|Torque Spec. on Ritchey WCS Stem||croy|
Jan 25, 2002 8:43 AM
|I just got my new WCS stem, and the torque specs state 150 Kg/Cm for the steerer bolts and 90 kg/cm for the four face bolts. Any idea on what this means in Foot Pounds? Or, can I forgo the torque wrench and just tighten them reasonably by hand.
|Whatever it takes.||grzy|
Jan 25, 2002 10:43 AM
|I just do it by hand with an Allen wrench - this assumes you have a developed feel for what's right. |
Doing the math will give you the exact answer:
150 kg-cm x 2.2 lbs./1 kg x0.0328 ft/1 cm = 10.82 ft -lbs = 130 in-lbs
90 kg-cm / 150 kg-cm = 0.6
so multiply the above answers by 0.6 (or plod through the units) and get:
90 kg-cm = 6.5 ft-lbs = 78 in-lbs.
Here's the rub - most torque wrenches have a range and the typical 3/8" unit will be above these settings. You'll need one that works in the in-lbs range to be able to accurately get 78 in-lbs. Unless you're ham-fisted you really don't need to spend the money.
|Math is correct, but 130 lb.in. is tooooo much. (nm)||mja|
Jan 25, 2002 1:53 PM
|Funny you should ask...||nee Spoke Wrench|
Jan 26, 2002 5:55 AM
|I was think about that very subject last night.
130 in/lbs is around 10 ft/lbs. That strikes me as being on the low side for the application. Greasy's right, you need a 1/4 drive torque wrench to measure that. I'll bet almost everybody's stems are torqued higher than that.
To put it into perspective, the torque spec for cassettes is 30 ft/lbs, which strikes me as a pretty high spec.; and for bottom brackets and crank arms is around 30 ft/lbs, which strikes me as about right.
|Funny you should ask...||mja|
Jan 26, 2002 3:30 PM
|No, the steerer-tube clamp-bolt torque specs are all over the place, and this is as it should be: I have seen stems with either M5, M6, or M8 bolts and the bolts of steel, stainless steel, or titanium. I am just urging some caution after having snapped off a bolt in a TTT Zepp stem on one of my bikes!|
|Funny you should ask...||croy|
Jan 27, 2002 5:24 PM
|Thanks for all of the feedback. I have not yet installed the new stem. Due to the smaller steer tube clamp height, I needed some additional spacers. I went to my LBS to get some 1" spacers, and the a-holes wanted $2.99 each for silver 2.5 mm spacers. I said no thanks and walked out. For 2.99, I can get fricken carbon fiber! I should have ordered some from Excel when I got the stem. They have a price of 60 cents each regardless of size. Gotta love the high school mechs at the LBS!|
|Installing the face plate...||PsyDoc|
Jan 28, 2002 9:38 AM
|...Ritchey recommends tightening the top two face-plate bolts until the sliver face-plate just touches the black part of the stem. Then, tighten the bottom two face-plate bolts to the correct torque. As for torque conversions (or any other for that matter), try http://www.onlineconversion.com/|
|I have the Ritchey WCS Stem and...||Paul|
Jan 30, 2002 11:30 AM
|was warned by the LBS not to overtighten the 4 screws holding the bar, as you could strip them. I just tighten them enough so that nothing moves. The stem, if you want to believe it, was designed for carbon steerers. I have both a carbon and alloy steerer. The WCS is on an alloy steerer. I have a Ritchey pro on the carbon steerer, and did it by hand also. My friends have carbon steerers, and also torgued by hand. No problems. |