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.

Chain Slips

Old 05-19-18, 09:04 AM
  #1  
ak08820
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Central NJ
Posts: 566

Bikes: MGX MTB, Fuji Supreme, Miyata 90 and a Trek 700 in the works

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Chain Slips

I have a 21 speed low end MTB (Mongoose/MGX S20) which serves my needs perfectly but now the chain slips when I am in the largest chain ring and climbing a slight incline. I thought that the chain was stretched and reduced it by 1 link and it made a very small but negligible improvement. Am I looking for a new crankset? I measured the chain and the pics are attached. In 6" there seems to be exactly 12 links to/from the edge of the pins. The middle and smaller chain rings work fine. The teeth on the large rig do look worn.


ak08820 is offline  
Old 05-19-18, 09:14 AM
  #2  
Crankycrank
Senior Member
 
Join Date: Jan 2009
Location: San Diego, CA
Posts: 1,334
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 184 Post(s)
Likes: 0
Liked 11 Times in 8 Posts
If your chain is worn removing links will do almost nothing to reduce slippage. Find a tutorial explaining how to measure chain wear with a ruler (an easy Google search) which will tell you if yours is actually worn. The chainring teeth look to have some wear but if the chain is done for a cheap new one may solve your problem. There is also the possibility that the rear sprockets may be worn and will also slip with a new chain needing replacement as well but first determine if your chain is worn. If you have a Co-op nearby probably worth a visit to sort everything out without spending a load of cash.
Crankycrank is offline  
Old 05-19-18, 12:10 PM
  #3  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 6,220

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

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 657 Post(s)
Likes: 0
Liked 49 Times in 45 Posts
Make very certain that you have not shortened your chain too much; it must still be long enough to engage the big chain ring/big rear cog combination without strain. Check this by gently turning the cranks by hand and stop if anything gets tight.
dsbrantjr is offline  
Old 05-19-18, 12:20 PM
  #4  
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 41,398

Bikes: 8

Mentioned: 188 Post(s)
Tagged: 0 Thread(s)
Quoted: 6838 Post(s)
Likes: 0
Liked 217 Times in 180 Posts
new chainrings chain and freewheel/cassette all at once?
fietsbob is offline  
Old 05-19-18, 01:35 PM
  #5  
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 29,267

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

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1164 Post(s)
Liked 33 Times in 25 Posts
Chainrings have to be seriously worn before they will cause skipping. Yours doesn't look that bad to me yet. The teeth look real pointy when badly worn.

Since you've been messing with the chain, I'd check for a tight link if, for no other reason, it doesn't cost anything.
Prop your bike up and turn the crank backwards with your hand while watching where the chain exits the derailleur. If you have a tight link you will see the derailleur arm hiccup as the tight link exits. Loosen up that link and you'll be good-to-go.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
Retro Grouch is offline  
Old 05-19-18, 07:28 PM
  #6  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 2,305

Bikes: '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 867 Post(s)
Liked 28 Times in 25 Posts
If you haven't just put a chain on it, then get one. If it still skips, then get a new chainwheel or entire cranksets. Might be a good excuse for a new bike. But still get the old one fixed. Never can have too many.
Iride01 is offline  
Old 05-21-18, 11:19 PM
  #7  
woodcraft
Senior Member
 
woodcraft's Avatar
 
Join Date: Apr 2012
Location: Nor Cal
Posts: 4,218
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1021 Post(s)
Likes: 0
Liked 33 Times in 19 Posts
It's on the cogs in the back where the skipping happens, most often on the smallest cogs,

but skipping can happen from just the derailler being out of adjustment, so that's the first thing to check.

Replacing the cassette or freewheel is next, but mismatched wear between chain & cogs frequently causes skipping,

so replace chain as well. Chainrings last a long time- unlikely that's the issue.

The freewheel or cassette hub can also gum up and cause skipping although that would probably happen on all chainrings.
woodcraft is offline  
Old 05-22-18, 04:41 AM
  #8  
ak08820
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Central NJ
Posts: 566

Bikes: MGX MTB, Fuji Supreme, Miyata 90 and a Trek 700 in the works

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I checked the chain for stiff links and there are none. The chain length seems to be correct too, there are 12 links in exactly 6 inches indicating not much stretch.
I rode the bike yesterday and it felt like the freewheel pawls may be slipping under strain and not the chain. What I mean by chain slipping is that when the bike is pedaled hard, in the largest chain ring and in almost any rear sprocket and on a slight incline, there is loud cracking noise and the pedal moves forward without any resistance for a few inches and engages again. I am clarifying so that the symptom is not mistaken for unintentional sideways movement of the chain which is not the case. Is it possible for the pawls to give way against force beyond a certain limit, which may be happening with the largest chain ring engaged?

I guess I will have to verify by swapping the rear wheel.
ak08820 is offline  
Old 05-22-18, 08:28 AM
  #9  
zacster
Senior Member
 
Join Date: Jul 2004
Location: Brooklyn NY
Posts: 6,064
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Likes: 0
Liked 8 Times in 7 Posts
Looking at the last picture, your measurement looks like it is stretched. Your zero is not nearly on center with the pin, nor is the 6, or pin edge to pin edge. A new chain is relatively cheap. I'd also say that your chainrings ARE worn. Just replace the big ring.

I am going to do exactly this on my commuter when I get a chance as I also experience skipping, and also have had the chain completely slip off the front a few times. I just need to look for a new 48t 110bcd ring, which shouldn't be hard to find as they were pretty standard.
zacster is offline  
Old 05-22-18, 08:40 AM
  #10  
hokiefyd
Senior Member
 
Join Date: Feb 2017
Location: Northern Shenandoah Valley
Posts: 2,189

Bikes: 2018 Redline Zander, 2018 Giant Roam 2, 2015 Trek Verve 3, 1997 Trek 750, 1969 Peugeot PO-18

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 741 Post(s)
Liked 46 Times in 42 Posts
Originally Posted by zacster View Post
Looking at the last picture, your measurement looks like it is stretched. Your zero is not nearly on center with the pin, nor is the 6, or pin edge to pin edge.
I agree with this. You should have exactly 6" between 12 pins on the chain. Your 6" end on the ruler is lined up pretty good on one pin, but the 12th pin, counting down the ruler, falls way off the end of the ruler. It should line up exactly with the 0" end of your ruler. You can see by 3" or even 4" on your ruler, your pins are not exactly in line with the mark. Unless I'm interpreting your photograph incorrectly, I'd say that chain is significantly worn.

Edit: you normally measure 24 pins across 12" to get a more accurate measurement of chain wear. You can see (again, if I'm interpreting your photo correctly) significant wear across only 6". It looks like 12 of your chain pins measure about 6-1/16" or so (or maybe even 6-1/8"). 24 pins would probably measure between 12-1/8" and 12-1/4", which is way beyond the acceptable measurement. Bike Radar (below) says that any chain with a measurement of longer than 12-1/16" should be replaced, and anything beyond 12-1/8" is worn to death (their words), and a new cassette or freewheel is likely needed as well.

https://www.bikeradar.com/us/road/ge...plained-46015/

Last edited by hokiefyd; 05-22-18 at 08:45 AM.
hokiefyd is offline  
Old 05-23-18, 01:01 PM
  #11  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 2,305

Bikes: '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 867 Post(s)
Liked 28 Times in 25 Posts
Bike shops around me are always willing to let the mechanic look and give advice for free, in hopes you'll let them fix it and just for the good will of keeping you coming to the shop. Will your shops around you do that? They'll check the chain and slap a new one on pretty cheap I'd bet if that's all you need. You still might need a cog too, but if that is also worn then the chains definitely gone if it hadn't recently been replaced.
Iride01 is offline  
Old 05-24-18, 07:09 AM
  #12  
Glenn6870
Member
 
Join Date: Jan 2017
Posts: 25

Bikes: 2017 Giant Contend SL2 Disc; 1997 Trek Singletrack

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Your issue sounds a lot like what i had a few months back. Going up a hill with added tension, the chain felt like it was slipping. i too thought it was my chain, and like you i did all of the measurements with a ruler, ( i even used a chain gauge tool), but they all indicated no chain stretch. I finally brought it in to the shop and they gave the derailleurs a slight adjustment. The problem wasn't chain slipping, it was chain moving down a gear. My problem went away immediately. Other than the "slippage" i experienced on hills, the gears shifted with no problem whatsoever, so there was no reason to think the gears were out of adjustment. But that was definitely the issue, because it didn't happen anymore after the adjustment.

Not saying this is your problem, and i agree with others, your chain looks a little stretched, but it's something worth looking at if you haven't already.
Glenn6870 is offline  
Old 05-29-18, 11:16 AM
  #13  
ak08820
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Central NJ
Posts: 566

Bikes: MGX MTB, Fuji Supreme, Miyata 90 and a Trek 700 in the works

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
After a thorough cleaning of the rear derailleur and chain and reinstalling them, the problem has minimized. It must be mainly due to the RD pulley ceasing plus a couple of stiff links.

Now, I tried to replace the front shifting cable as it was frayed at the pinch point and find that the inside of the TDQ-PRO HS-220 grip shifter seems to be wearing out as there was black powdery stuff inside. The front D. did not shift well, too. If I adjust the cable so that it shifts to the largest ring, it would not go down to the lowest ring and vice versa. Looks like the cable is not pulled along its intended helical path but along a new worn out path in the grip shifter. Is this a known issue in plastic bodies shifters and need a replacement now? In that case is this Microshift Grip Shifter a good replacement ? I cant find TDQ-PRO brand anywhere, seems to be out of business.
ak08820 is offline  
Old 05-30-18, 08:44 AM
  #14  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 2,305

Bikes: '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 867 Post(s)
Liked 28 Times in 25 Posts
Are you adjusting the DR correctly? You need to have your high adjusted so the jockey wheel is in line with the high gear before attaching the cable. It's not a final adjustment, but it assures you'll get the cable attached at a point where all other adjustments can usually be accomplished with the range of adjustment allowed by them.

If you aren't certain about how all the pieces parts work together and how the adjustments affect all the others then you really need to get the manual for your model and go through all the steps in order.
Iride01 is offline  
Old 06-07-18, 05:25 AM
  #15  
ak08820
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Central NJ
Posts: 566

Bikes: MGX MTB, Fuji Supreme, Miyata 90 and a Trek 700 in the works

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I replaced the front shifter yesterday and it rides mush better in the largest chain ring without almost any slipping. Backpaddling still shows issues with the chain or pulley and will be looking at that.
ak08820 is offline  
Old 06-07-18, 05:36 AM
  #16  
wphamilton
Senior Member
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 14,504

Bikes: Nashbar Road

Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 2511 Post(s)
Liked 58 Times in 35 Posts
The chain is stretched, more than 1/8" over 12".
wphamilton is offline  
Old 06-07-18, 07:57 AM
  #17  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,503

Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 477 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
1. The reason it slips on the large chainring is usually because it overall has higher gears than the other two, requiring more pedal pressure at a given speed. Your description of a large amount of travel before catching does make the freewheel/freehub suspect. Those chainring teeth are nowhere near worn enough to cause skipping.
2. 6" is not long enough to determine wear, especially if the chain is not under tension. 12" is the norm.
3. Not a good idea to be on the large chainring on a slight incline unless you are in one of the largest rear cogs, which I doubt is the case.
4. I would suggest you plan on a chain and freewheel if you have any further slipping under pressure. Once skipping starts usually wear on the small cog(s) is sufficient to cause skipping with a new chain.
5. It's unclear what you mean by "issues" with backpedaling, but if the chain is drooping when you backpedal that is often due to excess friction in the freehub/freewheel. Coupled with possible slipping when engaged I would say you need to flush it out.
__________________
There's no such thing as a routine repair.

Don't tell me what "should" be - either it is, it isn't, or do something about it.

If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

Please respect others by taking the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

Last edited by cny-bikeman; 06-07-18 at 08:04 AM.
cny-bikeman is offline  
Old 06-10-18, 06:34 AM
  #18  
wphamilton
Senior Member
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 14,504

Bikes: Nashbar Road

Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 2511 Post(s)
Liked 58 Times in 35 Posts
Originally Posted by cny-bikeman View Post
1. The reason it slips on the large chainring is usually because it overall has higher gears than the other two, requiring more pedal pressure at a given speed. Your description of a large amount of travel before catching does make the freewheel/freehub suspect. Those chainring teeth are nowhere near worn enough to cause skipping.
2. 6" is not long enough to determine wear, especially if the chain is not under tension. 12" is the norm.
3. Not a good idea to be on the large chainring on a slight incline unless you are in one of the largest rear cogs, which I doubt is the case.
4. I would suggest you plan on a chain and freewheel if you have any further slipping under pressure. Once skipping starts usually wear on the small cog(s) is sufficient to cause skipping with a new chain.
5. It's unclear what you mean by "issues" with backpedaling, but if the chain is drooping when you backpedal that is often due to excess friction in the freehub/freewheel. Coupled with possible slipping when engaged I would say you need to flush it out.
You can see from his photograph that it's stretched almost the width of a pin over six inches, and the pins appear to be about 1/8" across. At least that's what it looks like to me, and it would mean that his chain is stretched enough to warrant replacing.
wphamilton is offline  
Old 06-10-18, 10:48 AM
  #19  
wrk101
Thrifty Bill
 
wrk101's Avatar
 
Join Date: Jan 2008
Location: Mountains of Western NC
Posts: 22,019

Bikes: 86 Katakura Silk, 87 Prologue X2, 88 Cimarron LE, 1975 Sekai 4000 Professional, 73 Paramount, plus more

Mentioned: 67 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Likes: 0
Liked 43 Times in 37 Posts
+100 Chain is worn out. Freewheel will wear out next. Crank chain rings will go last. I buy 5/6/7 speed new chain at a nearby co-op for a whopping $4.
wrk101 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Gary Fountain
Classic & Vintage
16
07-02-11 09:44 PM
iforgotmename
Touring
1
02-13-11 01:49 PM
mzeffex
"The 33"-Road Bike Racing
0
01-13-10 08:15 PM
Pamestique
United Kingdom
1
08-07-08 04:28 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.