The Slip

[Chief Broom]

So once upon a time the sun was shining, the birds were singing and our hero [me] was powering across the landscape on his trusty steed. Approaching a slight rise in the road steely muscles applied more power...and GRAUNCHHHH! WTF was that said a passing crow yer gunna need to fix that!
Being a relative newbie ive been following the sage advice of replacing drive chain components together and a new chain ring was ordered. So with new chain/chainring/cassette did this fix the slipping chain....nope There was play in the rear wheel so i reckoned loose/worn bearings could be causing imprecise chain alignment and the dreaded graunching. I informed the LBS of the problem who sorted the bearings and told me i needed yet another new cassette as i had chewed up the teeth on 8th gear. Brought the bike home and fitted new cassette and took it out for a spin....was it now graunch free? was it **** jeez whats next. I hadnt considered the derailleur could be at fault as it had been working as it should but....there seemed to be some stiffness and lack of springiness in the upper part which bolts to the frame. I had a new one stashed so on it went.... and hallelujah that did it! The LBS missed this so as a newbie i dont feel too silly about taking so long to find the answer to the graunch. The guy at the bike shop asked me to tell him how it was going so i relayed the good news. He said 'well done' and interestingly- "Bike repair is a process of illumination"

 

[Paulus]

To a point it is a process of illumination.
Some things are quickly evident, some things like drive trains can be difficult unless they whole train is changed at the same time..
Maybe your LBS could of road tested your machine a bit more rigorously though before handling it back.

 

[Chief Broom]

To a point it is a process of illumination.
Some things are quickly evident, some things like drive trains can be difficult unless they whole train is changed at the same time..
Maybe your LBS could of road tested your machine a bit more rigorously though before handling it back.

I agree, i think they got hung up on thinking the chewed up cassette was at fault when it was a symptom of the chain slip rather than the cause.

 

[Ming the Merciless]

The old derailleur may be okay with a bit of maintenance. You’ll need to remove derailleur from the hangar it’s attached to in your photo. Then the top part you refer to is the B pivot. It comes apart where you’ll find a spring. It can get gunky in there. Clean it out, fresh grease, spring back in, and hopefully derailleur back to buttery smoothness. The end of the spring fits into one of two holes at the back, depending on how much tension you want.

 

[Paulus]

I agree, i think they got hung up on thinking the chewed up cassette was at fault when it was a symptom of the chain slip rather than the cause.

By the way, is the rear mech salvageable. Could it just need a good clean up, or has the tension gone right out of it?

 

[Chief Broom]

The old derailleur may be okay with a bit of maintenance. You’ll need to remove derailleur from the hangar it’s attached to in your photo. Then the top part you refer to is the B pivot. It comes apart where you’ll find a spring. It can get gunky in there. Clean it out, fresh grease, spring back in, and hopefully derailleur back to buttery smoothness. The end of the spring fits into one of two holes at the back, depending on how much tension you want.

Thanks, i shall do that today

By the way, is the rear mech salvageable. Could it just need a good clean up, or has the tension gone right out of it?

it could be as i didnt know the spring can be tensioned [post above] I did clean it regularly but will give it a thorough going over

 

[Drago]

Altus mechs are horrific. Even when they're working as they should their plastic construction gives them so much flex they feel horribly mushy and imprecise. A step up to humble Alivio makes a notable difference.

 

[fossyant]

Bit of maintenance and attention to any pivot points during wet weather. A squirt of GT85 is enough.

 

[Ming the Merciless]

Bit of maintenance and attention to any pivot points during wet weather. A squirt of GT85 is enough.

I see the GT85 sniffers have found this thread 😂

 

[All uphill]

Altus mechs are horrific. Even when they're working as they should their plastic construction gives them so much flex they feel horribly mushy and imprecise. A step up to humble Alivio makes a notable difference.

Or my favourite, the old-fashioned Acera. Metal construction and works forever.

 

[fossyant]

Or my favourite, the old-fashioned Acera. Metal construction and works forever.

Minimum XT all the way !

 

[Sharky]

So once upon a time the sun was shining, the birds were singing and our hero [me] was powering across the landscape on his trusty steed. Approaching a slight rise in the road steely muscles applied more power...and GRAUNCHHHH!

Great opening line for a post - could be the start of a murder mystery novel!

 

[silva]

It reads more like a Monty Python episode.