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

Do I need a torque wrench to install rotors?

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.
View Poll Results: Do I need a torque wrench to install brake rotors
Yes
13
41.94%
No, a good guestimate of 3 to 6 Nm is good enough
18
58.06%
Voters: 31. You may not vote on this poll

Do I need a torque wrench to install rotors?

Old 06-01-19, 12:37 PM
  #1  
tyrion
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,011 Times in 972 Posts
Do I need a torque wrench to install rotors?

Yes.

No - a guestimate between 3 and 6 Nm is good enough, as long as it's consistent between the 6 bolts and sequenced in the proper star sequence.
tyrion is offline  
Old 06-01-19, 02:02 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,999

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4171 Post(s)
Liked 3,791 Times in 2,270 Posts
Originally Posted by tyrion
Yes.

No - a guestimate between 3 and 6 Nm is good enough, as long as it's consistent between the 6 bolts and sequenced in the proper star sequence.
I have always felt this "cross tightening" method, which is what I was taught to do on car wheel studs/bolts, is nonsense for a bike rotor. The rotor will just bend and take to whatever surface flatness (or not) that the hub is faced off at. I don't think there's anyway a rotor could induce a warping to the hub, and since we gladly true a rotor any run out of it is easily dealt with (whether or not run out is hub induced or in the rotor before installing).

Now I have no problem maintaining a false belief if it makes us pay more attention and take due care to insure a correct outcome. But in my eyes that is what is cross tightening is for bicycle disk brake rotor bolts. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Likes For Andrew R Stewart:
Old 06-01-19, 02:38 PM
  #3  
jimc101
Senior Member
 
Join Date: Oct 2007
Location: West Yorkshire, United Kingdom
Posts: 5,773
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 453 Post(s)
Liked 104 Times in 87 Posts
Go by the rotors instructions, yes, when I worked in a LBS, we did it with a digital torque wrench, for personal use, no, have been using discs for pushing 20 years and not had any bolts come loose, I do with centerlocks, simply as they are the same setup torque wrench wise as a cassette install.
jimc101 is offline  
Likes For jimc101:
Old 06-01-19, 03:35 PM
  #4  
davidad
Senior Member
 
Join Date: Feb 2009
Posts: 6,660
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 582 Post(s)
Liked 171 Times in 138 Posts
Yes.
davidad is offline  
Old 06-01-19, 07:04 PM
  #5  
August West
Senior Member
 
Join Date: Jun 2009
Location: Land of Enchantment
Posts: 468

Bikes: Domane SLR7 Project One

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 152 Post(s)
Liked 173 Times in 105 Posts
Haven't had to change out rotors yet but when the time comes I'll use a torque wrench. I've gotten to the point where I torque just about everything on the bike. I figure I've since spent the money on the torque wrenches I might as well use them.
August West is offline  
Old 06-01-19, 07:08 PM
  #6  
Cyclist0108
Occam's Rotor
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
It is easy to damage a soft aluminum thread in a hub if you over-tighten or mis-thread a bolt. The problems of too loose bolts should be obvious.

You could probably get away with having only three of the six bolts in, if they are symmetrically disposed. The point is to have some redundancy, and having each bolt torqued the same amount contributes to that.
Cyclist0108 is offline  
Old 06-02-19, 08:30 AM
  #7  
hokiefyd 
Senior Member
 
hokiefyd's Avatar
 
Join Date: Feb 2017
Location: Northern Shenandoah Valley
Posts: 4,123

Bikes: More bikes than riders

Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 749 Times in 559 Posts
I've experienced the effect of loose bolts, in the form of the disc rotating on the hub when rocking the bike back and forth. It seemed to be more than just the pads shifting in the caliper, and indeed discovered that the disc itself was shifting. Combining this with the unsavory possibility of stripping a hole in the hub, I've used a torque wrench to install discs ever since.
hokiefyd is offline  
Old 06-02-19, 10:23 AM
  #8  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
I have access to a preset click torque wrench with a Torx bit in it.. for disc brakes .. in the LBS..

You can buy a preset torque key if you do a lot of them.. know what torque is specified?

but ... after decades of dealing with 5 mm bolts, on bikes in the shop,

You may need a torque wrench I do Not.















...

Last edited by fietsbob; 08-09-20 at 03:12 PM.
fietsbob is offline  
Old 06-02-19, 11:00 AM
  #9  
Racing Dan
Senior Member
 
Racing Dan's Avatar
 
Join Date: Aug 2015
Posts: 2,224
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 1332 Post(s)
Liked 316 Times in 214 Posts
Install it with a cordless drill, with the torque setting at some reasonable point and use a dab of loctite. At least then you know they are all torqued the same and wont fall out. I just made that up in my head. Never tried it ;-)
Racing Dan is offline  
Old 06-02-19, 11:04 AM
  #10  
DrIsotope
Non omnino gravis
 
DrIsotope's Avatar
 
Join Date: Feb 2015
Location: SoCal, USA!
Posts: 8,553

Bikes: Nekobasu, Pandicorn, Lakitu

Mentioned: 119 Post(s)
Tagged: 0 Thread(s)
Quoted: 4905 Post(s)
Liked 1,731 Times in 958 Posts
Well, I install mine with one of these,


A 12V Bosch Impactor, fitted with one of the countless 2" T25 bits I have from buying equally countless boxes of decking screws. I give each bolt a brrt-brrt-brrt from the impact driver, and tighten in criss-cross. Like on a car.

Never had a bolt loosen at all. Miles: lots.
__________________
DrIsotope is offline  
Old 06-02-19, 01:43 PM
  #11  
Kapusta
Advanced Slacker
 
Kapusta's Avatar
 
Join Date: Feb 2017
Posts: 6,187

Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2749 Post(s)
Liked 2,516 Times in 1,422 Posts
Been using discs since 2001. Never used a torque wrench for the rotor bolts, even though I have one that I use for other things. Never had one come loose or strip any threads.

Not making a recommendation for what others should do, as I don’t know how ham-fisted others are.
Kapusta is offline  
Old 06-02-19, 02:10 PM
  #12  
tyrion
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,011 Times in 972 Posts
I was thinking just get a tool like this and crank it down almost as hard as I can with only 4 inches of leverage:

tyrion is offline  
Old 06-02-19, 07:50 PM
  #13  
Kapusta
Advanced Slacker
 
Kapusta's Avatar
 
Join Date: Feb 2017
Posts: 6,187

Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2749 Post(s)
Liked 2,516 Times in 1,422 Posts
Originally Posted by tyrion
I was thinking just get a tool like this and crank it down almost as hard as I can with only 4 inches of leverage:

Pretty sure I could do some damage with that if I tightened as hard as I could.
Kapusta is offline  
Likes For Kapusta:
Old 06-02-19, 07:53 PM
  #14  
Cyclist0108
Occam's Rotor
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Originally Posted by DrIsotope
Well, I install mine with one of these,


A 12V Bosch Impactor, fitted with one of the countless 2" T25 bits I have from buying equally countless boxes of decking screws. I give each bolt a brrt-brrt-brrt from the impact driver, and tighten in criss-cross. Like on a car.

Never had a bolt loosen at all. Miles: lots.
I have one of those, too, but it never occurred to me to get it anywhere near my bikes.
Cyclist0108 is offline  
Old 06-02-19, 07:53 PM
  #15  
Marcus_Ti
FLIR Kitten to 0.05C
 
Marcus_Ti's Avatar
 
Join Date: Sep 2014
Location: Lincoln, Nebraska
Posts: 5,331

Bikes: Roadie: Seven Axiom Race Ti w/Chorus 11s. CX/Adventure: Carver Gravel Grinder w/ Di2

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 2349 Post(s)
Liked 406 Times in 254 Posts
Originally Posted by tyrion
I was thinking just get a tool like this and crank it down almost as hard as I can with only 4 inches of leverage:
Yea....doing that you'll sheer the fastener head right off.
Marcus_Ti is offline  
Old 06-02-19, 07:54 PM
  #16  
tyrion
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,011 Times in 972 Posts
Originally Posted by Kapusta
Pretty sure I could do some damage with that if I tightened as hard as I could.
Thanks for the tip.
tyrion is offline  
Old 06-02-19, 08:12 PM
  #17  
sdmc530
Heft On Wheels
 
sdmc530's Avatar
 
Join Date: Nov 2014
Location: South Dakota
Posts: 3,124

Bikes: Specialized,Cannondale,Argon 18

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 887 Post(s)
Liked 560 Times in 346 Posts
It is my very humble opinion that anyone who works on a bike should absolutely be using a torque wrench
sdmc530 is offline  
Old 06-02-19, 08:42 PM
  #18  
drlogik 
Senior Member
 
drlogik's Avatar
 
Join Date: Mar 2016
Location: North Carolina
Posts: 1,763

Bikes: '87-ish Pinarello Montello; '89 Nishiki Ariel; '85 Raleigh Wyoming, '16 Wabi Special, '16 Wabi Classic, '14 Kona Cinder Cone

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 698 Post(s)
Liked 405 Times in 251 Posts
Yes. These are your brakes, not a seatpost bolt. The tightness of each bolt must be the same or the rotor can warp (bad) or work loose ("more badder"). Others will argue that you don't need to torque, but why? If you have a torque wrench or can borrow one, why wouldn't you torque them down?


..

Last edited by drlogik; 06-02-19 at 09:04 PM.
drlogik is offline  
Old 06-03-19, 07:27 AM
  #19  
leob1
Senior Member
 
Join Date: Jul 2006
Location: Middle of the road, NJ
Posts: 3,137
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 292 Post(s)
Liked 106 Times in 69 Posts
No, you don't need one.
But buy one and use it anyway. You'll also use it on other stuff that has a specific torque requirement, like carbon parts.
leob1 is offline  
Old 06-03-19, 08:33 AM
  #20  
Kapusta
Advanced Slacker
 
Kapusta's Avatar
 
Join Date: Feb 2017
Posts: 6,187

Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2749 Post(s)
Liked 2,516 Times in 1,422 Posts
Originally Posted by drlogik
Yes. These are your brakes, not a seatpost bolt.
..
Actually, I am more likely to use a torque wrench for a seat post clamp than for rotor bolts.
Kapusta is offline  
Old 06-03-19, 12:38 PM
  #21  
Kapusta
Advanced Slacker
 
Kapusta's Avatar
 
Join Date: Feb 2017
Posts: 6,187

Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2749 Post(s)
Liked 2,516 Times in 1,422 Posts
Rotor bolts are really not that hard to get right. Tight enough to not come loose, but not so tight that you strip the threads or break off the bolt heads. For people who wrench regularly, that is pretty simple. There is no risk of crushing the rotor or having it slip.

Things like seatpost clamps and stem face-plates are a different story. you need to get the torque high enough to keep the seatpost/bar from slipping, but not too high to crush/damage it, and it is really hard to know what that feels like when tightening.

But like someone else said, even if you don't use a torque wrench for rotor bolts, you should still get one for all the parts that you DO want one.
Kapusta is offline  
Old 08-08-20, 10:13 PM
  #22  
MinnMan
Senior Member
 
MinnMan's Avatar
 
Join Date: Aug 2009
Location: Minneapolis
Posts: 5,734

Bikes: 2022 Salsa Beargrease Carbon Deore 11, 2020 Salsa Warbird GRX 600, 2020 Canyon Ultimate CF SLX disc 9.0 Di2, 2020 Catrike Eola, 2016 Masi cxgr, 2011, Felt F3 Ltd, 2010 Trek 2.1, 2009 KHS Flite 220

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 4261 Post(s)
Liked 2,936 Times in 1,810 Posts
How about for centerlock rotors? Recommendation is 40 Nm.

I have a torque wrench, but not one that goes to 40 Nm and I don't have a ratchet large enough to fit over the Lockring tool. Also, I don't see much other need for having a torque wrench that goes to such high torques. Certainly I've never felt the need for one in order to install a cassette. Is this different?

These seem less finicky than the rotors with multiple bolts. Seems I should be able to wrench it down tight without being in danger of making it too loose or damaging the threads?

No?
MinnMan is online now  
Old 08-08-20, 10:40 PM
  #23  
alcjphil
Senior Member
 
alcjphil's Avatar
 
Join Date: Jun 2002
Location: Montreal, Quebec
Posts: 5,869
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1792 Post(s)
Liked 1,671 Times in 955 Posts
Originally Posted by Andrew R Stewart
I have always felt this "cross tightening" method, which is what I was taught to do on car wheel studs/bolts, is nonsense for a bike rotor. The rotor will just bend and take to whatever surface flatness (or not) that the hub is faced off at. I don't think there's anyway a rotor could induce a warping to the hub, and since we gladly true a rotor any run out of it is easily dealt with (whether or not run out is hub induced or in the rotor before installing).

Now I have no problem maintaining a false belief if it makes us pay more attention and take due care to insure a correct outcome. But in my eyes that is what is cross tightening is for bicycle disk brake rotor bolts. Andy
I totally agree about the "cross tightening" method. This made total sense for car wheels in the days when all cars had drum brakes. Not so much now that most cars have 4 wheel disc brakes, However, it does make sense that all bolts of a disc brake rotor be tightened to the same torque value. If the installer wants to go around a second time, so be it
alcjphil is offline  
Old 08-09-20, 06:59 AM
  #24  
Marcus_Ti
FLIR Kitten to 0.05C
 
Marcus_Ti's Avatar
 
Join Date: Sep 2014
Location: Lincoln, Nebraska
Posts: 5,331

Bikes: Roadie: Seven Axiom Race Ti w/Chorus 11s. CX/Adventure: Carver Gravel Grinder w/ Di2

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 2349 Post(s)
Liked 406 Times in 254 Posts
Originally Posted by MinnMan
How about for centerlock rotors? Recommendation is 40 Nm.

I have a torque wrench, but not one that goes to 40 Nm and I don't have a ratchet large enough to fit over the Lockring tool. Also, I don't see much other need for having a torque wrench that goes to such high torques. Certainly I've never felt the need for one in order to install a cassette. Is this different?

These seem less finicky than the rotors with multiple bolts. Seems I should be able to wrench it down tight without being in danger of making it too loose or damaging the threads?

No?
Cassette lockrings and bottom brackets have torque specs in this realm.
Marcus_Ti is offline  
Old 08-09-20, 03:04 PM
  #25  
Kapusta
Advanced Slacker
 
Kapusta's Avatar
 
Join Date: Feb 2017
Posts: 6,187

Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2749 Post(s)
Liked 2,516 Times in 1,422 Posts
This is not rocket science. Just tighten until the bolt head breaks free and back off 1/8 turn.
Kapusta is offline  

Thread Tools
Search this Thread

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

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.