R8000 Rear Indexing

Discuss light weight issues concerning road bikes & parts.
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hlvd
Posts: 165
Joined: Sat Mar 05, 2016 4:54 pm

by hlvd

I seem to be inbetween two clicks on the Indexing screw on the back of the R8000 rear derailleur.

When I get perfect up and down shifting I get slight noise on the lowest cogs. When I turn the screw one click to increase tension and eliminate rubbing noise, the shifting into the high gears suffers as there's a split second delay.

New dérailleur, cassette and chain, and everything was fine till about eight rides after installation.

Am I being too fussy?

wingguy
Posts: 4198
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

Any time it's not the same on one end of the cassette than the other I'd double check the hanger alignment first.

by Weenie


mattr
Posts: 3821
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

I usually find Shimanos sweet spot is about 2 clicks wide. So if you're struggling with a half click, either check for draggy cables (outers, internal routing, old bottom bracket guide) or as above, bent hanger.

hlvd
Posts: 165
Joined: Sat Mar 05, 2016 4:54 pm

by hlvd

Thanks for the replies guys, so you're saying if there's noise in the highest hear it should carry right on through to the lowest cog, and not as you get to the last three or four highest (largest) gears?

Thanks

mattr
Posts: 3821
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Yes, any error/noise/rubbing/hesitation *should* be consistent across the block if it's only the cable adjustment thats out. If the problems change (noise, hesitation, rubbing) there is probably something else wrong.

alcatraz
Posts: 1295
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

If the problem is increasing over time it's probably the wear in the cables. You can help by avoiding too tight bends and inspect the cable guides for wear. Put a piece of liner where bare cable touches.

When you cut cable housing you can try to file down the ends which also will help to reduce compression.

If the problem is with a new setup then problem is likely elsewhere. Only reason a new setup would be tricky is of crazy tight bends or incompatibility. Check that your cables aren't crossed in the downtube.

To eyeball issues with the derailleur hanger just focus on the upper derailleur pulley (not der. cage). Check it's angles. It should be perfectly parallel with the cassette in both planes. Make sure your rear skewer is tensioned properly before doing hanger related checks or adjustments.

/a

XCProMD
Posts: 632
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

The problem you describe is an alignment issue. Check hanger first. If the problem persists it could be down to the parallelogram arms being slightly twisted. Not usual out of the box but I’ve come across some cases.

hlvd
Posts: 165
Joined: Sat Mar 05, 2016 4:54 pm

by hlvd

Ok, thanks for your replies guys, I've an alignment tool so I'll check that and take it from there.

hlvd
Posts: 165
Joined: Sat Mar 05, 2016 4:54 pm

by hlvd

I put the bike on the stand and tried the hanger screws to see if they were tight, they weren't, so removed applied thread lock and re tightened.

I checked the hanger alignment and it was out by a fair amount, so managed to get it back to within +/-1mm. It's scary how much pressure you need to adjust the hanger, hope it'll be ok.

I've re indexed the dérailleur and the shifting seems ok, I'll know better when I take it on the road as I find it's difficult getting it perfect on the stand.

Hopefully a happy ending, thanks guys!

TobinHatesYou
Posts: 1874
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Slight noise on the smallest cogs is pretty normal. Sounds like your chain had a super thick layer of lube or its factory grease on it to start, then things got noisy as the lube wore thin. Normal.

1415chris
Posts: 1109
Joined: Sat Apr 18, 2009 8:59 am
Location: Surrey UK

by 1415chris

Glad to hear the problem is sorted now.
I remember the days turning barrel adjustment back and forward.
Hanger alignment tool was one of the best awarding investments for me ;)

hlvd
Posts: 165
Joined: Sat Mar 05, 2016 4:54 pm

by hlvd

TobinHatesYou wrote:
Sat May 26, 2018 7:05 am
Slight noise on the smallest cogs is pretty normal. Sounds like your chain had a super thick layer of lube or its factory grease on it to start, then things got noisy as the lube wore thin. Normal.
It's a new chain, so you're right :)

by Weenie


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