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

Disc brake adapter bolt head hitting seatstay

Notices
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.

Disc brake adapter bolt head hitting seatstay

Old 12-20-20, 02:44 AM
  #1  
LMM2855
Junior Member
Thread Starter
 
Join Date: Dec 2020
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked 3 Times in 3 Posts
Disc brake adapter bolt head hitting seatstay

Hello,
I had a 140mm disc brake rotor on my rear wheel and would like to replace it with a 160mm rotor, so I bought a 20mm adapter. Unfortunately, I have a small bike frame, and I discovered that the head of the bolt (and its washers) that passes through both the caliper and the adapter hits the seatstay. It appears that the adapter would work fine if the bolt could get past the frame and be tightened. I thought about filing a small spot on the inside of the aluminum seatstay down about 1mm to allow the bolt head enough clearance, but my husband and I were discussing it and we are concerned that it could create a dangerous weak spot in the seatstay. Please see the attached photos. Thank you for any advice or other ideas you may have!

Frame: Diamondback Haanjo 2, small
Brake: Tektro Lyra
Adapter: Tektro TRP A-11 20mm adapter





LMM2855 is offline  
Old 12-20-20, 03:44 AM
  #2  
cobba
Senior Member
 
Join Date: Aug 2006
Posts: 1,867
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 166 Post(s)
Likes: 0
Liked 52 Times in 41 Posts
See how it is when the adapter is put on the correct way around with the shorter bolt.

The 'up arrow' only points up when that adapter is on a fork, when that adapter is on a chain stay mount it points forward and down.

Last edited by cobba; 12-20-20 at 03:49 AM.
cobba is offline  
Likes For cobba:
Old 12-20-20, 07:06 AM
  #3  
dsaul
Senior Member
 
Join Date: Jan 2013
Location: South Jersey
Posts: 2,129
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 659 Post(s)
Liked 632 Times in 394 Posts
As mentioned, the adapter goes the other way around, with the higher post in the front. Those CPS washers are probably not necessary. I haven't used any of those since the original Avid calipers that used them above and below the caliper. I don't see where they do much good with just one set above the caliper.

I have a frame with a seatstay clearance issue like this and I had to cut a hex wrench down, so it would fit in there to tighten the bolt. If the clearance is too tight, you could use an M6 bolt with an external hex head and use a regular wrench to tighten it.
dsaul is offline  
Likes For dsaul:
Old 12-20-20, 07:24 AM
  #4  
cobba
Senior Member
 
Join Date: Aug 2006
Posts: 1,867
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 166 Post(s)
Likes: 0
Liked 52 Times in 41 Posts
Originally Posted by dsaul View Post
Those CPS washers are probably not necessary. I haven't used any of those since the original Avid calipers that used them above and below the caliper. I don't see where they do much good with just one set above the caliper.
Why those washers are used above the caliper with that type of adapter...
cobba is offline  
Likes For cobba:
Old 12-20-20, 04:53 PM
  #5  
LMM2855
Junior Member
Thread Starter
 
Join Date: Dec 2020
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked 3 Times in 3 Posts
Thanks so much cobba and dsaul! The adapter came without any documentation, so I guessed on the orientation, based on how it looked on the front wheel. When I turned it around, the bolt just barely cleared the seatstay. I appreciate your help, and I'm so glad I asked here before I took a file to my frame! :-)
LMM2855 is offline  
Likes For LMM2855:

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 - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.