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

Back pedaling - chain comes moves to smaller sprocket

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.

Back pedaling - chain comes moves to smaller sprocket

Old 08-09-20, 01:52 PM
  #1  
ibarense
Newbie
Thread Starter
 
Join Date: Aug 2020
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Back pedaling - chain comes moves to smaller sprocket

Hi - Just took my bike to the shop to have the bottom bracket bearings and the rear cassette replaced. Rear cassette is exactly the same as original. I have a cross country mtn bike with 2x10 gearing. Now when I back pedal, as little as a half a rotation, when chain is on the front largest ring and the rear is on the 1st or 2nd largest sprocket, the chain drops off the rear sprocket and goes the next one or two sprockets smaller in the rear.

Is that normal behavior or should the chain remain on the same sprockets during back pedaling in all gears? I don't think the bike was acting this this way before I took it in, but not 100% sure.
Thanks much for the feedback.

Ian
ibarense is offline  
Old 08-09-20, 01:58 PM
  #2  
Unca_Sam
The dropped
 
Unca_Sam's Avatar
 
Join Date: Oct 2018
Location: Columbus, OH
Posts: 2,283

Bikes: Pake C'Mute Touring/Commuter Build, 1989 Kona Cinder Cone, 1995 Trek 5200, 1973 Raleigh Super Course FG, 1966 Schwinn Deluxe Racer, 1960/61 Montgomery Ward Hawthorne "thrift" 3 speed, by Hercules

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 1653 Post(s)
Liked 923 Times in 636 Posts
Originally Posted by ibarense View Post
Hi - Just took my bike to the shop to have the bottom bracket bearings and the rear cassette replaced. Rear cassette is exactly the same as original. I have a cross country mtn bike with 2x10 gearing. Now when I back pedal, as little as a half a rotation, when chain is on the front largest ring and the rear is on the 1st or 2nd largest sprocket, the chain drops off the rear sprocket and goes the next one or two sprockets smaller in the rear.

Is that normal behavior or should the chain remain on the same sprockets during back pedaling in all gears? I don't think the bike was acting this this way before I took it in, but not 100% sure.
Thanks much for the feedback.

Ian
Was the chain also replaced?
You should check your indexing.
Unca_Sam is offline  
Old 08-09-20, 02:22 PM
  #3  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,209

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1713 Post(s)
Liked 1,791 Times in 1,110 Posts
Well that makes sense. Back pedaling while cross chaining big-big is sure fire way to jump a chain to a smaller cog.

John
70sSanO is offline  
Likes For 70sSanO:
Old 08-09-20, 04:30 PM
  #4  
ibarense
Newbie
Thread Starter
 
Join Date: Aug 2020
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Chain rings, spider, and chain were replaced. Shifts well.

I didn't think the bike chain jumped before getting the work done. Thought somehow the front chain rings got moved to the right during BB bearing replacement, thus enhancing the crossing of the chain. Can't verify this though.

So it's normal for the chain to move to a smaller sprocket during back pedaling in big to big position? My road bike doesn't do that. Just try to determine "normal" behavior for a mtn bike before returning to the shop.

Thanks again -- Ian
ibarense is offline  
Old 08-09-20, 04:31 PM
  #5  
shelbyfv
Expired Member
 
shelbyfv's Avatar
 
Join Date: Jun 2007
Location: TN
Posts: 10,099
Mentioned: 32 Post(s)
Tagged: 0 Thread(s)
Quoted: 2996 Post(s)
Liked 3,853 Times in 1,978 Posts
Yep, don't do that, either direction.
shelbyfv is offline  
Old 08-09-20, 05:34 PM
  #6  
kennyc23
Junior Member
 
Join Date: Jul 2013
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I had the similar problem before. It was fixed after did re-indexing
kennyc23 is offline  
Old 08-09-20, 06:23 PM
  #7  
Homebrew01
Super Moderator
 
Homebrew01's Avatar
 
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,745

Bikes: Old Steelies I made, Old Cannondales

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1121 Post(s)
Liked 684 Times in 464 Posts
Indexing has nothing to do with pedaling backwards. The problem is "cross chaining". There is nothing to guide the chain when pedalling backwards. The chain is stressed sideways, and is pulled towards a center cog. Combine that with gravity pulling the chain to a smaller cog, and jumping sprokets is the result.

FIX...Don't pedal backwards when cross-chained.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.

FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Homebrew01 is offline  
Likes For Homebrew01:
Old 08-09-20, 06:55 PM
  #8  
rosefarts
With a mighty wind
 
Join Date: May 2015
Posts: 2,064
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 808 Post(s)
Liked 542 Times in 325 Posts
None of my road bikes do this but my mountain bike does. They all shift excellent.

I'm not going to change the chainline on it, it works too well to mess up.

The only way it's a problem is starting on a rough hill. Sometimes whatever made me stop caused me to backpedal a bit.
rosefarts is offline  
Old 08-09-20, 08:48 PM
  #9  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,209

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1713 Post(s)
Liked 1,791 Times in 1,110 Posts
It is a pick your poison. If you ride big-big and you hardly, or never, ride small-small, you might be able to bring the crank closer by removing any spacers. As long as you have chainstay clearance, you can see how it works.

Mountain bike chainstays are usually longer and shading the crankset inward will help with the cross chaining. There can be quick terrain changes riding trails so set it up for how you ride.

John
70sSanO is offline  
Old 08-10-20, 04:49 AM
  #10  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,280

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

Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1420 Post(s)
Liked 1,038 Times in 695 Posts
Originally Posted by rosefarts View Post
None of my road bikes do this but my mountain bike does. They all shift excellent.

I'm not going to change the chainline on it, it works too well to mess up.

The only way it's a problem is starting on a rough hill. Sometimes whatever made me stop caused me to backpedal a bit.
The root cause is cross-chaining. You should work on shifting to a smaller front ring earlier on hills instead of staying in the big ring and going to larger cogs, to avoid getting into the situation.
dsbrantjr is offline  
Likes For dsbrantjr:
Old 08-10-20, 05:14 AM
  #11  
Amt0571
Senior Member
 
Join Date: Dec 2014
Location: Catalonia
Posts: 913

Bikes: Canyon Grand Canyon AL SL 8.0, Btwin Ultra 520 AF GF, Dahon Mu P27, Triban Road 7, Benotto 850

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 385 Post(s)
Liked 180 Times in 120 Posts
Originally Posted by ibarense View Post
Chain rings, spider, and chain were replaced. Shifts well.

I didn't think the bike chain jumped before getting the work done. Thought somehow the front chain rings got moved to the right during BB bearing replacement, thus enhancing the crossing of the chain. Can't verify this though.

So it's normal for the chain to move to a smaller sprocket during back pedaling in big to big position? My road bike doesn't do that. Just try to determine "normal" behavior for a mtn bike before returning to the shop.

Thanks again -- Ian
Why did the chainrings got moved to the right? they should be at the same place if everything was done correctly.
Amt0571 is offline  
Old 08-10-20, 07:12 AM
  #12  
rosefarts
With a mighty wind
 
Join Date: May 2015
Posts: 2,064
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 808 Post(s)
Liked 542 Times in 325 Posts
Originally Posted by dsbrantjr View Post
The root cause is cross-chaining. You should work on shifting to a smaller front ring earlier on hills instead of staying in the big ring and going to larger cogs, to avoid getting into the situation.
I said mountain bike.

Anymore, unless we're talking about the vintage MTB groups, we should assume that mountain bikes are 1x unless explicitly stated otherwise.

And yes, 1x itself is likely the culprit here. The rider can't adjust the front chain position relative to the rear, get it close and functional, and just ride.

The OP does have 2x, and something the shop did is causing the problem.

Possibly a thicker body on the chainrings effectively moving them right. Possibly didn't get that right cup seated all the way in. Possibly didn't tighten the crank all the way.

A shorter chain can do this easier too, so when they replaced it, they may have properly measured it rather than just laying the new one next to the old one.

Last edited by rosefarts; 08-10-20 at 07:17 AM.
rosefarts is offline  
Old 08-10-20, 08:10 AM
  #13  
Pop N Wood
Senior Member
 
Join Date: Jun 2020
Location: Maryland
Posts: 1,163

Bikes: 1982 Bianchi Sport SX, Rayleigh Tamland 1, Rans V-Rex recumbent, Fuji MTB, 80's Cannondale MTB with BBSHD ebike motor

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 552 Post(s)
Liked 438 Times in 290 Posts
There was a recent thread on this. A member had the same problem than after a year posted a fix. Can't remember what it was, can't seem to find the post. Might have been a bent derailleur hanger
Pop N Wood is offline  
Old 08-10-20, 01:19 PM
  #14  
madpogue 
Senior Member
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 6,098
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 2059 Post(s)
Liked 1,164 Times in 850 Posts
Originally Posted by rosefarts View Post
Anymore, unless we're talking about the vintage MTB groups, we should assume that mountain bikes are 1x unless explicitly stated otherwise.
We shouldn't assume that anyone's assuming anything:
Originally Posted by ibarense View Post
... with 2x10 gearing...
madpogue is offline  
Likes For madpogue:
Old 08-10-20, 02:56 PM
  #15  
rosefarts
With a mighty wind
 
Join Date: May 2015
Posts: 2,064
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 808 Post(s)
Liked 542 Times in 325 Posts
Originally Posted by madpogue View Post
We shouldn't assume that anyone's assuming anything:
That was in response to someone who responded to me, to school me on how I ought to use the chainrings on my mountain bike.

The OP was clear about what he has and I gave suggestions based on that.

I still say, in 2020, if someone mentions a mountain bike drivetrain, it's 1x unless otherwise stated.
rosefarts is offline  
Old 08-10-20, 03:15 PM
  #16  
madpogue 
Senior Member
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 6,098
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 2059 Post(s)
Liked 1,164 Times in 850 Posts
^^^^^ Likewise, in 2020, if someone mentions a "bicycle", it's electric unless otherwise stated, I suppose.
madpogue is offline  
Old 08-10-20, 06:55 PM
  #17  
Pop N Wood
Senior Member
 
Join Date: Jun 2020
Location: Maryland
Posts: 1,163

Bikes: 1982 Bianchi Sport SX, Rayleigh Tamland 1, Rans V-Rex recumbent, Fuji MTB, 80's Cannondale MTB with BBSHD ebike motor

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 552 Post(s)
Liked 438 Times in 290 Posts
Too funny.

I just converted a 3x MTB to electric.

Now it is 1x.

Everybody wins.
Pop N Wood is offline  
Likes For Pop N Wood:
Old 08-10-20, 08:29 PM
  #18  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,209

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1713 Post(s)
Liked 1,791 Times in 1,110 Posts
1x are really dependent on the terrain and how well someone can climb. If you can push a 30t to a 40t/42t cog then a 1x is the way to go.

On more level terrain it is not an issue and you can use whatever.

John
70sSanO is offline  
Old 08-10-20, 09:57 PM
  #19  
ibarense
Newbie
Thread Starter
 
Join Date: Aug 2020
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Amt0571 View Post
Why did the chainrings got moved to the right? they should be at the same place if everything was done correctly.
Exactly! My fear that the chain rings did get moved to the right for some reason. A mistake I presume. That's the only explanation I have for why the chain is more crossed than it was before I had the work done.

I can back pedal on my three other bikes when on the two big rings. That's enough of an indicator to me that I need to go back to the bike shop and have them fix this issue. One would think that I would be able to use all the gearing on my most expensive bike.

Thanks all for your input!
ibarense is offline  
Old 08-10-20, 10:22 PM
  #20  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,209

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1713 Post(s)
Liked 1,791 Times in 1,110 Posts
You might be able to have them center the big ring on the cassette, if they have the room on the inside. This will kind of give you a 1x with a granny just for those times you need it... if that is how you ride. I’m assuming it is since you were in the big-big.

I will admit that if you lined up the big ring with the center of the cassette and took off the inner ring, there would be those that would say it’s 1x so you’re not cross chaining. But put that small ring back on and the big-big is now cross chaining.

John
70sSanO is offline  
Old 08-11-20, 04:43 PM
  #21  
jp911
Full Member
 
Join Date: Feb 2017
Location: Bend
Posts: 225

Bikes: Trek Madone 5.2 Dura Ace, Niner RLT9 aluminum, Santa Cruz 5010 CC, Niner Air 9 rigid 29er

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 66 Post(s)
Liked 33 Times in 30 Posts
I had this issue on a MTB and found that the B-screw was set too far in (jockey wheel too far from the cassette in the largest rear cog). Backing out the B-screw to the right spot, which took some trial and error, solved it for me. Not saying it's THE cause-solution to back-pedaling gear jumps, but it worked in this case.
jp911 is offline  
Old 08-12-20, 01:46 PM
  #22  
rydabent
Senior Member
 
rydabent's Avatar
 
Join Date: Apr 2010
Location: Lincoln Ne
Posts: 9,540

Bikes: RANS Stratus TerraTrike Tour II

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2896 Post(s)
Liked 904 Times in 533 Posts
Simply put if you cant backpedal with out the chain jumping sprockets, something is wrong, if you are not in an extreme cross chain situation.
rydabent is offline  
Old 08-12-20, 05:32 PM
  #23  
tomtomtom123
Senior Member
 
Join Date: Jan 2017
Posts: 1,027
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 337 Post(s)
Likes: 0
Liked 113 Times in 81 Posts
If you want to know whether your chainring moved outward, why not simply measure and find out?
tomtomtom123 is offline  
Old 08-12-20, 08:44 PM
  #24  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,209

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1713 Post(s)
Liked 1,791 Times in 1,110 Posts
Originally Posted by jp911 View Post
I had this issue on a MTB and found that the B-screw was set too far in (jockey wheel too far from the cassette in the largest rear cog). Backing out the B-screw to the right spot, which took some trial and error, solved it for me. Not saying it's THE cause-solution to back-pedaling gear jumps, but it worked in this case.
Never heard of this. Will file this in the back, well maybe way back, of my brain just in case.

John
70sSanO is offline  
Old 08-12-20, 08:52 PM
  #25  
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 ibarense View Post
when I back pedal, as little as a half a rotation, when chain is on the front largest ring and the rear is on the 1st or 2nd largest sprocket, the chain drops off the rear sprocket and goes the next one or two sprockets smaller in the rear.


Is that normal behavior or should the chain remain on the same sprockets during back pedaling in all gears? I don't think the bike was acting this this way before I took it in, but not 100% sure.

Originally Posted by ibarense View Post
Chain rings, spider, and chain were replaced. Shifts well.


I didn't think the bike chain jumped before getting the work done.


So it's normal for the chain to move to a smaller sprocket during back pedaling in big to big position? My road bike doesn't do that. Just try to determine "normal" behavior for a mtn bike before returning to the shop.

Keep the chain in a straighter line.

Old worn chains can flex sideways easier then a new chain.

There's nothing to guide the chain when back pedalling


nothing to guide the chain + a chain that want's to stay straight = a chain that jumps sprockets to a straighter line when backpedaling



cobba is offline  
Likes For cobba:

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.