Wednesday, December 28, 2016

Merida Scultura 5000: Dura-Ace 7900, 165mm Crankset

A lot of times, the reason for me getting new bike components is due to a combination of a few factors as listed below:

1) Want to try out component with new feature
2) Discount on website
3) Replacement for worn out component
4) Upgrade on existing component
5) Improve fitting on existing bike

In this case, I decided to get a new crankset because of reason 2 and reason 5. I came across this article regarding the bio-mechanics of cycling, and it discussed the crank arm length in detail. Seems that most bikes in the market are actually equipped with crank arm lengths that are too long for most people.

Link below:

In summary, for a person with height of 168cm (me), I should be using a crank arm length of 165mm. However, I have been using crank arm length of 170mm for as long as I can remember, due to the fact that it is the default length for most bikes in my size, and is also the most common length available.

Although I don't have a problem using 170mm crank arm length, I feel that when I am in the drops on the Merida road bike, it feels like my hip angle is too small when my knee is at the top of the pedaling stroke.

At the same time, I also came across a great online offer from Rodalink, where they are selling the Dura-Ace 7900 crankset for only $200+, when it usually costs $600+. The catch is that it is 53/39T, and also has 165mm crank arm length. Most of the time, people will not buy a crankset with 165mm crank arm length. However, in this case, it is perfect as it gives me a chance to test out a shorter crank arm length, and I am also getting a great deal on a Dura-Ace crankset.

Although this Dura-Ace 7900 crankset is 2 generations old, having already been replaced by the newer 9000 and R9100 series, it is still iconic, with the two-tone surface treatment and integrated chain ring appearance.

With that, I ordered the Dura-Ace 7900 crankset with a 165mm crank arm length, and will install it on the Merida Scultura 5000 to try out.

Since the crank arm is 5mm shorter, it also means that I can raise the saddle 5mm higher, and still get the same leg extension at the bottom of the pedaling stroke.

Current setup on the Merida road bike. Dura-Ace 9000 crankset with 170mm crank arm length.

With the Dura-Ace 7900 crankset, one difference is that 7900 is for 10 speed, while Dura-Ace 9000 is for 11 speed. There is a small difference in distance between the chain rings, but it should not affect the shifting performance greatly.

Let's take a look at the new (old?) Dura-Ace 7900 crankset!

Unboxing the Dura-Ace 7900 crankset! Always a wonderful experience

Iconic 5 arm crankset with integrated chain ring appearance

Polished aluminium! Still so shiny even after a few years of storage.

Weighs only 643 grams for the whole crankset. The weight is in between Dura-Ace 9000 and Ultegra 6800.

During installation, I found that I had to move the front derailleur upwards, as the previous setting was for the 50/34T crankset, while this Dura-Ace 7900 crankset has 53/39T. Also, the chain had to be lengthened due to the larger 53T chainring. Not a straightforward crankset swap due to the different chain ring sizes.

Installed on the bike, with the Ultegra 6870 Di2 FD moved upwards

Swapping a Dura-Ace crankset for another

Installation completed!

After testing it out for a couple of months, I found that there is some difference in the pedaling stroke. When using the drops, the knees will not come up as high, and the hip angle is not so tight, making it more comfortable when using the drops. When using the hoods, there is no noticeable difference as the hip angle does not get so tight.

Although there is a difference, this difference is quite small, and I am comfortable with using either 165mm or 170mm crankarm length. Perhaps for long distance riding or high cadence riding there will be a difference over longer periods of time.

In conclusion, using a shorter 165mm crank arm length will make a difference only if you are using the drops frequently, and if you are concerned with getting maximum pedaling efficiency and perfect bike fitting. Otherwise, it is OK to stick with 170mm crank arm lengths for most purposes.

Sunday, November 6, 2016

Avanti Inc 3: Ice Tech Disc Brake Pads

On my all-weather commuting bike, the Avanti Inc 3, the disc brakes have been giving out some noise recently. Upon braking, just when the bike is about to come to a stop, there will be a loud squealing noise coming from both the front and rear brakes. This means that it is time to service the brakes!

Usually, when there is a squealing noise from the brakes, it means that the brake pads or brake rotors have been contaminated with oil. Most of the time, this contamination comes from the dirt and oil on the roads, which is unavoidable. Other sources would be from dirty hands touching the brake rotor, and in rare cases, a leaking hydraulic brake.

Front Ice Tech rotor SM-RT81 which was installed 1.5 years ago.

The black marks on the braking surface are tell tale signs of oil on the rotors or brake pads.

Same rotor used on the rear Alfine 11 internal hub

The rear rotor also has black marks on the rotor braking surface

The standard procedure for cleaning the brake pads and rotors are:

Brake Pads:
1) Remove brake pads from brake caliper.
2) Wipe clean brake pads with isopropyl alcohol.
3) Sand off top layer of brake pads, to remove glazed or contaminated layer.
4) Clean with isopropyl alcohol again.

Brake Rotor:
1) Remove brake rotor from hub.
2) Wipe clean brake rotor with isopropyl alcohol.
3) Sand off surface of brake rotor. This removes the scratched surface of the rotor and "resets" the microscopic surface of the rotor.
4) Clean with isopropyl alcohol again.

This usually works to eliminate the squealing noise of the brakes as both the brake pad and brake rotor surfaces have been restored. At the same time, this also means that there is a need to break in the brake surfaces again, in order to get proper braking force.

However, I decided to change the brake pads to new Ice-Tech disc brake pads, as I wanted to see how the finned brake pads will look. I had gotten these brake pads long ago, but did not change them earlier as the original brake pads from the brake calipers were still working fine.

Now that the original brake pads are getting old, and are contaminated with oil, it is the perfect chance to change to these Ice-Tech brake pads.

Shimano Ice-Tech Disc Brake Pads, with finned surfaces to help keep the brake temperature low.

Compatible with the models as listed above. Each set is for 1 brake caliper, so you need 2 sets for a bike.

These are resin pads, and come with the parts as shown.

Weigh 22 grams for the pair of brake pads

The aluminium fins of the brake pad backing are exposed to air, acting like a heat sink to quickly transfer heat away from the brake pads.

Brand new look before installation.

Original look of the brake caliper with standard brake pads... look with the Ice-Tech brake pads! Looks more aggressive with the finned brake pads.

From further away, these finned brake pads are not that obvious though.

Same for the rear, the picture before the change...

...after the change! Not much difference la...

Nice look when in close up

When viewed from far, the finned brake pads are not really visible

In this case, there is no need for finned brake pads on this Avanti Inc 3 commuting bike as the bike is not going downhill, and there is no chance of the brake temperatures reaching a level that requires finned brake pads. For me, it is more of changing the look of the brake calipers.

The conclusion is that the brake calipers and brake pads are not really visible and it does not really change the look of the bike. The only advantage that I have from this change is getting to use new brake pads, which stop well and are not squealing.

Sunday, October 9, 2016

Shimano Ultegra 6800 vs Shimano 105 5800: Crankset

The two most popular road groupsets are Shimano Ultegra and Shimano 105, and this is largely due to the value and performance that these two groupsets have.

Ultegra is the second tier road component, just below the top end Dura-Ace. It has 90% of the function and performance of Dura-Ace, and yet cost half the price. It is a great buy for those who value performance and are willing to spend a bit more than average.

As for Shimano 105, it is the third tier road groupset, just below Ultegra and above Tiagra. This is probably the most popular and common groupset for road bikes in most countries. With performance that is probably 70-80% of Dura-Ace, and at one-third the price of Dura-Ace, it is great value. It weighs a bit more than Ultegra, mainly due to higher usage of steel as compared to aluminium for Ultegra. It is perfect for those who want to experience high end technology but are on a tighter budget.

This time, I will compare the crankset of Ultegra 6800 and Shimano 105 5800, both of which are 2x11 speed road cranksets. Let's take a look at their physical differences and similarities before comparing the technical differences.

In order to make a more thorough comparison, I removed the chainrings from the crank arms and compared them separately.

Ultegra has a dark grey finishing, while 105 has a black finishing. Both will match well with most bikes. From far, these look similar, except for the size and shape of the logo.

The back of the crankarms also look similar, with not many obvious differences.

The Ultegra crankarm (top) has a chamfered edge, while the 105 crankarm (bottom) has a more rounded edge.

The 4 arm area of the crankarms have more differences. The 4 arm area of the Ultegra crankarm on the left is bonded together front to back, while the 105 crankarm on the right side is one piece with a hollow area.

Another view showing the difference. The Ultegra crankarm has a joint line, while the 105 crankarm on the right does not. By making the crankarm in one piece, it eliminates the bonding process and lowers the production cost of the 105 crankset.

For more information on the Ultegra 6800 crankset, check out these other two comparisons.
Ultegra 6800 vs Ultegra 6700: Crankset
Dura-Ace 9000 vs Ultegra 6800: Crankset

Ultegra 6800 right crankarm weighs 331 grams...

...105 right crankarm weighs 340 grams. A 9 gram difference, not that much.

As for the left side crankarm, one interesting difference I noted is the direction of the logo printing. The Ultegra logo looks upright when the crankarm faces forward, while the 105 logo looks upright when the crankarm faces to the rear.

The 105 crankarm on the right side looks a bit slimmer at the middle portion.

Ultegra left crank arm plus crank arm fixing bolt weighs 201 grams...

...105 left crank arm plus crank arm fixing bolt weighs almost the same at 205 grams.

Inner 36T chainring of the Ultegra crankset weighs 34 grams...

...inner 36T chainring of the 105 crankset weighs 37 grams. Almost the same.

Ultegra chainring on the left has an aluminium shell bonded to the outside of the teeth, while the 105 chainring teeth is one piece with the outer shell.

105 chainring on top is basically made up of an aluminium shell, which ends in the gear teeth at the edges. Ultegra chainring teeth and the shell are made separately and bonded together.

Big differences when viewed from the back. Ultegra chainring has the original Hollowglide chainring construction, which is made up of a ring of gear teeth, bonded on both sides by the outer shell and inner shell, which makes it hollow and yet lightweight and rigid.
Shimano 105 chainring is a lower cost version, with an outer aluminium shell + teeth on the outside, and a composite structure on the inside for strength and rigidity. 

Closer look at the differences in chainring construction. 105 chainring on the right side with composite material and lots of ribs. Gives the rigidity of a Hollowglide construction but at lower cost.

A closer look at the injection molded ribbed design at the back of the 105 large chainring.

Weight of Ultegra 52T outer chainring is 121 grams...

52T 105 5800 Outer Chainring weighs 164 grams, a substantial increase over the Ultegra.

Ultegra uses the lightweight aluminium chainring bolts which weigh only 5 grams in total

105 has the more standard steel chainring bolts which weigh a bit more at 12 grams.

Ultegra FC-6800 52/36T: 692 grams
105 FC-5800 52/36T: 758 grams

Main differences:
1) Weight (105 is 66 grams more than Ultegra, for 52/36T spec)
2) Cost (105 is about 1/3 cheaper than Ultegra)
3) Hollowglide outer chainring construction
4) Chainring bolt material (steel vs aluminium)
5) Construction of right side crank arm (4 arm area)
6) Surface finishing

In my opinion, the differences between these crankarms are mainly cosmetic, with lower cost construction methods used for the lower priced 105 crankset. Every component of the Ultegra crankset weighs just a bit lighter than the 105 crankset, which all adds up to give the total weight difference. Otherwise, the performance should be similar, which makes the 105 crankset great value as it is affordable and yet works well.

Sunday, September 25, 2016

Shimano Dura-Ace 9000 vs Ultegra 6800: Road Shifters

During the latest upgrade of the Wheelsport Fantasy mini velo, I had the chance to take a closer look at the Dura-Ace road shifter ST-9000. This was also a good chance to compare it with the Ultegra ST-6800 road shifter.

As I have already done many times, I like to do a feature-by-feature comparison of various components of different grades. This makes it easy for us to make an informed comparison to decide which grade of component to use.

Today, I will compare the Dura-Ace ST-9000 road shifter with the Ultegra ST-6800 road shifter. They are both 2x11 speed road shifters that are cross compatible. So, how are they similar and different?

As a Dura-Ace shifter, the utmost importance is to ensure the smoothest and lightest shifting performance possible, while also keeping weight down to the minimum. The next grade down, Ultegra would aim to replicate most of the performance of the Dura-Ace shifters, while ensuring that the weight is kept low and at a more affordable price.

Dura-Ace ST-9000 on the left, Ultegra ST-6800 on the right. Note the black axle on the Dura-Ace brake lever for the slightly more integrated look.

The rubber hood on the Dura-Ace shifter has a two-tone colour that supposedly has a softer compound at the grey area, but I cannot really feel a difference. The grip size and feeling is the same across the two shifters.

To save weight, the Dura-Ace shifter on the right side has a titanium clamp band, as opposed to the plated steel clamp band used on the Ultegra and below grades of road shifters.

The carbon brake lever on the Ultegra shifter on top is chunkier on the inside and has a rather thick steel insert within the carbon fiber lever for strength, while the Dura-Ace brake lever at the bottom is slimmer on the inside, and has a very thin piece of reinforcement. Most of the Dura-Ace brake lever is carbon fibre, which is where most of the weight difference comes from.

The clear coat finishing on the brake levers look very different up close. The Dura-Ace finishing is super smooth and glossy, while the Ultegra finishing is not as smooth. Not obvious from this picture, but visible when viewing the actual part.

Dura-Ace right side shifter weighs 186 grams...

...while the Ultegra right side shifter weighs 212 grams, just 26 grams more.

These are the 5 main physical and visual differences for the road shifters:
1) Hood colour and material
2) Titanium vs steel clamp band
3) Brake Lever reinforcement
4) Quality of clear coat finishing
5) Weight

As for performance, the Dura-Ace shifters have a very refined, smooth and light clicking feeling, as it uses sealed bearings for some of the shifting mechanism inside. The Ultegra shifters work very well too, although it just lacks that extra bit of smoothness as compared to Dura-Ace. That is totally excusable, given that the Ultegra shifters cost half of the Dura-Ace shifters, and yet works 90% as well.

If you like to have the best, the Dura-Ace shifters are the best that you can buy. However, Ultegra and 105 shifters are much more commonly seen on bikes, as they are much more affordable and work almost as well.