cakake

I've recently put together a bike with a triple crank on it. Everything seems to be working well, except when the chain is on the small chain ring up front. The chain doesn't release from the small chain ring when pedaling. When spinning, the chain starts to come off the small chain ring but there are some protrusions on the middle chain ring that 'hold' the chain for a second. It makes it very jerky and the small chain ring all but unusable.

The crank is an Ultegra crank, the deraileurs are 105 with a Shimano hg53 9 speed chain. Does anyone have any suggestions? Thanks.

Al1943

Are you talking about when you try to shift to the middle ring or when you are just riding?
Are you cross-chaining?
Do you have the correct bottom bracket for a triple?

HillRider

If you are on the granny ring with a 9-speed brifters and want to upshift to the middle ring, you first move the larger shift lever (the brake lever) a small amount inward until you get a slight "click". Then back it off and do a full sweep and the shift should complete properly. You have to make this first "trim" click before the major shift.

Al1943

Back off? It should go to the middle ring with one big sweep past the trim and to the second full stop.

Al

HillRider

What I meant was after the trim click you have to relax the shift lever to pick up the next position on the shifter ratchet. If you do the trim click and continue sweeping the lever all in one motion, the shift isn't completed.

Al1943

You and I nearly always agree but not this time. I've never had a problem with just a single sweep of the brake lever. That's the way my wife does hers also.

HillRider

My 105 9-speed won't do the granny to middle ring shift reliably in one uninterrupted sweep. Sometimes it goes through but most of the time is doesn't quite make it and hangs up rattling against the side if the middle ring. Doing the shift in two clicks always works.

Shimano's installation sheet that came with the brifters also says two clicks may be necessary so that's what I recommended.

cakake

I'm not referring to shifting. Just when I'm in the small chain ring pedalling.

There are protrusions on the middle chainring that "catch" the chain when it's coming off the bottom of the small chainring.

I bought the bottom bracket/crank off ebay and the seller claimed that the bottom bracket was for a triple.

HillRider

Ok, that's different. Your front derailleur is not moving in toward the frame far enough to let the chain settle on the small ring completely. Back off the low gear limit screw a bit. That should fix it.

roadfix

I think the OP is crosschaining and the chain is hitting the ramp pins on the middle ring. That's how I interpret his post.

HillRider

Good observation. That could be an explanation too.

Al1943

Or it could also be excess cable tension is not letting the derailleur travel to the low limit. Or other cable and cable housing problems. Or a dirty shifter.

Al

cakake

Ok, I'll check the limit screw to see if that helps.

What is the OP and what is crosschaining?

HillRider

OP means Original Poster, that is the person who started the thread.

Crosschaining is shifting into the extreme opposite gear positions. Typically it means using the smallest chainring and the smallesr cog or the biggest chainring and the biggest cog simultaneously. Those combinations put the chain at the most severe angle and are hardest on it and so should be avoided. The chain is literally "across" the drivetrain.

cakake

Oh, the OP is me!

I'm not cross chaining, it makes me cringe just looking at the chain when you do that. Besides, my Dad taught me not to do that when I was 10.

Most of the time the chain has been in one of the middle cogs, but it even happens when it's on the bigger cogs too.

Al1943

If you want to learn to do your own derailleur adjustments I suggest that you go to the Park Tools web site and locate the instructions. The steps must be done in the correct order and don't leave out any steps.

Al

Alphonso

+1

Never have a problem

cakake

I looked at it again, and it's definitely worse on the smaller cogs. It's noticable when the chain's on the biggest rear cog, but doesn't prevent pedalling. However, by the time the chain's in the middle of the rear cogs, the chain continually gets hung up on the protrusions of the middle chain ring in the front. I also noticed if I spin the cranks backward I can't even get 1 revolution. Just like spinning forwards, and tab/protrusion on the middle chain ring prevents the chain from releasing.

What are those protrusions on the inside of the middle chain ring? This is highly annoying, I'm considering filing down those protrustions.....

HillRider

This is beginning to sound like a severe chainline problem.

Al1943

I'm getting more confused. Are you saying that when the chain is on the small chainring (in the front) the chain is dragging against the side of the middle chainring? That doesn't seem possible.
Is the chain dragging on the front derailleur also?
Is there any chance that either the middle or small chainring are installed backwards? The tooth count stampings (30, 42) should face to the left, toward the frame, on the middle and small chainrings on Shimano 9-speed triples. The big ring faces right.
The bottom bracket should be the triple version.
If you release the cable from the front derailleur does the derailleur seat against the low limit screw?
It is possible to move the crankset out, to the right, by adding a bottom bracket spacer between the bottom bracket and the frame. That would improve the chainline. But be sure you have the correct bottom bracket before you try that.
Don't go filing anything off of the chainrings.

Al

cakake

It's not dragging, it's just on the bottom when the chain is coming off the small chain ring the protrusions on the middle chain ring catch and hold the chain. Hard to explain. I'll try and get some pics.

The chain is not dragging on the front derailleur. I'll check to see if the chainrings are installed backwards. As I said, I bought the crank and BB off ebay, so anything's possible, including that the BB is a double (which I'm beginning to suspect is the problem).

I'll try and get and post some pics Saturday. Thanks for trying to help.....


Eric

pur1138

Those pins are there to help lift the chain from the small ring to the next higher ring. They grab the chain and lift it as you're shifting.
Try looking here : https://www.parktool.com/repair/readhowto.asp?id=74
Poke around on this site and there's some other stuff that could apply to your problem.
Seems like either your front D.R. isn't adjusted correctly or the bottom bracket is too short. Did you notice the numbers on it when you installed it? It wll have stamped on it how long it is.

Kevin

cakake

Ok, I'll take a look at the park website.

Meanwhile, here are some pics. The first 3 illustrate what's actually happenning.

https://www.millsisland.net/gallery/album11/P5060058
https://www.millsisland.net/gallery/album11/P5060059
https://www.millsisland.net/gallery/album11/P5060060

Here's a shot from the top.

https://www.millsisland.net/gallery/album11/P5060062
https://www.millsisland.net/gallery/album11/P5060063

It appears like the small and middle chain ring are too close to each other. I looked at my mountain bike, and it looks the same, except there's more space between the 2 so the chain doesn't get caught. Can you put a spacer in to add space between the 2?

I'm not a bike mechanic, but I can't imagine that a derailleur adjustment would make a difference. The chain's not dragging on the derailleur now, so I don't see how moving it either direction would change it.


Eric

cakake

Bump. Any other suggestions after looking at the pics?


Eric

oilman_15106

Looks like classic dry link. Assume a new chain. If it was a Shimano did you clean the sticky gunk they put on it to prevent rust prior to installing it? If so, is the chain properly lubricated? If all that is Ok then inspect the chain to make sure none of the links appear bent. Especially the master link setup with Shimano.

Hate that pin system. Try re lubricating the chain anyway.