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


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-05-04, 07:01 PM   #1
akirafist
Member
Thread Starter
 
akirafist's Avatar
 
Join Date: Apr 2004
Bikes:
Posts: 42
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Had to ride 3 miles on a nub.

I'm riding up a steep hill and hammering to get to the top when I feel my left pedal tilting outward. I'm thinking, "Is that my imagination or is my..." SNAP! The stupid pedal comes completely off. I stop and examine it, and my pedal threads are covered in metal goo and the crank head is totally smooth inside:



Brand new bike too (Specialized Sequoia). What causes this? The actual pedal is just fine, threads are in tact but my crank is 100% stripped and smooth. Any suggestions on alternate pedal/crank shaft so I don't take another nosedive in mid-street with cars coming?

Last edited by akirafist; 05-05-04 at 07:12 PM.
akirafist is offline   Reply With Quote
Old 05-05-04, 07:23 PM   #2
wrench_meister
Senior Member
 
wrench_meister's Avatar
 
Join Date: Aug 2003
Location: Las Cruces, NM
Bikes: The only one I'll ever need...
Posts: 102
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Could be that the pedal was not properly tightened upon installation....
wrench_meister is offline   Reply With Quote
Old 05-05-04, 07:48 PM   #3
seely 
The Rabbi
 
seely's Avatar
 
Join Date: Apr 2004
Bikes:
Posts: 5,087
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'm guessing the pedal was cross threaded... no crankset except those on Walmart bikes ever does that really, so its a bad installation most likely. It will require replacement of the crankarm, and if they try to salvage the arm with a helicoil or anyhting like that just tell them no thanks, you want a new one.
seely is offline   Reply With Quote
Old 05-05-04, 08:02 PM   #4
supcom
You need a new bike
 
supcom's Avatar
 
Join Date: Aug 2002
Bikes:
Posts: 5,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It looks like the pedal was crossthreaded when installed and instead of the mechanic owning up to his mistake and replacing the crank, he just used the long pedal wrench to force it in. This cut new threads in the aluminum crank alongside the original and weakened the holding force of the crank. Repeated pressure on the pedal caused the axle to pull through the weakened threads.

Assuming these are the original pedals installed by the LBS where you bought the bike, you have a beef with them. Since you stated the bike is brand new, there should be no question of warrantee repair. If you installed these pedals yourself, the issue gets a bit dicey.

For the benefit of the home mechanic: It's very easy to crossthread a steel bolt into aluminum. The aluminum is softer than steel so it's easily possible to get a half turn or more with the bolt before you realize it's crossthreaded. Whenever possible, one should always turn a bolt backwards until you feel the threads 'click' into place, then turn forward to engage the threads. Turn gently and if there is any binding, back the bolt out and check for crossthreading.
supcom is offline   Reply With Quote
Old 05-05-04, 08:16 PM   #5
John E
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Bikes: 1959 Capo; 1980 Peugeot PKN-10; 1981 Bianchi; 1988 Schwinn KOM-10;
Posts: 17,056
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 66 Post(s)
The dealership owes you a new crank, a big apology, and a sigh of relief that you were uninjured. I used to see similar problems back in the bad old days, when French bikes used 14mm x 1.25mm pedal threads, instead of everyone else's 9/16 x 20 TPI.
__________________
"Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1981 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline   Reply With Quote
Old 05-05-04, 08:18 PM   #6
Rev.Chuck
The Red Lantern
 
Rev.Chuck's Avatar
 
Join Date: Apr 2003
Location: Raleigh NC
Bikes:
Posts: 5,965
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The pedal was not tightened on installation, if it had been crossthreaded fully into the crankarm it would, more likely, just be there for ever, crooked.
If you bought it from a bike shop they should give you a new crank arm. If you bought it from a Wallyworld or similar they will give you another bike.
__________________
Are you a registered member? Why not? click here to register. Its free, and only takes 27 seconds!
Help out the forums, abide by our community guidelines.

I am in the woods and I have gone crazy.
Rev.Chuck is offline   Reply With Quote
Old 05-05-04, 08:53 PM   #7
Cycliste
Member
 
Join Date: Sep 2003
Bikes: Surley LHT, Cannondale R1000, IBEX Ignition, Bianchi Boardwalk, KHS Milano Tandem
Posts: 880
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Good picture though, maybe you should get that fixed where you bought your camera . Sorry, couldn't resist.
Where do the crank and pedal originate from and who put them together ? Can we help ?
Cycliste is offline   Reply With Quote
Old 05-05-04, 10:45 PM   #8
Robert Gardner
Senior Member
 
Join Date: Nov 2003
Location: Sierra Madre, CA, USA
Bikes: Trek 5300
Posts: 303
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Could it be that your bike was fitted with two right hand pedals by some accident? Check the pedal and make sure it is labeled "L". That is the only way I can emagine that it could be stripped out so cleanly.
Robert Gardner is offline   Reply With Quote
Old 05-06-04, 06:13 AM   #9
dirtbikedude
Gravity Is Yer Friend
 
dirtbikedude's Avatar
 
Join Date: May 2002
Location: "Over the Hill" and going down fast in the 805.
Bikes: Scott Gambler, Scott Ransom, Kona Bear, Bianchi 928 Carbon/Chorus, C'Dale Rize4
Posts: 2,961
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I would guess cross threaded or some one used a bit to much elbow grease. There is also the possibility that the metal had some structural defect from the company. Either way if the bike is new the shop should replace it for you free of charge.

dirtbikedude is offline   Reply With Quote
Old 05-06-04, 08:45 AM   #10
AndrewP
Senior Member
 
Join Date: Sep 2001
Location: Montreal
Bikes: Peugeot Hybrid, Minelli Hybrid
Posts: 6,521
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The uneven gouge on the face of the crank shows that the pedal wasnt in straight - i.e. cross threaded. Since Wallyworld doesnt sell Sequoias, take it to the bikeshop.
AndrewP is offline   Reply With Quote
Old 05-06-04, 09:32 AM   #11
sorebutt
Über member!
 
sorebutt's Avatar
 
Join Date: Sep 2001
Location: Sunnyvale, CA.
Bikes: 2004 Albert Eisentraut
Posts: 993
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
if you want to fix it yourself, you can try the pedal thread repair kit from biketoolsetc.com it is not cheap but will save you a new crank.
sorebutt is offline   Reply With Quote
Old 05-06-04, 03:39 PM   #12
Phatman
Senior Member
 
Join Date: Sep 2002
Location: NC
Bikes:
Posts: 3,411
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
i remeber reading about the truvativ elita cranks having trouble where the steel thread insert to the aluminum cranks was prone to coming out the older models. perhaps this happend to yours?
Phatman is offline   Reply With Quote
Old 05-06-04, 04:15 PM   #13
akirafist
Member
Thread Starter
 
akirafist's Avatar
 
Join Date: Apr 2004
Bikes:
Posts: 42
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Well I took it back to my LBS, told them what happened and the manager sicked two guys on it immediately after apologizing. I also mentioned my wheel went awry as the pedal broke and I did a Grassy Knoll so he volunteered to true it for me too. Twenty minutes later I had a new crank and true wheel - good as new. I watched them put the force of Jesus on that pedal when they got to the end of tightening, so shouldn't be a recurring problem I hope.

I'm definitely giving this shop more of my business.
akirafist is offline   Reply With Quote
Old 05-06-04, 04:26 PM   #14
khuon
DEADBEEF
 
khuon's Avatar
 
Join Date: Aug 2002
Location: Catching his breath alongside a road near Seattle, WA USA
Bikes: 1999 K2 OzM, 2001 Aegis Aro Svelte
Posts: 12,242
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by akirafist
I watched them put the force of Jesus on that pedal when they got to the end of tightening, so shouldn't be a recurring problem I hope.
I'm not so sure overtorquing the pedals... especially the left-side pedal is a good idea. My technique is to grease the threads and then thread the pedal on by hand to make sure I'm not crossthreading. Then I take the pedal wrench and snug them up. Park Tool recommends 30 lbs-ft. I guestimate. At anyrate, the left-side pedal will work its way tight on its own; no need to give it too much torque during installation.
__________________
1999 K2 OzM 2001 Aegis Aro Svelte
"Be liberal in what you accept, and conservative in what you send." -- Jon Postel, RFC1122
khuon is offline   Reply With Quote
Old 05-06-04, 05:17 PM   #15
supcom
You need a new bike
 
supcom's Avatar
 
Join Date: Aug 2002
Bikes:
Posts: 5,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by khuon
I'm not so sure overtorquing the pedals... especially the left-side pedal is a good idea. My technique is to grease the threads and then thread the pedal on by hand to make sure I'm not crossthreading. Then I take the pedal wrench and snug them up. Park Tool recommends 30 lbs-ft. I guestimate. At anyrate, the left-side pedal will work its way tight on its own; no need to give it too much torque during installation.
Why would the left side have any more tendency to tighten than the right side? Since the right side is reverse threaded, shouldn't each pedal see the same forces relative to the thread direction?
supcom is offline   Reply With Quote
Old 05-06-04, 06:27 PM   #16
khuon
DEADBEEF
 
khuon's Avatar
 
Join Date: Aug 2002
Location: Catching his breath alongside a road near Seattle, WA USA
Bikes: 1999 K2 OzM, 2001 Aegis Aro Svelte
Posts: 12,242
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by supcom
Why would the left side have any more tendency to tighten than the right side? Since the right side is reverse threaded, shouldn't each pedal see the same forces relative to the thread direction?
Sorry... I didn't mean to imply that the left side will tighten up more than the right. You're right that each pedal would see the same forces although there is the whole dominant leg thing but let's disregard that for now. I should have left the sidedness out of the statement. At anyrate, the pedals will have a tendency to tighten themselves over time.
__________________
1999 K2 OzM 2001 Aegis Aro Svelte
"Be liberal in what you accept, and conservative in what you send." -- Jon Postel, RFC1122
khuon is offline   Reply With Quote
Old 05-06-04, 07:03 PM   #17
borneo_cyclist
Member
 
borneo_cyclist's Avatar
 
Join Date: Apr 2004
Location: Kuching, Malaysia
Bikes: china cheap bikes
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by akirafist
Brand new bike too (Specialized Sequoia). What causes this? The actual pedal is just fine, threads are in tact but my crank is 100% stripped and smooth. Any suggestions on alternate pedal/crank shaft so I don't take another nosedive in mid-street with cars coming?
I have a new USD 45 mountain bike and the pedal has fall off and change 4 times in 2 weeks when I am using it....but I finally find the solution :

1. remove the pedal bearing cover at the side of the pedal
2. put in some car engine oil (new)
3. rotate the pedal until it turns as smooth as a wheel
4. If it is not smooth, add in more oil
5. rotate in another direction and make sure it is smooth and noiseless also.
6. use an old cloth to clean the extra oil
7. install it into the crank
8. Make sure pedal turns smoothly and noiselessly at the crank
9. install back the pedal bearing cover

make sure u do not screw it too tight as this may damage the crank. remember that right pedal and left pedal are different. Try to ride the bike for few days and see how it goes. Carry the tools to open the pedal (15mm) wherever u go.
borneo_cyclist 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 05:24 AM.