Thorn Cycles Forum
Technical => General Technical => Topic started by: in4 on May 03, 2023, 04:05:43 PM
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Probably covered already but:
Mindful of the conditions my Nomad has recently come through I thought it a good idea to protect the EBB screws, as far is feasible. Experimenting thus: piece of inner tube ( I had one of a road bike) cut a length off and cut two slits in the tube. Keep them small and spaced so as you have to stretch the tube from one screw to the other. I might use a couple of small cable ties but for now, it looks like this:
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I do not know if that could trap and hold water where you have metal that can corrode. I like it when any place that can get wet can easily dry out.
I am sure that my eccentric bolts (Nomad Mk II) get wet every time I ride through a puddle, but they can quickly dry out.
The rubber bands are to make sure that a bolt can't unthread from vibration if it gets loose.
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Good point re water. I’ll leave the ‘rubber sleeve’ open-ended and monitor for a while. I think your solution was at the back of my mind when I thought I’d try this out.
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Not sure I like the idea, whatever you do it's going to trap dirt and moisture. Best protection for the underside of a BB is to keep the nasty stuff off with a long mudflap, second line of defence for me is to use plenty of marine grease.
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I use thin stainless "jam" nuts on my eccentric screws. They only require a very small torque, given the fine thread size. The bosses on my Nomad are stainless, but to protect the powdercoat, I still place a thin stainless flat washer under the jam nut.
Cost was about USD$3 for the lot on eBay, including shipping.
Works a treat for me. :)
Best, Dan.
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Is a jam nut like a split washer?
Matt
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Is a jam nut like a split washer?
Matt
My guess is it's an Americanism for a lock nut, a thin nut to go under the head of the screw and against the EBB shell.
If so that's a pretty good idea, does it need a thin spanner to tighten it?
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Is a jam nut like a split washer?
Matt
My guess is it's an Americanism for a lock nut, a thin nut to go under the head of the screw and against the EBB shell.
If so that's a pretty good idea, does it need a thin spanner to tighten it?
Ah yes Your suggestion makes sense.
We'll wait for Dan to surface in USA.😉
Matt
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I have been content with the standard bolt that comes on the frame for the eccentric. Having a bolt with a 15mm wrench size (same as a pedal) is convenient. One of mine worked loose early in my experience with that bike. I tried a removable thread locker, but decided later I did not like that, so cleaned that off. Then went with a rubber band. Actually a pair for when one breaks, redundancy is good. I also bought a spare bolt to carry on tours.
Some time back I elaborated further on how I adjust the chain, that involves removing one of the screws, thus the thread locker was an inconvenience. That description is here:
http://thorncyclesforum.co.uk/index.php?topic=14475
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Paul pondered...
My guess is it's an Americanism for a lock nut, a thin nut to go under the head of the screw and against the EBB shell.
If so that's a pretty good idea, does it need a thin spanner to tighten it?
...and Matt commented...
Ah yes Your suggestion makes sense.
We'll wait for Dan to surface in USA.😉
...and Dan replies (wondering how this question was missed! I usually get them all and right away...)
Yes! Paul has it. These are simply thinner nuts with the same threads that spin on the shaft of the machine/grub screws that hold the eccentric in place. Because the eccentric screw threads are so fine (M8 x 0.75...same as chainring bolts), the jam nuts don't have to be tightened very much to lock things in place -- just a bit more than finger tight will do it. Mine happen to be 3mm thick and 12mm across the flats, so they do require a wrench specific to them or (shudder!) pliers (as the torque needed is so very low). I use my needlenose Vise-Grips (think: MoleGrips) for the task and have no problems with scarring or rounding, again because the torque needed to lock everything in place is so little.
They do work a treat and I made sure mine are stainless so there's no problems with rust. I have installed them with some very thin stainless flat washers between them and the stainless bosses on my Nomad, only because I didn't want to ruck up or mar the powdercoat on the BB shell posts.
Hope this helps, apologies for the late reply, Dan.