Sunday, September 25, 2022

Dura-Ace C50 R9270 vs Ascent Zenith Elite Wheelset

Here is a comparison between two carbon road wheelsets with similar specifications. Both are 700C road wheelsets, with 50 mm rim height. The wheelset weight is is also similar as you will see below.

In this comparison, it is mainly about the physical characteristics of each of the wheelset. Let's check out the new Dura-Ace C50 R9270 wheelset, versus the previous Ascent Zenith Elite wheelset. For the detailed analysis of each wheelset, check out the individual posts via the links.

Dura-Ace C50 R9270 vs Ascent Zenith Elite wheelset! Different spoke lacing pattern as seen here.

50 mm rim height, as well as external spoke nipples and bladed spokes.

C50 on the left comes with tubeless ready rim tape, while the Zenith uses spoke hole plugs which are lighter than rim tape. Not tubeless ready.

Zenith has an old school internal rim width of just 17 mm.

Despite the narrow internal width, the Zenith has a modern external rim width of 28 mm.

When Continental GP5000 28 mm tires are mounted on the Zenith Elite wheelset, the actual tire width is actually almost nominal, at 28.5 mm. This is on the narrow 17 mm internal rim width. As mentioned before, the GP5000 tires will measure wider than normal when mounted on more modern rim widths of 21 mm.

C50 internal rim width is modern at 21 mm.

C50 external rim width also follows the latest trend, at 28 mm wide.

When the same GP5000 28 mm tire is mounted on the C50 wheelset, the actual tire width becomes 30 mm, which is noticeably wider than on the Zenith Elite wheelset. The only reason is because the internal rim width is wider (21 mm vs 17 mm).

Luckily the wider tire still manages to fit within the mudguards on the same Focus Paralane, although the clearance is now even smaller.

Next, let's check out the freehub body of these wheelsets.

The Zenith Elite has a unique freehub, using magnetic pawls for quiet coasting and a large bushing for reduced weight and added stiffness. As for the Dura-Ace C50 wheelset, it also uses a relatively new Direct Engagement construction that is a little bit similar to the DT Swiss star ratchet type.

Zenith Elite has a 6 degree engagement angle, which is really short for a road bike wheel. There are 2 points of engagement at any one time.

C50 has a 7.2 degree engagement angle, and many more points of engagement (unknown) due to the star ratchet look-a-like system.

As for the freewheeling sound, both are considered quiet, compared to super loud Hunt wheelsets or DT Swiss hubs.

New road spline on the C50 wheelset on the left, and conventional HG spline on the Zenith hub on the right. Both freehubs are made of aluminium.

Zenith Elite front wheel is 682 grams, which is average.

Zenith Elite rear wheel is 822 grams, which is quite lightweight.

Total wheelset weight of Zenith Elite is 1504 grams, which is quite good for a 50 mm profile wheelset. Weight includes all spoke hole plugs.

C50 front wheel weighs 693 grams which is relatively heavy. I suspect that the front hub is heavier than most.

C50 rear wheel is lightweight at just 800 grams. A lot of it is due to the aluminium freehub body.

Wheelset weight of C50 is 1493 grams (with rim tape), which is just 11 grams lighter than the Zenith Elite wheelset. Practically no difference in weight.

Based on ride quality comparison, using the same GP5000 28 mm tires and Schwalbe SV15 inner tubes, they feel very similar. It is actually what I expected, as both have similar weight, rim profile and freehub engagement angle. Going from the Zenith Elite to the C50 is not a big upgrade, as the Zenith Elite is already a very good wheelset.

Saturday, September 24, 2022

Dura-Ace Cassette: 11 Speed R9100 vs 12 Speed R9200

On the latest Shimano road 12 speed drivetrain, the 11-30T cassette is still the most common cassette used. With a good gear range and also enough closely spaced gears, it is suitable for all-round road use if you pair it with a front double crankset.

From 11 speed to 12 speed, the 11-30T cassette has gained a sprocket, although the range is still the same. This means a tighter gear step in the middle of the cassette, which I will elaborate on later.

Let's check out some of the physical differences between the 11 speed and 12 speed 11-30T cassettes.

11 speed R9100 cassette on the left, vs the new 12 speed R9200 cassette on the right.

The 5 largest sprockets are made of titanium for weight savings, and is why the Dura-Ace cassette costs 3 times more than the Ultegra cassette.

New cassette on the right has an additional sprocket in the middle.

Rear view shows a lot more rivets on the 12 speed cassette on the right.

Both use aluminium spiders for the largest sprockets, but the construction looks quite different.

Weight of 11 speed R9100 11-30T cassette is 207 grams.

Weight of 12 speed R9200 11-30T cassette is increased to 223 grams, due to the additional sprocket.

11 speed vs 12 speed cassette lock rings, both are made of aluminium. These are not interchangeable.

I noticed the differences in Dura-Ace font, especially around the letters A and E.

12 speed lock ring on the right is longer, as the smallest 11T sprocket protrudes a bit more from the freehub body.

11 speed lock ring is 5 grams

12 speed lock ring is also 5 grams despite being a bit longer.

There are 2 main differences to the sprocket design, between 11 speed and 12 speed. First, the 12 speed sprockets have HG+ function, which enable smoother and quicker outward shifts. This is a real benefit that can be felt, and it only works when you use a compatible Shimano 12 speed chain and rear derailleur.

Second difference is the internal spline pattern, where the sprockets engage the freehub body. The new 12 speed spline design can match both new 12 speed and older HG splines. In other words, the new 12 speed cassettes are compatible to older wheels with HG spline freehubs as well.

11T sprocket of old vs new (right side) cassettes.

New 11T sprocket has small splines that interlock with the 12T sprocket, this makes it look rather delicate.

Here are the 12T sprockets. On the left is the 11 speed version, while the 12 speed version looks complicated with many small splines.

The new 13T sprocket on the right is embossed in the middle, which will be paired to the 1 mm spacer later.

All the new 12 speed sprockets have a new internal spline pattern, as shown on this 14T sprocket. This is what makes it compatible to the new and also old freehubs.

Showing the overlap between the old and new spline patterns.

Here is the additional 16T sprocket in the 12 speed cassette that is not found in the 11 speed cassette.

This additional 16T sprocket weighs 16 grams, and is exactly the weight difference between the 11 and 12 speed cassettes.

This 16T sprocket is added to the middle of the gear range, to give a smaller gear step between the 15T and 17T sprockets. Check out the difference below.

11 Speed CS-R9100 11-30T
11-12-13-14-15-17-19-21-24-27-30

12 Speed CS-R9200 11-30T
11-12-13-14-15-16-17-19-21-24-27-30

Adding a 16T sprocket in between the 15T and 17T sprocket may not seem like much. For those who are not so sensitive to cadence, they can adapt to bigger gear steps without issue. However, for those who work best in a narrow cadence range, this additional 16T sprocket ensures that the perfect gear is always available, without being stuck between a gear that is slightly too high or too low.

When I was using the 11 speed cassette, I often find myself in between gears 6 and 7, which is the 17T and 15T sprocket. Using the 17T sprocket is too light, while the 15T sprocket is a bit too heavy. The gear difference between these two gears is 13%, which is not really big but annoys me sometimes.

After switching to the 12 speed cassette, I find myself using the 16T sprocket quite often. It is the sweet spot for me for comfortable cruising, and I can step it up or down slightly without a big jump in cadence or effort. It is a small improvement but something I can appreciate.

Layout of the 17T to 30T sprockets, with the 11 speed cassette on the left.

On the 11 speed cassette, the largest 2 titanium gears are riveted to a thin aluminium spider. The next 3 titanium gears are riveted to a carbon spider. Then, the steel 17T sprocket is a loose sprocket.

On the 12 speed cassette, the 4 largest titanium gears are riveted to a large aluminium spider. The titanium 19T sprocket and steel 17T sprocket are riveted to a smaller spider.

Unusual to see a titanium sprocket riveted to a steel sprocket.

6 large rivets join the 19T and 17T sprockets to an aluminium spider.

Stack of 17-30T sprockets on the 11 speed cassette is 142 grams.

Stack of 17-30T sprockets on the 12 speed cassette is 149 grams.

The new construction adds 7 grams to the larger sprocket set, and this does not even include the additional 16 grams from the additional 16T sprocket. This means that there are some weight savings from the smaller sprockets on the 12 speed cassette.

Finally, let's compare the spacer thickness. The thickness is critical to maintain the correct distance between the sprockets to ensure good shifting performance and no noise.

The spacers are helpfully labelled to avoid any mix up.

There are 2 different spacer thickness on the 12 speed cassette, which confuses things a bit.

11 speed spacer is about 2.2 mm thick.

12 speed spacer is about 1.95 mm thick, about 0.25 mm thinner than the 11 speed version.

The thinner 12 speed spacer is just 1 mm thick. This is matched with the 13T sprocket to achieve the correct sprocket spacing.

There are many differences between the 11 speed and 12 speed cassettes, from the sprocket spacing, to the spider construction, and the spline pattern. This is good info if you ever need to identify any loose sprockets or check cross compatibility.

Sunday, September 11, 2022

Dura-Ace Di2 Rear Derailleur: R9150 vs R9250

Time for a comparison between the new 12 speed Dura-Ace Di2 rear derailleur and the previous 11 speed Dura-Ace Di2 rear derailleur. On first glance, they look pretty much similar, but there are definitely some differences that are not obvious at first sight.

Left side is the new 12 speed rear derailleur, beside the 11 speed version on the right.

From the above picture, the overall structure looks similar. Both still use the same adapter design to attach to the frame derailleur hanger, and the motor unit location looks similar.

Outer link design is different, as the new design language looks more angular compared to the rounded design of the previous version. Colour wise, the new derailleur uses a uniform black anodizing, instead of the grey to black gradient on the previous version.

Inner link seems to be made of fibre reinforced plastic, either with carbon or glass fibres. End of the rivets are covered with a black sticker for better appearance.

Motor unit location is quite similar, tucked away behind the rear derailleur and under the cassette. Limit screws are located more or less at the same positions.

Saver unit design looks similar as well.

Inner plates are made of carbon fibre, although the new 12 speed cage is quite a lot longer since it has to accommodate 11-34T cassettes as well.

Cage length of new 12 speed Dura-Ace rear derailleur R9250 is about 93 mm.

Cage length of old 11 speed Dura-Ace rear derailleur R9150 is about 72 mm.

Another view showing the differences in cage length. There is a stopper plate on the left that is molded into the outer plate, as compared to a separate stopper pin seen on the right.

Some differences in the outer plate construction as well. New plate on the left has the plate stopper molded directly into the carbon plate, as compared to a separate stopper pin as seen on the right side.

Here is the biggest difference. New derailleur on the left has a charging port, hidden under a cover. It also houses the wireless units and other electronic stuff for wireless communication with the 12 speed Di2 shifters.

Weight of previous R9150 rear derailleur is just 197 grams, very lightweight.

New R9250 rear derailleur is slightly heavier at 216 grams, but packs a lot more electronics into it. It also has a longer cage to cater to larger cassettes.

Overall, the biggest changes would be the longer cage for larger chain capacity, and the integration of electronics to allow wireless communication with the shifters, plus charging as well.