over the chain. Chain will bloody knuckles every time.
dsbrantjr is offline  
Likes For dsbrantjr:
Old 06-01-19, 02:24 PM
  #7  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
I'm pretty sure it cut to the bone, but the wound was too bloody to see. I take blood thinners, which compounds the problem quite a bit. It was very painful after the anesthetic wore off, and I was worried that I had popped a stitch by continuing to work on the bike after I got back from the ER. I took the dressing off and the stitches were intact, but I'd aggravated the wound enough that it started bleeding like hell again. Plavix will do that. It looked a lot better when I changed the dressing this morning. I did a little light work on the bike today, but I didn't use my left hand for very much.
BobFishell is offline  
Old 06-01-19, 02:30 PM
  #8  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
Originally Posted by wgscott
Sorry about the wound. I hope it heals rapidly and fully.

Wrap the chain around the (big) ring.
The chain was already off the bike. I was doing a complete drivetrain overhaul – repacked the wheel bearings, overhauled the rear derailleur, new cassette, chain, chainwheels. The fixing bolt on the crank arm was a little stubborn, and when I put a little more oomph into the wrench, it let go and my hand went into the chainring. That was incredibly stupid. I knew better than to loosen it the way I did, but I was getting impatient; wanted to finish the job so I could ride the bike.
BobFishell is offline  
Old 06-01-19, 03:24 PM
  #9  
delbiker1 
Mother Nature's Son
 
delbiker1's Avatar
 
Join Date: Mar 2016
Location: Sussex County, Delaware
Posts: 3,111

Bikes: 2014 Orbea Avant MD30, 2004 Airborne Zeppelin TI, 2003 Lemond Poprad, 2001 Lemond Tourmalet, 2014? Soma Smoothie

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 838 Post(s)
Liked 1,414 Times in 801 Posts
Originally Posted by BobFishell
The chain was already off the bike. I was doing a complete drivetrain overhaul – repacked the wheel bearings, overhauled the rear derailleur, new cassette, chain, chainwheels. The fixing bolt on the crank arm was a little stubborn, and when I put a little more oomph into the wrench, it let go and my hand went into the chainring. That was incredibly stupid. I knew better than to loosen it the way I did, but I was getting impatient; wanted to finish the job so I could ride the bike.
I did almost the same thing about 2 weeks ago. I also had the chain off, switching out chain rings. When I did it, I lost my balance when the bolt let go, and my arm scraped along the big ring . I had a nasty scratch from the heel of my hand all the way up the inside of the forearm, and a couple of inches above the elbow. The wound was not dirty as the rings were brand new. It bled a fair amount and for the next few days people kept asking my how I got a such a long, jagged scratch on my arm. My answer was impatience and a moment of stupidity.
delbiker1 is offline  
Likes For delbiker1:
Old 06-01-19, 03:48 PM
  #10  
jideta
Senior Member
 
Join Date: Apr 2019
Location: Honolulu
Posts: 262
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Liked 139 Times in 74 Posts
I feel your pain.
Okay, not really.
Almost did myself a bad too a couple weeks ago as I was working on my cranks.
I usually err on the side of haste gets you injured but I stared at that narrow wide bad boy for a second and decided that I'm too old for that *****. Wrapped the ring with a rag. Twice.
Still hurt when I broke the pedal and hit the ring but at least I didn't break skin.
Put on some Neosporin to help that boo boo along.
jideta is offline  
Likes For jideta:
Old 06-01-19, 04:14 PM
  #11  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
Good tips, but if I had been patient enough to wrap a rag around the chainwheel, I'd have been patient enough to get a different grip on the wrench. I've done this job dozens of times, too.
BobFishell is offline  
Old 06-01-19, 04:15 PM
  #12  
ridelikeaturtle
Senior Member
 
ridelikeaturtle's Avatar
 
Join Date: Nov 2015
Location: Dublin, Ireland
Posts: 1,259

Bikes: Bianchi Ti Megatube; Colnago Competition; Planet-X EC-130E; Klein Pulse; Amp Research B4; Litespeed Catalyst; Trek Y11

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 596 Post(s)
Liked 476 Times in 258 Posts
I've learned, the hard way, to either push with an open hand, or if you have the option, to pull up on a wrench.

But I still make mistakes, like crushing my finger in a fold-up bed. At least that was a hospital's fold-up bed, so the A&E ("accident and emergency"; or "emergency room" for North Americans) was right there. Pro-tip: if you tell the A&E receptionist you suffered your injury in the hospital, they don't even ask you about insurance details, and you get to skip the queue...
ridelikeaturtle is offline  
Likes For ridelikeaturtle:
Old 06-01-19, 04:39 PM
  #13  
LAJ
So it is
 
LAJ's Avatar
 
Join Date: Sep 2008
Location: Westminster, CO
Posts: 21,226

Bikes: Luzerne, 684, Boreas, Wheelhouse, Alize©®, Bayamo, Cayo

Mentioned: 245 Post(s)
Tagged: 1 Thread(s)
Quoted: 11321 Post(s)
Liked 4,635 Times in 2,701 Posts
Originally Posted by Bill Kapaun
have you tried the head in the vise trick?
I did, but my ears got in the way. It made me forget about the pain in my hand though.
LAJ is offline  
Likes For LAJ:
Old 06-01-19, 05:00 PM
  #14  
Cyclist0108
Occam's Rotor
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Originally Posted by BobFishell
Good tips, but if I had been patient enough to wrap a rag around the chainwheel, I'd have been patient enough to get a different grip on the wrench. I've done this job dozens of times, too.
I hurt my hand every time I do this, which was as recently as yesterday. I never take the time to wrap a chain on the big ring and/or wear work-gloves.

But I should. I think you just convinced me.
Cyclist0108 is offline  
Old 06-01-19, 05:34 PM
  #15  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,936

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3571 Post(s)
Liked 3,367 Times in 1,916 Posts
I wear leather welder's gloves for jobs like that.
JohnDThompson is offline  
Likes For JohnDThompson:
Old 06-01-19, 06:30 PM
  #16  
gearbasher
Senior Member
 
gearbasher's Avatar
 
Join Date: May 2009
Location: Sitting on my butt in front of a computer
Posts: 1,535
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 440 Post(s)
Liked 835 Times in 363 Posts
Whenever I'm working on the crankset, I angle the wrench so I can grab the crank arm and the wrench with both hands and squeeze. Always breaks easily and no chance of mangling anything.
gearbasher is offline  
Old 06-02-19, 05:22 AM
  #17  
Last ride 76 
1/2 as far in 2x the time
 
Last ride 76's Avatar
 
Join Date: Nov 2013
Location: Northern Bergen County, NJ
Posts: 1,935

Bikes: Yes, Please.

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 499 Post(s)
Liked 285 Times in 222 Posts
Originally Posted by gearbasher
Whenever I'm working on the crankset, I angle the wrench so I can grab the crank arm and the wrench with both hands and squeeze. Always breaks easily and no chance of mangling anything.
My grip isn't that strong. If the crank bolt really doesn't want to break free, I take the bike off the stand and back on the floor and put my shoulder into it . Same for the pedals...

Sorry for your injury. Here's to healing quickly, and fully!
Last ride 76 is offline  
Old 06-02-19, 08:13 AM
  #18  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 3,036

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1152 Post(s)
Liked 340 Times in 250 Posts
Been there. Done that, but not quite as severely. You did it big time. I think that the judges would give you a 7 of 10 style points, where 10 is the loss of a digit or limb. I hope you heal rapidly and completely.

Your sharing may help several people avoid this disaster, so thanks.

Practically, this points out that
1) Folks applying large forces in the vicinity of sharp bike objects should be aware of potential injuries like this and take steps to avoid, to wit:
2) One should have a safety chain to put around the chainring. Home mechanics if possible. Shops, for sure.
3) One should avoid applying a lot of torque to a crank when balancing the force with the pedal or crank ON THE SIDE OPPOSITE THE WRENCH. This means
a) If you can, get the wrench handle set up nearly parallel to the crank arm on the same side. This results in applying two forces in opposite directions. So tightening (or loosening) involves squeezing the arm and wrench rather than trying to apply 100 lbs or more of force to the wrench arm on one side of the crank, and balancing this with more than 100 lbs force using the crank arm on the side opposite the wrench. So that if something lets go you are applying a couple hundred pounds of force in the same direction.
b) I find squeezing the crank arm and wrench together is easy and best for me but I have large hands. If squeezing doesn't work for you then with the wrench and crank arm on the same side you can at least have one hand straight out bracing the crank arm, and the other straight out pulling(best) or pushing (ok). With both arms straight, the force is through your shoulders, and if something lets loose there's not a lot of travel that your arms traverse before the force is disippated.
4) Best to do work so that if something does let loose the hand that is freed and traveling at high velocity is not oriented to travel towards the chainwheel, or the floor, or your chin.

This also points out why you should use as short a socket as possible so that the force of the wrench is entirely tranlsated to bolt torque, and so that you don't have to use one hand to balance the socket end of the wrench. The Park Tool is nice because the socket is so shallow and very little axial moment is introduced. This also pointed out to me just how well-suited-to-purpose the old stamped steel wrenches were. Force was applied just about as close to the center plane of the bolt head as possible.

Don't ask me how I know this stuff or why I thought through it in such detail.


WizardOfBoz is offline  
Old 06-02-19, 08:16 AM
  #19  
02Giant 
Senior Member
 
Join Date: Jan 2011
Posts: 2,977
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1638 Post(s)
Liked 741 Times in 495 Posts
A follow up, post stitches, picture is warranted.
__________________
nine mile skid on a ten mile ride
02Giant is offline  
Old 06-02-19, 06:37 PM
  #20  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
Addendum: the swelling in my thumb was down enough for me to ride the bike I was working on when this little tragedy happened. New rings, chain, and cassette – ah, the dead quiet and silky-smooth shifting of a new powertrain.
BobFishell is offline  
Old 06-02-19, 06:38 PM
  #21  
BobFishell
Senior Member
Thread Starter
 
BobFishell's Avatar
 
Join Date: Apr 2019
Location: Chicago area, IL
Posts: 61

Bikes: 1990 Klein Quantum, 1995 Klein Quantum Pro, 1997 Klein Pulse Comp, Cannondale 3.0 (junk box build - year unknown)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 6 Times in 6 Posts
It should leave a pretty impressive scar. I already have quite a collection. It's why I never felt the need for a tattoo.
BobFishell is offline  
Old 06-02-19, 06:43 PM
  #22  
Cyclist0108
Occam's Rotor
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Soo ... which blood type makes the best chain lube?
Cyclist0108 is offline  
Old 06-02-19, 08:59 PM
  #23  
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: Metro Indy, IN
Posts: 16,217

Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked 345 Times in 225 Posts
Originally Posted by wgscott
Soo ... which blood type makes the best chain lube?
O negative would be the universal donor chain lube - good for all chains...........
__________________
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
JanMM is offline  
Old 06-03-19, 04:10 PM
  #24  
Last ride 76 
1/2 as far in 2x the time
 
Last ride 76's Avatar
 
Join Date: Nov 2013
Location: Northern Bergen County, NJ
Posts: 1,935

Bikes: Yes, Please.

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 499 Post(s)
Liked 285 Times in 222 Posts
+1 for any version of peanut butter wrench... Deep socket bad.
Last ride 76 is offline  
Old 06-03-19, 04:47 PM
  #25  
seedsbelize 
smelling the roses
 
seedsbelize's Avatar
 
Join Date: Nov 2010
Location: Tixkokob, Yucatán, México
Posts: 15,428

Bikes: 79 Trek 930, 80 Trek 414, 84 Schwinn Letour Luxe (coupled), 92 Schwinn Paramount PDG 5

Mentioned: 104 Post(s)
Tagged: 1 Thread(s)
Quoted: 7081 Post(s)
Liked 901 Times in 612 Posts
I got my wrist/forearm scar trying to remove a freewheel incorrectly, while under the influence of cold medicine. Another form of impatience. A stupider form.
Heal well.
__________________
Originally Posted by Bah Humbug
Auto-pause is a honey-tongued devil whispering sweet lies in your ear.


seedsbelize is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.