Damaged rear Mech & chain etc

[derrick]

On some mountain bikes it’s diffIcult to avoid this, you don’t want to run too long a chain as you get loads of chain slack when running downhill. So it can be an unfortunate compromise.

You dont compromise with the lengh of the chain. You get it right.

 

[taximan]

Quick update, Bike now repaired and running perfectly

 

[SkipdiverJohn]

On some mountain bikes it’s diffIcult to avoid this, you don’t want to run too long a chain as you get loads of chain slack when running downhill. So it can be an unfortunate compromise.

When I've swapped a chain on a double/triple equipped bike, I tend to size it for length using the large front/second largest rear - NOT large/large as it's considered bad practice to use that combination anyway.
You just need to remember not to try to use the "bad" gear. Having a chain jump when riding on rough ground is rather irritating, so I like to run them a bit on the short side, so long as they will cleanly engage the second largest freewheel sprocket.

 

[Mike_P]

You just need to remember not to try to use the "bad" gear.

But if you forget say hello to a bent rear mech and possibly broken mech hanger.

 

[taximan]

But if you forget say hello to a bent rear mech and possibly broken mech hanger.

Like I did

 

[gbb]

Quick update, Bike now repaired and running perfectly

Did they say what was wrong at the second visit ?. Just more tweaking of the gears which is understandable...or perhaps replace the hanger, which given they'd straightened the old one, is again acceptable, they had a go and tried to save you money.
The followup can be interesting, either way, they have sorted you which is good.

 

[taximan]

Did they say what was wrong at the second visit ?. Just more tweaking of the gears which is understandable...or perhaps replace the hanger, which given they'd straightened the old one, is again acceptable, they had a go and tried to save you money.
The followup can be interesting, either way, they have sorted you which is good.

The bike has a steel frame & the hanger is actually part of this. When I first consulted my LBS they told me that the Mech was completely wrecked (which I knew anyway) and that the hanger was twisted. They fit a new mech and tried straightening the hanger without the Parks Tool designed for the job. I tried the bike and found it to be still running very badly so they collected the bike again, ordered the tool & when it arrived the hanger was repaired, this time to my complete satisfaction. I am happy with the repair even though it took a little longer than I expected and the total cost was I thought, very reasonable at £45