Wednesday, January 25, 2023

Specialized Aethos: Tripeak Ceramic Bottom Bracket and Dura-Ace Crankset

In the previous post, I had already started the assembly of the Specialized Aethos. After assembling the fork and headset area, I continued by testing the bottom bracket.

Normally I would not install the bottom bracket first, as the internal cabling needs to be done before that. However, since this Aethos frame uses a threaded bottom bracket instead of a press fit type, it is easy to install and test to see if it fits well. It can be removed easily just by unscrewing the bottom bracket from the frame.

During this test installation, I found that the Dura-Ace R9100 bottom bracket does not spin well at all. There was a lot of resistance, which prevented the crankset from even spinning one round when I spun it by hand.

In the end I decided to give up on using the Dura-Ace bottom bracket, as the rotation feeling is just too poor. Instead, I decided to go for a smoother spinning bottom bracket, of which there are many other options.

I considered the Hambini bottom bracket, but the price of SGD 450 for a single bottom bracket is too much for me to accept. I looked for alternatives, such as the Ascent Revolution BB, but that was a bit heavy.

In the end I decided to try this Tripeak BB with ceramic bearings, which is not too expensive at around SGD 100, while being lighter than the Ascent Revolution BB. The reason I chose the ceramic version is not for smoother operation, as at such low rotation speeds, using steel or ceramic bearings make no difference. Rather, the reason is that ceramic balls are a little bit lighter than steel balls.

Tripeak bottom bracket for 68 mm English threaded frames, and for 24 or 22 mm spindles.

On the non-drive side, there is an adapter so that you can use it with SRAM cranksets that have a stepped 24/22 mm spindle.

Here is the adapter to reduce the internal diameter on the non-drive side from 24 mm to 22 mm.

Since I am using a Shimano crankset with a straight spindle of 24 mm, the adapter is not required.

It comes with a few shims/spacers if you need to adjust the chain line, and also a wave washer if you are using a SRAM crankset that needs the pre-load from the wave washer.

Tripeak ceramic BB weighs 98 grams. It is 32 grams heavier than the Dura-Ace R9100 bottom bracket, but I accept this weight tradeoff for the much smooth rotation.

Tripeak bottom bracket installed! Since the outer diameter of the bottom bracket is larger, it matches the frame nicely.

I'm using the older Dura-Ace R9100 crankset, instead of the latest R9200. This is because the new version is 72 grams heavier than the older version, which is quite a lot.

I'm happy with the new bottom bracket as it spins so much smoother! Now I can continue with the rest of the bike build.

Sunday, January 22, 2023

Specialized Aethos: Assembly Part 1 with Dura-Ace R9100 Bottom Bracket

With all the various parts of the Specialized Aethos collected, it is now ready to be assembled. Normally I would start with the assembly of the fork to the frame, and this will involve cutting the steerer tube to the required length.

Installing the super lightweight expander plug inside the Aethos fork.

Also using the stem spacers with a special scalloped design. Doesn't save any weight over standard thin carbon spacers though.

According to the manual, this steerer tube and expander plug allows the stem to protrude up to 3 mm above the expander plug. This allows a clean setup without a spacer on top of the stem.

Frame and fork ready for the components! Steerer tube still needs to be cut.

Subtle Aethos logo, the way I like it.

Just a small S-Works logo along the top tube.

The shimmering paint looks awesome in the sunlight!

Lots of glitter in the paintwork of the frame and fork.

As this frame uses a standard threaded bottom bracket, it is easy for me to install or remove the bottom bracket. For minimum weight, I chose the Dura-Ace BB-R9100 as it is the lightest one available.

Dura-Ace BB-R9100, English Threaded.

Weighs only 66 grams!

As the outer diameter is smaller than most, it will not match so well with the frame's curves.

Threaded bottom brackets are so much easier to service, compared to press fit types.

After installing the bottom bracket, I noticed that the inner race of the bottom bracket does not spin well. In fact, it has a lot of resistance, so much so that it feels like it is defective.

I went to get a warranty replacement, but found that the replacement bottom bracket also has a lot of resistance. When I put the crankset on, it does not even spin one full round.

Over the years, I have installed many Shimano bottom brackets, but this is the one with the worst rotation feeling. I'm sure this is due to the very good contact seals, but it degrades the riding experience with the additional resistance.

On the Fnhon DB12, I installed the Ascent Revolution BB which spins so much better. Therefore, instead of using this Dura-Ace BB, I will be getting another bottom bracket with less rotational resistance.

Sunday, January 15, 2023

Specialized Aethos: PRO Stealth Team Saddle + Camera Mount

A new saddle is needed for the Specialized Aethos, as it is an additional bike to my bike stable. Normally if I am replacing a bike, I will just transfer the saddle from the existing bike over to the new bike.

As you may already know, I am very comfortable with the PRO Stealth series of saddles, ever since I did a proper bike fitting at LOUE Bicycles. In fact, I bought many PRO Stealth saddles to replace most of my existing saddles.

The first Stealth saddle that I got was the PRO Stealth Superlight, which is found on the Focus Paralane all-weather commuting bike. Subsequently I also changed to the PRO Stealth Off-Road saddle on the Cervelo Aspero gravel bike and also the Fnhon DB11/12 folding bike.

Although there are many other saddles that are lighter than the PRO Stealth series, comfort and compatibility is more important. I would not want a superlight saddle that looks good but is not as comfortable. Therefore there was no doubt that I would get another PRO Stealth saddle for the Specialized Aethos.

Some additions to the PRO Stealth saddle lineup included the Stealth Team saddle, which is also a lightweight saddle that is different from the original Superlight model. This new model looks more appealing to me as it costs less, although it does weigh a little bit more. Check out the differences below and also at this link.

New PRO Stealth Team saddle, with an edgier appearance. This is the version with 142 mm width.

The shape of the Stealth saddle suits me very well, with good support at the rear and a shorter nose.

The new series has a cutout between the left and right cushions, for extra weight savings.

Team series is the highest end (lightest, most expensive) of the Stealth series (apart from the Superlight).

The Team saddle also has carbon rails, but it is inserted into the shell as separate pieces, instead of being molded together as on the Superlight. This reduces the cost greatly but adds a bit of weight.

There is a marking at the point where the saddle is 80 mm wide. Useful if you want to transfer your saddle position from one saddle to another.

Oval shaped carbon rails, for reduced weight.

Actual weight of the Stealth Team saddle is 160 grams. Only 3 grams more than the Superlight version!

Side by side comparison of the Team (left) vs the Superlight (right). Note the edgy vs rounded design.

The new Team saddle is slightly longer by 5 mm, with a completely different shell and rails design.

Basically 95% identical in terms of the fitting, shape and weight, but the Team version is quite a lot cheaper.

Same familiar shape for the butt, means no transition time is needed when using the new saddle.

I'm pleased with the new Team saddle, as it is basically just as good as the Superlight saddle, but with a lower price.

One nice feature about most PRO saddles is the ability to mount an accessory directly under the saddle, with the use of an adapter. This allows a rear light or GoPro to be mounted, while still looking integrated.

If you get a compatible camera mount as shown, you can mount any accessory that uses the GoPro-style of connection.

The camera mount will be fixed onto the bottom of the saddle, using two screws that thread into the shell of the saddle.

Here is the official PRO version, which is rather hard to come by.

There are also generic versions as shown on the right side. These are longer, and does not use countersunk screws. Works just as well though.

With this, basically all the parts of the bike are ready, and I can begin assembling the Specialized Aethos.

Sunday, January 8, 2023

Latex and TPU Inner Tubes

In the earlier post on the Specialized Aethos, I introduced the Dura-Ace C36 wheelset, which is lighter in weight than the Dura-Ace C50 wheelset. This time, I still chose a normal clincher type of tire, which means that an inner tube is required. The Continental GP5000 tire is available in both tubeless and tubed type depending on the rider's preference.

The C36 wheelset is tubeless ready, with rim tape already installed. This setup can be used for both tubed and tubeless tires. Since I am using a tubed setup, I would need to select inner tubes for this wheelset.

Previously I have been using normal butyl inner tubes, such as those from Schwalbe. They work well, however there are now alternatives that has some advantages over normal butyl tires.

Butyl inner tubes are cheap and relatively durable, but have more rolling resistance and weigh more. The air retention is good compared to other types. It is the safe but boring option.

Latex inner tubes are a bit more expensive, and are rather fragile. The rolling resistance is very low, about the same as using a tubeless setup. The weight is about 30% less than butyl, while the folded size is about the same as butyl. Biggest disadvantage of latex inner tubes is the poor air retention, as the air pressure can drop drastically over a day. It is usually necessary to pump the tires just before going for a ride.

TPU inner tubes are relatively new, but they have the potential to become an excellent option. They are the most expensive type for now, although they are also more durable than latex tubes. Rolling resistance is also low, although not as low as latex tubes. Weight can be 1/3 that of butyl, while the folded size is reduced by half. Air retention is acceptable as it can last a few days before needing a top up.

From left to right, TPU vs Latex vs Butyl inner tubes.

TPU tube is about half the size of the other two types, which makes it ideal for packing as a spare.

Weight of butyl inner tube (60 mm valve) is 113 grams, which is an average weight for this spec. 
This spec is for 700C tires that are 28 mm wide.

Vittoria latex inner tube for 25-28 mm wide 700C tires, with a plastic 48 mm valve.

Latex tube weighs 81 grams, which is 32 grams less than the butyl type.

TPU inner tube, compatible for 18 to 28 mm wide, 700C tires.

Very lightweight at just 37 grams, which is 1/3 the weight of the butyl type.

Lightweight plastic valve is bonded to the TPU tube. Failure point is usually the bonding area on the TPU surface.

Joint on the TPU tube, one of the common failure points.

If you are a weight weenie, you would definitely choose the TPU inner tube, as it can save about 150 grams per bike (2 wheels), at a reasonable cost. One of the easiest and most affordable way to reduce weight on the bike.

What you need to take note, when using the TPU inner tube, is to inflate it only slightly during installation, just enough to give it some shape. Without the tire to maintain the shape, the TPU tube will stretch and bulge even if you just lightly exceed the atmospheric pressure.

Other than that, the TPU tube air retention is pretty OK, as I only need to pump it every 2-3 days even if I ride every day. For the butyl tubes, it will last at least 1 week without needing to pump.

The butyl inner tube has been tried and tested for a long time, and is in use on the C50 wheelset that is on the Focus Paralane. As for this new C36 wheelset on the Specialized Aethos, I will try both the latex inner tubes and the TPU inner tubes to see which is more suitable.