Where did we f up!?

itsrob

Please can I have some opinions / advice?

Decided to change the gearing on the bike.
Checked specs and got a 11-28 cassette. Fitted, rode worked great.
Bought a compact sram red chain set, didn't fit my bike so then had to buy a push fit bottom bracket (moda used an adapter to convert to Gxp which I found out after seeing that it didn't fit)

Went to mates to change them over he's fairly handy changed his before worked on motor bikes would say competent.

Change the crankset, front derailler all to cock decide that will be alright if I avoid cross chaining and take it into lbs for them to adjust. Chain sagging, so we take out 2 links. Goes in all the gears but rubs on FD when cross chaining.

First commute tonight struggle to get into the front big ring unless in 5 at back. Notice it's rattling but decide that I'll make it home and then go shop tomorrow. Also notice that the crank doesn't seem to be exactly true but possibly optical illusion - ran true on the work stand last night. Try to stay in front and about 5/6 at back and adjust on a hill noisy change and then the Rd wraps itself into back wheel and kind of explodes.
Mrs comes to collect.
Damage is chain, RD, wheel marks on frame

Now it's a mate whom I trust and I'm not looking to blame him, hindsight I'd have turned around at 2 miles but I just thought it was badly adjusted gearing

SO where did we F up??

antsmithmk

Sounds like the chain wasn't joined correctly to me. I had the same thing happen in March. Bike was running like a bag of spanners... It eventually got caught up in the derailleur and same result as yours. £150 bill for a £15 chain...

trailflow

What front derailleur you are using ? sounds like it wasnt set up correctly.

When you shortened the chain did you undo (then use a tool to shorten it) and reuse a split link ? or did you use a tool to push one of the pins out and rejoin ?

Because if it was a SRAM or KMC chain you need to use a split link to rejoin it. They cannot be rejoined with a pin like a Shimano chain. The pins are different.

Maybe thats what caused it ?

Also was the b-tension screw adjusted correctly? the jockey wheel might of been too close to the cassette. Causing it to jam.

itsrob

Good morning
Thanks for the replies,
We used a chain shortening tool to take out a pin, removed the links and used it to pop the pin back in, didn't use that powerlink..!

Jockey wheel shouldn't have been a problem as it had been in the lowest gear when on the stand and was fine, when it happened was in about 4 so nowhere near the wheel

How frustrating!

StillGoing

A couple of questions; did the sacrificial mech hanger bend at all? And did you set the chain length using the big ring and largest sprocket on the cassette? I'm curious as to whether you've shortened the chain too much and when trying to go into a low gear the tension has ripped the rear derailleur apart, the weakest point being the arm for the jockey wheels?

itsrob

I've just had another look at it, couldn't face it last night!

The chain is bent, but no indication a pin has come loose,
The rear mech, difficult to tell if it bent as it's kind of shattered, one of the jockey wheels is broken in half and in the bin, it looks bent towards the wheel.

Chain length I believe so, but gearing wise at that time was 50 on the front and I'd say 15 going into 19 when it went

I suspect that it has jammed somewhere with the changing thinking back would have been that moment when you do a change and think something ain't right and the chain pops off or something


I've also just noticed that on the frame the reinforced bit that holds the wheel half is still attached to the derailleur

I'm going to call by the lbs and assess the costs

Looks like
rear mech
Chain
Frame repair
Wheel repair (if poss)

jermas

You can't reuse a chain pin on narrow chains. The pin has a mushroomed head which stops the chain side plates separating. When the pin is extracted the head comes off.
Also it sounds like the front and rear derailleurs H and L screws weren't set up properly.

itsrob

Have been to the LBS.
It could have been a stone, or it could have been - pick any one of these

- Crank had travel in it
- Chain shouldnt have had the pin removed
- FD too high for the compact
- gears not set up properly

Or a combination of all the above that caused the jam

Hopefully Ive picked up a derailleur off the classifieds, and could have it all sorted for next week.
In the meantime, I'm Cleaning up the 7 year old SCR 1.5 for the commute!

birdie23

Sounds like the chain jammed in the cage.

Also sounds like the front derailleur wasn't set up right.