The 'Un-Official' Campagnolo Ekar thread

[thirdgenbird]

Originally Posted by morrisond

No it wouldn’t. I don’t doubt that the amount of cable pulled is different for each click for the different speeds however I would be surprised if the ratio of how the RD moves for each mm of cable pulled changes.

History would say otherwise

It changed from mid way through 9 speed
It changed from 10 to 11
It changed from 11 to 12

Shimano had two different ratios for 8spd
Two ratios for 10spd which was different than anything before
They have two ratios for 11spd and it is different than anything before

I don’t know what the ratio is for 12spd shimano, but hear it is different than 11. They also not have a 10spd road group that uses the 11spd ratio.

[morrisond]

Originally Posted by thirdgenbird

History would say otherwise

It changed from mid way through 9 speed
It changed from 10 to 11
It changed from 11 to 12

Shimano had two different ratios for 8spd
Two ratios for 10spd which was different than anything before
They have two ratios for 11spd and it is different than anything before

I don’t know what the ratio is for 12spd shimano, but hear it is different than 11. They also not have a 10spd road group that uses the 11spd ratio.

Yes Cable pull changed but not the Rear Derailleur shift ratio. Which was the same for 9, 10, 11 at 1.5. This works as cable pull * shift ratio = how much the RD moves.

No idea what 12 or 13 are - but if they are the same it could work.

Good info in here https://en.wikibooks.org/wiki/Bicycl...ing_Dimensions

[thirdgenbird]

Originally Posted by morrisond

Yes Cable pull changed but not the Rear Derailleur shift ratio. Which was the same for 9, 10, 11 at 1.5. This works as cable pull * shift ratio = how much the RD moves.

No idea what 12 or 13 are - but if they are the same it could work.

Good info in here https://en.wikibooks.org/wiki/Bicycl...ing_Dimensions

No.

Rear derailleur ratios changed too.

Campagnolo 8spd, 10spd, 11spd and 12spd rear derailleurs all have different ratios. It’s not huge, but the ratios changed. You have to slightly modify a 10 speed derailleur to work properly in an 11spd system as it will under shift. Going the other way will slightly over shift and be acceptable but it’s not the same. This trend has seemed to continue as cogs are added.

Shimano mountain bike and road bikes have different ratios. Shimano 10 and 11 speed also have different ratios. 7400 used different ratios than the rest of the period line.

I believe sram has used 3 ratios in the modern area.

This isn’t all inclusive, but examples of situations where you can’t mix shifters and derailleurs.

[morrisond]

Originally Posted by thirdgenbird

No.

Rear derailleur ratios changed too.

Campagnolo 8spd, 10spd, 11spd and 12spd rear derailleurs all have different ratios. It’s not huge, but the ratios changed. You have to slightly modify a 10 speed derailleur to work properly in an 11spd system as it will under shift. Going the other way will slightly over shift and be acceptable but it’s not the same. This trend has seemed to continue as cogs are added.

Shimano mountain bike and road bikes have different ratios. Shimano 10 and 11 speed also have different ratios. 7400 used different ratios than the rest of the period line.

I believe sram has used 3 ratios in the modern area.

This isn’t all inclusive, but examples of situations where you can’t mix shifters and derailleurs.

That's not what that table says from 9 to 11. But other than arguing that it may or may not have changed and how frequently it has - do you have any info if 12 is different than 13?

[thirdgenbird]

Originally Posted by morrisond

That's not what that table says from 9 to 11. But other than arguing that it may or may not have changed and how frequently it has - do you have any info if 12 is different than 13?

It’s pretty well documented here or on weight weenies with photos, measurements, and modifications.

I have no idea what 13 is. It could be the same as 12 but I would be skeptical. As cogs get tighter, small variances become bigger deals. My original point is there is zero benefit to keeping derailleur ratio the same. 2x12 and 1x13 are different ecosystems with different rear derailleur designs so making the ratio the same has no practical benefit. If it is the same, it wouldn’t serve any purpose. You can’t use an ekar RD in a 2x configuration and a 12spd derailleur won’t follow the 13spd cassette profile properly and doesn’t have a clutch.

[thirdgenbird]

To better explain, check out the following photos.

Ekar


11-34 12 speed:


I apologize about the different photos but this angle isn’t the most common online.

These wide range cassettes are not nearly as cone shaped as the traditional road cassette. Traditional systems use a slant parallelogram to follow the basic cone shaped profile of the cassette. A b-screw or similar allows you to dial in the space from top pulley to cassette. There is obviously room for variance, I can swap from 11-34 to 11-29 without issue on my 12spd bike or 13-29 to 12-25 on 10spd without issue, but there is a big difference in the “normal” cassette below and the wide range cassette above. Probably too much for the current slant parallelogram to cope with, the slant would need to be greater. Gap from cassette to derailleur would also vary across the cassette due to the non-linear shape in the middle.

Campagnolo (along with shimano and sram) get around this by using a horizontal parallelogram that relies on chain length and an offset pulley to change the gap from pulley to cassette. It’s directly proportional. When you shift to a larger cog, the effective chain length gets shorter, the cage rotates, and the offset pulley moves further away. You can’t use this extreme offset design in 2x because shifting the front rings would also impact this cassette to derailleur spacing.

The 9-36 is probably within the margin of error on an existing slant parallelogram but I don’t see a compelling case to maintain derailleur ratio for this obscure use case. If a 2x13 system comes, the derailleur will likely follow a more traditional slant parallelogram design so again, no benefit for 1x and 2x systems to share ratio as they won’t be the same derailleur anyway. Sure, you could share rear shifters between 1x and 2x but in this scenario, Campagnolo designed the shifter with gravel and 1x in mind. If a 2x13 group came, multi-shift would be wanted to account for front shifts. You would get the benefit of shared internals, but is this worth designing two fundamentally different systems around? I am guessing Campagnolo made the ekar derailleur ratio what it needed to be for optimal performance without regard to 12 speed compatibility. It’s a non-issue. If they happen to be the same, it’s chance. It would be logical to start with the same ratio for a 2x13 design, but the common ratio would have no benefit to the consumer beyond less spare part SKUs if/when you had to rebuild your shifter.

Sram was praised for keeping their road and mtb derailleur ratio the same, but this was coming from people that wanted drop bar shifters, 1x, and a clutch RD. Ekar gives this to you out if the box.

[morrisond]

I think we are talking about different things.

The shift ratio times the amount of cable pull defines how much the derailleur moves left to right or right to left across the cassette.

According the article I linked above that had not changed from at least 9-11 speed.

It has nothing to do with the shape of the cassette. How the derailleur follows that is as you described and you design the derailleur for that use case.

Of course if you use something like a Wolf Tooth Roadlink it changes all that and can allow a much greater range.

Who nows though. From reports the internal of EKAR looks just like Chorus - just with 13 steps - if the internal spool is the same it may be 13 steps in the space of 12 or an extra step if space allows but that doesn't seem like it would make a lot of sense.

Does anyone know if the distance between the small and big gears on a 13s vs 12s are the same? If yes - that would probably mean shift ratio is the same and they just added an extra click in the same space up front with less cable pulled.

Someone needs to just try it. It should be simple to do if one has the parts on hand. Just try an Ekar Shifter/cassette/chain with Chorus Shifter. Then worry about 2x and whether or not it will work with 12s Chainrings without mods. 12 works on 11 up front.

[thirdgenbird]

We are not taking about different things. I provided reason to why keeping the ratio the same is not important to drivetrain designers. It also explains why a current chorus rd wouldn’t be ideal (or work at all) with a current ekar cassette. Narrowing the cassette range also diminishes the value of the added cog. Current 12spd cassettes are pretty tight with good range on 2x road applications. More range is compelling off-road, but then you have to start considering at the added benefit of 1x in those applications.

It also appear that ekar cantilevers the cassette further over the hub flange than 11 or 12 speed. Total speculation, but if this is the case, then it will limit the smallest size of the large cog. This is the same reason why shimano 11 “road” cassettes required a longer freehub but “gravel and mountain” versions fit on the shorter 8-10spd body. Combine this with the limits of slant parallelogram (see above) it could put usable cassette ranges somewhere between 11-36 and 11-45 based on systems with similar design restrictions. Not a typical offering for 2x road bikes. Cassettes that big often come with fat tires and rough surfaces. Fat tires and rough surfaces are compelling reasons to ditch the front derailleur. I recall seeing some Campagnolo patent applications that are focused at making derailleur travel non-liner so who knows what the future holds. Current state, Campagnolo has a fantastic 2x12 offering and what looks like a great 1x13 offering but mixing the two with known solutions would probably be a niche offering at best. All of this is probably what drove Campagnolo to say this:

Originally Posted by Velocipede

Quite a few people have asked about a 2x13. It's an absolute no. Can't be done.

Sure, it probably “could” be done, but it probably wouldn’t yield a product that is useful. A wider hub or thinner chain would would alter these restrictions, but then you are back to products not compatible with chorus 12 or ekar 13. These same limitations are probably how sram ended up with two totally different 12spd systems. They couldn’t fit their 12 speed mtb spacing into a traditional road application and they ended up with a cassette and chain spacing near identical to Campagnolo 12. Campagnolo used the extra space provided by the larger range cassette to add another cog. Sram may have done the same had they started with their road group and then moved to mtb.

All of this is to say derailleur ratio is pretty far down on the list of compatibility concerns. If it doesn’t match, it’s the easiest problem to fix in the aftermarket. If it does match, there are a number of reasons that would keep 2x13 from being a practical solution using existing Campagnolo hardware.

A road link only lets you clear a larger cog. Your b tension will be incorrect at the small end of the cassette. A fine hack in some cases.

Originally Posted by morrisond

Someone needs to just try it. It should be simple to do if one has the parts on hand. Just try an Ekar Shifter/cassette/chain with Chorus Shifter. Then worry about 2x and whether or not it will work with 12s Chainrings without mods. 12 works on 11 up front.

Are you suggesting using an ekar derailleur in a 2x stystem?

[oldpotatoe]

Holy moly...

https://forums.thepaceline.net/showthread.php?t=259785

[Velocipede]

Originally Posted by oldpotatoe

Holy moly...

https://forums.thepaceline.net/showthread.php?t=259785

I'm staying out of it. lol.

[AngryScientist]

haha, bickering about gear ratios and shifter compatibility is practically the cornerstone of cycling forums.

carry on gentlemen.

[thirdgenbird]

If we all are expected to leave with the same idea we started with and we are not supposed to express a dissenting view, what’s the point? We could all just read Bicycling magazine.

I thought we were having a civil conversation on drivetrain design.

[AngryScientist]

Originally Posted by thirdgenbird

If we all are expected to leave with the same idea we started with and we are not supposed to express a dissenting view, what’s the point? We could all just read Bicycling magazine.

I thought we were having a civil conversation on drivetrain design.

I agree 100%. i was just joking

for the record: anytime anyone says "it cant be done" with regard to drivetrain compatibility - it almost certainly can be done somehow - at least in my experience.

my lynskey runs a friction shifted 9-sp rear cassette with campy-11 FD+RD, a 12-sp subcompact crank and record 12 brakes. i'm sure on paper someone would say that combination would never work, but in practice - it all sings together beautifully.

i would never take for gospel someone who says "it cant be done" because of what they have read about, or calculated to the tenth of a mm. sometimes, you just have to buy the parts and give it a try.

[Velocipede]

Originally Posted by AngryScientist

I agree 100%. i was just joking

for the record: anytime anyone says "it cant be done" with regard to drivetrain compatibility - it almost certainly can be done somehow - at least in my experience.

my lynskey runs a friction shifted 9-sp rear cassette with campy-11 FD+RD, a 12-sp subcompact crank and record 12 brakes. i'm sure on paper someone would say that combination would never work, but in practice - it all sings together beautifully.

i would never take for gospel someone who says "it cant be done" because of what they have read about, or calculated to the tenth of a mm. sometimes, you just have to buy the parts and give it a try.

Yes, it CAN be done, but not without some serious compromise to the shifting system. It's not going to work right. The rear derailleur alignment/movement is the issue. If the point is to make a 2x13, why? You'll have to modify the crank or rings to get closer, modify a shifter(rear) and use a Chorus 12 rear and hope you can get the chain wrap to work plus not touch the cogs when going up the range.

I get people like a challenge. Go for it. Post some pics and give us a ride report. We can post it to the new Campy forum when it's up.

[thirdgenbird]

I knew you were joking.

I think the “can’t be done” was to avoid the conversation above and is in the context of current hub width and chain spacing.

If cable pull matches, you probably could make 2x13 work if you made a longer b-link to clear the large cog and a longer cage to take up the extra chain required. The gap between derailleur and cassette would be far from idea however. Probably functional, but not to the standard of a top tier manufacturer.