Installing pedals - how much torque?
02-11-07, 10:05 AM
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Installing pedals - how much torque?
Hi all. I've been riding for years, but here's a "noobie" style question: just bought new Look Keo pedals which install with an 8mm hex -- instructions recommend 40nm of torque. I have never installed my own pedals and do not own a torque wrench, an am worried about stripping out the crank threads. So here's the question: should I just go ahead and put these on myself without a torque wrench, and if so, how far should I torque them -- in other words, how critical is it, and how easily will I strip out the crank threads (Ultegra 9-sp cranks)? Thanks in advance for your advice.
02-11-07, 11:03 AM
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Don't worry about the torque wrench. Just tighten the pedals nice and tight - tight enough so you're using your muscles, but not so tight that you're straining them. Be sure to apply grease to the threads. Your feet will do the rest, over time, as you pedal.
02-11-07, 11:56 AM
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The tighter you put them on, the more likely you will have blood involved when you are taking them off.
02-11-07, 12:27 PM
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My method is once the pedal is tight to the crank, I torque it one-half of a turn.
02-11-07, 01:29 PM
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Originally Posted by FlatFender
snug.
02-11-07, 01:40 PM
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Originally Posted by Coyote2
So, pedals will not fall off if they are under-torque'd?
40nm is firm enough to tense your arm, but your jaw should still be relaxed.
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02-11-07, 02:21 PM
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Originally Posted by Coyote2
So, pedals will not fall off if they are under-torque'd?
02-11-07, 03:03 PM
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Originally Posted by OLDYELLR
Bicycle builders got by without torque wrenches for centuries.
02-11-07, 03:15 PM
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Originally Posted by Coyote2
Hi all. I've been riding for years, but here's a "noobie" style question: just bought new Look Keo pedals which install with an 8mm hex -- instructions recommend 40nm of torque. I have never installed my own pedals and do not own a torque wrench, an am worried about stripping out the crank threads. So here's the question: should I just go ahead and put these on myself without a torque wrench, and if so, how far should I torque them -- in other words, how critical is it, and how easily will I strip out the crank threads (Ultegra 9-sp cranks)? Thanks in advance for your advice.
Stripping the threads happens when they're too loose, so they move around in the threads.
If you're using a typical length 8 mm Allen wrench, make them as tight as you can get them.
Normally pedals are installed with a wrench over a foot long.
Sheldon "ELDI" Brown
02-11-07, 07:50 PM
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[QUOTE=Eatadonut]doubtful. You'd have to REALLY undertorque them, and pedal backwards a lot./QUOTE]
Don't bet the rent money on that one. If pedals aren't put on pretty snugly they can definitely come off.
Don't bet the rent money on that one. If pedals aren't put on pretty snugly they can definitely come off.
02-11-07, 10:41 PM
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I put them in snug enough while not going crazy on it. I've struggled with too many stuck pedals to make the mistake of over tightening. I count on the fact they'll be kept tight by the forward pedal motion
02-11-07, 10:47 PM
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Originally Posted by Portis
The tighter you put them on, the more likely you will have blood involved when you are taking them off.
Amen
02-12-07, 12:17 AM
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Originally Posted by Portis
The tighter you put them on, the more likely you will have blood involved when you are taking them off.
02-12-07, 06:20 AM
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Originally Posted by OLDYELLR
The reason pedals are threaded left and right the way they are is so they don't loosen. Don't obsess over torque. Bicycle builders got by without torque wrenches for centuries. In my opinion, on bikes they're only required by people with absolutely no mechanical empathy.
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02-12-07, 10:08 AM
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Originally Posted by nitropowered
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
02-12-07, 01:45 PM
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Originally Posted by nitropowered:
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
02-12-07, 01:52 PM
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Originally Posted by Coyote2
Originally Posted by nitropowered:
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
02-12-07, 01:55 PM
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Originally Posted by operator
I'd really like to see what happens when someone uses an 8mm and strips out the the hole, now what?
02-12-07, 02:13 PM
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I rarely use my pedal wrench anymore and usually just go with the hex key. I've never had any trouble, although I do have my pedals on and off fairly often switching my favourites between bikes. Don't forget those pedals were put on with a key too, so they won't be as tight as normal anyhow.
If someone did strip the hex you could always go the ez-out route (well, on the rh pedal at least.) Same argument if you round off the flats on a standard pedal anyhow...
If someone did strip the hex you could always go the ez-out route (well, on the rh pedal at least.) Same argument if you round off the flats on a standard pedal anyhow...
02-12-07, 02:31 PM
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Originally Posted by Coyote2
Originally Posted by nitropowered:
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen,
"Wow, that seems like a pretty boneheaded design decision."
Is it gonna be murder to eventually remove those pedals?
Now really bizarrely, each side of my pedals uses a different size hex wrench. No one has been able to give me a good reason why that would be.
02-12-07, 03:03 PM
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28lb-ft-regular 5" allen-impossible to strip
40NM is about 28lb-ft of torque. Sheldon is right of course (big surprise); it will be close to impossible to overtorque these with the typical 8mm Allen wrench which is about 5" long.You would have to be capable of putting out 80 lbs of force with one hand, on a short, thin allen wrench. Superman-maybe-the rest of us, no way. Now, if you have allen bits for a socket wrench(-7"-8" long) you would still have to put out close to 60 lbs of force-a lot for one hand.
Put them on with antiseize or grease.Clean the threads on the crankarms very well first.
Luck,
Charlie
Put them on with antiseize or grease.Clean the threads on the crankarms very well first.
Luck,
Charlie
02-12-07, 04:43 PM
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Originally Posted by phoebeisis
40NM is about 28lb-ft of torque.
I've given up correcting folks who ignorantly use "foot pounds" when they should be referring to lb-ft.
The foot pound is a unit of work or energy. The pound foot is the unit of torque. At least that's what I learned in high-school physics.
Sheldon "Units" Brown
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