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 349 grams. An 18 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 203 grams. Virtually identical in terms of weight.

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

...inner 34T chainring of the 105 crankset weighs 33 grams. Not a fair comparison since the chainring sizes are different.

Larger Ultegra 52T outer chainring vs 105 50T outer chainring. The 52/36T Ultegra crankset was used on the Wheelsport Fantasy mini velo.

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.

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

...105 50T outer chainring is 140 grams. It is heavier despite the slightly smaller chainring size.

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.

This is the 50/34T Ultegra 6800 crankset which was earlier fitted onto the Merida Scultura 5000. Weighs 677 grams.

Shimano 105 5800 50/34T crankset weight is 731 grams, which is about 54 grams heavier than the Ultegra crankset.

Main differences:
1) Weight (105 is 54 grams more than Ultegra)
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.

Sunday, September 4, 2016

Avanti Inc 3: New Bottom Bracket SM-BB52

As you may already know, the Avanti Inc 3 is the ideal all weather commuting bike, according to my requirements for a commuting bike. Besides being able to handle all weather riding with little or no maintenance, it needs to work and ride well with good durability.

I have had this bike for almost 3 years, and the bottom bracket has also been used for almost 3 years, ever since I upgraded the crankset to the Hollowtech II type. The bottom bracket used is a SM-BB51 Hollowtech II type, which is considered the Deore grade of Hollowtech II bottom bracket in the MTB range.

SM-BB51 Hollowtech II BB on the Avanti Inc 3

During the past few rides, I have noticed a difference in the pedaling feel on this Avanti Inc 3 bike. It felt a bit rough and unstable. Since I ride and customize all my bikes personally, I am quite sensitive to changes to the feel of the bike. For example, if the seat post height has been changed slightly, or if the tire pressure is lower than usual, I will be able to feel and detect these differences.

Finally, after finding some time to take a closer look at the bike and do an inspection, I found that the crankset felt loose. There was quite a bit of play between the crankset and the bottom bracket. My initial suspicion was that the crankarm was loose, but after removing the left crankarm, I found that there was quite a big amount of play between the crankset spindle and the bottom bracket bearings.

This means that the bearings or ball races in the bottom bracket are probably worn out, causing the large amount of play and also rough rotation feeling. The bottom bracket is considered a consumable part (similar to the chain, cassette, brake pads), which means that it is prone to wear and needs to be replaced after running for a certain amount of mileage.

In order to change out the bottom bracket, the crankset needs to be removed. Due to the belt drive system, this bike uses an eccentric BB insert for adjusting the belt tension. As such, it will not be possible to remove the crankset without first removing the belt from the front pulley.

It is possible to remove the front pulley from the crankarm and just remove the crankarm from the bike, but due to the belt tension and also the rusted chainring bolts, I decided that it would be easier to just remove the entire crankarm than dismantle the front pulley from the crankarm.

This brings us to the next step. In order to remove the belt from the front pulley, it will be necessary to remove the rear wheel, so that the belt tension is released for the belt to disengage from the front pulley.

Removing the rear wheel. I took a picture to remember that the green non-turn washer is on the left side, while the blue non-turn washer is on the right side. Your bike may have different coloured washers, depending on the angle of the rear dropout.

With the rear wheel removed, there is no more tension on the belt and the belt can be removed from the front pulley easily.

Since the rear wheel is out, I weighed it (Alfine 11 hub rear wheel + sprocket + disc rotor + inner tube + tire), and it is 3.4kg! A typical road bike rear wheel would weigh about 1.5kg (rear wheel + inner tube + tire + cassette).

As mentioned earlier, the left crankarm is first removed to expose the crankset spindle.

Gritty bottom bracket, as it has never been serviced despite riding the bike in rain often. Also shown here is the eccentric BB insert that is used to adjust the belt tension.

The crankset removed. Black grease shows that it has been in use for quite some time. Also shown is the rusty chainring bolts, which I would rather not touch as it is likely to give me more problems.

Time to remove the old SM-BB51 bottom bracket!

The bottom bracket was very tightly fixed to the frame, and it was too tight to remove with a normal Hollowtech II tool. The solution is to slip on a Dahon seatpost, which is large enough to go over the handle of the original tool. This gives plenty of leverage which makes it easy to unscrew the bottom bracket.

Once the old bottom bracket is removed, I took the chance to clean up the whole bike, since the rear wheel is also already out of the frame. After that, it is time to put in a new bottom bracket and reinstall all the components!

Deore grade SM-BB52 Bottom Bracket, an updated version of the older SM-BB51. From what I heard, they improved the sealing to be equal to the higher grade SM-BB70.

Close up view of SM-BB52 bottom bracket. If the sealing has been improved, it will last longer than the SM-BB51 that was previously on the bike.

It came with a few spacers of assorted thicknesses, which is great if you need to fine tune your chain line. Will be useful on Dahon bikes too from my previous experience with modifying Dahon bikes.

Cleaned up eccentric BB and frame, ready to accept the new SM-BB52 bottom bracket!

SM-BB52 bottom bracket installed easily

Sufficient grease on the metal-to-metal contact surfaces to prevent binding and improve sealing against water.

It is recommended to use a torque wrench to achieve proper tightening torque at critical areas, such as crank arm bolts.

After the new bottom bracket has been installed, all the other components can be fixed back onto the bike.

Although changing out a bottom bracket may take quite a bit of effort and time, it is not a difficult job if you are using a Hollowtech II type of bottom bracket. Also, it is not often that you change a bottom bracket, as a good bottom bracket can last at least a few years.

With the new bottom bracket, the pedaling feel is smooth again! There is no more play in the crankset, and the bike is now running well again after this servicing.

Saturday, August 20, 2016

Avanti Inc 3: DIY Steering Stabilizer

Do you ride a bike that has a heavy front? By heavy front I mean that when the bicycle is parked, the handlebar tends to tilt to the side, and over-rotate. This causes the whole front wheel to flip to the side, and if the front of the bicycle is heavy, the whole bike will fall over, even if it is resting on a kickstand or resting against the wall.

For most road bikes, they can be supported easily against a wall or on the kerb using the pedals, as they are lightweight. Mountain bikes are usually placed with the bar end against the wall, or just laid down on its side on the ground. Other bikes may have kickstands to hold the bike up when parked.

In my case, I have some problem with parking the Avanti Inc 3 when outside. As there is no kickstand, I will rest the bar end of the Ergon GP3 grips against the wall when parked. However, the bike will sometimes roll forward or backwards due to a slight incline of the ground. This causes the handlebar to rotate and the whole bike will fall over.

When there is no wall to lean against, I will rest the bike against my body when stopping for a short while. Even then, the heavy front end will rotate and cause the bike to fall over easily. This is due to the wide handlebar and the many accessories on the handlebar.

To solve this issue, I decided to get a steering stabilizer to prevent over-rotation of the handlebar. It looks like a very simple device, with just a spring to prevent the fork from rotating too much to either side. After failing to get it from Taobao as it was out of stock, I decided to DIY my own steering stabilizer from some common parts.

The basic component of a steering stabilizer is the spring, together with the mounting brackets at each end that mount to the front fork and the downtube of the frame respectively. The spring has to be sufficiently strong to hold the front fork, yet have some play to allow normal steering.

The spring comes from an unused kickstand, which seems to have a suitable length and spring force.

The L-shaped mounting bracket is something that I found from my box of random hardware, and it fits nicely on the back of the front fork.

Basic construction of the DIY steering stabilizer. One end of the spring is held to the front fork by a bracket, while the other end is fixed to the cable holder.

One end of the spring is hooked around the bolt that fixes the cable holder to the frame. Since the force is transmitted through the metal bolt, there is no strength issue here.

The other end of the spring hooks onto the L-shaped bracket, and is fixed to the front fork using the fender mount.

After that, it is a matter of adjusting the spring force to ensure that there is little or no spring resistance during normal steering. On the other hand, the spring force will be activated when the handlebar is rotated beyond a certain angle. This is adjusted by stretching and deforming the spring.

After installing the spring, the handlebar will encounter resistance when rotated beyond 20 degrees to either side. This is more than the steering angle required for normal riding.

As shown here, the spring prevents further movement of the handlebar, which enables the bike to be parked this way without falling over.

When the bike is held by the saddle, the handlebar can only rotate naturally 20 degrees to either side. Does not affect steering at all.

DIY steering stabilizer fixed under the downtube of the bike, and is not obvious at all.

With this steering stabilizer installed, parking this bike is now easy, with little risk of the bike tipping over. Riding and steering of the bike is not affected at all because there is almost no spring resistance at normal steering angles.

If you have the same problem with your bike, this steering stabilizer will solve the issue!