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

loctite for crank splines?

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.

loctite for crank splines?

Old 07-08-19, 09:53 AM
  #1  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
loctite for crank splines?

I still haven't done anything about my mr whirly left crank falling off, I keep putting off buying a new crank because I'd rather find a Surly dealer somewhere with a replacement crank in stock, but that takes research.

My buddy suggested why not just loctite red that mutha on there? And I thought, hey why not? The crankset is apparently a writeoff already, so if the crank has to be removed destructively, no loss. And if it works, I've got my bike back for maybe another month or year or whatever.

Thoughts? How well do I need to clean all the grease off? Should I go for red or green?
RubeRad is offline  
Old 07-08-19, 10:40 AM
  #2  
02Giant 
Senior Member
 
Join Date: Jan 2011
Posts: 2,977
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1638 Post(s)
Liked 741 Times in 495 Posts
Pinch bolt issue on the NDS arm? Heilcoil repair possible?

I don't see locktite helping bad threads or splines. If considering potential destructive removal of temp repairs, I would consider an epoxy, like JB Weld, Permatex Steel Weld, etc.
__________________
nine mile skid on a ten mile ride
02Giant is offline  
Old 07-08-19, 11:06 AM
  #3  
sch
Senior Member
 
Join Date: May 2003
Location: Mountain Brook. AL
Posts: 4,002
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 303 Post(s)
Likes: 0
Liked 136 Times in 104 Posts
Pinch bolt threads buggered, may be fixable with next larger bolt size and an undersized drill out of old threads and retapping.
Helicoil needs a much larger hole to be made for the insert.

As to the splines, this crank appears to have fine splines and a keyed area for crank location. If some of this is buggered then
using a space filling compound (loktite/epoxy) might work for awhile. For thin layers not much difference between the two,
both are relatively soft compared with metal, epoxy probably a little harder. Both can be damaged by heat so removal might
need a heat source that can heat the junction to 300-400F+ . Under normal cycling torque I think space fillers would only
work with a very small gap before coming loose. So a marginal repair. I assume the spindle is ok?

Space fillers require assiduous removal of grease, more than just a wipe-off for best results.
sch is offline  
Old 07-08-19, 11:27 AM
  #4  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
Hmm, nobody on the previous thread suggested that the pinch bolts might be stripped and failing to pinch. I hadn't thought of that. I'll pull those bolts out and try to have a look, but if there are not spiral aluminum threads actually falling out, is it easy to tell if that kind of thing might be the problem? When I retightened the pinch bolts on the trail, I did not perceive that either pinch bolt felt stripped.

One thing for sure, the end-cap for preloading the crank arm before tightening the pinch bolts, has some stripping. The threads can only engage when the crank is already pushed all the way on, you can't really use it to snug it up. I'm sure the first time the crank worked its way off (which may have been during my ownership or a previous owner) it took some of those threads with it.

"Pinch bolt threads buggered, may be fixable with next larger bolt size and an undersized drill out of old threads and retapping."

What about the possibility of just forcing the next larger bolt size right in? Would steel bolt threads just cut themselves new threads in the softer aluminum crank? I've never tapped before.

"I assume the spindle is ok?"

My understanding is the spindle is steel and the arms are aluminum, so it should be more likely that the problem would be in the arm. Certainly the spindle looks ok visually, but I know a problem like this would not be easy to see with the eye.
RubeRad is offline  
Old 07-08-19, 11:32 AM
  #5  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times in 82 Posts
Originally Posted by RubeRad
What about the possibility of just forcing the next larger bolt size right in? Would steel bolt threads just cut themselves new threads in the softer aluminum crank? I've never tapped before.
It's worth a try. BTW, what thread pitch are you dealing with, before/after?
AnkleWork is offline  
Old 07-08-19, 11:47 AM
  #6  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
Not sure about thread pitch, but I believe the pinch bolts have 5mm heads, probably whatever the most standard metric size is.
RubeRad is offline  
Old 07-08-19, 11:54 AM
  #7  
phughes
Senior Member
 
phughes's Avatar
 
Join Date: Mar 2011
Posts: 3,064
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked 1,252 Times in 724 Posts
Originally Posted by RubeRad
"Pinch bolt threads buggered, may be fixable with next larger bolt size and an undersized drill out of old threads and retapping."

What about the possibility of just forcing the next larger bolt size right in? Would steel bolt threads just cut themselves new threads in the softer aluminum crank? I've never tapped before.
No. No, and no. Get a tap, do it right.
phughes is offline  
Old 07-08-19, 12:41 PM
  #8  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 3,036

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1152 Post(s)
Liked 340 Times in 250 Posts
Originally Posted by RubeRad
My buddy suggested why not just loctite red that mutha on there?

Thoughts? How well do I need to clean all the grease off? Should I go for red or green?
If you want to have to saw the crank off when you finally do the change, go ahead with red. May not work, though. It's meant to keep stuff in close proximity stuck together. Not sure about it being good as a structural adhesive.

Red = permanent, Blue = medium, reversible, Green = medium to high strength, wicking (you can apply it after tightening the bolt, or for a sleeve).

Check out: https://henkeladhesivesna.com/blog/t...threadlockers/

The classic repair would use thread repair inserts, like Helicoils. To install those, you'd want a good drill press to drill and a vise to hold the arm. Drill. Then thread. Then put the coil or thread insert in using a tool. Not sure you have enough meat in your crank arm for this, though.

You might be able to do a temp job: I'd find longer bolts of the same size as your crank arm clamp bolts. Then find nuts to go on the ends. Then you should be able to get the current arm to work, but this would be reversible. You'd also have the nuts pretty visible and ugly, but its cheap and if you muck up the crank arm, you can remove it easily.

Using a steel bolt to form new threads would be called form tapping. Normally, you do this only in appropriate alloys that you know the heat-treat history of, using a hardened steel form tap. Can work fine if you had an untapped hole of the correct size in a the proper alloy. For a hole that's already drilled and tapped and has been rounded out, not a very good approach. Probably not a good approach for the Al crank arm alloy.

By the time you mess around finding the right threadlocker or adhesive, or Helicoil, you may be time and dollars ahead just buying a new crankarm.

Last edited by WizardOfBoz; 07-08-19 at 01:04 PM.
WizardOfBoz is offline  
Old 07-08-19, 01:28 PM
  #9  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times in 723 Posts
Originally Posted by phughes
No. No, and no. Get a tap, do it right.
Consider what will happen if you break the bolt off in the hole. You will have a steel screw stuck in a softer alloy hole; good luck drilling it out.

"I've never tapped before". That is pretty clear. Except for a deliberately designed press fit, "force it in" has no place in machine work.
dsbrantjr is offline  
Likes For dsbrantjr:
Old 07-08-19, 01:58 PM
  #10  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
Originally Posted by dsbrantjr
Consider what will happen if you break the bolt off in the hole. You will have a steel screw stuck in a softer alloy hole; good luck drilling it out.

"I've never tapped before". That is pretty clear. Except for a deliberately designed press fit, "force it in" has no place in machine work.
Yes, the closest I've come to 'machine work' is drilling the brake caliper mounting hole a tiny bit wider in a steel fork.

But if something goes wrong I dremel through the eye of the crank to get it off. A lost crank still lost.

Last edited by RubeRad; 07-08-19 at 02:03 PM.
RubeRad is offline  
Old 07-08-19, 02:02 PM
  #11  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
Originally Posted by WizardOfBoz
You might be able to do a temp job: I'd find longer bolts of the same size as your crank arm clamp bolts. Then find nuts to go on the ends. Then you should be able to get the current arm to work, but this would be reversible. You'd also have the nuts pretty visible and ugly, but its cheap and if you muck up the crank arm, you can remove it easily.
Now that's a great idea. I will definitely try that -- if the pinch bolt holes go all the way through, which I don't recall if they do. The schematic seems to indicate they do.

This would determine, anyways, whether the problem is in the pinch bolts, or as I originally thought, the aluminum receiving splines are worn or rounded or something and can't stop from rocking and eventually moving off.

Note also, I am a fattie and I use 20mm pedal extenders, so that exerts a probably unusual amount/direction of leverage on the crank. Surly always says, though, "fatties fit fine"
RubeRad is offline  
Old 07-08-19, 03:02 PM
  #12  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times in 723 Posts
Originally Posted by RubeRad
I use 20mm pedal extenders, so that exerts a probably unusual amount/direction of leverage on the crank. Surly always says, though, "fatties fit fine"
Make certain that you get the pedals adequately torqued so that you do not strip out those threads.
dsbrantjr is offline  
Old 07-08-19, 04:25 PM
  #13  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 3,036

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1152 Post(s)
Liked 340 Times in 250 Posts
The Mr. Whirly spindle is chrome-moly, the arms are 7075 aluminum, so any wear should be in the arms. But its hard finding parts (and a set of arms seems to be around 120 bucks) - is this still an item that Surly offers and supports? You may have better luck just finding a different make/model of crank.

The pics I saw look like the clinch nuts use a through-hole and not a blind one. Put the bolt in,tighten it a little. Then put the nut on the bolt where it extends and tighten it pretty good. Then torque the bolt, using a wrench on the backing nut. My goal with this advice is to preserve as much of the existing thread as you can.

If you are a big guy, and using extensions, this makes it extremely important to torque the clinch nuts down. Which I think reinforces what dsbrantjr says above.
WizardOfBoz is offline  
Old 07-08-19, 04:31 PM
  #14  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
I called my LBS, they said they could not order me a replacement arm from QBP, so I don't think Surly is making/selling them anymore. Online listings also say out of stock

Instructions say that the pinch bolts should be torqued to 10Nm=7ft-lb, which seems laughably loose (drive side is 50Nm, like a normal drive side crank bolt). What would be the effect of over-tightening?

Last edited by RubeRad; 07-08-19 at 04:38 PM.
RubeRad is offline  
Old 07-08-19, 05:08 PM
  #15  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times in 723 Posts
Originally Posted by RubeRad
Instructions say that the pinch bolts should be torqued to 10Nm=7ft-lb, which seems laughably loose (drive side is 50Nm, like a normal drive side crank bolt). What would be the effect of over-tightening?
Stripping the threads, cracking the part, or distortion of the mating surfaces (which might compromise the clamping function) for starters. If you look you might notice that the crank bolt is much larger and serves a totally different function than the pinch bolts, so one might surmise that the difference in torque specifications could be appropriate. The drive side also has to resolve forces from both the crank and the chainring, while the non-drive side has only the crank.
dsbrantjr is offline  
Old 07-09-19, 08:44 AM
  #16  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 3,036

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1152 Post(s)
Liked 340 Times in 250 Posts
The instructions https://surlybikes.com/uploads/downl...structions.pdf illustrate what dsbrantjr has said. The DS bolt is like 14mm or so in diameter, and the cinch bolts are like 6. 10Nm for an M6 bolt is not laughably low.

There's a reason they make instructions! Follow 'em!

But unless you find a used crank or someone with some old stock of Mr. Whirly parts, I think you're gonna have to consider a different crank. Too bad, though, cuz "Surly Mr. Whirly" is like the best model name ever. But I think that there's better performing cranks out there.
WizardOfBoz is offline  
Old 07-09-19, 09:00 AM
  #17  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
I don't need performing. All I need is not breaking. The biggest reason I would like to hang onto this crank if I can is the tiny bcd for the Surly 28-tooth narrow-wide chainring I bought which is still basically brand new. Nobody else makes a 1x smaller than 32 (that I can find)

Last edited by RubeRad; 07-09-19 at 09:09 AM.
RubeRad is offline  
Old 07-09-19, 09:09 AM
  #18  
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
Keep your eye out on eBay... the Local shop here has done several Motor Conversion, Mid Drives ,

Replacing the whole Crankset .. Just not on Surlys (so no Mr Whirlys getting listed) ..

But that is a source of no longer imported parts..






...
fietsbob is offline  
Old 07-09-19, 09:50 AM
  #19  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 4,847

Bikes: Schwinn Varsity

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1931 Post(s)
Liked 741 Times in 421 Posts
I googled Mr Wurly crank. (I hate these names..... made for a 6th grader) and a lot comes back saying that crankset falls apart.
Buy something new and different.
trailangel is offline  
Old 07-09-19, 10:00 AM
  #20  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times in 82 Posts
A tiny bit of diagnosis would make this into a very different thread.
AnkleWork is offline  
Old 07-09-19, 05:08 PM
  #21  
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 9,856

Bikes: Kirk Custom JK Special, '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque

Mentioned: 104 Post(s)
Tagged: 0 Thread(s)
Quoted: 2304 Post(s)
Liked 2,741 Times in 1,499 Posts
think big picture what is the bike worth? is it work it to replace the whole crankset? or cranset and bb if moving to another brand?

Also what happens if you kludge a repair and it goes south, fast and hard when you are riding? How good is your health insurance.

This is some thing to do right and not kludge
__________________
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)



squirtdad is offline  
Old 07-09-19, 05:15 PM
  #22  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
bike is worth ~$1k, I'm just probably too stuck on the fact that I just bought the chainring, and I don't think anybody but surly ever made a 58bcd crankset, and it doesn't look like surly even sells cranksets anymore.

I guess now is the time to jump off the sinking (sunken?) ship of surly's proprietary bcd standard
RubeRad is offline  
Old 07-09-19, 08:47 PM
  #23  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 3,036

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1152 Post(s)
Liked 340 Times in 250 Posts
Originally Posted by RubeRad
bike is worth ~$1k, I'm just probably too stuck on the fact that I just bought the chainring, and I don't think anybody but surly ever made a 58bcd crankset, and it doesn't look like surly even sells cranksets anymore.

I guess now is the time to jump off the sinking (sunken?) ship of surly's proprietary bcd standard
I remember moving to my current house 20 years ago(!). Just prior to the move, we'd purchased a new Maytag Dependable Care Gas dryer. Got to the new house and... No gas line hookup. No gas main. Now, some guys would sell the Maytag, buy an electric dryer, and move on. I ended up having 833 feet of gas line laid (for which I paid 600 bucks) and replacing the water heater and stove. For a 600 dollar dryer.

On the plus side, my neighbors are all jealous. We're the only ones with a gas stove around here.

Point is, you can get too wrapped up with one thing to see the big picture. Step back and check it out.

But if you can find a Mr. Whirly crank, used, it may be cheaper to do that. But they don't seem to be very durable judging by the reviews.

Good luck.
WizardOfBoz is offline  
Old 07-10-19, 09:53 AM
  #24  
RubeRad
Keepin it Wheel
Thread Starter
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 10,238

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked 3,400 Times in 2,511 Posts
Originally Posted by WizardOfBoz
I ended up having 833 feet of gas line laid (for which I paid 600 bucks)
?!?!?! I would have guessed that would cost like $10,000
RubeRad is offline  
Old 07-10-19, 10:34 AM
  #25  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 4,847

Bikes: Schwinn Varsity

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1931 Post(s)
Liked 741 Times in 421 Posts
Show pic of $1,000 bike
trailangel 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.