How close is too close?
03-24-20, 01:49 PM
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How close is too close?
Having several low end Raleighs, I'm familiar with the mystery threading in the eyelets in the rear dropouts. I know a 5mm screw will go in there, but not exactly tighten up very well. Most of my bikes have rear racks, and I usually insert a 5mm Allen head, button head screw from inside the dropout, and then use a nut outside the rack leg. I'm trying this on the Super Course I'm currently working on, and using a 6 speed Shimano freewheel. There's a point when -- passing from the smallest rear cog to the second smallest -- the chain only has about a 1/16" clearance from the button head of the screw. Is that enough? Is a miss as good as a mile? How much minimum clearance do I need?
03-24-20, 02:17 PM
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If it works, it works. If it doesn't , it doesn't. I would try it out. If it becomes a problem, use a short screw from the outside and lock tight it.
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03-24-20, 02:45 PM
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In this case, a miss is a miss in my book. I have a couple bikes where the chain in the high gear barely clears the inside of the dropout. I know it's not quite the same situation, but there's negligible flex between the cogs, chain, and dropout--unlike clearance at the rim or bottom bracket, where frame/wheel flex can turn a miss into contact. The only slight concern I might have is if you get a stiff link that impacts the nut. Perhaps file a bit off the nut. Alternatively, you could drill out the eyelet and tap it to 6mm.
03-24-20, 05:33 PM
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I'm probably going to try riding it like this, and I guess time will tell. Just wondered if anyone had any specific reason not to trust the close tolerance.
03-25-20, 02:56 PM
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I've had the same type of issue on some bikes. On a tour I noticed that every once in awhile the chain would hit the head of a screw that attached the fender to the dropout. When the outer link just lined up wrong, it would hit. Solution was to swap out the screw for a button head. Maybe 100 microns of clearance in the worst case, but it never hits now.
How much clearance do you need? Just enough.
How much clearance do you need? Just enough.
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03-26-20, 02:07 PM
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You and I are at least at the right distance
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