Saturday, March 18, 2023

Campagnolo Ekar: Crankset

Next component on the list is the Campagnolo Ekar crankset. Initially I thought of using another crankset, but I realized that I might have a problem finding a suitable chain ring. Due to the unique 13 speed chain which is extra narrow, a special chain ring is needed. Obviously the Ekar crankset and chain ring will fit, but third party options are limited.

During my research, it was not clear if there are suitable third party chain rings that will fit the Ekar 13 speed chain. In order to avoid any potential compatibility issue, I decided to use the Ekar crankset and chain ring to ensure 100% compatibility.

Campagnolo Ekar crankset designed for the 1x13 speed Ekar drivetrain. This set has 170 mm crank arm length and a 38T chain ring.

I would have preferred a smaller 36T or 34T chain ring to match the 9-42T cassette, but it is not available. In this case, a 38T chain ring with the 9-42T cassette on a 700C gravel wheelset gives a gear range of about 25" to 118", which is quite high for gravel riding.

Another unique Campagnolo design, with the spindle split into two halves.

Carbon Ekar crankset! Crank arms look good, with a very simple looking chain ring.

Ekar logo laser marked and pad printed on the crankarm which has a raw carbon finish.

Nice to see that this crankset comes with rubber boots to protect the end of the carbon crank arms.

Rubber boots are secured to the ends just with a rubber band. Crude but effective.

Rubber boots can be removed easily, as long as the pedals are not installed yet.

Narrow wide chain ring teeth. From this I can see that 38T is probably the minimum chain ring size possible, without interfering with the 4 arms of the crankset.

Due to the narrow 13 speed chain, even the wide teeth are just 3.15 mm wide.

The narrow teeth are thin and sharp at just 1.5 mm.

Compared to the SRAM 12 speed and Shimano 11 speed chain rings, the teeth on the 13 speed Ekar chain ring are even thinner. As of that time (August 2022), I don't know of any third party chain ring that is specifically compatible to the Ekar 13 speed chain.

The bottom bracket bearings come fitted on the spindle, instead of inside the bottom bracket adapters.

Another unusual aspect of Campagnolo cranksets is the spindle and bottom bracket design. The bearings are press fitted onto the spindle, instead of inside the bottom bracket adapters like every other brand. This also means that you need to use a Campagnolo bottom bracket to fit Campagnolo cranksets.

There is a large bolt that is used to join the two halves of the spindle together. It requires a massive amount of torque, with a range of 42 - 60 N.m. 

As the crank bolt is located deep inside the spindle, a standard Size 10 Allen key will not be able to tighten the crank bolt to the required torque. A special tool is needed to reach inside the spindle in order to fix the crank bolt properly.

Here is the bolt that will be used to join the two halves of the spindle.

Each end of the spindle makes up a Hirth joint, which is a self centering and self aligning joint. Campagnolo claims that this construction allows a wider bearing stance and a flatter crank profile around the spindle.

Splitting the spindle into two halves means that it may be harder to control the cylindricity of the spindle when joined, as compared to having a one piece spindle.

Right crankarm with half a spindle, chain ring, fixing bolt and bearings weigh 389 grams.

Left crank arm with half a spindle and bearings weigh 229 grams.

In total, this carbon Ekar crankset weighs 618 grams, including the bearings and rubber boots. If we add the Campagnolo bottom bracket (without bearings, 57 grams), this total crankset + bottom bracket set would weigh 675 grams.

For comparison, a Dura-Ace R9100 crankset (610 grams) with Dura-Ace BB-R9100 (66 grams) would weigh almost the same at 676 grams. Given that the Dura-Ace crankset has a double chain ring, and uses aluminium crank arms, the Ekar carbon crankset should actually be much lighter.

In other words, even though the Campagnolo Ekar crankset is made of carbon, it is not actually lighter than a high quality aluminium crankset. There are lighter carbon crankset options available in the market.

Here is how it a Hirth joint looks like.

Hirth joint in the middle, and bottom bracket bearings press fitted onto the spindle at both ends. Only Campagnolo uses this construction to make a crankset.

Once again, we see the unique construction used by Campagnolo to design the crankset, especially at the spindle area.

Technically speaking, the Campagnolo method of press fitting the bearing to the spindle is of sound engineering design, as the recommendation is for the rotating part (spindle) to be press fitted to the bearing to avoid any slippage.

However, practically every other bottom bracket and crankset manufacturer has the bearings press fitted to the fixed part (bottom bracket adapter) instead. This is for ease of assembly and replacement, as the bottom bracket can be replaced easily along with the bearings.

The next post will show the special Campagnolo bottom bracket and the super narrow Ekar 13 speed chain.

Friday, March 17, 2023

Campagnolo Ekar: 13 Speed 9-42T Cassette

Here comes the highlight of this Campagnolo Ekar 13 speed gravel groupset! In my opinion, the cassette is the most outstanding component of this groupset. Not only is it well engineered, it is also beautifully designed. See for yourself with the pictures below!

Simple packaging, with the small sprockets tucked into the corner.

This is the 9-42T spec with the widest gear range. It is also available in a narrower 9-36T spec and a lower 10-44T spec.

Campagnolo Ekar 13 Speed Cassettes:
Endurance: 9-36T (9-10-11-12-13-14-16-18-20-23-27-31-36) 400%
Gravel Race: 9-42T (9-10-11-12-13-14-16-18-21-25-30-36-42) 466%
Gravel Adventure: 10-44T (10-11-12-13-14-15-17-20-23-27-32-38-44) 440%

The cassette comes in just two sub-modules, the larger part which has 9 sprockets, and the smaller part with the 4 smallest sprockets.

Entire 9-42T 13 speed cassette weighs 397 grams, which is close to the claimed weight of 390 grams.

The 4 smallest sprockets, along with the lock ring are pre-assembled as a sub-unit.

A special lock ring tool is needed for Campagnolo cassettes.

The 4 smallest sprockets (9-10-11-12) are machined from a single block, which avoids complicated spline designs such as those found on the new Dura-Ace/Ultegra 12 speed cassettes.

The inside of this 4 sprocket cluster is splined to engage the proprietary N3W freehub body.

In the pictures below, there are many beautiful pictures of the cassette. The actual part looks even better, as the surface treatment, texture and design is just so good. This contrasts starkly with some of the other Ekar components, such as the rear derailleur and shifters.

Here are the larger 9 sprockets of the 13 speed cassette, with 13-14-16-18-21-25-30-36-42 teeth.

Simple looking shifting gates and minimally shaped teeth to aid shifting performance.

The gear steps between the larger sprockets are relatively big, unlike at the other end where there are five 1 tooth close gear steps.

All 9 sprockets are machined from a single block of steel! Similar construction method as the SRAM Red or XX1 cassettes, but looks much better here.

Large 5 arm aluminium spider fixed to the rear of the 13 speed cassette.

Check out the details of the connecting bridges between each sprocket. Imagine how much time is needed to machine every slot!

The aluminium spider has 4 splines to engage the N3W freehub body, so as to transmit the torque from the sprockets to the wheel.

I like how the bridges that connect different sprockets to each other are perfectly aligned to the teeth.
For example, the 36T sprocket has 36 bridges which connect it to the 42T sprocket.

The teeth and slots are perfectly aligned on every sprocket, which gives it a well balanced appearance.

With background lighting, the cassette literally glows through the slots, highlighting each of the teeth at the same time.

Sometimes, you come across components that are so well designed and beautiful, that you almost can't bear to use it. This Campagnolo Ekar 13 speed cassette is definitely one of them. The Dura-Ace 12 speed cassettes come close, but are not as neat and well balanced as the Ekar cassette.

Gravel Race: 9-42T (9-10-11-12-13-14-16-18-21-25-30-36-42)

The cassette gear ratios are also pretty well thought out. With close ratios at the top end (9-10-11-12-13-14), it minimizes the gear steps when travelling at higher speeds. In the middle of the range, the steps are quite standard (14-16-18-21). At the lower end of the gear range, the steps become bigger (21-25-30-36-42). Usually bigger gear steps are acceptable at lower speeds, such as when grinding up a steep slope. Generally, since this cassette has 13 speeds, it enables both a wide gear range while maintaining reasonable gear steps at the same time.

Saturday, March 11, 2023

Campagnolo Ekar: Rear Derailleur

Next component of the Campagnolo Ekar would be the rear derailleur. As it is a 13 speed drivetrain, the rear derailleur needs to be very well constructed and robust in order to achieve good shifting performance across all 13 gears.

In the previous posts, the Ekar shifters, brake calipers and rotors were introduced. Other components will be introduced subsequently.

13 speed rear derailleur, unique to Campagnolo Ekar

Unboxing begins

Overall view of the Campagnolo Ekar 13 speed rear derailleur, with an all black appearance.

Weighs 289 grams, which is about the same weight as the GRX RD-RX815 Di2 rear derailleur.

Cheap looking barrel adjust without much indexing feeling, similar to what you find on an entry level Tourney rear derailleur.

1x B-tension screw and 2x limit screws located near to each other. It's not labeled so you need to be careful not to adjust the wrong screw.

In the manual it shows how to use the cage lock feature, to hold the derailleur in the open position for easier wheel installation and removal.

During normal operation, the button stays inside and the derailleur position is fixed.

If the rear derailleur is pulled backwards past a certain point, the cage lock engages and holds the rear derailleur in this open position. To release, push in the button that has popped out as shown above.

I think this cage lock feature is pretty useful as it makes it easier to install or remove the rear wheel. However, the mechanism feels rather flimsy due to the plastic button and other small parts which makes me wonder how durable it will be when actually used in the field.

Aluminium outer and inner links, with a large guide spring in the middle.

Cable routing is interesting as it routes along a large plastic cam that is attached to the outer link. This changes the pull ratio throughout the shifting stroke.

This aluminium cap houses the clutch mechanism inside. Not sure if it is meant to be serviceable or not.

Sticks out from the bike frame by a fair bit, as it does not have a Shadow design unlike Shimano rear derailleurs.

The support arm for the barrel adjust is a separate aluminium piece that is bolted onto the bracket member. Looks like an afterthought to me.

Large pulleys are used to help reduce the cage length. The guide pulley on top has 12 tall teeth, while the tension pulley below has 14 shorter teeth.

Cage length is 76 mm, which is considered quite short. This is possible because it is designed exclusively for front single drivetrains, so it only has to cater for the chain capacity of the cassette.

The guide pulley has an offset of 40 mm from the centre of cage rotation. This helps the pulley reach the larger sprockets at the lower gears.

The Ekar rear derailleur looks like a pretty standard mechanical rear derailleur with a traditional construction, except for the unique cage lock feature located on the bracket member. It has a traditional cable stopping point, and sticks out quite a bit with respect to the bike frame. The clutch mechanism and effectiveness is unknown yet.

In the next post, I will introduce the highlight of this groupset, which is the 13 speed Ekar cassette!