Bicycle Mechanics - Ratcheting feeling while pedaling - what can I do ?

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babel
08-26-07, 04:43 PM
I am riding a three-year-old Trek 7300 Hybrid.

For the past several weeks I have been feeling a "ratcheting" while pedaling. I don't hear anything with it, but feel this in my feet. Does anyone have any suggestions as to what might be causing this and what I can do to fix it ? I am not very knowledgeable about bicycle mechanics but would like to try to fix this.

Here are the details: The problem began about four weeks ago. I feel this "ratcheting" in my feet while pedaling, but do not hear any noise. It is not affected by the position of the front derailleur, but MAY be worse with the rear derailleur in gears 4 or 5 but I am not positive about this.

Two weeks ago I brought the bike into the shop for its annual service and I told them about the problem. When I got the bike back the ratcheting was worse :(

I guess they tightened the cables because I can get into gears 1 & 2 on the rear derailleur and gear 3 on the front derailleur more easily but am having more difficulty getting into gear 1 on the front derailleur.

Other than returning the bike to the shop (not as easy as it sounds due to distance & traffic & time), does anyone have any suggestions for me ?


joejack951
08-26-07, 05:44 PM
By "ratcheting" do you mean the chain feels like it's slipping causing a jerking motion while pedalling or do you mean a clicking sensation while pedalling?

If the former, that's usually caused by an improperly adjusted rear derailler. The Park Tool website has some good information on how to properly set up a rear derailler. It consists of setting the high and low limit screws then adjusting tension to make sure that the indexing properly aligns the rear derailler with each cog.

If the latter, it could be caused by the upper rear derailler pulley teeth hitting the cassette teeth. This should be able to be dialed out by adjusting the b tension screw which is right near the rear derailler mounting point on the frame. Screw it in to move the pulley further from the cassette.

I'm sure there are other causes but that's all that's coming to mind for me right now.

Handyman
08-27-07, 12:30 AM
Lack of any noise and more apparent in tall gears? I'm going to guess a bearing problem in the pedal crank. One ball may have got stuck on a grain of sand for awhile and developed a flat side, then started rolling again and you feel the flat side bumping as it rolls across the cone and cup. Maybe that grain of sand is embedded in there and you feel the balls bumping over the sand. Either way, cleaning the bearings and regreasing might fix it.


wroomwroomoops
08-27-07, 02:18 AM
I am riding a three-year-old Trek 7300 Hybrid.

For the past several weeks I have been feeling a "ratcheting" while pedaling. I don't hear anything with it, but feel this in my feet. Does anyone have any suggestions as to what might be causing this and what I can do to fix it ? I am not very knowledgeable about bicycle mechanics but would like to try to fix this.

Here are the details: The problem began about four weeks ago. I feel this "ratcheting" in my feet while pedaling, but do not hear any noise. It is not affected by the position of the front derailleur, but MAY be worse with the rear derailleur in gears 4 or 5 but I am not positive about this.

Two weeks ago I brought the bike into the shop for its annual service and I told them about the problem. When I got the bike back the ratcheting was worse :(

I guess they tightened the cables because I can get into gears 1 & 2 on the rear derailleur and gear 3 on the front derailleur more easily but am having more difficulty getting into gear 1 on the front derailleur.

Other than returning the bike to the shop (not as easy as it sounds due to distance & traffic & time), does anyone have any suggestions for me ?


I exactly know what you're talking about, and have never found a suitable solution to it. I've checked my pedals, checked the BB, tightened up everything real good, but nothing helps. And this low-frequency thing which one can feel in the feet, comes and goes. Its appearence doesn't seem to be related to how hard I pedal.

Only Sheldon Brown can help us, as I have never been able to find help, fix it myself, or get help from the LBS, so I kinda learnt to live with it.

For the record, I have mostly singlespeed bikes, but by now, I have noticed this effect in almost all my bikes. Maybe it's a common thing, but people don't notice it because their feet are numb or something.

babel
08-27-07, 02:21 AM
joejack951, it's the latter, a clicking sensation while pedaling.
I will check the Park Tool Website when I get the chance during this new workweek.

Handyman, opening up the pedal bearings may be beyond my mechanicical skills, but I will investigate if the above doesn't bring results.

Thank you !

redirekib
08-27-07, 02:25 AM
Remove the chain from the front chainrings (sprokets) and turn the crank by hand. It should feel smooth, if not, have the LBS repair it.

wroomwroomoops
08-27-07, 03:16 AM
Handyman, opening up the pedal bearings may be beyond my mechanicical skills, but I will investigate if the above doesn't bring results.

Do you have this sensation during the downstroke of only one foot - or both? If it's both, then the pedal is probably not the culprit, just like it isn't in my cases.

operator
08-27-07, 06:58 AM
Put the bike on a stand and start pedalling with your hands. Can you feel it?

BigBlueToe
08-27-07, 07:41 AM
Clicking noises could be lots of things - pedals, bottom bracket, even loose stem. I'd try to hone in by seeing exactly when it happens - same rhythm as pedaling, standing, sitting, etc. - then repost or talk to mechanic at LBS.

wroomwroomoops
08-27-07, 08:49 AM
Clicking noises could be lots of things - pedals, bottom bracket, even loose stem. I'd try to hone in by seeing exactly when it happens - same rhythm as pedaling, standing, sitting, etc. - then repost or talk to mechanic at LBS.

Eccept, this is not a noise. You can't hear jack - you feel it in your feet. As is written in the title of this thread, doh!

joejack951
08-27-07, 08:57 AM
joejack951, it's the latter, a clicking sensation while pedaling.
I will check the Park Tool Website when I get the chance during this new workweek.

I just remembered having experienced something similar on my commuter bike when swapping wheelsets where each wheelset had a different cassette on it. In some gears I would get a clicking sensation using the spacer wheels/cassette which I got rid of with small adjustments to the rear derailler. Either the wheelsets fit slightly differently or there were small differences in the alignment of the cogs from cassette to cassette. A tension adjustment fixed the issue.

babel
08-27-07, 04:27 PM
Thank you everyone for the advice. It seems that most of the focus is on the pedal ball bearings and on the rear derailleur. Today an opportunity presented itself for me to get away from work a little early so I used the time to bring the bike over to Local Bike Shop. Technician was not convinved of a rear derailleur problem and will give bike to mechanic tomorrow.

To answer some questions I di not test standing up while pedaling. It is not just the downstroke of one foot versus the other.

I hope to get an answer before the next weekend; I told them I'll take it back Friday & return it Monday if they need to order parts.

wroomwroomoops
08-27-07, 10:55 PM
It is not just the downstroke of one foot versus the other.

So, if it happens at the downstroke of both feet, it's likely not the pedal. As I suspected all along.

DieselDan
08-28-07, 06:21 AM
Sounds lore of a technique problem then mechanical problem, like you're pedaling in squares instead of spinning in a circle.

operator
08-28-07, 06:38 AM
Sounds lore of a technique problem then mechanical problem, like you're pedaling in squares instead of spinning in a circle.

Not necessarily, I have experienced something quite similar recently on a shimano nexus hub. Properly adjusted and everything. You can feel a "rumble" through the drivetrain.

cny-bikeman
08-28-07, 07:23 AM
Given the symptoms and the age of the bike I would advise checking the chain for wear ("stretch"). A worn chain/cogs will start to feel rough as you describe before it actually skips. I don't know if it is a factor in this case but it's not unusual for the problem to show up after the chain has been cleaned. Your symptoms do not sound like anything that would originate anywhere in the crank/bb area.

http://www.sheldonbrown.com/chains.html

wroomwroomoops
08-28-07, 07:38 AM
Not necessarily, I have experienced something quite similar recently on a shimano nexus hub. Properly adjusted and everything. You can feel a "rumble" through the drivetrain.

Yep, I had that feeling with a SRAM Spectro gear hub. I did have it with other bikes too, and to the best of my knowledge, after extensive analisis of the bikes, I am fairly sure it wasn't the pedals or the BB or the rear hub. Or the chain. This would happen with various newnesses of chain, and with various tensions of the chain. No direct correlation to any of them.

babel
08-28-07, 04:56 PM
It sounds like this may be a complex problem. So yesterday I dropped off the bike at not-so-local bike shop. Today I called. Mechanic said he rode the bike & couldn't reproduce problem. So I drove back to not-so-local bike shop & took the bike home, changed out of suit, into shorts & rode down the block. I don't know if I am just imagining it, but I think the ratcheting is less. Could almost be gone. Now watch it return tomorrow.

Possible explanations: over cleaned/overlubricated chain, as cny suggested ? I will say that there is so much lube on it since bike shop service a few weeks ago that I am practically bathed in grease after a long ride.

One difference between riding today and previously is I haven't put the rack pack & saddlebags back on [for some reason I have kept the saddlebags on since the winter when I'd have to strip down the further I rode and needed a place for the extra layers ! But I checked and they were never touching the chain or derailleurs.

Maybe when I start my weekend ride the problem will be back - I don't know. I'll have to see.

I will keep all informed. All ideas are always welcome.

Babel .

wroomwroomoops
08-28-07, 11:48 PM
It's a problem that comes and goes. During a single ride you could have "spells" that last for a minute, or less, or more, or almost the whole ride... and now I'm starting to think it's more common than I thought before, but not many notice it. ("numb feet").

babel
08-29-07, 06:50 PM
I just took the bike out. The ratcheting is very noticable - I think it was just wishful thinking on my part that I didn't feel it the other day when i took it home from the shop. I suppose I could start reading about deraileur mechanics and just try playing around with different adjustments. I don't think I'll ever get used to this ratcheting.

wroomwroomoops
08-30-07, 12:50 AM
I just took the bike out. The ratcheting is very noticable - I think it was just wishful thinking on my part that I didn't feel it the other day when i took it home from the shop. I suppose I could start reading about deraileur mechanics and just try playing around with different adjustments. I don't think I'll ever get used to this ratcheting.

yeah, well... don't be too disappointed if it turns out it's got nothing to do with the derailleur, either. Both I and operator experienced this with derailleur-less bikes.

babel
08-31-07, 06:10 PM
I guess I'll have to learn to ignore it - won't be easy - or perhaps replace the chain. I don't know. Will be riding this weekend, no matter what the bike does !

wroomwroomoops
09-01-07, 03:22 AM
Not easy to ignore, because I feel a chunk of my energy is wasted, when this happens. I am big on drivetrain efficiency, and anything that drops precious % of what I pedal into my bike, is B.A.D. Our only hope is in Sheldon Brown.

babel
09-01-07, 11:00 AM
Who is Sheldon Brown?

I just did a ride. The ratcheting seems to occur in any gear, through it MIGHT be worse in front 3 than in front 2 or front 1, but I am not sure.

wroomwroomoops
09-02-07, 02:20 PM
Who is Sheldon Brown?

I just did a ride. The ratcheting seems to occur in any gear, through it MIGHT be worse in front 3 than in front 2 or front 1, but I am not sure.

Sheldon "Capt. Bike" Brown is the foremost authority in bike mechanics:
http://bikeforums.net/showthread.php?t=253025

George
09-02-07, 03:16 PM
I had the exact problem and it was after I put a new chain on. I lubed everything I could think of and checked to make sure everything was lined up.. When I lubed the chain it went away. After a while it seemed to come back, but it was only a hint of the feeling were talking about and I don't know if the chain seated it's self or what, it just went away, been fine since.

babel
09-09-07, 04:36 AM
Judging from the replies it seems that a chain problem & a rear deraileur problem are the prime candidates with a pedal bearing problem also under consideration. One thing of note is the problem got worse after I brought the bicycle in to the LBS for annual service. To me, that suggests derailleur problems as I am sure they tightened the cables as they always do (I know they did, from the shifting pattern). They lubed the chain so much that my sneakers & calves are black when I come home from a long ride so I don't think that more lube is the answer.

Yesterday I had the slightest suggestion that the ratcheting was less. Are the cables stretching? I will observe over the next few rides & if no further improvement I may study the rear derailleur diagrams and try some adjustments myself.