Friday, April 23, 2010

Report on the Dambala

Well I've been a little remiss. I have had a new working, fully built bike for a couple of months now with no report on what it's like. Though in my defence I've been busy trying to renovate a house, which doesn't actually work as an excuse for my lack of posting as I really should be putting up at least a little information about that.

Anyway enough of my waffling on, time to show off the bike.

First off I want to say that I bought this bike piece by piece and assembled it myself. I bought most of the bits from eBay at I have to say excellent prices. One piece, the Handlebars was given to me as a birthday present, so I have to say a big thanks to Dad.


While the price was good and I had time to research each piece before I bought it, it did take an excruciating 6 months of purchases to finally have enough pieces for a working bike. Six months of riding a barely working bike around. I did get impatient several times but there was not much I could do.

What I did get out of it though is a bike that fits perfectly with what I want. I needed a commuter bike to get me around the 'Ville' with speed and with more ease than I've had with my dual suspension bike. Because of my size though I needed a tough bike that could handle the bumps. To that end I had decided on a mountain bike frame but build it up with more road or hybrid type parts.


Most hybrid bikes have large Road bike size wheels but I needed strength as well so I needed to buy a mountain bike wheel. This prompted me to look into an emerging part of the mountain bike market called 29ers.
The basic concept of the larger diameter is simple: there is less of an angle when ever you encounter an obstacle and it's easier to roll over the obstacle. The larger wheel offers increased centrifugal force, which in turn improves the bike’s stability. The extra three inches also increases the amount of tire contacting the ground at any one moment offering better traction.

So I decided to buy a 29er, probably in steel to keep cost down. I needed a slick or semi-slick tyre to keep rolling resistance down so I looked into Schwalbe tires and found the Marathon tires. In the end the Marathon Supreme seemed to suit my purposes best. Next I had to think about a drive train. I had decided to simplify the drive train on my new bike and only have a nine speed bike. I love the clean look of a single speed bike but I'm a slacker and decided I needed at least a few gears. the solution was to only have the rear gears (see the third photo). Lastly but definitely not least I had to figure out the Forks for my bike. I wanted simple and long lasting so I decided not to get a suspension fork. They need maintenance occasionally and are much more prone to failure than solid forks. With that decision made I chose to go with some light weight Carbon forks.

The last important piece was of course the one less car sticker.

I now have a fast fairly light and above all reliable bike that gets me around. Ride Quality is not nearly as forgiving as my dual suspension Specialized, but it is fast and brilliant on the roads where I ride it %90 of the time. I have so far beaten my previous best time to the strand from uni by nearly 10 minutes.

I really have enjoyed building and then riding my new bike. I hope it likes me too as over the next probably 10 years we will be doing a lot of Kilometres together.

2 comments:

Anonymous said...

Great looking bike. It'd pull up a treat with those 8" rotors and slicks too! There's some really nice other parts on it too. The gear shifting would be fantastic on it.

The fork looks great, but I don't think it's the correct axle-to-crown length for the frame. This is dropping the front of the frame down, making head angle steeper (probably 4 degree's or more from when using a fork of the length the frame was designed to take) which will make it a handfull to steer. It'll also throw the riders weight over the front, reducing rear wheel traction (especially under brakes) and adding to twitchiness, and it'll lower the bottom bracket height meaning you'd clip your pedals going around corners more often. The other examples of bikes using that frame I've seen all have either suspension forks or rigid forks with longer a much longer crown to axle measurement.

Looks like a fair bit of thought has gone into the bike though so I may be barking up the wrong tree - may even be intentional to speed up the handling for zipping between cars etc! I just know that my good lady Melanie has got a Voodoo that her mates put together for her from spare parts - they put a cheap suspension fork that's too short for the frame on it and it's a real bugger to handle!


Anthony Connell

Unknown said...

I finally got the picture of the bike up. glad you read it. On to the Bike Questions.

First off now that I have the gears sorted out they change really fast and smooth. I am also loving the 9 speed, really simplifies things.

Brakes: I wouldn't have chosen the 200mm rotors but they where a Cheep package deal with the Code 5 brakes. only $250 for Front and Rear set! On the up side though I can stop really quickly and Its already helped me in traffic a couple of times.

No to the harder question, and the short answer is that Anthony is right but it's not much of a problem. The bike is designed with a 100mm Travel suspension fork in mind with an Axle to Crown length of about 495mm. That would give the Bike a head angle of about 72 degrees. 72 degrees on a 26 inch wheeled bike would already be considered very steep. 29ers though tend to have slower steering due to the larger sized wheels so often have steeper head angles to start with, to compensate for their slower steering characteristics. The forks I bought are 465mm Axle to Crown. Since you steepen your head angle by about .5 degrees for each 10mm I've increased my head angle to about 73-74 degrees. This has probably dropped the bottom bracket height by 5-10 mm which actually increases stability during cornering, but can lead to the pedals clipping the ground when cornering hard.

My old bike was more of an all mountain type bike and had quite slack head angle, so I definitely noticed the faster steering and that the bike was more Twitchy. It took some getting used to but I decided to give it a go rather than judge straight away. Now though I'm reasonably happy with the steering performance of the bike. I think I will add some spacers under the Head-tube of the frame to decrease the head angle but I have not yet read up on that so it can wait for a while. The other thing is that pedals scraping during cornering is not much of an issue on the road it's more of a problem when I get a set of Off-road tires and start hitting the trails with this beast. Off-road I think I will definitely need a slacker head angle and more relaxed steering.

Cheers Lewis