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Tightening your bearing bolts?

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  • #16
    45 in-lbs is about 4ft-lbs. The same as hanging a 4lb weight on the end of a 1 foot long wrench =8lbs on a 6 inch long wrench, etc. So grab your wrench 6" away from the bolt and apply the same force as lifting a 1 gallon jug of water (gal =8.3 lbs, so at 6 inches =4.15 ft-lbs). Or better yet hang the jug by fishing line on the wrench (just make sure the wrench is parallel to the ground at the point it tightens, so you have a true 90 degree gravity vector force). Personally, I just snug up until no play in the wheel and feels feels smooth (a firm hand grab on the frame) when the wheel is spun.

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    • #17
      Holding my "L" shaped 5mm hex tool at the short end, I tighten the bearing cap bolts to the point where I start struggling. That's my rule of thumb. If I had the added leverage of the long end of the tool, I could easily over-tighten the bearing caps.

      I recently had the LBS modify a 26" Nimbus Muni frame for installation of my Schlumpf hub. I explained the installation options to the repairman and gave him Schlumpf's installation instructions. He chose to install it without the tiny metal plugs that fit into the gaps between the frame and caps. Anyhow, I was concerned that this could result in slipping. I asked him if he tightened the caps to a particular spec. I think the answer I got was "snug". So, took it home, went on a few rides, swapped out the tire a couple times (had to remove the bearing caps for this), and I'm happy to say there has been no slipping of the bearings. I don't understand the mechanics of the Schlumpf hub very well, but some other riders pointed out that slipping bearings could cause it to freewheel (whereas the same situation on a conventional hub would not cause freewheeling. Bottom line: the bearing cap tightness may matter more on my Guni than on my other unis.

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      • #18
        45 inch pounds is about 5 Newton Meters (N-m)... (for europe riders) and that is very loose.
        My lightest torque wrench is 5 to 30 Newton Meters (N-m) and at 5 Nm my bearing is already a little "tightend" and the wheel a little bit slowed down...

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