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

Disc Rotor Sometimes Centered, Sometimes Not

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 Rotor Sometimes Centered, Sometimes Not

Old 07-24-20, 06:48 PM
  #1  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Disc Rotor Sometimes Centered, Sometimes Not

Do you know why sometimes when I do up my rear thru axle the disc sometimes is perfectly centered and sometimes is more to one side? I can't seem to figure out what I need to do to get it centered again. I only touched the thru axle bolts.
RowdyTI is offline  
Old 07-24-20, 06:52 PM
  #2  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
I thought through-axles would help eliminate this kind of thing. I have conventional quick-releases, and this is a frequent occurrence. There seems to be quite a bit of potential slop when using drop-outs. The only suggestion I have is to use a torque-wrench and make sure you get the same (preferably recommended) torque setting each time you put the wheel on.

If it really bugs you, push the pistons all the way back into the calipers before mounting a wheel, and let them reset to the rotor after a few squeezes. If you make sure the slot of the caliper itself is centered on the rotor, I find it makes it more reproducible.
wgscott is offline  
Likes For wgscott:
Old 07-24-20, 11:57 PM
  #3  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Yes, after some trial and error I found that most times it's perfect, sometimes not. I'm not sure what exactly happens in the case where it's sometimes out of whack and what is causing that. I'm now using a hex key like this: https://images-na.ssl-images-amazon....AC_SL1000_.jpg

I go as tight as it will go without getting aggressive. This is getting me a good result. I have a maxle thru axle with a low max torque specification, so basically if I can't undo it with a mini tool then it's over-torqued.
RowdyTI is offline  
Old 07-25-20, 07:48 AM
  #4  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 4,253

Bikes: Schwinn Varsity

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1577 Post(s)
Liked 294 Times in 187 Posts
Why do you need a hex wrench to tighten a Maxle thru axle? I'm not seeing it in my mind.
trailangel is offline  
Old 07-25-20, 08:21 AM
  #5  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
Originally Posted by trailangel View Post
Why do you need a hex wrench to tighten a Maxle thru axle? I'm not seeing it in my mind.



Your mind's eye needs glasses.
wgscott is offline  
Old 07-25-20, 08:24 AM
  #6  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
Originally Posted by RowdyTI View Post
Yes, after some trial and error I found that most times it's perfect, sometimes not. I'm not sure what exactly happens in the case where it's sometimes out of whack and what is causing that. I'm now using a hex key like this: https://images-na.ssl-images-amazon....AC_SL1000_.jpg

I go as tight as it will go without getting aggressive. This is getting me a good result. I have a maxle thru axle with a low max torque specification, so basically if I can't undo it with a mini tool then it's over-torqued.
If yours is the axle pictured, I would use a torque wrench and tighten it to 13.5 Nxm every time (which is a fairly substantial torque, probably more than I could deliver reproducibly with a multi-tool, or possibly even those hex-keys -- I have the same ones).
wgscott is offline  
Old 07-25-20, 09:29 AM
  #7  
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 29,930

Bikes: Catrike 559 I own some others but they don't get ridden very much.

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1446 Post(s)
Liked 356 Times in 218 Posts
My bet is that you're flipping your bicycle upside down to install your front wheel. When you do that, sometimes you don't get the axle bottomed on both sides.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
Retro Grouch is offline  
Old 07-25-20, 09:44 AM
  #8  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
Originally Posted by Retro Grouch View Post
My bet is that you're flipping your bicycle upside down to install your front wheel. When you do that, sometimes you don't get the axle bottomed on both sides.
It's a through-axle.
wgscott is offline  
Likes For wgscott:
Old 07-25-20, 09:50 AM
  #9  
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 29,930

Bikes: Catrike 559 I own some others but they don't get ridden very much.

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1446 Post(s)
Liked 356 Times in 218 Posts
Originally Posted by wgscott View Post
It's a through-axle.
So you're ASSUMING that it's seated and I'm GUESSING that it's not. Neither one of us can see what's really going on. The bottom line is that the OP isn't satisfied with how it's working right now.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
Retro Grouch is offline  
Old 07-25-20, 10:54 AM
  #10  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 4,321

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 1625 Post(s)
Liked 516 Times in 396 Posts
Getting the disc centered on what? The pads? How much off?

Don't the pads float and center themselves to where the disc is once you actuate the levers a few times?
Iride01 is offline  
Old 07-25-20, 02:03 PM
  #11  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Originally Posted by Retro Grouch View Post
My bet is that you're flipping your bicycle upside down to install your front wheel. When you do that, sometimes you don't get the axle bottomed on both sides.
It's the rear wheel. Why would the bike being upside down make it more difficult to install the wheel correctly?
RowdyTI is offline  
Likes For RowdyTI:
Old 07-25-20, 02:08 PM
  #12  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 4,253

Bikes: Schwinn Varsity

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1577 Post(s)
Liked 294 Times in 187 Posts
There is slop in the fitment of the thru axle thru the hub. That's why.
trailangel is offline  
Likes For trailangel:
Old 07-25-20, 02:09 PM
  #13  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 4,321

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 1625 Post(s)
Liked 516 Times in 396 Posts
Originally Posted by RowdyTI View Post
It's the rear wheel. Why would the bike being upside down make it more difficult to install the wheel correctly?
Some people are horrified if you turn a bike upside down. Don't know why. There were a few early hydraulic brake systems that it maybe played heck with air bubbles getting in the lines, but only one or two early ones.

Otherwise, I think it was some people trying to sell bike stands that started the rumor.<grin>
Iride01 is offline  
Likes For Iride01:
Old 07-25-20, 02:17 PM
  #14  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
Originally Posted by Iride01 View Post
Some people are horrified if you turn a bike upside down. Don't know why. There were a few early hydraulic brake systems that it maybe played heck with air bubbles getting in the lines, but only one or two early ones.

Otherwise, I think it was some people trying to sell bike stands that started the rumor.<grin>
If it is a (non-thru-axle) drop-out, Retro Grouch would be right, in my experience. The only way to reproducibly get a conventional quick-release absolutely positioned reproducibly every time is to weight the bike on the wheel. (The same issue can happen if you do it on a stand -- it isn't the upside-won part per se). With thru-axles, the round hole is symmetric, so it shouldn't matter at all. The only variable (unless you cross-thread it) is the torque.
wgscott is offline  
Likes For wgscott:
Old 07-25-20, 02:33 PM
  #15  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Taking it in to a shop to see what they say. To the one who said the brake pads would adjust anyway, but then the gearing will be slightly out of whack if the wheel is mounted slightly different, and anyway I don't want to ride the bike if the wheel isn't perfectly mounted.
RowdyTI is offline  
Old 07-25-20, 03:20 PM
  #16  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Originally Posted by wgscott View Post
If yours is the axle pictured, I would use a torque wrench and tighten it to 13.5 Nxm every time (which is a fairly substantial torque, probably more than I could deliver reproducibly with a multi-tool, or possibly even those hex-keys -- I have the same ones).
No my max nm is only 11, and that's probably with dry threads. That means about 7 nm with lubricated threads should be ideal.
RowdyTI is offline  
Old 07-25-20, 09:07 PM
  #17  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
So how come just undoing the thru axle and re-tightening it to proper torque, I'm getting rub sometimes?
RowdyTI is offline  
Old 07-25-20, 09:31 PM
  #18  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
I think the problem might be your pads, not the wheel, assuming you are replacing the wheel and torqueing the thru axle the same each time. If the caliper isn't centered about the disc, then the pads will retract asymmetrically, and less reproducibly.

To fix this, take the wheel off, pull out the brake pads, push the pistons all the way back into the caliper, put the wheel back on, tighten to exactly 11 Nxm with a torque wrench, then center the slot of the caliper, front and back, over the disc. Only then replace the pads, then pump the brakes to reset them.

When you next take the wheel off, just put it back in and torque it to 11. I think you will find the pads don't rub.
wgscott is offline  
Old 07-25-20, 09:33 PM
  #19  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Originally Posted by trailangel View Post
There is slop in the fitment of the thru axle thru the hub. That's why.
So what do you suggest?
RowdyTI is offline  
Old 07-25-20, 09:34 PM
  #20  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
Originally Posted by wgscott View Post
I think the problem might be your pads, not the wheel, assuming you are replacing the wheel and torqueing the thru axle the same each time. If the caliper isn't centered about the disc, then the pads will retract asymmetrically, and less reproducibly.

Take the wheel off, pull out the brake pads, push the pistons all the way back into the caliper, put the wheel back on, tighten to exactly 11 Nxm with a torque wrench, then center the slot of the caliper, front and back, over the disc. Only then replace the pads, then pump the brakes to reset them.

When you next take the wheel off, just put it back in and torque it to 11. I think you will find the pads don't rub.
OK. Another question: am I going to have to have the shifting cables and deraileur adjusted after doing that? It seems there's going to be different alignment. What symptoms will I notice if I need to have those adjusted? Noisy chain, or just poor shifting?

And you don't think the axle should be torqued less if the threads are well-lubricated?

Guys working on their cars had tissue with over torque after using anti-seize. The anti-seize they were using gave them 40% more torque at the same torque value.

Last edited by RowdyTI; 07-25-20 at 10:37 PM.
RowdyTI is offline  
Old 07-26-20, 05:48 AM
  #21  
shelbyfv
Banned.
 
Join Date: Jun 2007
Posts: 7,172
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 1810 Post(s)
Liked 1,182 Times in 672 Posts
Originally Posted by RowdyTI View Post
Taking it in to a shop to see what they say.
This is the best plan. You seem to have had a multitude of issues with this part of your bike. Let the shop check it out. If all is well, ask them to demonstrate wheel removal/replacement and follow their lead in the future.
shelbyfv is offline  
Likes For shelbyfv:
Old 07-26-20, 09:28 AM
  #22  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 4,321

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 1625 Post(s)
Liked 516 Times in 396 Posts
Originally Posted by RowdyTI View Post
Guys working on their cars had tissue with over torque after using anti-seize. The anti-seize they were using gave them 40% more torque at the same torque value.
Sometimes the manufacturer in their installation instructions or other maintenance doc's will state whether to grease, not grease or even use anti-sieze (which is another form of grease for non-moving parts)
Iride01 is offline  
Old 07-26-20, 09:40 AM
  #23  
wgscott
Occam's Rotor
 
wgscott's Avatar
 
Join Date: Jul 2013
Posts: 6,281
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 1,369 Times in 705 Posts
Wipe off the excess grease and torque it to the torque spec. if a greased thread were likely an issue, how probable is it that you are the first person to discover this potential problem, and that your irreproducibility has nothing to do with your decision to deliberately under-torque the thru-axle. You don't tighten it to spec, and the wheel positioning is problematic. The paralysis is striking.

But I agree, maybe you should take it to a bike shop.
wgscott is offline  
Old 08-06-20, 01:18 AM
  #24  
RowdyTI
Senior Member
Thread Starter
 
Join Date: Aug 2017
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 5 Times in 5 Posts
What I found is that the disc is too far to one side of the frame when I don't push on the part of the frame at the drive train side. Every time I do up the thru axle without pushing the frame in on that side, it's not centered. It's centered every time, however, when I make sure to push on that part of the frame when I am doing it up. Since the bike was initially set up by a good shop, I'm guessing I should do up the thru axle that way versus adjusting the brake calipers to be centered when doing it up without pushing in that part of the frame.

Have you heard of anything like this?

I've also read:
I always put the wheel on the ground and compress the fork straight down loading the axle as I finish tightening it. This insures that the normal direction of force has already been applied and the wheel is completely seated. I've had the best luck with this method getting the wheel back exactly into its normal location.
If I do that without pushing in the part of the frame at my drive side, I'll not get a centered disc, same as if I do it up like that with the bike upside down. In my case the key point is pushing in the frame at the drive side.

Just wondering if this is normal or if I should adjust the disc rotor to be centered without this manoeuvre. Could this be the reason why I get some disc rub when I am cornering when going down hills?

Last edited by RowdyTI; 08-06-20 at 01:32 AM.
RowdyTI is offline  
Old 08-06-20, 03:45 AM
  #25  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 4,253

Bikes: Schwinn Varsity

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1577 Post(s)
Liked 294 Times in 187 Posts
I actually have no idea WTF you are talking about.
trailangel is offline  
Likes For trailangel:

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

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