Avanti Inc 3: Continental Grand Prix 4 Season Tires

After changing the rear wheel on the Avanti Inc 3, I realised that I have upgraded both the front and rear wheel on that bike. As such, both the front and rear rims have a higher profile compared to the stock wheelset. The Schwalbe Marathon Supreme tires that I have had for a few years does not seem to match so well to the high profile rims, as the tires has a reflective strip all around.

Also, after changing to drop bars and road crankset, the bike is now a more sporty bike that wants to go faster. As such, I decided to change the tires on the bike to something narrower and hopefully faster.

Having heard of many positive reviews about Continental tires, I decided to try it out instead of sticking to my usual Schwalbe brand. As an all weather commuting bike, I have to ensure that the tires have sufficient grip in wet weather, while also having some level of puncture protection. Therefore, the more race oriented Continental GP4000 is not so suitable even though it is fast.

While browsing through the wide range of tires that Continental has, I came across this Grand Prix 4 Season Tires that seem to provide what I need. Let's take a look!

Continental Grand Prix 4 Season Tires, folding version

28mm wide, for a good balance between comfort, grip and speed. The previous Schwalbe Marathon Supreme is 32mm wide.

The tire circumference is helpfully provided for programming the cycle computer. Max pressure is 115 PSI, which is high for a commuting tire.

Robust race tire due to the layers of puncture protection available.

There is a tread wear indicator on the tire, but I can't find it.

New tires!

Slick in the middle for low rolling resistance, grippy design at the sides for cornering grip

Made in Germany! I didn't realise it came with brown sidewalls though...

284 grams for 1 tire, which is about 90 grams lighter than the previous Schwalbe Marathon Supreme

After changing the tire on the rear wheel, I compared it to the front wheel to see the difference in width. However, there seems to be very little difference in width...

Rear wheel with new 28C Continental tire, front wheel with 32C Schwalbe tire.

Visually, there is almost no difference in width...

Front wheel with Schwalbe Marathon Supreme tires is 30.66mm in width

Rear wheel with Continental Grand Prix 4 Season tires is 30.04mm in width

Front wheel with Continental Grand Prix 4 Season tires is 29.02mm in width

Comparing the front wheels, the Continental tires are about 1.6mm narrower in width as compared to the Schwalbe tires. This is much smaller than the 4mm that the sizes (28C vs 32C) indicates. Seems that the Schwalbe tires were narrower than specified, while the Continental tires are wider than specified, causing this condition.

I was rather disappointed as this meant that this tire change only yielded a small difference in width, when I was expecting more. If I had knew this was the case, I would have gone for the 25C Continental tires (which might turn out to be 26mm in width).

Fresh logo on the Continental tires, as installed on the rear wheel

From far, the brown tire sidewalls are not so visible. Without the reflective strips on the tires, the rim profile looks deeper.

This upgrade turned out to be rather inconsequential as the tire width was not changed much. At least it looks quite good on the bike. After testing it out for a few months, I find that the ride quality is good and feels faster than the Schwalbe tires. However, it may be due to the change in riding posture (from flat handlebar to drop bar) that yielded the increase in speed.

Avanti Inc 3: Installation of 60mm FSA Stem

After completing the modification of the Avanti Inc 3 to have a narrower Q factor, it seemed that the geometry had been dialed in already. However, even after using a road crankset with road drop bars, something still did not feel right.

I found that while riding, the reach on the Avanti Inc 3 seemed longer than the Merida Scultura 5000 road bike. When holding the shifters, I felt that I had to reach further than what I am comfortable with. This is not my intention as the road bike should have the most aggressive posture out of all my bikes, since it is the fastest bike that I have.

During the previous modification to change to Alfine 11 Di2 with a drop bar setup, I used a shorter 80mm stem to compensate for the longer top tube of the Avanti Inc 3 frame. To double check my previous measurements, I measured from the saddle (area where the sit bones contact the saddle) to the centre of the handlebar.

Distance on Merida road bike is about 665mm.

Distance on Avanti Inc 3 is about 668mm.

The distance from saddle to handlebar is almost the same. Both the bikes are using a compact drop bar from FSA, which means a 80mm reach on the drop bar itself. Therefore, the different reach is not from these areas. Finally, I realised that the bracket on the shifters might be different in length.

Ultegra Di2 6770 road shifters, gripping distance is about 100mm from centre of handlebar.

ST-RS785 shifters, with a gripping distance of about 120mm from centre of handlebar.

Finally, I realised that the bracket length on the shifters are different in length, which means a different reach distance. On the Avanti Inc 3, the road hydraulic disc brake shifters ST-RS785 has a bracket that is about 20mm longer, which is probably to fit in all the hydraulic components.

This extra 20mm of reach is the difference that I feel when riding the bikes. As I ride all my bikes often, I am able to feel any subtle geometry differences.

It is easy to fix this, as I can just change to a shorter stem. There is no worry of a shorter stem making the steering less stable, as the longer shifter bracket makes up for it. As long as the overall distance from the steerer tube to the gripping area on the shifters are the same, it should feel the same.

Simple FSA stem with a 60mm reach

+/- 6 degrees of tilt, depending on which way you fix the stem

Weighs 115 grams for this 60mm length. If it was a more expensive stem, it will weigh less, probably 100 grams.

Comparing the difference in stem length. 60mm in front, 80mm behind. See how much difference it makes to the handlebar position.

New FSA 60mm stem installed! Short stem indeed.

Now the handlebar reach and height is the same as on the Merida road bike!

With this modification, both bikes will ride more similarly as the geometry is now almost the same.

The Avanti Inc 3 can now be classified as an all-weather commuting road bike

Some rearrangement of the accessories is required, due to the shorter stem. Looks rather cluttered, think it needs more work.

View of the full bike. Handlebar area looks a bit cramped due to the short 60mm stem, but it rides really nicely.

With this change of stem length, the geometry has been nicely adjusted and feels perfect. After testing the bike on a half round island ride, passing through Mandai road, I was pleased to find that the gear range is perfect. The highest gear was just sufficient for continued pedaling even when rolling down the Mandai slopes at close to 50km/h. The lowest gear has not been used yet, but it will definitely come in useful if I need to go up steeper slopes such as in NTU or Mount Faber.

Avanti Inc 3: Installing Eccentric BB + Dura-Ace Crankset

Time to assemble the new components onto the Avanti Inc 3 bike! The new components are the Bushnell eccentric BB, the Dura-Ace 7900 crankset, the 46T Gates front sprocket and 118T Gates belt.

After I had changed to Alfine 11 Di2, the chain line has been moved inwards. Now, since the crankset will be changed, I will need to ensure that the chain line is maintained more or less the same. To make the job easier, I checked the clearance between the right side chain stay and the 42T Gates front sprocket, while still using the Deore crankset. The final clearance should be around this value after changing to road crankset and 46T front sprocket.

2.5mm clearance between 42T front sprocket and right side chain stay

As shown in a previous post, the stock eccentric BB was removed, and replaced by the new Bushnell eccentric BB. A shim was used to reduce the internal diameter of the frame BB shell from 55mm to 54mm, in order to be able to use the Bushnell eccentric BB.

Bushnell eccentric BB installed, with the shim visible around it

A road BB should be used since the width is 68mm and a road crankset is used. Shown here is the SM-BBR60 bottom bracket.

New road BB installed in the eccentric BB

New crankset, front sprocket and belt installed!

Good clearance between the right side chain stay and the 46T front sprocket

This clearance is measured to be about 3.5mm. Chain line is straight.

Black coloured Bushnell eccentric BB blends in well with the black frame

Shiny Dura-Ace 7900 crank arm, with 46T Gates front sprocket and 118T Gates belt

Final picture of the Gates drivetrain

The crankset after some wet weather usage

The modification has been completed, and the Q factor has been reduced from 182mm to 146mm. This means a Q factor reduction of 36mm which makes a big difference in pedaling feeling and comfort.

At the same time, the gear ratio has been adjusted due to the changes in sprocket sizes. With the 46T front sprocket and a 28T rear sprocket, the gear ratios of the latest Alfine 11 setup can be seen below. On the Alfine 11, the lowest gear, Gear 1 has a big 29.2% difference from Gear 2, which some people like while some people don't. I personally don't mind having this big step, as it gives an extra low gear for climbing.

Range of Alfine 11 gear ratios with 46T front and 28T rear

With that, the objective to reduce the Q factor has been achieved. At the same time, the adjusted gear ratios means that most gears will be used most of the time, with a top and bottom gear reserved for slope riding.

Avanti Inc 3: Dura-Ace 7900 Crankset + Gates Belt and Sprocket

In the previous post, the Bushnell Eccentric BB was used to replace the stock eccentric BB on the Avanti Inc 3. This changed the BB width from 73mm to 68mm, allowing the use of a road crankset.

The road crankset that I can use should have a 5 arm design, and 130mm BCD. I would have preferred to use the new 4 arm road crankset, but Gates does not make their belt drive sprockets in that specification. Therefore, I have to select the crankset to match the available belt drive sprocket from Gates.

The smallest 5 arm, 130mm BCD front sprocket from Gates is 46T. This is smaller than the stock 50T, but still larger than the 42T that I was previously using. Together with the 28T Alfine Di2 rear sprocket, the gear ratio will be changed again.

46T, 5 arm, 130mm BCD Gates front sprocket.

Weighs 81 grams

The road 5 arm cranksets that I can choose from are the Ultegra 6700 (on Dahon MuEX), and Dura-Ace 7900 (removed from Merida Scultura 5000). In order to maintain a full Ultegra 6700/6770 groupset on the Dahon MuEX, I decided to use the Dura-Ace 7900 crankset on the Avanti Inc 3. Only the crankarms will be used, while the chain rings will be removed.

Since the Alfine 11 Di2 hub has a blue accent line running around the hub shell, I was thinking if I should use some blue chain ring bolts to match that.

Blue accent line on the Alfine 11 Di2 hub

Blue chain ring bolts. However, too many colours on the crank arm (blue, black, dark grey, silver) makes it difficult to showcase the beauty of the Dura-Ace crankset. 

Using black chain ring bolts makes the crankset look less busy, giving a more stealthy look

Gates 46T front sprocket mounted on Dura-Ace 7900 crankarm

Front sprocket needs to be mounted behind the tab to maintain straight chain line with rear sprocket

409 grams for right side crankarm plus 46T Gates front sprocket

A comparison picture of the front single sprockets. Crankarm on the left will be installed on the Avanti Inc 3, while the Dura-Ace 9000 crankarm + Wolf Tooth chain ring on the right has already been installed on the Wheelsport Fantasy mini velo.

Next, due to the change in sprocket size, a new longer Gates belt is required. I have no choice but to order a new belt.

Gates carbon drive belts come in a large box to prevent mishandling (twisting, bending) of the belts

118T, which is the next step up in size from the previous 115T belt.

118T Gates belt weighs 90 grams

With all the components gathered, the next step is to install all of them on the Avanti Inc 3. This modification will allow the use of a road crankset, which will have a narrower Q factor for more comfortable pedaling. This is quite a lot of work and modification required just to change the Q factor! To be continued...