Front Derailleur Support Bolt
#1
Senior Member
Thread Starter
Front Derailleur Support Bolt
Just picked up a new Trek Domane. Noticed that the front derailleur (shimano 105) was rubbing on the chain a little. Did some investigation and noticed that the support plate was missing from the seat post and the support bolt wasn't engaged. My investigation reveals that the support bolt swings the back end of the derailleur around so that it's parallel with the chain ring. I assume that is necessary for everything to work properly?
Page 9 on the attached document.
Page 9 on the attached document.
Last edited by prj71; 03-31-21 at 08:16 AM.
#2
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If it's missing from the seat tube then you might need one unless Trek did something different.
New bike.... let your Trek dealer handle it. They need to know or else they'll explain why it's not needed so you'll know.
The rub might be the the DR not correctly held by it's mount or a few other reasons..
New bike.... let your Trek dealer handle it. They need to know or else they'll explain why it's not needed so you'll know.
The rub might be the the DR not correctly held by it's mount or a few other reasons..
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#4
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So what did they tell you about the noise? Or is that not an issue now? Is there even a question or was this just a PSA?
#5
Senior Member
Thread Starter
Just a PSA and looking for some feedback. Maybe people find that the support bolt isn't always necessary?
They LBS didn't say anything about the noise. Just said to bring it in.
When I went for the initial ride on the bike last night, in some of the gears the chain was rubbing on the front derailleur while in the big chain ring and even the trim shifting wouldn't make it go away. Having dealt with this before on previous bikes my first thought was just to adjust the cable tension so the derailleur would swing out farther. So after researching online and finding the support plate in my bag of parts that came with the bike, I discovered that the support bolt kicks out the back of the derailleur to ensure that it's parallel with the chain ring.
The LBS has been crazy busy. They had to assemble 30 bikes before mine and since I picked it up they've added another 20 to their list. I'm sure it just got missed in all the craziness..
They LBS didn't say anything about the noise. Just said to bring it in.
When I went for the initial ride on the bike last night, in some of the gears the chain was rubbing on the front derailleur while in the big chain ring and even the trim shifting wouldn't make it go away. Having dealt with this before on previous bikes my first thought was just to adjust the cable tension so the derailleur would swing out farther. So after researching online and finding the support plate in my bag of parts that came with the bike, I discovered that the support bolt kicks out the back of the derailleur to ensure that it's parallel with the chain ring.
The LBS has been crazy busy. They had to assemble 30 bikes before mine and since I picked it up they've added another 20 to their list. I'm sure it just got missed in all the craziness..
Last edited by prj71; 03-31-21 at 08:45 AM.
#6
Senior Member
Yes you can. Trek carbon frames haven't needed the support plate for at least 2-3 years. On some frames there isn't room for it. The front derailleur mount area is reinforced and you won't hurt it w/ the support screw.
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#8
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#10
Senior Member
Just a PSA and looking for some feedback. Maybe people find that the support bolt isn't always necessary?
They LBS didn't say anything about the noise. Just said to bring it in.
When I went for the initial ride on the bike last night, in some of the gears the chain was rubbing on the front derailleur while in the big chain ring and even the trim shifting wouldn't make it go away. Having dealt with this before on previous bikes my first thought was just to adjust the cable tension so the derailleur would swing out farther. So after researching online and finding the support plate in my bag of parts that came with the bike, I discovered that the support bolt kicks out the back of the derailleur to ensure that it's parallel with the chain ring.
The LBS has been crazy busy. They had to assemble 30 bikes before mine and since I picked it up they've added another 20 to their list. I'm sure it just got missed in all the craziness..
They LBS didn't say anything about the noise. Just said to bring it in.
When I went for the initial ride on the bike last night, in some of the gears the chain was rubbing on the front derailleur while in the big chain ring and even the trim shifting wouldn't make it go away. Having dealt with this before on previous bikes my first thought was just to adjust the cable tension so the derailleur would swing out farther. So after researching online and finding the support plate in my bag of parts that came with the bike, I discovered that the support bolt kicks out the back of the derailleur to ensure that it's parallel with the chain ring.
The LBS has been crazy busy. They had to assemble 30 bikes before mine and since I picked it up they've added another 20 to their list. I'm sure it just got missed in all the craziness..
Last edited by bikeme; 05-30-22 at 02:54 AM.
#11
Senior Member
That's not what the Trek rep told me--he said "follow the instructions and install the plate"
#12
Senior Member
Which instructions? Shimano's? You can trust me on this one, I had an [MENTION=336420]Trekbike[/MENTION]s.com email address for years, was a service manager at a Trek owned store and have been through the Trek Expert Tech class in Waterloo. When I say I probably know more than 'the Trek rep' when it comes to the technical stuff you can believe me. Our old rep had no clue about any of the that stuff.
#13
Senior Member
Thread Starter
I guess I never followed up on this post from a year ago. LBS wasn't sure when I asked them about it so they contacted Trek Directly. Turns out cxwrench is correct. You don't need it.
The Shimano instructions are just generic in nature in case the shifter does get installed on a bike that needs it.
After some adjustments, I got the chain rub to go away and haven't had any issues with the front derailleur since.
The Shimano instructions are just generic in nature in case the shifter does get installed on a bike that needs it.
After some adjustments, I got the chain rub to go away and haven't had any issues with the front derailleur since.
Last edited by prj71; 05-31-22 at 10:13 AM.