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  #226  
Old 09-27-2020, 02:55 PM
Mark McM Mark McM is offline
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Originally Posted by Velocipede View Post
Of course it does. If the rear spacing is 130mm and the cassette sits too close to the inside of the dropout or chain/seatstay and the chain rubs on the stays, pretty sure a 135mm spacing is going to give 2.5mm more spacing on the drive side to avoid that happening.
These kinds of discussions are a bit academic, because as a practical matter, that's not the difference beween 130mm and 135mm axle width hubs/cassettes. In simplest terms the difference between a 130mm and 135mm hub is that that there is 5mm of length added to the left side. All the other dimensions are typically same, just shifted 2.5mm to the right to keep the wheel centered. So, the distance between right dropout and the cassette remains the same, the distance between the cassette and the right flange remains the same, and the distance between the flanges remains the same. Because everything is offset to the right, the wheel has less dish. To keep the chainline the same the chainrings are usually offset further outboard also.

In terms of rear shifting, there is no difference between 130mm and 135mm wheels. The same cassettes, derailleurs (and shifters) work the same way.
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  #227  
Old 09-27-2020, 09:07 PM
NHAero NHAero is offline
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Design 2 is the top drawing, right?

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Originally Posted by thirdgenbird View Post
There are two designs. It’s not early vs late. It’s a manner of what type. Shimano makes both type of derailleurs for current groups. You can use a 2x RD in 1x but not a 1x in a 2x setup. At least not without issue.

Design 1 uses a slat parallelogram. This design uses the parallelogram geometry to follow the cassette profile. When you shift from the small ring to the large ring, the cage rotates and it doesn’t dramatically change the distance from the cassette.

Design 2 uses a near horizontal parallelogram with a pulley cage with a very offset upper pulley. This design uses chain length/tension to control distance to the cassette. You can do this on 1x because the only thing that changes the chain length is rear cog size. If you were to use this design with a front derailleur, you would have two variables. Your front derailleur would be changing your effective b-tension. You would either be too far away in the big ring or crashing onto the cassette in the little ring.

You can see this in action if you watch a video of ekar or similar designed derailleurs shifting.

Edit: retroactively adding this nifty drawing that shows what I am trying to explain. Credit to yinzerniner for finding it.

Campagnolo 2x groups are similar to the bottom. Ekar is similar to the top.
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  #228  
Old 09-27-2020, 09:35 PM
thirdgenbird thirdgenbird is offline
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Quote:
Originally Posted by NHAero View Post
Design 2 is the top drawing, right?
Yep.
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  #229  
Old 09-27-2020, 10:52 PM
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Velocipede Velocipede is offline
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Originally Posted by thirdgenbird View Post
Yep.
2d movement vs 3d movement. that's the way Campy describes it.
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  #230  
Old 09-27-2020, 11:13 PM
thirdgenbird thirdgenbird is offline
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Originally Posted by Velocipede View Post
2d movement vs 3d movement. that's the way Campy describes it.
I suspect this also accounts for the direct mount vs standard mount.

Their 3D movement uses a pretty long slant parallelogram to clear a 34t. Combined with a concentric upper pulley and the more rear mounted b knuckle helps keep the pulley under the cassette.

The 2d movement relies on a pulley that is offset rearward. In this case, the forward mounting of the standard mount is probably an advantage. You do not need as long of a parallelogram as it’s only reaching across the cassette, not down and across. The offset cage does the up/down movement.

This may also explain why shimano 12 mtb went back to a standard mount as they increased pulley offset with the move to 12. They said going away from direct mount was to better accommodate larger cassettes. In a vacuum that dint make sense to me but now that I look at the pulley location, there seems to be correlation. The wider range your cassette is with this horizontal geometry, the more pulley offset you need.

Again, pure speculation (am I too old to intern in drivetrain design?)

Last edited by thirdgenbird; 09-27-2020 at 11:18 PM.
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  #231  
Old 09-27-2020, 11:45 PM
54ny77 54ny77 is offline
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Is the product name a collaboration with IKEA?
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  #232  
Old 09-28-2020, 12:41 AM
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saab2000 saab2000 is offline
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Is the product name a collaboration with IKEA?
No. It is named after a real place.

https://en.wikipedia.org/wiki/Cima_E...erving_Station
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  #233  
Old 09-28-2020, 07:22 AM
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oldpotatoe oldpotatoe is offline
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Is the product name a collaboration with IKEA?
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Originally Posted by saab2000 View Post
No. It is named after a real place.

https://en.wikipedia.org/wiki/Cima_E...erving_Station
Pretty sure he forgot the

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  #234  
Old 09-28-2020, 10:55 AM
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saab2000 saab2000 is offline
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So has anyone ordered this groupset? If so, where?

Or a bike which has it specced? I'm pleasantly surprised to see this offered as OEM on some brands of importance.

I'm definitely in the camp of intrigued and can imagine a Specialized Diverge with this groupset.
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  #235  
Old 09-28-2020, 11:03 AM
yinzerniner yinzerniner is offline
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Originally Posted by saab2000 View Post
So has anyone ordered this groupset? If so, where?

Or a bike which has it specced? I'm pleasantly surprised to see this offered as OEM on some brands of importance.

I'm definitely in the camp of intrigued and can imagine a Specialized Diverge with this groupset.
Someone just woke up on page 16 of this thread....


But for real see all the posts by Velocipede, as he's been invaluable in providing dealer information.

And the Diverge already has a "limited" Diverge spec'd with Ekar.
https://www.bikeradar.com/news/specialized-diverge-ltd/
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  #236  
Old 09-28-2020, 11:10 AM
Mark McM Mark McM is offline
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Originally Posted by thirdgenbird View Post
There are two designs. It’s not early vs late. It’s a manner of what type. Shimano makes both type of derailleurs for current groups. You can use a 2x RD in 1x but not a 1x in a 2x setup. At least not without issue.

Design 1 uses a slat parallelogram. This design uses the parallelogram geometry to follow the cassette profile. When you shift from the small ring to the large ring, the cage rotates and it doesn’t dramatically change the distance from the cassette.

Design 2 uses a near horizontal parallelogram with a pulley cage with a very offset upper pulley. This design uses chain length/tension to control distance to the cassette. You can do this on 1x because the only thing that changes the chain length is rear cog size. If you were to use this design with a front derailleur, you would have two variables. Your front derailleur would be changing your effective b-tension. You would either be too far away in the big ring or crashing onto the cassette in the little ring.

You can see this in action if you watch a video of ekar or similar designed derailleurs shifting.

Edit: retroactively adding this nifty drawing that shows what I am trying to explain. Credit to yinzerniner for finding it.

Campagnolo 2x groups are similar to the bottom. Ekar is similar to the top.

This just goes to show that there's nothing new under the Sun. The offset jockey pulley (design) was used decades ago, including by Campagnolo with their Rally derailleur from the '70s and '80s:




This design feature was also found in the Shimano Crane derailleur (the fore-runner of Dura-Ace):




Of course, most derailleurs don't use a single mechanism to maintain chain gap across the cassette, but incorporate multiple mechanisms. Some mechanisms for maintaining chain gap are:

- Slant parallelogram (or the variation, the slant plunger rod, as found on Mavid Mektronik and White Industries LMS).
- Offset jockey pulley (design 2)
- B spring pivot (including the variation found on Direct Mount derailleurs).


A close cousin of the B sprint pivot was found on the Huret Duopar, which added a second parallelogram that move vertically to track the cassetted:

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  #237  
Old 09-28-2020, 11:35 AM
thirdgenbird thirdgenbird is offline
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Some offset has been the norm form for a long time. Campagnolo 8-11spd derailleurs do not have a concentric upper pulley. I think shimano did the same.

This crop of new 1x derailleurs appear to have a lot more offset than above. Though, I do seem to recall vintage derailleur with a big offset.
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  #238  
Old 09-28-2020, 11:59 AM
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saab2000 saab2000 is offline
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Quote:
Originally Posted by yinzerniner View Post
Someone just woke up on page 16 of this thread....


But for real see all the posts by Velocipede, as he's been invaluable in providing dealer information.

And the Diverge already has a "limited" Diverge spec'd with Ekar.
https://www.bikeradar.com/news/specialized-diverge-ltd/
I’ve been following the thread and also am aware of that Diverge. Not buying anything right now but I’m definitely interested. I’m not in love with my 2x setup for the short, sharp hills of the gravel riding I do when I head to Michigan, which is semi-regularly.
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  #239  
Old 09-28-2020, 12:36 PM
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Velocipede Velocipede is offline
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Wilier, Specialized, 3T, Bixxis, Grandis, Pinarello, Cervelo, Ridley have stock offerings. I've seen/heard more than that will including Trek, Giant and Cannondale are working on offerings.

Bixxis did a launch in Italy with Campy in house for EKAR. Looked like a lot of fun.

Yes, I've ordered the group. Ordered/have more than 1. The only places to order it was thru Campy directly. No one distributor wise had it. QBP has 10 kits on order but they just put their order in like Friday. The original Campy importer has 10 kits on the way. Should be about a week. They asked for 50 and were told only 10. Online retailers like CRC and others, they have a 30 day hold on selling it.

Last edited by Velocipede; 09-28-2020 at 12:42 PM.
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  #240  
Old 09-28-2020, 02:37 PM
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charliedid charliedid is offline
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Man, I'd ride that Diverge in a second.
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