Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Eroded frame because downtube shifter

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Eroded frame because downtube shifter

Old 07-06-13, 09:39 PM
Thread Starter
Join Date: Jul 2013
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Eroded frame because downtube shifter

Hi all, i have a problem with my downtube shifter. I think it because my mistake don't check regulary the connection between my shifter and frame. The bolt didn't attach well in the bosses so it eroded the frame everytime i use my shifter. My question is is it will cause a danger to my frame, e.g : my frame will crack and cut into pieces. Is there any solution to my problem ? E.g change my shifter model or attach smal metal plate between frame and shifter?

thanks for your help

Attached Images
File Type: jpg
image.jpg (47.4 KB, 49 views)
Bohlamon is offline  
Old 07-06-13, 09:45 PM
bike whisperer
Kimmo's Avatar
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 7,948

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 384 Post(s)
Liked 17 Times in 14 Posts
Almost certainly not a big deal.

If your frame is aluminium, there's a tiny chance it could be a problem, but I doubt it. If it's steel, you can put it out of your mind altogether.
Kimmo is offline  
Old 07-06-13, 10:57 PM
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 36,049

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 121 Post(s)
Tagged: 1 Thread(s)
Quoted: 4342 Post(s)
Likes: 0
Liked 1 Time in 1 Post
The back plate should be 100% bulletproof stationary on the frame. Usually these are riveted or bonded to the frame, though some depend on a tight fit over the square boss.

I can't tell your arrangement from the photo, but I'd disassemble the lever, and if possible epoxy (or super glue) the back plate to the frame, tighten the assembly until it cures then stop worrying about it.

Note that a good glue bond depends on clean surfaces, so clean everything well and finish with an acetone wipe (not nail polish remover which leaves an oily residue).
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 07-06-13, 11:51 PM
Retro Grouch
onespeedbiker's Avatar
Join Date: Oct 2007
Location: Santa Cruz
Posts: 2,210

Bikes: Yes

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The conical sleeve over the back plate is held in place by the center bolt that screws into the boss. A possible explanation is the center bolt is loose or there is some blocking the threads in the boss that will not let the bolt screw in all the way. I would remove the shifter and make sure the bolt screws all the way without an obstruction. If there is an obstruction (not uncommon) it is probably some brazing material that needs to be cleaned out with the appropriate tap.
onespeedbiker is offline  
Old 07-07-13, 09:05 AM
Thread Starter
Join Date: Jul 2013
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for all your suggestion guys ... I'll try to start fix it. Btw My frame is alu
Bohlamon is offline  
Related Topics
Thread Starter
Last Post
Drillium Dude
Classic & Vintage
12-11-18 02:27 PM
Bicycle Mechanics
04-29-16 06:50 AM
Bicycle Mechanics
06-01-09 05:35 PM
General Cycling Discussion
07-01-08 10:58 PM
sparrow vs. CR
Bicycle Mechanics
04-06-06 03:26 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.