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Old 08-12-09, 10:59 AM   #1
johnknappcc
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Hollowtech II Crank Installation (Adjustable Cap Question)

Put on my new R700 cranks yesterday, and I wanted to know how much I should tighten the adjustable cap. I currently have it to where there is a very slight gap between the cup and the crank arm. I'm using the Park BBT-9 to turn the cap, and I don't want to overtorque it, but I have no way of measuring this.

I'm assuming there needs to be a slight gap (less than a half mm) so that the crank arm doesn't rub on the cup housing?

I took it for a 30 mile spin yesterday and everything seemed great (all other things, BB cups, Crank bolts) were installed using a torque wrench.

Sorry about the pic, my wife has the camera today.
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Old 08-12-09, 11:52 AM   #2
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It's been a while since I installed a Hollowtech II crank (in my case a Deore LX M581), but if I recall the Shimano instructions correctly, the cap is used to preload the bearings. They give a torque spec, but it's very low (something like 1.0 N-m), and I don't know anyone who makes a torque-wrench compatible version of their tool anyway so it's kind of academic. I recall reading somewhere that the way to do it is to screw in the cap until it just starts to feel very slightly snug, and that's good enough. There should be no noticeable increase in resistance when you turn the cranks.

Here's the Park Tool page on Hollowtech II installation:
http://www.parktool.com/repair/readhowto.asp?id=95
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Old 08-12-09, 12:03 PM   #3
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The cranks should have come with a little plastic serrated finger tool.
The torque specified is indeed small, (1.5Nm as I recall); I have always simply tightened it medium-finger-tight using that, then sequentially tightened the 4mm bolts on the left crank, (a half turn apiece) until they get to 15Nm.

Because the tightening of these bolts will ultimately crimp down on the cap, their proper torquing is more crucial, IMO.

I learned this the hard way when my left crank suddenly popped off, still clipped to the bottom of my shoe during a romp up Palomar Mountain one day. (My fault for assuming that the LBS who conducted the initial assembly was following Shimano's instructions.)

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Old 08-12-09, 12:37 PM   #4
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Here is the Shimano page:
http://www.shimano.com.au/media/tech...9830616000.pdf
0.7 - 1.5 N-m is the spec. I picked up a tool that has one side for the adjustable cap and one side for the BB cups and it works with a 3/8" wrench (I beleive it was from Nashbar but can't find it on their web site now) so I can torque the cups but don't have a torque wrench with a low enough setting for the adjustable cap. As others noted, tighten it snug and concentrate on getting the screws in the crank arm torqued to spec.
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Old 08-12-09, 01:55 PM   #5
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6 - 13 inch-pounds on the cap. Here's the directions:

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Old 08-12-09, 05:05 PM   #6
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Thanks for the tips, but maybe I didn't phrase my question properly. I followed the instructions, I'm just having trouble feeling that small of an amount of torque. From the picture I posted above, is that small gap pretty typical, because I could torque the cap more, but I think I would just be overdoing it

Also I don't think Shimano includes that TL-C16 or whatever the tool is called with its new cranks. That is why I bought the BBT-9 although I already had the BBT-19.
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Old 08-12-09, 05:21 PM   #7
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Use a torque-wrench - not 'feel.' It doesn't need to be tighten more than the directions state. It will be further compressed by the two little bolts. This sets the pre-load.
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Old 08-12-09, 05:26 PM   #8
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Quote:
Originally Posted by Panthers007 View Post
Use a torque-wrench - not 'feel.' It doesn't need to be tighten more than the directions state. It will be further compressed by the two little bolts. This sets the pre-load.
On the adjustable cap? I used a torque wrench on everything else, the BB cups, and the clamp bolts. Its the adjustable cap using this tool:

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