Is my derailleur setup in the wrong position? (Pics)

Akelu

Active member
Jul 31, 2020
201
137
Australia
So i've been having trouble with my new Focus Thron bike. The chain doesnt seem to be releasing from the chainring properly mainly when going uphill and putting a lot of pressure on the pedals. (Video: ). Focus has said they believe the wrong chainring might have been put on the bike and have sent out a new one, however ive found pics of my bike online with what looks like the same chainring (and other pics have a different chainring). So we will see if that helps when it arrives. But in the meantime, i have noticed something else different and that is that it appears my shimano 12 speed XT derailleur is aimed at a very different angle to every other Thron bike picture i can find online.

Here is a picture demonstrating my bike (on the left) vs other pics i found online of my same bike. You can see on my bike the derailleur is aimed more towards the back, where as the others are more forward. Its clear that my bikes setup results in the chain coming off the chainring at a much steeper angle and was wondering if that might be causing the problem.
derailleur.jpg
 
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CavMan

Member
Jun 9, 2020
37
38
Australia
Yeah, that doesn't look or sound right. As for your rear derailleur, the angle of the second jockey wheel is all dependent on the gear you are in. On higher gear the wheels moves backward to take up the loss of tension, on lower gear (big cog) it moves forward under tension.

If you have the incorrect front chain ring, then that may mean the chain tension is wrong, which may be cause the gripping of the chain.

I went through something similar when I changed the chain on my road bike and forgot to remove some links and the chain was too long, it was all over the place with the angle of the derailleur. One size does not fit all. All better after I removed 3 links

Also check the derailleur hanger and make sure where it mounts onto the frame that it has not moved, I banged mine and it shifted and caused a few issues with noise and gears jumping. I loosened the screw where it mounts to the frame and it suddenly dropped back into place, I then tightened it up and all was good again.

Let us know how it goes with the new front chain ring.
 

IanVersion2

New Member
Jun 12, 2020
64
79
Stroud, Glos, UK
Looks like you have the same issue as here...

Edit. Oh, you're the same person, that's why!

Rear mech looks fine to me.
 

FSEngineer

New Member
Jul 14, 2020
64
40
Kent
That definitely looks like a chainring issue to me. From my experience of the Shimano 12 speed stuff, the chain design is different to their 11 speed and even SRAM's 12 speed and so requires a different chainring design - otherwise it won't engage properly or will get 'stuck' on the teeth. Seems like they may have stuck and 11 speed 'ring on there by accident, or one that's "12 speed compatible" but wasn't designed to work with Shimano 12 speed.
 

CavMan

Member
Jun 9, 2020
37
38
Australia
Ok I just looked at your video again and noted you are using a (I think) FSA Megatooth Chain ring.

As best I can tell it uses a long tooth profile ..."which enhances chain retention via thick-thin tooth design for maximum chain engagement."

It is designed for 11 speed, not 12 speed.

 

GrahamPaul

E*POWAH Elite World Champion
Nov 6, 2019
1,127
1,088
Andalucía
Ok I just looked at your video again and noted you are using a (I think) FSA Megatooth Chain ring.

As best I can tell it uses a long tooth profile ..."which enhances chain retention via thick-thin tooth design for maximum chain engagement."

It is designed for 11 speed, not 12 speed.


Not necessarily true. I have the FSA Megatooth on my Jam², which is a 1x12 Shimano rig.

It's a custom part for Focus and not the stock FSA Megatooth.

Which could well mean that the wrong part fell into the box at FSA and got fitted when no one noticed. That video does rather look like a narrow wide ring isn't working properly.

Just one thing, @Akelu , have you tried moving the chain along one link on the chain ring? It's narrow/wide and shouldn't fit when not lined up with the correct link (wide tooth to wide link & narrow tooth to narrow link), but strange things do happen...

(Fairly easy to do. If you don't know how: make sure the clutch on the derailleur is set to "off". With the chain on the smallest cog at the back, you should have plenty of slack just to pull the chain away from the chain ring and move it around one tooth. If it doesn't fit, it was correct all along and the chain ring probably is the wrong one. If it does fit and the noise doesn't go away, then the chain ring is the wrong one. If it fits and the noise goes away, what are you doing reading this instead of being out there riding? ? ).
 

Akelu

Active member
Jul 31, 2020
201
137
Australia
The chain is aligned correctly with narrow/wide holes.

And my FSA chainring has the same markings. G4 34t.
 

urastus

⚡The Whippet⚡
May 4, 2020
1,548
995
Tasmania
Man, you attract dodgy chain rings. It looks like the chain ring again. I don't think it is the wrong chain or you'd have trouble out back as well, I would think. You should have known from the last one.
 

Akelu

Active member
Jul 31, 2020
201
137
Australia
I haven't replaced it yet. This is the one that came with the bike. Focus said it needed to be replaced and I'm waiting on my replacement to arrive from Germany. Fingers crossed.
 

Jackware

Fat-tyred Freakazoid
Subscriber
Oct 30, 2018
2,082
2,294
Lancashire
Check you've got the chain threaded through the derailleur correctly - ie the correct side of the small plate between the rollers, other wise it will drag across the small piece of metal.
PVllQ.jpg
 

Mooree

New Member
Jan 18, 2022
11
0
USA
For me, it is quite necessary to know how to adjust the bike chain on the derailleur. It can save you a few bucks from minor repairs and long-haul dangers. Plus, it even keeps you going even if the leash comes loose. It's important to carry a handy tool, like the Oumers multi-function bicycle chain tool, and other essentials wherever you go to make repairs easier than ever.
 
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