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Installing pedals - how much torque?

Old 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.
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Old 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.
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Old 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.
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Old 02-11-07, 12:15 PM
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So, pedals will not fall off if they are under-torque'd?
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Old 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.
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Old 02-11-07, 12:44 PM
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snug.
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Old 02-11-07, 01:29 PM
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Originally Posted by FlatFender
snug.
+1 I use antiseize compound rather than grease. It is only a few $ at the automotive store and will last for years.
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Old 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?
doubtful. You'd have to REALLY undertorque them, and pedal backwards a lot.

40nm is firm enough to tense your arm, but your jaw should still be relaxed.
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Old 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?
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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Old 02-11-07, 03:03 PM
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Originally Posted by OLDYELLR
Bicycle builders got by without torque wrenches for centuries.
Now that's a well researched statement.
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Old 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.
Worry about having them too loose, not too tight.

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.

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Old 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.
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Old 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
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Old 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
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Old 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.
since keo's dont have flats on the pedal spindle for a pedal wrench and only an 8mm allen, I make it tight enough so it doesn't just spin off, but loose enough that I can easily take off the pedal w/o taking off all the skin on my knuckles.
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Old 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.
or on CF components
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Old 02-12-07, 07:51 AM
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Really tight, with grease = you can take them off again.
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Old 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,
Wow, that seems like a pretty boneheaded design decision.
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Old 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?
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Old 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?
I'd really like to see what happens when someone uses an 8mm and strips out the the hole, now what?
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Old 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?

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Old 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...
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Old 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?
Same on my Time pedals. it means everything can be more snugly over against the cranks as there doesn't need to be any room for a spanner [wrench] to grab.

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.
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Old 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
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Old 02-12-07, 04:43 PM
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Originally Posted by phoebeisis
40NM is about 28lb-ft of torque.
Wow, somebody other than me who remembers the correct English units for 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.

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