Chain wonkiness?

rubez

Pics/photographic evidence...

How does the chain look, length wise?

small-small


big-big


On further inspection, the derailleur is almost, or actually fully relaxed in the small-small cogs. So... chain needs a link taken off?

Chunkers1980

Tyre looks wonky

Chunkers1980

Oh, and you've spent unwisely.

coulddobetter

Never mind the b screw you have left the pins in the pedals .

cooldad

If anything chain looks short. QR is on wrong side. Front mech looks a bit low. Something looks wrong on the rear but can't quite work out what (my eyes are old). Is the B screw up against the stop?

rubez

B-screw is right in.

I thought if the derailleur can be fully relaxed (no tension) then the chain is too big?

I can fit a 50p exactly inbetween front mech and cogs, seems about right.

raldat

Rubez, is that actually your bike? This was your original post...


Fully rigid MTB
Hi, are there any good non-suspension MTB's out there? I have a Cube Analogue, which is a couple of years old (and hardly used) but it has front suspension, which I hate and think is useless. Supposedly the lock out thing is no good for hard bumps and landings. Cube make great looking bikes, but the...


I don't read so well but last time I checked you don't spell Cube r.a.e.l.e.i.g.h

cooldad

Wasn't the Cube trashed, so he upgraded!?

Chunkers1980

That was shite and it fell apart

philcubed

Why are you having to do all this work on your bike, it doesn't look like its been ridden once! (Tho you did trash your cube after 6 rides allegedly, I can't believe even someone with your 'skills' can trash a bike BEFORE you've ridden it!)

raldat

cooldad wrote:

Wasn't the Cube trashed, so he upgraded!?

Argh, I can't keep up...

welshkev

Found your problem

It's upside down

coulddobetter

What's more worrying , looking at the photos and the car wheels , you may be doing your own motor vehicle maintenance.

supersonic

Model numbers of the cassette and rear mech please.

cooldad

supersonic wrote:

Model numbers of the cassette and rear mech please.

EOT/.

rubez

Cassette is Shimano HG20 7 speed, RD is Shimano Alivio 7/8 speed.

Not really worrying about the wonkiness now, as long as I can get the chain to stop rubbing off the FD, have tried every adjustment it seems, always rubs in certain gears, and usually always rubs in the middle ring no matter what.

Thing is, the wonkiness is probably the reason I can't get the chain to run rub-free on the front mech! There isn't the ability to fine tune the mech closely to the chain enough, as I have to allow for it running wonky, so even if I get it running rub-free, it has a knock on effect for adjusting the other stop limit... can adjust one or the other to fun rub-free, not both.

So two questions pop into mind...

The FD Tourney was originally for a 6-speed. The bike is now a 7-speed, do you think this has any bearing on the chain rubbing or wonkiness?

And do you think chain length - too long or too short has any bearing on the chain rubbing off the front mech?

Cheers.

The Rookie

Please explain this 'wonkiness' you mention, is the chain moving side to side at the front as the pedals rotate?

rubez

Yes I believe so.

Since, say the derailleur is fully rubbing against the chain, and I slowly bring it out with the limit screws, it will start to clear the chain, but it will still rub on and off the chain - so it must be moving side to side...

So it must take too much derailleur clearance to fully clear the entire chain through a full cycle (needing to account for a big margin of error) that I can't then get the adjustment right when I go to set the other inner or outer limit.

Does this makes sense?

That seems to be what is happening... :shock:

Chunkers1980

Have you looked at some guides on the internet of how to do it.

If you're not completely matching stuff that's designed to work together then rubbing in the extremes can happen, but generally you shouldn't use them anyway.

Front mechs require very precise angle and heights to work right.

rubez

So I need a different front derailleur?

An Alivio?

I looked last night, and they are discontinued. May still still one somewhere...

7-speed front mechs are rare now.

Chunkers1980

Just saying it might work fine. Set it up as well as possible and you'll not have issues bar perhaps the extremes. Nothing new needed. but you should have kept the cube, what you have there is borderline BSO - with parts as you're seeing that are harder and harder to come by.

rubez

Set it up fine? What does that mean?

The height was pre-done, so I assume that is fine, and I can't get the limits right due to the chain wonkiness... hence the problem.

Chunkers1980

Set up fine means correctly.

Assumption is the mother of all fukkups.

drlodge

Assume makes an ass out of u and me

rubez

I can fit a coin and no more inbetween the mech and the cog, that is the standard height. So that is fine.

If you don't have an idea of what is wrong, don't make vague pointless posts to pretend you know what you're talking about.

cooldad

I think it's that darned wonkiness that's to blame.

6,7,and 8 speed chains are the same size (ie there is only one size for all) as are mechs.

So must be wonkiness, obviously not user error.

larkim

Surely if the chain is moving left / right during a pedal stroke, the obvious cause would be either a front cog which is bent (if it happens just in one cog, e.g. largest) or some issue with the front crankset mounting on the BB?

welshkev

is your bottom bracket screwed in correctly?

rubez

Happens in all 3 chainrings.

I doubt the whole thing is fucked.

I could try my old 6-speed cassette wheel to see if the chain is still wonky with that.

What is the bottom bracket? Where the crank goes into?

welshkev

rubez wrote:

What is the bottom bracket? Where the crank goes into?

yes