jojimbo

Hi everyone, I don't know a lot about tinkering with my bike but I'm trying to learn. I took my back wheel off to practice getting it off an on again, I watched a video that said to align the chain on the smallest chainrings when taking it on and off so I did that but now it rubs like crazy on the bottom of a part of the derailleur and I don't know how to fix it. Once I shift it into 4th in the rear it stops rubbing, thanks a lot for any help. Apparently I can't post a picture or even a link to one yet, but I'll add it shortly.

thook

so, the chain never rubbed before you began tinkering and watched the video? usually that would indicate you have a front derailleur that's either set too high on the seat tube or the derailleur is being used beyond it's capacity. but, if it didn't do it before, something else is happening...possibly. are you running a triple ring crankset?

jadocs

Tough to diagnose without seeing what is going on.

For your awareness, the recommendation of the chain being in a certain gear (small/small) is simply reducing tension and creating enough slack where it is easier to remove and reinstall the wheel. Don't get hung up on that. All you should need to do is put the wheel on, get the chain in the gear it was in when you took it off and turn the pedals to make sure. If it's not in the exact gear, turning the pedals usually moves the chain so it corrects itself. Conversely you could take the wheel off in any gear, then shift until the derailleurs are in the small/small, then reinstall the wheel and put the chain on the small/small.

The rubbing on your front derailleur could be that you accidently shifted it and it is not positioned over the small ring, but it is on the large ring and you are trying to jam the chain on the small ring or vise versa.

Bill Kapaun

First time I ever swapped a chain, I got it wrong.
I misrouted it through the RDER and it was rubbing on a "tab".

Easiest thing to do, if you have another bike handy, is to look at the working bike and make it look like that.
Else, there's thousands of pics of correct chain routing on the net.

Pepper Jack

Is it very easy to do actual damage when working with the chain or is it generally pretty easy to do if you know what your doing?

oldbobcat

Depends on what you did.

If it's a mountain bike with triple chainrings, or a road bike with triple rings and a wide-range rear cluster, chances are you did nothing wrong. These drivetrains just aren't made to use the small-small combination. The small "climbing" ring is only to be used with the slow end of the cassette, i.e., the big cogs. Every derailleur system has "forbidden" combinations. Generally, the small chainring is for the slow end of the cassette, the middle ring can cover the entire cassette, and the big ring is only for the fast end.The important thing, though, is to have enough chain to shift into big-big without jamming everything up.

Shift into the middle ring and report back.

cxwrench

We still have no idea what you did, so impossible to say.

Iride01 

Post your picture somewhere on a hosting site and write the share link to that pic in the plain text of your next message. Remove the https:// and also put a space between the . (dot)

So something like https://www.bikeforums.net/g/picture/21308428 becomes www . bikeforums . net/g/picture/21308428

Most of us here know how to make it a working URL again.

jojimbo

Thanks, I'd just thought about that but since I'm new I'd reached a 5 post within 24 hour limit, I'm out of purgatory though so here's a picture

Gresp15C

Without venturing any idea as to what actually happened, it's noticeable that the chain is rubbing against one of the derailleur pulleys. One thing to try is to go all the way up and back down in gears, and see if it settles down. And also to watch closely what happens when you do so while turning the crank slowly by hand.

Is the chain also on the smallest chain ring in front? The "small-small" combination can be problematic on many bikes, and is usually avoided.

jojimbo

Yeah it was on the smallest chain rings in the front and the back so I could take the tire off, I didn't know it was a bad thing and isn't really supposed to be like that any other time.

Iride01 

Doesn't look like it's on the small sprocket. Looks like it is on the lock ring.

And if it is on the cog, then is the chain on the chain wheels up front at the crank? You chain looks too loose since it's touching the jockey wheel and that little tab. Gravity might be playing a part in things too here. It's best to do this with the bike right side up. Though it takes a few times to learn how to hold and get the wheel in place properly.

Bill Kapaun

Either you didn't have the chain on ANY ring, or it's too long.
Here's a pic of my Altus in Small:Small. I have the chain sized a bit long so I can go to a slightly larger cog if I want. (I change cassettes seasonally)



Here's how I typically size a chain-
Put it on BIG:BIG
See how much "slack" you can pull without forcing it.
You want between 1-2".

jadocs

I think this is just a matter of the OP never having it in the small/small until it was put there to take off the wheel. What we just found out is his chain is too long.

JohnDThompson 

Looks like your chain is too long. Did you trim the new chain to match the length of the old chain?

cxwrench

Take the photos right-side-up...please.

SoSmellyAir

I did head stand (assisted) to look at the photo, which seems to show that the chain is too long (assuming it is routed correctly).

vane171

You might have it on small chainring in front (well, pretty sure of that) which creates too much slack in chain and the RD tries to take the slack up and basically collapses the tensioning wheel arm to maximum. Chain when its is in use, like when you ride your bike, should never be on the small chainring in front and small sprocket on cassette in the rear. As explained above, you can do this to make the chain slack for easier removal and installation of the rear wheel but that is not a gear you should ever ride in.

Some bikes are able to deal with this extreme setting and they wouldn't rub the chain as your bike does when put into 'small small' gears, but that still doesn't mean the bike should be put in that gear when you ride on it. That is called cross chaining and there is no reason for selecting such a gear setting except here to get the most slack in chain.

The chain at bottom when it starts to enter the RD bottom jockey wheel rubs on the top jockey wheel (you got the bike upside down but top jockey wheel here means the one that is closer to cassette)

I take it, you didn't do anything with your chain (like disconnecting it for removal from the bike), only removed the wheel and put it back.