New groupset day! R8000 rear derailleur mounting

Discuss light weight issues concerning road bikes & parts.
Bergwerk
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Joined: Mon Dec 19, 2016 10:06 am

by Bergwerk

So the derailleur alignment gauge should be in the mail tomorrow. That way I can at least check if the alignment is off.

Any worries around adjusting a derailleur hanger directly mounted to full carbon dropouts (Cervelo)? With the wheel in place, skewer secure and light touch that should be possible, right? Tips, tricks?

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ms6073
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by ms6073

Michael - The Anaerobic Threshold is neither...

by Weenie


kode54
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by kode54

Bergwerk wrote:
Tue Apr 03, 2018 5:56 am
Wow. Lot's of great info, thanks for posting all!

So I'm going to get the hanger checked out, or see if I can get my hands on an alignment tool. I think It's mainly the picture though, the measurements show it's not parralel tot the spokes by a long shot. But better be sure as you say.

I didnt know the cable housing on these was a bit of custom tubing. Will replace that with the original.
on both my two friends R5s...the OEM hanger bolts were both loose...as you can turn them with your fingers. odd that it was a coincidence. same year and same model 2015 or 2016 year with red top tube. in both cases, i swapped out the Cervelo hanger with a Wheels Mfg one and after installing...both were off, if you can believe that. at least they were consistent. check the two M4 bolts that goes into them just to make sure.
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Boshk
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by Boshk

So those of you who build your own bike or spend time in the LBS while they build it, how 'straight' should your derailleur be??

I'm using a cheaper version of the Park Tool and just measured my new C60, the only thing it has on there is a crank. Measured against my existing Zonda wheels and its off but only by about 5mm.
My Bianchi is off by 10mm.

Anyone ever bought a new frame and it was the frame that was 'misaligned'??
Colnago C60

TobinHatesYou
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by TobinHatesYou

Boshk wrote:
Wed Apr 04, 2018 10:00 am
So those of you who build your own bike or spend time in the LBS while they build it, how 'straight' should your derailleur be??

I'm using a cheaper version of the Park Tool and just measured my new C60, the only thing it has on there is a crank. Measured against my existing Zonda wheels and its off but only by about 5mm.
My Bianchi is off by 10mm.

Anyone ever bought a new frame and it was the frame that was 'misaligned'??
Derailleur hanger, not the derailleur itself.

What do you mean off by 10mm? Do you mean if you measure the distance at 12 o'clock, then measure the distance at 6 o'clock, the new position is 10mm off? Yes it should be straight and you should be taking several pairs of measurements. When you bend the hanger, use a firm, progressive force...no sudden jolts.

mattr
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by mattr

Boshk wrote:
Wed Apr 04, 2018 10:00 am
So those of you who build your own bike or spend time in the LBS while they build it, how 'straight' should your derailleur be??
As straight as you can reasonably get it. Most of mine are within 2 or 3 mm 12 o'clock/6 o'clock.
Boshk wrote:
Wed Apr 04, 2018 10:00 am
Anyone ever bought a new frame and it was the frame that was 'misaligned'??
Yes, many times. It's all about how flat you can get the mating face of the frame.

It's why so many make the mistake of thinking new dropout = correctly aligned hanger.

Boshk
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by Boshk

TobinHatesYou wrote:
Wed Apr 04, 2018 11:04 am
Boshk wrote:
Wed Apr 04, 2018 10:00 am
So those of you who build your own bike or spend time in the LBS while they build it, how 'straight' should your derailleur be??

I'm using a cheaper version of the Park Tool and just measured my new C60, the only thing it has on there is a crank. Measured against my existing Zonda wheels and its off but only by about 5mm.
My Bianchi is off by 10mm.

Anyone ever bought a new frame and it was the frame that was 'misaligned'??
Derailleur hanger, not the derailleur itself.

What do you mean off by 10mm? Do you mean if you measure the distance at 12 o'clock, then measure the distance at 6 o'clock, the new position is 10mm off? Yes it should be straight and you should be taking several pairs of measurements. When you bend the hanger, use a firm, progressive force...no sudden jolts.
yea, 12 o'clock is measured, 6 o'clock there is around 10mm+ left, hangar bent inwards.
Colnago C60

LiquidCooled
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by LiquidCooled

Boshk wrote: yea, 12 o'clock is measured, 6 o'clock there is around 10mm+ left, hangar bent inwards.
I believe Shimano recommends 4mm or less as acceptable.
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2003 Cannondale R1000 (CAAD7)

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ms6073
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by ms6073

Boshk wrote:
Wed Apr 04, 2018 11:31 am
yea, 12 o'clock is measured, 6 o'clock there is around 10mm+ left, hangar bent inwards.
Which is the most likely reason for you derailleur being so close to the spoke in the images in the original post.
Michael - The Anaerobic Threshold is neither...

Bergwerk
Posts: 13
Joined: Mon Dec 19, 2016 10:06 am

by Bergwerk

My new derailleur hanger alignment gauge arrived, and what do you recon?

Image
Image

That's not off by a few millimeters... :shock:

You were all clearly right, many thanks for pointing this out: new hanger ≠ straight hanger.

Well. You live, you learn, you acquire some more tools. And so it goes :D

alcatraz
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by alcatraz

On my bike the skewer tension quite drastically changes the angle of the hanger. So I try to tension the skewer as if I were riding before straightening the hanger. Afterwards I try to remember to keep the tension almost the same every time the wheel is mounted.

You might not have this problem. Just giving you a heads up.

Another heads up is that if you have a rear derailleur that has seen better days, but isn't ready for the trash can. The trick is then to adjust the hanger not for straightness to the cassette but so that the upper pulley of the derailleur is parallel to the cassette. To achieve this the hanger might require an angle that is not the same as the tool would give. I compare upper pulley angles in both planes to the cassette. I do this in both ends of the gear spectrum so I can find an angle that suits both. One is not enough because when the cage spring is under different tension it often changes the angle of the upper pulley slightly.

/a
Last edited by alcatraz on Wed Apr 04, 2018 3:44 pm, edited 1 time in total.

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Calnago
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by Calnago

That needs aligning for sure. 4mm is a good guide to shoot for, I usually try to get closer, like perfect if I can... just depends how much varaince I was starting with and how lucky I think I am going to be in the pursuit of perfection. If it had to be bent a huge amount, the chances of it breaking are much higher. Or, if that hanger has been aligned several times already, it has been weakened and is more likely to break. I'd align it for now, and in the meanitme order a replacement from either Wheels Manufacturing if you're in America or Pilo if you're in Europe. Both very high quality hangers. As I think I said in my previous post, some hangers are made of cheese. Some manufaturers for certain models will actually specify to remove the hanger from the frame before "aligning" it. But that makes the whole process exremely tedious in that it becomes a trial and error process of removing, bending, reinstalling, checking, repeat if not right... until it is. And you'd need some kind of vice etc. to be able to hold the hanger firmly off while you're bending it off the bike. Whether you take that approach or not is a judgemnet call, trying to factor in how fragile you think the frame dropout itself is, because if you break the dropout along with the hanger then you have a much bigger problem.
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wingguy
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by wingguy

Bergwerk wrote:
Wed Apr 04, 2018 1:48 pm
My new derailleur hanger alignment gauge arrived, and what do you recon?
Yeah, that'll do it :P

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bearsdidit
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by bearsdidit

kode54 wrote:
Mon Apr 02, 2018 9:29 pm
i've seen a few Cervelo's that had misaligned hangers right out of the box.

i always check with a alignment tool to make sure or straighten it out.
60-80% of all the bikes we've built needed an adjustment or two to the hanger. Don't even get me started on the the softness of Pinarello hangers... :evil:

by Weenie


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