Bicycle Mechanics - My pedal fell off!

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:

http://www.mydogatemyrebate.com/pedal.gif

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?

Could be that the pedal was not properly tightened upon installation....

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.

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.

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.

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.

Good picture though, maybe you should get that fixed where you bought your camera :D . Sorry, couldn't resist.
Where do the crank and pedal originate from and who put them together ? Can we help ?

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.

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.

:beer:

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.

if you want to fix it yourself, you can try the pedal thread repair kit (http://www.biketoolsetc.com/index.cgi?id=59272898813&d=single&c=Tools&sc=Thread%20Repair&tc=Complete%20Kits&item_id=EL-2299) from biketoolsetc.com it is not cheap but will save you a new crank.
http://www.biketoolsetc.com/Product_Images/EL-2299.jpg

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?

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.

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.

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?

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.

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.