Stem on carbon steerer & torque wrenches??? (5nm or else??)
 

So I'm planning on doing some stem playing & was wondering how critical it is to get 5nm (or 6nm) correctly on my carbon steerer.

I've got alloy stems & when the LBS was playing with it, I remember the guy first just used a butterfly-handled hex key but at one point said, "Wait a minute, I'm gonna get my cool-wrench cuz you've got a carbon steerer."

It was similar but for preset torque. (Great, can I get one of those?)

Anywho.......I'm guessing there's plenty of folks that just get it tight enough to work & not worry about torque wrenches, etc. What say ye??

And for giggles, anybody recommend a cheap torque wrench for small stuff like this?? (I've got an automotive ft-lbs torque wrench but a bit of overkill on a 4mm hex key) ;)

You certainly don't need a torque wrench for something so small. You can just guess, right?

i don't use a torque wrench, but i wouldn't say i am just guessing. and i suppose there are those with little experience and/or a poor feel for tightening things that must use a torque wrench. like my brother-in-law, for instance.

A Ritchey Torque Key.

Or something like that. That's close enough to do a google search. You can find them on eBarf and Amazon.

I use mine all of the time on stuff exactly as you describe.

Be safe. Just get a torque key. They're like $15.

I use a torque wrench for stems on carbon steerers and am always surprised how little torque a plain L-shaped allen key provides when I think i've made the bolts REALLY tight. The torque wrench assures me i've done it right.

Just guessing doesn't cut it w/ carbon components, a crushed steerer/bar/seatpost fitting or one that slips will ruin your day/wallet.
Cheap insurance to have a quality tool that will be used for years.
And use CF assembly paste while you are at it.....

http://ritcheylogic.com/wp/wp-conten...130207_web.pdf

Indeed I will. I assumed those wrenches would cost more than that. Ritchey it is. (They even have 'em stock at the PB near me.......that'll work).

I'll inquire about carbon paste while I'm there.

Got the Ritchey key. (very cool & confidence inspiring, I have to admit)

Question........if a bolt says 6nm, using this Ritchey key, would it be wise to just go to the preset 5nm & be done with it or maybe a 1/4 turn or so beyond the click??

Noticed I've got 5nm, 6nm and 8nm in different places.

These are calibrated tools, one would need a 5, 6 & an 8nm for your fittings w/the appropriate hex fittings for each bolt size.
I have three Ritchey tools for my requirements in the tool box, still a bit less $ than a Park torque wrench and I like the feel of the Ritchey tool.

Do NOT loosen any fitting w/ the R-tool or under-torque and guess.
We are a far cry from the old "just lean on it" ham-fisted days.....but we don't have 3 gears or a 32lb bike either......(well, I do).....

-Bandera

A plain 1/4"-square drive beam-type torque wrench will cover all the torque requirements of small bolts and is far more versatile than a single value one. Craftsman, Park or even Harbor Freight have them at reasonable cost.

At these low values, and high cost components, I'd trust a Park or Craftsman 1/4" torque wrench and leave it up to someone else to validate the Harbor Freight version........

At ~$90 the Park TW-5 is a fine tool but I have all three of my spec's covered for $30 less w/ the Ritchey tools, suits me and I'm not running a shop (anymore).

-Bandera

Well, and I'll go on the ledge & say for as much as I've had to torque (Sea Doo watercraft stuff all the way to old 36mm Volkswagen axle nuts) I've found that a good sense of what a diameter and pitch of bolt can handle goes a long way in at least know what's far too light & what's far to hard.

On that same ledge, I'd say that 5nm is probably sufficient for both stem clamp 4mm hex bolts that say "6nm max" on them.

I was just curious if anybody tweaked beyond that. (5nm is pretty friggin' tight on a 4mm hex bolt)

Well, those who do calibrate such things have reported the HF tools are quite accurate and reliable. Also, do you really think the Ritchey tools (how many for that $60, all three?) are really that much more precise?

"Those who?"? I'll take your word for it, but "quire accurate" is what I try to avoid in sort of precision instruments.
I'm a good w/ what tools I have, thank you very much, and I hope that you are too.

Yes, a three for $60 deal, 4, 5 , 6nm and a handy carrying pouch, it's red and matches my eyes.....

-Bandera

It's not hard to accurately check the calibration of a torque wrench provided you have an accurate kitchen scale and a ruler. It's unlikely the Ritchey tools are any more than +/- 10% accurate in any case.

Have you used your "accurate kitchen scale and a ruler" to check the calibration on the Ritchey Tools?
Actually, I don't care and I'm sure you never would anyway.

The point of my replies to the OP are:

1) With carbon fiber components the ham-fisted "tight enough is good enough" of the past does not cut it.
B) Get proper torque wrenches and use them to mfg specs.

Any Questions?

-Bandera

What makes you think the Ritchey tool is any more accurate than the HF tool the OP suggested?

When you think you're applying 5nm with your Ritchey it could be anywhere from 4.5 to 5.5 and more likely from 4 to 6nm.

OK, time for you to trot out the "accurate kitchen scale and a ruler", purchase a set of Ritchey & HF torque wrenches and get back to us on the accuracy results. It will be riveting to see if your estimates of "from 4.5 to 5.5 and more likely from 4 to 6nm" are good on the kitchen scale method.

BTW: The OP never suggested an HF tool, but let's not get lost in that.

I really don't care/doubt HF accuracy on their 1/4" torque wrenches, I'm not a potential customer, but you can provide a service to the community w/ your results.

Once more:

The point of my replies to the OP are:

1) With carbon fiber components the ham-fisted "tight enough is good enough" of the past does not cut it.
B) Get proper torque wrenches and use them to mfg specs.

Any Further Questions?

Why bother, you didn't answer the simple question I posed.

ya, i've got a question *guy in the back with his hand up* :lol:

what's the reasoning behind ""tight enough is good enough" of the past does not cut it.""?

isn't "tight enough is good enough anymore" true anymore? seems to be an intrinsically true statement.

Excellent point, when "true", yes without a doubt.
When brutally applied by the ham-fisted "tight enough" is just below the failure-point of materials.
Not so un-common with steel & aluminum components "back when", CF components will accommodate no such guff.

I should have written "tight as possible does not cut it" for those not familiar w/ the ham-fisted "mechanic".

Thanks for the excellent question.

-Bandera

A couple of things for clarity.......

First, *I* (OP) didn't suggest any HF torque wrench. It may be just fine. It's hit and miss on stuff like that. I'd suspect the error isn't horrible, but who knows.

Second, suggesting that the Ritchey tool is off by any particular amount would suggest that you even know how the thing's built/engineered. Not that it isn't safe to assume it has error, I just think it's probably not the wisest statement to know it's a half nm or full nm whilst armchair quarterbacking the situation.

Again, I think that 5nm on a 6nm torque spec (the only one I'm really concerned about) is just fine. I've checked the torque w/ a hex key afterward by loosening/tightening and it's certainly as tight or tighter than I'd put on a bolt of that size by feel.

Ritchey is not a tool maker. They make bikes and bike parts. No wrench is perfect and similar torque wrenches from quality tool manufacturers are in the 10% range.

For reference, wiha tools (Torque Control! Easy-Torque Economy Drivers Factory Pre Set From Wiha) are in the +/- 10% range for a $45 tool. If you want +/- 6% the price goes up to over $200.

It's possible the $16 Ritchey tool is accurate to +/-2% but if you believe that I have a little bridge to sell you...

That 6 nm is the recommended maximum. And if you are using carbon assembly paste, it probably doesn't need to be even 5 nm.

The stem clamp on the steerer needs to be tight enough to not slip side-to-side when pulling on the bars, and also not slip vertically to affect the bearings load. I think the side-to-side slipping is the most likely, since that's where the highest loads are, and the stem cap helps to limit the vertical movements anyway. So if your stem and bars get out of alignment sideways, you didn't tighten the bolts enough.

I don't think there's any structural/safety reason to go to the max 6 nm if the stem and bars aren't moving.