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  1. #1
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    Over torque retaining bolts in upper link of TallboyC and others

    There seems to be an issue with people (such as myself) snapping their upper linkage retaining bolts.

    The first time I removed the upper link I snapped one of the M5 bolts (locking bolt with the tapered washer) when tightening to 100 in/pounds. The second time I set my wrench to 90 but I stopped at less then that. Everything ran fine for the rest of the season. Now this week I am giving the linkage it's scheduled maintenance and found that the one bolt was severely stretched and just shy of snapping. The trouble area seams to be the bolt that attaches the link to the rear triangle. The upper bolt made it to 100 in/p the first time and didn't look damaged. This time I am tightening all bolts in the upper and lower links to 60 in/p. Everything seems to move freely and is nice and snug. We'll see how it plays.

    Here's a picture of the over stressed bolt. It's hard to see but I could really feel that it was skinny in the middle.
    Attached Thumbnails Attached Thumbnails Over torque retaining bolts in upper link of TallboyC and others-screw-4.jpg  

    Last edited by Man from Utopia; 01-20-2013 at 04:51 PM.
    Help, I'm a rock!

  2. #2
    Ninja Master Powers
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    I have had the same problem with my 2012 Nomad Carbon. SC will replace the bolts but it will happen again if you use the SC spec'ed bolts.

    I've changed my bolts out to stainless, so far so good. But the proof of the fix is when you remove the bolt for maintenance then re-torque it the second time.

    My guess is it not the right material and/or bolt size for the application.

  3. #3
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    I going to look for SS at my local lomo depot.

    On a side note, I noticed once I removed the upper link and had full mobility of the swing arm with the lower link still attached that there was bit of friction. So when I cleaned, regreased and reattached the lower link and tightened the pivot axles to where there was no friction or play and then installed the tightening bolts with tapered washers and tightened down to 60 in./p that there was once again some friction in the pivot. So it seems that tightening the bolts turns the pivot axle
    Help, I'm a rock!

  4. #4
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    When I brought it in to a shop to have them drill out my snapped bolts, they put the SC replacements back in by hand to some "medium" torque without a torque wrench. So far so good.
    definite malingerer

  5. #5
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    This is a recognized problem and there are several threads on it. I've thought about converting to stainless steel but I am afraid I will get the wrong bolt specs. If anyone has sorted this out and can post up the SS sizing - see: Standard Metric Bolt Shank Dimensions (which, for all I know isn't relevant but stops me cold) - then please let us know.
    Will trade for some chicken.

  6. #6
    Ninja Master Powers
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    Quote Originally Posted by edley View Post
    This is a recognized problem and there are several threads on it. I've thought about converting to stainless steel but I am afraid I will get the wrong bolt specs. If anyone has sorted this out and can post up the SS sizing - see: Standard Metric Bolt Shank Dimensions (which, for all I know isn't relevant but stops me cold) - then please let us know.
    I took the SC bolts into Ababa Bolt in El Cajon Ca. They have any fastener you can possibly imagine in stock. They matched the bolt, the only issue is I had to buy a dozen of each size.

    You can probably also get a match from Marshals Industrial Hardware or Grangers

    One thing to keep in mind; it's not the best practice to use a SS bolt in the AL axel. I used blue loctite paste and made sure to coat the threads of the bolt completely. I also remove them to maintain the pivot every 90 days; which is probably overkill and I plan to replace the bolts and axels every 12-18 months.

  7. #7
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    I snapped my bolt in the lower axle of the upper link at at 8 nm. I now torque to 6 nm. This is way below spec but works fine as long as you check the bolt regularly. I am using the factory replacements which SC was kind enough to send me.

  8. #8
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    Stupid me...I paid $50+ for mine. I just picked up a couple SS M5s at Lowes for a buck fifty. Will try them next time.
    Help, I'm a rock!

  9. #9
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    Quote Originally Posted by Man from Utopia View Post
    Stupid me...I paid $50+ for mine. I just picked up a couple SS M5s at Lowes for a buck fifty. Will try them next time.
    Hopefully you won't need to - getting my snapped bolt out was an exercise in true patience.

  10. #10
    Ted
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    After going through the pain of extracting a broken bolt I now measure the bolt length before I use them. If they don't feel right when torquing them I take them out and measure them again. If they are stretching I throw them away and use new ones. I got the replacements from a local industrial fastener store (same size SS bolt). I don't go up to the spec torque because that will almost always stretch the bolts. I serviced my upper pivot today and had to throw away two bolts due to stretching. What a poor design. I spoke with Santa Cruz and they suggested I reduce the torque to 90 in-lb but even this is too high and will result in stretching. I now use about 70 in-lb. I wish there was a stronger bolt I could use. I am surprised there is not more discussion about this.

  11. #11
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    I just found this thread, and have had a similar experience. I was doing a full bearing replacement on a Nomad 2 for a friend and when I went to tighten that bolt with my torque wrench I got that feeling that something was not right. It's the same feeling when removing a fastener and you realize the bolt is no longer turning but stretching (usually just before it snaps).....I loosened the link bolt and tightened by hand. Since Santa Cruz recommend using loctite on the fastener, I don't see a problem with it being tightened to 50in lbs and it holding perfectly fine.

  12. #12
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    That occurs when you use santa torque specs... I went with proper 10 class screw, not s.steel, and torqued to 70% of recommended torque only. Loctite applied. Solved

    here is my case: New NOMAD alu - torque specs - BEWARE!!!

  13. #13
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    I had the same problem with the upper link bolt my aluminum Tallboy last week. Snapped the bolt around 80 psi after servicing. Called Santa Cruz tech who sent out a few complimentary replacement bolts since it is a known issue. He also said 75 inch pounds was a more appropriate torque for that upper bolt. That's interesting due to the fact that the 100 psi value is listed in their own tech guides and video on VPP. To make matters worse, my LBS can't remove the bolt and wants to drill the entire sleeve out......

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