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Torque guide?(28 posts)

Torque guide?Kristin
Apr 8, 2003 8:40 AM
Are there any standard torque guides? (I think there is one in the back of my Zinn book.) And are they worth following? In otherwords, can you trust a generic guide for all types of metal?? Lastly, are there any comprehensive torque charts downloadable online?

One of my thoughts about this steerer--since its bulged in 2 different spots and all the people who worked on my bike are pretty experienced--is that perhaps this steerer is prone to stretching. Mabey the wall isn't as think as other forks. Or perhaps the Aelle alloy used is softer than other types of steel steerers.
simple answer - follow the MFGRs published guidelines (nm)terry b
Apr 8, 2003 8:59 AM
We're talking about DeBernardiKristin
Apr 8, 2003 9:41 AM
They hardly have anything published. And not ever manufacturer puts out this info.
What "DeBernardi" part is being torqued?terry b
Apr 8, 2003 10:02 AM
is it a DeBernardi thing or is it someone else's thing attaching to your DeBernardi?

When I can't find the real-live answer I use someone else's spec. Similar parts by different MFGRs are often close. I'm guessing the tables in Zinn are probably derived from averages across MFGRs.
Kristin, when you say the steerer is bulged, what exactly dobill
Apr 8, 2003 10:01 AM
you mean? Is it a cro-moly steel steerer? Is it threaded or threadless? Where exactly is it bulged, how much, and how does the bulge manifest itself? What kind of stem are you using?
Most components come with a guide that tell you how much to torque the bolts. It wouldn't be from the frame manufactur. I think that the reason for this is that no one, certainly not I, can imagine that torqueing the heck out of little 4 and 5 mm bolts until they break ever, under any circumstances, would cause any part of the frame or fork to be damaged (with the exception of water bottle cage busses -- you can strip those -- and carbon steerers, which, if you use the wrong kind of stem or the wrong kind of bolt anchor/expander-nut thingies, you can damage a carbon steerer).
I posted that in another threadKristin
Apr 8, 2003 10:21 AM
In the other thread, I described the damage exactly. But I'm not looking for advice on the damage here. I've already assessed it and made a decision regarding the damaged fork. If you want to read about it, just check out my post about threaded forks.

I this post, I am simply wondering if anyone has compiled like tons of torque info for bike parts and perhaps has published that online...which would be really cool. If not, I know I can probably get the info, it will just take a few phone calls and some patience.

The other question I'm asking is how much the torque might vary from fork to fork. And if different types of steel have more give than others (which I assume would be true).
All steel threaded forks are similarMR_GRUMPY
Apr 8, 2003 10:42 AM
With your new steel fork, just crank the stem bolt down enough to make it tight, but not too tight. You want the stem to be able to turn when you crash. One good way to check the tightness is to stand in front of the bike, with the front wheel locked between your legs. You should be able to make your stem move from side to side, when you pull on the bars. If you get it too tight, you might "bulge" the stearer tube.
I don't know of any torque numbers for stems. It depends on the bolt size and how well it is greased.
re: Torque guide?Spoke Wrench
Apr 8, 2003 10:46 AM
I'd think that the specs in the Zinn book are reliable as long as you don't have specific directions from the component manufacturer that say otherwise. Basically, if you have a feel for torque, the Zinn recommendations say that most parts should be tightened snugly but not necessarily as tightly as you can manage.

In your case, Zinn says to tighten quill stem bolts to about 15 or 20 ft/lbs. Imagine a 20 pound weight hanging on the end of a 1 foot bar. That's snug, but most people can tighten a 6mm allen key a lot tighter than that if they try.

A stem doesn't have to be SUPER secure. It just has to be tight enough to maintain the height adjustment and to not twist in the steerer tube when you try to turn or if your wheel hits a bump. Since the wheel turns pretty easily in the headset bearings, the stem to steerer connection doesn't have to resist very much torque. Tightening the stem bolt enough to bulge the steerer tube doesn't sound like very competent wrenching to me.
See, my problem is interpretting the abiguityKristin
Apr 8, 2003 11:16 AM
Everyone says it should be tight, but not too tight. But if you're me, and have no frame of reference, then there is no way to know what too tight is, or if you've passed that point. So that's why I'm thinking about just getting a torque wrench so I don't have to guess about it.

I don't who did the damage, and I would agree with you. But all of the people who turned wrenches on this bike have years of expereince building bikes. I wouldn't have doubted the abilities of any of them. But there has been lots of stem work on this bike. Its had 3 different stems and the fork was removed twice. I wonder too, if its cumulative damage.
erm...aMbiguity?Kristin
Apr 8, 2003 11:17 AM
re: Torque guide? Come on, Sheldon!Mariowannabe
Apr 8, 2003 10:50 AM
I'm not aware or such a guide but it would sure be nice. I've been doing a fair amount of maintenance and upgrades to a several bikes this over the last month and the lack of consistency and published specs is somewhere between frustating and challenging. I found the universal statements in Zinn to be misleading. Mfg specs are great if you can get them. Campy is great about this as are many of the better known parts mfg. Much of its on the web. (I don't know why they don't simply list torque specs on the component. An ITM stem I have has this descretely printed on the underside.

But, to answer your question, I'm not aware of a compendium of torque specs. Where's Sheldon Brown when we need him?
I think you should find a new mechanic. IMHO. nmSpunout
Apr 8, 2003 10:51 AM
Hey Kristin -- Don't you just love theOldEdScott
Apr 8, 2003 11:26 AM
very specific answers you get to your very specific questions?
Hey Kristin -- Don't you just love thebicyclerepairman
Apr 8, 2003 11:43 AM
The problem as I see it is this: should the fork steerer tube break or separate from the stem, Kristin's questions might quickly shift from torque specifications to which local hospital has the best staffed emergency room. Who wants to be liable for giving advice on a part no one online has seen or held or measured? Not me.
Dude, what a moronic statementKristin
Apr 8, 2003 12:04 PM
Scott's comment was funny and insightful. I never asked anyone if I should get a new mechanic. Who works on my bike is really not the business of anyone here. Also I did not ask you what friggin torque to use on my stem, did I? Please go back and read my post if you are in doubt. And even if I did, you can calm down Gumby, because I wouldn't be able to drag you into court, now would I?

Just imagine. I'll call the prosectutors office and say, "Um yes, I'd like to press charges against bicyclerepairman from RoadBikeReview.com....Yes, that's correct. He told me the wrong torque specifications for an unnamed fork I installed in my unnamed bike and I crashed as a result. Um...well, I don't think he has a last name. He's just bicyclerepairman."
Gumby? nmJS Haiku Shop
Apr 8, 2003 12:08 PM
I like Gumby.Leave him out of this:-) (nm)PEDDLEFOOT
Apr 8, 2003 12:12 PM
Inside joke. Gumby wasKristin
Apr 8, 2003 12:14 PM
what you got dubbed in my college circle when you irritated someone.
At least you didn't dis Pokey(nm)PEDDLEFOOT
Apr 8, 2003 12:25 PM
I'd never dis Pokey. nmKristin
Apr 8, 2003 12:55 PM
Dude, what a moronic statementbicyclerepairman
Apr 8, 2003 3:06 PM
The prosectutor?
That someone who teaches the art of dismembering. nmKristin
Apr 8, 2003 3:15 PM
Dammit. That IS somone who...Kristin
Apr 8, 2003 3:15 PM
I am not a moron
I am not a moron
I am not a moron
Check Here --Gregory Taylor
Apr 8, 2003 1:54 PM
http://www.parktool.com/repair_help/torque.shtml

This gives you a pretty decent breakdown of various recommended torque values, even going as far as to compare Mr. Zinn's recommendations to other common sources of wisdom. As always, go with what the manufacturer recommends, if they provide their own guidance.

For what it is worth, if you are really interested in working on your bike, you might consider taking a class or two on bike repair. Either that or slip your favorite bike mechanic a beer or three to get him or her to show you how to do jobs on your bike as they come up. I'm guessing from your questions that you are really starting from ground zero on the whole wrenching thing. It isn't rocket science, but doing it well without buggering up parts takes some experience. It can get expensive learning how to do things on your good equipment. Even experienced wrenches can leave behind bulged steering tubes...
Thanks, that's the kinda thing I'm looking forKristin
Apr 8, 2003 3:18 PM
I had to wade through a whole day of, "Get a new mechanic," and, "I refuse to tell you what to torque your stem too because you may crash and blame me for it."

It was worth the wait. Thanks.
I still think you should get a new wrench ;-P....Spunout
Apr 8, 2003 3:29 PM
Sounds like a very specific problem. Not torque, I don't know what it should be, never measured it either. But for the risk of breaking steer tubes, threading, cutting too short (ask Doug) I would just take it to a one stop shop and get it done right.

It would cost alot in tools to do it yourself.
Non-specific answer...Brooks
Apr 8, 2003 3:56 PM
I've never used a torque wrench, I don't own one and I don't know where guides might be. That said, I tighten the quill stem to "hand-tight" plus about 1/8 turn. That is, spin the allen wrench engaged with the bolt until it is firm (hand-tight)then give a bit of muscle for 1/8 turn. This is a "feel" kind of thing, but as others have posted, the quill and steerer don't need to be in a death grip together. You can subpoena me to court and I'll just say you didn't do it right!;-0

Good luck with all the wrenching work.
Brooks
Ugh! It's Barnett's, not Zinn that is compared. (nm)Gregory Taylor
Apr 8, 2003 3:24 PM