Why a chainstay bridge?
10-18-16, 11:30 AM
#26
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I have a 1984 Trek 610 frame, and it has a chainstay bridge.
Why were these designed with a chainstay bridge? What is the benefit of this element of a frame?
What happens if it is weakened? Is there a risk? I'm tempted to drill a 5 mm through-hole to install a Spring-thing.
Good chainline versus ,,, unknown effect on frame!
Why were these designed with a chainstay bridge? What is the benefit of this element of a frame?
What happens if it is weakened? Is there a risk? I'm tempted to drill a 5 mm through-hole to install a Spring-thing.
Good chainline versus ,,, unknown effect on frame!
Chainstay bridges (Jobst Brandt)
10-18-16, 12:07 PM
#27
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Thanks, Therm for your attempt at a constructive ending that continues to stimulate!
In this case, Zandoval made the same point in Post #2, but did not attribute it to Brandt. I'm glad to see he's remembered!
Or should I just say, "No, it CAN'T be!"
Feel free to bring in more (and more contentious!) Brandt-isms.
In this case, Zandoval made the same point in Post #2, but did not attribute it to Brandt. I'm glad to see he's remembered!
Or should I just say, "No, it CAN'T be!"
Feel free to bring in more (and more contentious!) Brandt-isms.
10-18-16, 02:19 PM
#28
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Problem Solvers Sheldon Fender Nuts Set, includes 32mm Front and 10mm Rear in Tree Fort Bikes Fender Parts
I was assuming this was for standard rim caliper? Replace the bake caliper nut with one of these, and you're done.
10-18-16, 03:19 PM
#29
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You can drill a small hole in the bottom of the brake bridge and use a short sheet metal screw to attach the fender.
10-18-16, 03:20 PM
#30
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That won't help me. I don't have a problem with the caliper bolt, since the caliper is an ancient Mafac center pull with nutted brake bolts, and the brake has the right kind of bolts.
I need to see what mounting setup will move the fender down from the crown to be about 10 mm above the tire. I think I can do it with the little L-bracket V-O put in the fender kit. The daruma bolt will not give me the correct spacing, and the frame is not set up for a bolt going up into the bottom of the fork crown.
My fork has extra-long blades since it was custom made to give low trail (the 1984 Trek 610 was not low-trail, in my opinion), and the fender needs to be mounted down-low from the crown to give good coverage to the tire. That is not the problem addressed by the Sheldon nut.
I need to see what mounting setup will move the fender down from the crown to be about 10 mm above the tire. I think I can do it with the little L-bracket V-O put in the fender kit. The daruma bolt will not give me the correct spacing, and the frame is not set up for a bolt going up into the bottom of the fork crown.
My fork has extra-long blades since it was custom made to give low trail (the 1984 Trek 610 was not low-trail, in my opinion), and the fender needs to be mounted down-low from the crown to give good coverage to the tire. That is not the problem addressed by the Sheldon nut.
Last edited by Road Fan; 10-18-16 at 03:24 PM.
10-18-16, 04:23 PM
#31
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Just plain steel twist drills with a variable speed 1/4 " electric drill, or would you suggest anything different? I guess I need a 5 mm drill, then to tap the hole for the standard M5 threading?
It would certainly be a quieter installation than a hand-formed sheet metal bent bracket - I find those rattle a bit with a plastic fender, so I'm sure to hear them with an aluminum fender.
I should probably use a punch to initially locate the hole, then a small drill with the pin vise to make a pilot hole, then use the M5 drill with the electric drill to carefully start the hole, then pray for alignment as I drill and tap the hole.
It won't be a blind hole, so it should not be too hard to clean out all the shavings before fender attachment.
I'm open to any advice on this point - how hard is it to drill a radial hole squarely? On one of the forums, one of us built a fixture to create a similar hole.
10-18-16, 08:16 PM
#32
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Well, true! I hadn't intended to get that deep into frame mods, but actually, why not? I've already got a special fork on the bike.
Just plain steel twist drills with a variable speed 1/4 " electric drill, or would you suggest anything different? I guess I need a 5 mm drill, then to tap the hole for the standard M5 threading?
It would certainly be a quieter installation than a hand-formed sheet metal bent bracket - I find those rattle a bit with a plastic fender, so I'm sure to hear them with an aluminum fender.
I should probably use a punch to initially locate the hole, then a small drill with the pin vise to make a pilot hole, then use the M5 drill with the electric drill to carefully start the hole, then pray for alignment as I drill and tap the hole.
It won't be a blind hole, so it should not be too hard to clean out all the shavings before fender attachment.
I'm open to any advice on this point - how hard is it to drill a radial hole squarely? On one of the forums, one of us built a fixture to create a similar hole.
Just plain steel twist drills with a variable speed 1/4 " electric drill, or would you suggest anything different? I guess I need a 5 mm drill, then to tap the hole for the standard M5 threading?
It would certainly be a quieter installation than a hand-formed sheet metal bent bracket - I find those rattle a bit with a plastic fender, so I'm sure to hear them with an aluminum fender.
I should probably use a punch to initially locate the hole, then a small drill with the pin vise to make a pilot hole, then use the M5 drill with the electric drill to carefully start the hole, then pray for alignment as I drill and tap the hole.
It won't be a blind hole, so it should not be too hard to clean out all the shavings before fender attachment.
I'm open to any advice on this point - how hard is it to drill a radial hole squarely? On one of the forums, one of us built a fixture to create a similar hole.
10-18-16, 09:12 PM
#33
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The right way to do this is either with a Riv-nut, or by drilling a larger hole and gluing in a threaded inset.
I suggest the OP take the time to analyze his options, buy the necessary and drill the hole with the diameter matching what his solution calls for.
Or he can simply drill a hole and use a screw and nut running through the bridge.
Or he can buy a flange nut (looks like the recessed nut used for brakes), pop it in from the front with a bit of glue to hold it steady. The tightened fender bolt will keep it home, and the flange will keep it from pulling through.
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Just because I'm tired of arguing, doesn't mean you're right.
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10-18-16, 10:56 PM
#34
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Thanks, Therm for your attempt at a constructive ending that continues to stimulate!
In this case, Zandoval made the same point in Post #2, but did not attribute it to Brandt. I'm glad to see he's remembered!
Or should I just say, "No, it CAN'T be!"
Feel free to bring in more (and more contentious!) Brandt-isms.
In this case, Zandoval made the same point in Post #2, but did not attribute it to Brandt. I'm glad to see he's remembered!
Or should I just say, "No, it CAN'T be!"
Feel free to bring in more (and more contentious!) Brandt-isms.
10-19-16, 04:58 AM
#35
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Odds are the OP wont be able to tap the holes. Hes drilling though a thin walled tube with walls not much thicker than the pitch of a single thread.
The right way to do this is either with a Riv-nut, or by drilling a larger hole and gluing in a threaded inset.
I suggest the OP take the time to analyze his options, buy the necessary and drill the hole with the diameter matching what his solution calls for.
Or he can simply drill a hole and use a screw and nut running through the bridge.
Or he can buy a flange nut (looks like the recessed nut used for brakes), pop it in from the front with a bit of glue to hold it steady. The tightened fender bolt will keep it home, and the flange will keep it from pulling through.
The right way to do this is either with a Riv-nut, or by drilling a larger hole and gluing in a threaded inset.
I suggest the OP take the time to analyze his options, buy the necessary and drill the hole with the diameter matching what his solution calls for.
Or he can simply drill a hole and use a screw and nut running through the bridge.
Or he can buy a flange nut (looks like the recessed nut used for brakes), pop it in from the front with a bit of glue to hold it steady. The tightened fender bolt will keep it home, and the flange will keep it from pulling through.
10-19-16, 06:10 AM
#36
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I wouldn't bother trying to tap it. I've successfully used a plain sheet metal screw in an untapped hole.
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