Question for the mechanics

[stien]

I'm typically a decent wrench but I'm stumped on this one and was thinking you guys might be able to help.

The wife got a new Cervelo R3 frameset (warranty) which I built with her previously used 6870 group. The only change being a wheels mfg BBright Shimano BB.

She rode it a few times this past week and raced a crit on it yesterday without issue but today while climbing I saw her RD twitching so we pulled off and checked it out.

It looks like the chain is at such an extreme angle in the small ring and two largest cogs that it's actually jumping to the outside of the lower jockey wheel and staying there until she backpedals. Rubbing the cage. This is how I killed an older 10s di2 RD so I'm concerned.

I've verified that the crank is completely flush with the BB on the drive side. It's a brand new chain. The group has 3k miles on it so the jockey wheels still look new. I might be able to space the cassette to the drive side slightly but shouldn't have to, you know? No crashes before or since.

Any assistance appreciated.

[Cicli]

Did you check the hanger?
They are almost always off, even on a new frame.

Check the hanger.

[Tandem Rider]

Have you done a quick check on frame alignment? Stick some tip tools or something like a rod in the rear, eyeball left side of head tube, left side of seat tube, to a spot on the tools, repeat for the other side. You can get within a mm or so this way. I had a frame warrantied because alignment was so far off (18 mm) it shifted badly and threw the chain frequently.

[dustyrider]

Sure it's not a limit screw adjustment? Checked hanger? Can you duplicate in stand?

[Bruce K]

My in house mechanic says BBrights are asymmetric

Is it possible you installed it backwards? (Offset to the drive side)

This could account for the weird chain line

BK

[stien]

I have not checked the hanger, thanks guys. I can duplicate on the stand and it's not the limit screw because it happens in the second largest cog as well.

The shop who handled the warranty put in the BB. I'll have to look up how it goes in. It's flush to the frame on the NDS and has a bunch sticking out on the DS.

[oldpotatoe]

I'm typically a decent wrench but I'm stumped on this one and was thinking you guys might be able to help.

The wife got a new Cervelo R3 frameset (warranty) which I built with her previously used 6870 group. The only change being a wheels mfg BBright Shimano BB.

She rode it a few times this past week and raced a crit on it yesterday without issue but today while climbing I saw her RD twitching so we pulled off and checked it out.

It looks like the chain is at such an extreme angle in the small ring and two largest cogs that it's actually jumping to the outside of the lower jockey wheel and staying there until she backpedals. Rubbing the cage. This is how I killed an older 10s di2 RD so I'm concerned.

I've verified that the crank is completely flush with the BB on the drive side. It's a brand new chain. The group has 3k miles on it so the jockey wheels still look new. I might be able to space the cassette to the drive side slightly but shouldn't have to, you know? No crashes before or since.

Any assistance appreciated.

I'd say the hanger or the der cage is bent.

[tumbler]

I would check the RD hanger. I had the same issue on one of my bikes. It's surprisingly easy for those soft aluminum hangers to get knocked out of alignment.

[Mikej]

Does it use a directional chain?

[nash]

Take a closer look at the chainline. Easy to do, in a broad way, by putting the chain in the middle of the cassette, seeing how the chain lines up in either chainring. Or put in in big/small and see how that looks. Is the chain straight in that position?

[stien]

During the ride I had mentioned that the cage (the whole RD) looked twisted in. It hasn't been crashed since I swapped the parts so I'm assuming hanger is twisted a bit. Hoping to bring to the shop tomorrow as it's one of the only tools I don't own yet.

Directional chain is a good idea but I've got it going the right way.

Pretty sure the chain does straighten out once in the middle of the range. I'll need to put it in the stand to verify tonight.

[ontarget]

Funny you mentioned that a derailleur hanger alignment tool is one of the few you don't have. After stopping by my LBS a few times for hanger checking/alignment, I threw down the money for my own tool. Am I glad I did! The convenience of having my own has been great. I do more checking than aligning. You won't regret it!

Sent from my XT1585 using Tapatalk

[OperaLover]

[QUOTE=ontarget;2149218]Funny you mentioned that a derailleur hanger alignment tool is one of the few you don't have. After stopping by my LBS a few times for hanger checking/alignment, I threw down the money for my own tool. Am I glad I did! The convenience of having my own has been great. I do more checking than aligning. You won't regret it!

Agreed! Money well spent. A former pro mechanic recommended it as an indispensible tool. Park Tool works great.

[Clancy]

First, double check the B limit screw. Saving it happens with both top cogs does not elimate the B limit screw from being the cause. Seeing the derailleur "twitch" is a pretty good sign that the guide pulley is hitting a cog.

If B is OK, double check chain line.

The B limit screw and chain line are easy to check, takes a minute.

If those two are both ok, then derailleur hanger. And with a good eye, it's possible to sight and see if its bent, usually noticeable. Very slightly bent, maybe not.

Usually with a bent hanger the chains jumps from one cog to the next, ghost shifting, or hunting for engagement. But I've seen bent hangers cause weird things.

[chiasticon]

Funny you mentioned that a derailleur hanger alignment tool is one of the few you don't have. After stopping by my LBS a few times for hanger checking/alignment, I threw down the money for my own tool. Am I glad I did! The convenience of having my own has been great. I do more checking than aligning. You won't regret it!agreed there. it's a must-have with modern drive trains. eleven speed especially seems very prone to being just a little noisy in one or two cogs if the alignment isn't perfect.

Usually with a bent hanger the chains jumps from one cog to the next, ghost shifting, or hunting for engagement. But I've seen bent hangers cause weird things.agreed there, but isn't "hunting for engagement" kinda what he's talking about, that it's doing? he said "twitching" and that's what I pictured. anyway, not sure what di2 does when the hanger's out, but I could imagine "twitching" being the thing.

[Clancy]

Final solution?

[stien]

It was the hanger, sorry for the delay.

I really need to get my own alignment tool. I hate having shops work on my bikes.

The twitching was the chain pins catching on the cage, fwiw.

No issues now that it's been fixed. I'm about to make a big tools order on Amazon since I don't have a campy cassette/BB tool and chain cleaner either.

[oldpotatoe]

It was the hanger, sorry for the delay.

I really need to get my own alignment tool. I hate having shops work on my bikes.

The twitching was the chain pins catching on the cage, fwiw.

No issues now that it's been fixed. I'm about to make a big tools order on Amazon since I don't have a campy cassette/BB tool and chain cleaner either.

http://www.ebay.com/itm/Park-Tool-DAG-1-Bike-Derailleur-Hanger-Alignment-Gauge-Road-Mountain-Shop-/401299646409?hash=item5d6f52a7c9:g:cN0AAOSwSlBY29Z k

[Tony]

It was the hanger, sorry for the delay.

I really need to get my own alignment tool. I hate having shops work on my bikes.

The twitching was the chain pins catching on the cage, fwiw.

No issues now that it's been fixed. I'm about to make a big tools order on Amazon since I don't have a campy cassette/BB tool and chain cleaner either.

I bought a NEW UNIOR DERAILLEUR ALIGNMENT TOOL for under $40.00 and it was awful, sloppy tolerances in the slider/gauge, not accurate.
Returned it and got the Park DAG-1, way better!

[shovelhd]

Abbey. It's what the pro mechanics use.

https://www.abbeybiketools.com/products/hag

[Cicli]

Abbey. It's what the pro mechanics use.

https://www.abbeybiketools.com/products/hag

Not any more.

https://www.abbeybiketools.com/collections/tools/products/team-issue-hag

Until the Rapha one comes out.

[gpendergast]

Amen! The machining tolerances on the HAG are incredible. You could literally spend three hours and get that hanger PERFECT.

Abbey. It's what the pro mechanics use.

https://www.abbeybiketools.com/products/hag

[ontarget]

Quick, buy the one Oldpotato linked to on eBay. You won't regret it.

Sent from my XT1585 using Tapatalk

[m_sasso]

Less expensive http://www.ebay.com/itm/Park-Tool-DAG-1-Derailleur-Hanger-Alignment-Gauge/282411991346?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%2 6asc%3D42807%26meid%3Dc68fc6b7c1174a7990b0838eb0f8 39c7%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D4012 99646409

[shovelhd]

Not any more.

https://www.abbeybiketools.com/collections/tools/products/team-issue-hag

Until the Rapha one comes out.

Sold out.

[FriarQuade]

Amen! The machining tolerances on the HAG are incredible. You could literally spend three hours and get that hanger PERFECT.

Takes less than 5 minutes once the RD is off the hanger.

Sold out.

We will have 3 more at Sea Otter latter this month. I'm also keeping a list of interested people should we make them again.

[stien]

To follow up:

In order to allow my wife to ride her bike on the trainer, I "eyeballed" a quick straighten using a Allen key in the RD bolt hole. Worked like a charm and I didn't go too far. It eliminated the chain jumping off the lower pulley.

Then the shop straightened the hanger.

I saw one instance of the chain jumping off the pulley during a ride afterwards.

Then I got the tool and checked it, it was out front to back. I called the shop, a little hot blooded but they told me that the stock hangers for Cervelo and others are so soft that they just go out of alignment and that I should replace with a Wheels Mfg one (which I had already ordered as a spare). I straightened it with my tool. The Wheels Mfg hanger is still in the tool box.

She has since ridden a bunch and won a race on the bike without issue.

I should check it again this week. Has anyone ever heard of hangers just going out of alignment? I certainly haven't.

Also, I used to clean chains with a rag, then re-lube. Now that I have the park chain washer (kick-ass BTW) I run it through a few times but it still has the degreaser on it after lots of wiping down. Puddles in a race on Saturday. Yesterday I rinsed it with water afterwards and it was sparkly. I then applied lube and wiped down after 15 mins and some pedaling. Also cleaned cassettes, pulleys, and chainrings. We rode after and the chains were pretty loud (they're only a few hundred miles old). I haven't had a chance to as much as look at one of the race bikes since then. Did I just need to apply more lube than normal because they were totally de-greased?

[CiclistiCliff]

So you're one of those customers. Rad.

Yes, some hangers are made from 6061B, B for butter and bend if you look at them the wrong way.

Those Cervelos had weird issues. Multiple customers who own those french canadian turds have had the same issue when switching to 11 speed from 10.