Thursday, February 24, 2011

Journey of the Boardwalk: Part 4 (Kojak & 9 Speed Cassette)

Previously, I documented the change of the crankset to the Shimano 105 crankset, and how it greatly improved the stiffness of the cranks. Today I will write about upgrading from 8 speeds to 9 speeds, and things to look out for when upgrading to 9 speeds.

In order to upgrade components, I bought some stuff from Chainreactioncycles, and it was the first time I ordered from them. Delivery speed was not too bad, took only about 1 week plus to arrive. Ordered a pair of Kojak tires and also a SRAM 8 speed cassette, 12-23. Also added some bike tools to the order.

In the meantime I also changed the chain to a SRAM 9 speed chain with a Powerlink (PC-971). This was because the original chain actually rusted when I didn't ride for 2 weeks. Probably because it wasn't lubed properly, but I wanted to change to a shinier-looking chain anyway haha.

Wanted to get lighter and faster tires, which is why I got the Kojaks. Duranos should be even faster, but they are too narrow for my liking and require very high pressures (around 115 PSI) for optimum performance.

Bike with practically no accessories. Has a very clean look.
First ride with the Kojaks!

First thing I noticed was that the Kojak tires look really good on the bike, it fits the rims and frame very well. Tested the tires by going on a ride at West Coast park. First impressions: Comfortable enough for me, although it was slightly more bumpy compared to the Marathon Racers. Not a major issue there. The noise level is much lower compared to the Marathon Racers (MR), especially on the tarmac road. The MRs used to give a humming sound at higher speeds, but the Kojaks remain silent all the way. Very shiok.

Another thing that I found helpful was that the Kojaks, due to its slick surface, tend to collect much less dirt on the tires. On the other hand, the MRs will bring in dirt and grass and other things in the surface treads of the tires, dirtying the floor at home.

I also bought the 12-23 8 speed SRAM PG-850 cassette in order to mix and match the sprockets with the 11-28 one that I already had. At this point I had not yet decided to change to 9 speeds. I realised that I hardly ever used the 11T sprocket on the cassette, so decided to get a cassette with the 12T small sprocket, to improve and reduce the jump between gears.
Took out the 21T sprocket from the 12-23 cassette, and added the 28T sprocket from the other cassette. Final sprocket sizes: 12-13-14-15-17-19-23-28. The gear change is pretty smooth, even from 19 to 23, and from 23 to 28, even though the jump is quite big.

However, with the benefit of hindsight and more testing, it seems that the gearing is not fine enough for me. I can still feel a significant difference in gear ratio even with this finer gearing. This is due to the "missing" sprocket with 16T. Because of that there is a missing "sweet spot" between gears 4 to 5.

Because of this missing sweet spot, I decided to take the plunge and upgrade the whole drivetrain to 9 speeds. Read up a bit and realised that the difference between 8 and 9 speed cassettes is only the width of the spacers. The sprocket thickness is actually the same, as is the width of the whole cassette. Therefore we can actually mix and match 8 and 9 speed sprockets, with best results if the cassettes are from the same company.

In order to create the sweet spot, with an even finer gear ratio, while maintaining the gear range, the only way is to add more sprockets/speed, and this can be achieved by going to 9 speeds. For 9 speeds, we need 9 speed compatible wheels, cassette, chain, rear derailleur and shifter. I already have the wheels and chain. As for the rear derailleur, although it is said that the Neos derailleur can only support up to 8 speeds, I believed that it can probably do 9 speeds also, since the derailleur does not care if it is 8 or 9 speeds, it is the shifter that does the indexing of the gears. Therefore what I needed was the cassette and the shifter.

Decided to get the SRAM PG-970 12-23 9 speed cassette as it fulfills my requirements for a close gear spacing. It was also on sale, got it at S$50 as compared to S$100 now! Also ordered the 9 speed version of the SRAM Attack shifter because I have been pleased with the performance of the SRAM Attack 8 speed shifter. Not that I have much of a choice, since it is quite difficult to find 8 speed shifters by Shimano in Singapore.

9 speed SRAM Attack shifter!

Merged the 9 speed 12-23 and the 8 speed 11-28 cassettes. Re-assembled the 12-23 8 speed cassette and sold it easily. As for combining the 2 cassettes, it was actually quite simple. I took out the 21T sprocket from the 9 speed cassette and added the 28T sprocket from the 8 speed cassette.

End result: 12-13-14-15-16-17-19-23-28

Sweet orange spacers!
Shiny new cassette!

Multiple gears for the higher end, with small jumps in the number of teeth from 4th to 9th gear. Always a sweet spot! As for the larger jumps between gears 1~3, it is not an issue since they are seldom used, and for low gears the big jumps don't affect cadence so much anyway. With the new customised cassette, I can now cruise comfortably while maintaining my cadence.

On hindsight, I should have just changed to 9 speeds in the first place, instead of dabbling in 8 speeds. This would have saved effort, time and money. But without all these tinkering, I would not have learnt so much about the drivetrain. I learnt how to install and remove cassettes, take apart and customise cassettes, install shifters and derailleurs and many other details.

In the next issue of the Boardwalk Journey, I will document the changing of the derailleur to the Shimano Ultegra SS derailleur and the adding of some gold bling to the bike.


  1. Can the Schwalbe Kojak be used for light off-road like the dirt route at Punggol PCN which is just about 2.4km?

    1. yes! no problem, I just tried that dirt route during the world water day ride. in fact Durano also can.

  2. so,it won't really puncture easily on dirt,gravel surfaces la?i am considering between the kojak and big apple thats why.

    1. don't worry, Schwalbe tires have a layer of Kevlar belt to protect from punctures. I am lucky to have gone over 3000 km on these Kojaks without puncture. usually it is metal pieces that cause puncture, don't worry about stones.

  3. cool.thanks lots bro!im digging your boardwalk alot too!

  4. hey. we are taking a bit of inspiration from your blog to buy a more basic dahon than we originally planned, and then upgrade it ourselves. one question we had is do you think it is possible/an ok idea to add a front derailleur to models that didn't have it originally?

    daan and jane.

  5. hi. nevermind, we just found part 16. thanks for all the info.
    daan and jane.

  6. Hi, how does Kojak perform on a wet day?

    1. No problem for me. Even though it is slick, there is good grip on the road.

      Any tire (included treaded and MTB knobbly tires) will be slippery on wet metal, tiles or painted lines. As long as you avoid those, any tire will be fine on the road.


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