Saturday, May 19, 2012

The Truth and Myths of Market Bikes

First, let me define what market bike is. Market bike is defined as bike that is used as a mode of transportation for buying groceries in the market. Hence, it is called "Market bike". Market bikes are usually sold in supermart, lowly priced and use the lowest quality components you can imaging. Why would I bother to spend time writing something about market bike? Well, it is out of social responsibility... (What? you must be kidding!). Well, let me explain...

My colleague, who is decades younger than me was positively influenced to pick up mountain biking. He came from a culture where riding is the mode of transportation. He rode daily to school, even going to shops and social events. The village where he came from were mountainous, and gravels trails were considered road. He had no idea what gear shifter was, as they only rode elephant steel bike with fixed gear. Consider that kind of training he had gone through over the decades, and the number of riding hours he had clocked, trail riding in Singapore should be a breeze for him.

For what he had gone through, I would not blame him when he bought a market bike from supermart despite being briefed on the physics and science of mountain bike. Well, I guess in science we need factual evident to prove a hypothesis. Unwillingly (as I know what will happen), I agreed to test ride the market bike at Gangsa and T15.

The virgin ride on Singapore easiest bike trail substantiated my hypothesis that market bike is structurally unsafe to be ridden off-road. The first sign of failure showed up when the front wheel jammed while climbing an easy slope. The front skewer needed to be loosen in order to free up the wheel. The dilemma was to chose between the two evils, a jammed front wheel or a loosely secured front wheel. The choice was obvious as we need to ride out of the forest. Half way through the ride, the v-brake failed to work properly after riding through a patch of muddy water. The unreliability of the brake (2nd failure) further substantiated my hypothesis.

The second test ride was performed at the Bukit Timah bike trail. The ride was totally disastrous, and it proved my hypothesis without a doubt that market bike is structurally unsafe to be ridden off-road. The third failure showed up when the front tire punctured (See right photo, I was replacing the tube). Come on! they were brand new tire & tube, and we not even covered 2 kilometers of smooth off road! Well, we changed the tube at the car park just before the rock garden. Refusing to give up, my friend continued with the ride up hill. He paid a heavy price for his stubbornness (but I respect his persistency spirit); he crashed 3 times along the way due to failure of fork, brake, drive train and possible wheel jammed. He finally conceded defeat, and agreed that market bikes from supermarts are structurally unsafe for off-road ride. We did not complete the trail, which I usually take 40 minutes to finish one loop. We pushed the market bike all the way back, and he needed medical attention for bruises all over his body and possible breaking his three left fingers.  

The test ride substantiated my hypothesis that market bike is structurally unsafe to be ridden off-road:
1. Failure of hub that cause front wheel to jam
2. Failure of brake
3. Failure of tire and tube
4. Failure of fork
5. Failure of drive train
5. Failure of geometry (non-scientific, based on observation analysis)

We have proven the myths of market bike to be true...mmm...I should rephrase it: "The results of the experiment has positively substantiated the hypothesis that market bike is structurally unsafe to be ridden off-road".

I feel obligated to inform the public about the consequences of buying a bike from supermart for off-road ride. My colleague was convinced by the sales people in the supermart that the "top of the range" bike he bought was fit to be ridden off-road. The sales people offered him a bike that happened to be the last piece on the shelf, which does not fit his size at all. I seriously doubt the salespeople knowledge about bike was any better than man on the street. After the test ride at Bukit Timah bike trail, my friend finally convinced that market bike is best leave it as market ride. I feel responsible for my friend's injury, as I was unable to convince him against using market bike for off-road ride. I wish him a speedy recovery...  

Saturday, May 12, 2012

Tuning Cane Creek CCDB Coil on Nomad Carbon

To tune your CCDB coil, the very first step you need to do is to chose the correct spring rate for the spring you purchase. Use the Cane Creek Spring Calculator to chose the correct spring rate. Based on 30% sag and 159 lbs weight on full gear, the recommended spring rate is 350 lbs for all-mountain ride and 300 lbs for XC ride.

Adjust Preload at 30% Sag
According to the CCDB manual, the Spring Adjustment Nut cannot be turned more than 6 rounds or less than 1 round. If 30% sag cannot be achieved within the the recommended range, change the spring to correct spring rate. The measurement for sag% = (free stroke length - weighted length) / shock stroke.
The shock specification for Nomad carbon is 8.5' to 2.5', meaning free stroke length (eye-to-eye) is 8.5 inch and the shock stroke length is 2.5 inch. To run 30% sag on Nomad carbon, the computation should read (8.5 - 7.75) / 2.5 x 100 = 30%, where 7.75 inch (weighted length) is the eye-to-eye measurement when the rider is on the bike at attack position (with full gear). The first photo shows how the free stroke length should be measured and it should read close to 8.5 inch, as the frame itself exerts some force on the shock when the bike is left seating on the ground.

Refer to the second photo, get on the bike with full gear in attack position, and ask someone to measure the eye to eye measurement (weighted length). For 30% sag, the eye to eye length should be 7.75 inch, otherwise adjust the spring preload (by turning the Spring Adjustment Nut) to achieve the reading.

Tuning CCDB Coil
Once the correct pre-load has been set correctly, tuning of CCDB coil can be done on your favorite local trail. As my favorite trails were temporary closed, I went to Bukit Timah bike trail to tune my new CCDB coil. The trail comprises of few technical climbs, short but steep descents, numerous bump and small logs obstacle, handful of tight switchback and few wet corners. Although the test ride was pretty short, the technicality of the trail was good enough for tuning traction and chassis stabilization. I am extremely impressed by the sensitivity of the 4-way adjustment features of the CCDB coil. The ability to precisely tune it to the sweet spot of your riding style is beyond my expectation.

Followings are the 4 adjustment features of the CCDB coil:
(1) Low Speed Compression (LSC)
  • Control traction and chasis stabilization
  • Eliminate pedal induced "bob"
  • Affect small bump sensitivity
(2) Low Speed Rebound (LSR)
  • Control traction and chasis stabilization
  • Maximize traction for technical climb, high-speed chatter, off-chamber corners, braking in shutter bumps
(3) High Speed Compression (HSC)
  • Absorb high impact forces
  • For square edge hit and harsh landing
(4) High Speed Rebound (HSR)
  • Enable bike to recover quickly from deep in suspension travel while enabling controlled take offs from jump faces
  • Eliminate bucking & packing up
The CCDB coils are shipped according to the following factory settings: LSC (12/25 clicks), LSR (12/25 clicks), HSC (2/4 turns), HSR (2/4 turns). The setting serves as a good starting point for riders to tune according to their riding style. IMPORTANT: The CCDB coil is designed in such a way that when you turn HSC, the LSC will turn with HSC. DO NOT hold the LSC adjuster when turning HSC.

When I did a bump hop over a root section, I realized a slight bucking upon landing. I increased (clockwise) the HSR by half a turn and returned to do the same bump hop again. The bucking effect was eliminated. The traction and cornering were spot on after I increased (clockwise) the LSC and LSR by half a turn (3 clicks: to slow the movement of the suspension). I did not encounter any harsh impact on square edge as the test ride was awesomely smooth. I might have unconsciously pedal push over those square edge obstacles. As drop does not exist in BT bike trail, opportunity to test bottoming out was challenging. So far, the CCDB coil handled awesomely well on those minor jumps over roots and rocks. I was impressed how those little adjustments affect the ride so drastically. Well, I guest the money was well invested.

For now, the CCDB coil was tuned for BT bike trail. The setting are LSC (15/25 clicks), LSR (15/25 clicks), HSC (2/4 turns), HSR (2.5/4 turns). Next on the task list would be Ketam bike park, Woodcutter and Butterfly. The objective is to continuously fine tune the CCDB coil to identify the 'sweet spot' for my riding style. This is what I describe, "In pursuing for SWEET SPOT!"



Thursday, May 10, 2012

CCDB Coil on Nomad Carbon


Should I concede or should I celebrate? Almost loss hope of owning the CCDB coil...justify myself to get an alternative after totally disappointed with the LBS. Fortunately or unfortunately, I came across AEBike.com while googling for shock, which happened to sell CCDB coil at a good price. After factor in the exchange rate, shipping charge and GST, the nett price from AEBike.com is still approximately 6% cheaper than LBS. Besides, AEBike.com took 2 weeks (International shipping) to deliver while LBS takes at least 6 weeks to deliver. To make thing worse, the LBS was unable to commit stock arrival. The LBS not even bother to contact me if stock arrive, the shop owner asked me to lookout for their Facebook for stock arrival. This is the kind of service we get from LBS. I will be a fool not to buy from online bike shop. After all, what do I have to lose since there is no service to talk about. Long live free market! the most efficient way to trade... 

Not all LBS are bad, one good example is DSP rep in Singapore who deliver DSP Krono ti-spring to my house. His service is exceptional: fast delivery...personal delivery... free installation ...and ensured you test ride and happy with the product! 

It is difficult to understand why would someone spend 40% of the price of a CCDB on a titanium spring? To be honest, what is the point of getting the best carbon frame without getting the best shock? Then again, what is the point of getting the best shock without getting the best spring? The logic seems to be endless but it is very true (ok, I am trying to justify my decision). To me, weight saver is the least priority to get ti-spring. The most important reason is better responsiveness and consistency. The next important reason is the awesomely sexy look, which is an art piece in its own right. Weight saving comes last, after all I would not have replaced by air shock if weight is top of my concern.

With the Nomad carbon and CCDB coil combo, no longer I have the excuse not to be the fastest on local trails. Couldn't wait to ride my new setup! Tuning of CCDB will be done on trail, will write a more detail analysis after the ride...