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Old 05-06-05, 08:19 AM   #1
DogBoy
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Front Derailleur Height

I recently changed from 30-42-52 chainrings to a 28-38-48 chainrings. I swapped out the cranks and adjusted the Derailleur just fine, but I didn't drop the derailleur down, since I would have to re-align and re-clamp the seatpost clamp. What kind of problems can arise from having the derailleur be higher than the 1-2 mm height suggested? In working through the gears there doesn't seem to be any problem shifting. At this point, would you drop it down or leave it be?
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Old 05-06-05, 08:23 AM   #2
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Originally Posted by DogBoy
I recently changed from 30-42-52 chainrings to a 28-38-48 chainrings. I swapped out the cranks and adjusted the Derailleur just fine, but I didn't drop the derailleur down, since I would have to re-align and re-clamp the seatpost clamp. What kind of problems can arise from having the derailleur be higher than the 1-2 mm height suggested? In working through the gears there doesn't seem to be any problem shifting. At this point, would you drop it down or leave it be?
I'm surprised it works well,but if it does, then you really don't have an issue. I'd of just done it right to start with.
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Old 05-06-05, 08:38 AM   #3
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Quote:
Originally Posted by DogBoy
I recently changed from 30-42-52 chainrings to a 28-38-48 chainrings. I swapped out the cranks and adjusted the Derailleur just fine, but I didn't drop the derailleur down, since I would have to re-align and re-clamp the seatpost clamp. What kind of problems can arise from having the derailleur be higher than the 1-2 mm height suggested? In working through the gears there doesn't seem to be any problem shifting. At this point, would you drop it down or leave it be?
A strong possibility of overshifting the big ring and throwing your chain off.

It's a simple job and should be done.
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Old 05-06-05, 08:56 AM   #4
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Planned to do it from the start, but when it worked fine after the crank swap thought I might only have to adjust the wire tension. That seemed to work fine, hence the question. I guess I'll adjust it tonight. Thanks.
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Old 05-06-05, 09:15 AM   #5
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Use a torque wrench. Check the ParkTool web site for torque specs so you don't crush anything. Use a penny or a dime as a spacer to get the height correct.
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Old 05-06-05, 09:20 AM   #6
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Originally Posted by NJWheelBuilder
Use a torque wrench. Check the ParkTool web site for torque specs so you don't crush anything.
Gimmie a break!....Altho I did hear of a ham fisted moron hack that hosed a seattube on an CF calfee. But,all really it takes is a bit of common sense.
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Old 05-06-05, 09:59 AM   #7
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Originally Posted by DogBoy
Planned to do it from the start, but when it worked fine after the crank swap thought I might only have to adjust the wire tension. That seemed to work fine, hence the question. I guess I'll adjust it tonight. Thanks.
If you feel that it's working fine now, what do you hope to gain by changeing it? If it ain't broke, why do you want to fix it?
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Old 05-06-05, 10:00 AM   #8
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How about I assume the current clamp is at the appropriate tension, and count the number of revolutions needed to "free" the clamp for movement, then tighten with the same number of revolutions. Or I can just tighten to "snug."
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Old 05-06-05, 10:08 AM   #9
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Originally Posted by DogBoy
How about I assume the current clamp is at the appropriate tension, and count the number of revolutions needed to "free" the clamp for movement, then tighten with the same number of revolutions. Or I can just tighten to "snug."
Honestly, it you don't know how to tighten a derailer clamp by feel,should you really be working on bikes? The same senario applies to tightening the cable clamp. The ARs would grab their US Bureau of Standards calibrated torque wrench. All others would just grab the seat of their pants and a hex wrench.
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Old 05-06-05, 10:36 AM   #10
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Quote:
Originally Posted by DogBoy
How about I assume the current clamp is at the appropriate tension, and count the number of revolutions needed to "free" the clamp for movement, then tighten with the same number of revolutions. Or I can just tighten to "snug."
"Snug" will be fine. I'm a believer in using torque wrenches, but I only use them for cranks and bottom brackets, which I think that most people under torque; and high dollar stems, which I think that most people over torque. A bigger problem with things like front derailleur clamps and the like is using worn out allen wrenches which can round out the bolts.
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Old 05-06-05, 10:43 AM   #11
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People do it all the time. You can do whatever you want without one. Its your bike. I always use a torque wrench.
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Old 05-06-05, 10:46 AM   #12
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Do it the right way. Use a torque wrench. That whole "feel" thing is nonsense. One persons "feel" is different from another persons "feel."
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Old 05-06-05, 02:36 PM   #13
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Originally Posted by NJWheelBuilder
Do it the right way. Use a torque wrench. That whole "feel" thing is nonsense. One persons "feel" is different from another persons "feel."
You are the one blowing the nonsense.
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Old 05-06-05, 03:59 PM   #14
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Originally Posted by sydney
You are the one blowing the nonsense.
Wrong.

What one person feels is tight, another would consider loose, and a third would not be able to budge. Everyone has different hand strength. Everyone has different levels of control on how tightly they turn a wrench.

I don't use a torque wrench. I wrench by feel. Every bike I have ever worked on, I did so as if I were going to be the one riding it. If I ever have an issue with a part that I installed coming loose because of improper tightness, I'll invest in a torque wrench.
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Old 05-06-05, 04:18 PM   #15
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Wrong.

What one person feels is tight, another would consider loose, and a third would not be able to budge. Everyone has different hand strength. Everyone has different levels of control on how tightly they turn a wrench.

I don't use a torque wrench. I wrench by feel. Every bike I have ever worked on, I did so as if I were going to be the one riding it. If I ever have an issue with a part that I installed coming loose because of improper tightness, I'll invest in a torque wrench.
.....The comment about nonsense was directed at the 'have to have torque wrench' nonsense....Certainly, everyone has a different sense of feel. But one developes their own correct sense of it. That's part of what the brain is for, unless you were born with a torque wrench in cranium instead of one.
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Old 05-07-05, 06:22 PM   #16
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So you are saying that you can adjust a bolt to the manufacturers recommended torque just by "feel?" You are saying that actually measuring the torque is not as good as guessing? That's truly amazing.
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Old 05-07-05, 06:36 PM   #17
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So you are saying that you can adjust a bolt to the manufacturers recommended torque just by "feel?" You are saying that actually measuring the torque is not as good as guessing? That's truly amazing.
I like chocolate....you must be a vanilla person.Whatever..........but I don't think the ones that forego a troque wrench are stupid or hacks. Read what moonogodo has to say in an immediate preceding post.
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Old 05-07-05, 07:48 PM   #18
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If you do it enough you do get the calibrated elbow. I use a torque wrench for a lot of things, like the new two piece cranks and stem clamps but not the pinch bolt on the der clamp. However a newb or a person that does not know their own strength might be better off using one to make sure. This also assumes the wrench is calibrated correctly.
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