Friday, December 23, 2011

Bukit Timah Reserve Mountain Bike Trail

(Photo Above) The Bukit Timah Nature Reserve is one of the Asean Heritage Parks,  covering 3,043 hectares and bounding four reservoirs: (i) MacRitchie Reservoir, (ii) Lower Peirce Reservoir, (iii) Upper Peirce Reservoir and (iv) Upper Seletar Reservoir. The forest reserve is rich in biodiversity that contains flora, fauna, Seraya, Mock Durian, Forest Praying Mantis and the Singapore Freshwater Crab, and other animals like the pangolin, Horsfield's Flying Squirrel and Colugo. Besides acting as water catchment for the reservoirs, the forest reserve also purify water in the reservoirs. A network of mountain bike trails offer bikers an environment to appreciate nature, practice biking skills and improve cardiovascular wellness. The following photos provide a glimpse of over 25km of mountain bike trails.
(Photo Above) This stretch of trail is one of my favorites, not because it was technically challenging, but one of the few trails that bound the reservoir. Some distance down is a narrow downhill section infested with roots - that leads to the water if you don't turn in time. One more thing, look out for fishing hobbyists!
(Photo Above) The bridge used to be a single narrow log hanging over the stream. Bikers usually carry the bikes and balanced over the plank. I admired those who wear clipless SPD shoe, having to tip-toe with 12kg to 15kg bikes on their arms. Thanks or no thanks, a more discern bridge is built across the water. You can easily cycle over it!
(Photo Above) This is the only section in the trial where you have to carry the bike up. Have yet to see anyone pedal up this hill. I wish they could construct a riding path up this section.
(Photo Above) The water in the forest reserve is crystal clear, after being filtered along the way downstream...
(Photo Above) Paradise... 
(Photo Above) This is what happen if it continue to rain non-stop for two days...
(Photo Above) The obstacles are both man-made and natural...
(Photo Above) The best and fastest way to go downhill is to bump hop over the root invested section. The challenge remains on climbing up! Any suggestion?
(Photo Above) A clever way to leverage on a dead giant tree to make a bike trail...
(Above Photo) Going down is fun, I cannot say the same for climbing up...
(Above Photo) Before: Good luck to you.
(Above Photo) After: Thanks to the team who maintain the trails, they make this section more interesting to ride :D
(Photo Above) I am always tempted to jump from this man-made logs' obstacles. Has anyone tried jumping this?
(Above Photo) This shot was taken up slope. Well, most of the bikers will choose the easy path rather than bump over the log. The challenge lies on charging down the pool of water without slipping your wheels.
(Above Photo) The mountain bike trail in Bukit Timah Reserve does not have a good drainage system. Three days of continuous rain had resulted some sections of the trail challenging to ride without slipping. To add fuel to fire, the greasy roots would certainly excite some bikers who love to drift the bike while turning. The consolation is that you will not hurt if you fall, even without gloves and protective guards.
(Above Photo) You don't ride in this section, you slide...
(Above Photo) Anyone can bunny hop over?
(Above Photo) This is the top of the Bukit Timah Hill. Most of the bikers will rest here to regain strength before charging downhill to the end point...unless you want to go another round.
(Above Photo) This is the end of one of the mountain bike trails.

Saturday, December 10, 2011

Recommended Tire Pressure for Off-Road Tire and Road Tire


Off Road Bike Tire Pressures
Generally, the tire pressures for off-road bikes depend on the the following factors:

1. Volume of tire 
Larger volume tire require lesser tire pressure, while smaller volume tire require higher tire pressure. Depending on the types of ride, the volumes of MTB tires varies according to the types of bikes. Generally, the tires of XC bike have smaller volume than trail and AM bikes, while that of DH bike have the largest volumes of tires.

Recommended tire pressures for off road bikes:
XC Bike: 1.85 to 2.0 (>35psi)
Trail Bike: 2.0 to 2.2 (30psi to 35psi)
AM Bike: 2.1 to 2.4 (20psi to 30psi)
DH Bike: 2.5 to 2.7 (18psi to 25psi)

2. Weight of the rider
Heavier rider require higher pressure. The recommended tire pressures as illustrated above are based on 140 lbs to 150 lbs riders. You may want to vary the tire pressure to suit your weight and ride.

3. Types of terrain
Lower tire pressure is more preferred in wet terrain to provide better traction and minimize slipping. Generally, if you are riding an AM bike under wet condition, adjusting the tire pressures to 18 psi for tubeless tire may not be uncommon. My favorite tire pressures for AM bike in wet condition is 18psi for front tire (Nevagal Tubeless 2.35) and 20psi for rear tire (Nevagal Tubeless 2.1). For dry condition,, I prefer 22psi for front tire and 25psi for rear tire.

4. Types of tires
Generally, tubeless tires require lower tire pressures than tube tires. Depending on all of the above factors, pump the tire pressures according to your comfort level. If speed is your priority, go for higher tire pressure but you will sacrifice traction. If the terrains are very rocky, too much pressure may bounce you off your saddle while too low pressure may puncture your tires. Try to experiment the ideal tire pressure that best suit your weight, the riding terrain and the types of ride you want. For XC bike, I prefer 35psi for both tires (XR3 2.2 tube tires) in normal trail condition.

Road Bike Tire Pressures

The tire pressures for road bikes are simpler and straight forward. The tubes are generally very thin and speedy is normally the priority. The recommended tire pressures for road bikes are as follows:
(1) 110 lbs: 95-105 psi
(2) 140 lbs: 105-115 psi 
(3) 170 lbs: 110-120 psi 
(4) 200 lbs: 120-130 psi 
(5) 230 lbs: 125-135 psi

Saturday, November 26, 2011

How to Replace Grease in Santa Cruz Nomad Carbon Lower Link


All purchase of Santa Cruz Nomad Carbon comes with grease gun as shown above. Load grease into the gun and squeeze the trigger until the grease flow out in a consistent manner without air pockets.


There are two grease fittings at the lower link. Insert the grease gun nozzle onto the grease fittings. Tighten the nozzle cap if the fitting is too loose or losen it if the nozzle unable to insert onto the grease fitting. Squeeze grease into the lower link until the grease flow out of the bearing seals is clean. Wipe off the excess grease.

Wednesday, November 23, 2011

How to Bunny Hop and Bump Hop over a Log on Mountain Bike

STEP 1
Position your pedals in parallel to the ground. Compress yourself downward to build up pressure before the jump. Keep your legs and arms bend, get ready to spring up.


STEP 2
Gauge your speed and distance from the log, once ready pull up your handle bar as you jump.


STEP 3
When your front wheel lift over the log, pull up the rear wheel with your rear foot. Position your body (forward or backward) to ensure the bike land on two wheels.


STEP 4
As you land, flex your legs and arms to absorb the impact even though you ride a full suspension bike.


HOW TO BUMP HOP OVER A LOG
Bump hop leverage on the re-bounce effect of the front tire on impact and the pedal to lift the bike over the log. It requires lesser energy then bunny hop, but produce better jump over obstacle. Watch the video carefully, and observe how the bike is lifted over the log.


HOW TO ROLL OVER LARGE LOG
If the log is too large for bunny hop, just roll over it!


Tuesday, November 22, 2011

Adjustable Seatpost KS i950R

Adjustable seat post has become an indispensable component for all mountain biking. The convenience of adjusting the saddle height on the fly allows bikers to tackle more challenging trails with confidence. The major considerations for selecting an adjustable seat post are ease of maintenance, adjustable height and remote capability. I owned the highly popular KS i950R adjustable seat post, and discovered one major design flaw. The KS i950R has an opening at the rear, directly facing the perfect location for collecting mud and water while riding on trails. The level can be easily jammed by sands and mud), especially in muddy and wet conditions. I remember once pedal like mad uphill at the lowest saddle position, as the level actuator of the adjustable seat post was jammed by sands and muds.
I nearly wanted to switch back to Thomson seat post for good. An idea struck me after seeking help in an online forum. I DIY a mini mud guard using materials from a used tire tube. Simply cut a small portion of the used tube and wrapped it over the hole with a Teflon strap (See Photo). As the tube is made of rubber, the stretchable characteristic enable the level actuator to function properly, and at the same time prevent dirt, mud and water from entering the hole. It works perfectly fine! The new setup was tested in trail rides under wet and muddy conditions, and passed with flying colors.

(Left Photo) This is the original mud guard produced by Kind Shock. I seriously doubt it will prevent the mud and sands from getting into the level. Well, they should have known better before mass launched the KS i950R. I wonder why the flaw did not shown up during product test.

How to Install MRP LRP Chain Guide (ISCG-05)

1. Removed the middle and low chain rings
Remove the crank arms according to the manufacturer service manual. Dissemble the chain rings and install the bashguard to the chain rings as illustrated on below's photo.



2. Cleaned, greased and installed the two chain rings and bash guard
After cleaning the chain rings, grease the four new bolts that come with the MRP LRP. Firstly, secure the larger chain ring to the bash guard, then install the smaller and larger chain rings on the bash guard. Ensure the washers are fitted on the bolts, resting on the outer and inner part of the bash guard. Otherwise, the bash guard will not be able to securely attached to the chain rings.


3. Installed the chain guide and chain tensioner (ISCG-05)
The are four different mounting standards for the MRP LRP, namely; (1) Direct bottom bracket mount single roller arm attaches to the bottom bracket with pressure from the bottom bracket cup; (2) ISCG single roller arm attaches to three tabs around the bottom bracket shell; (3) ISCG-05 Larger bolt circle diameter than ISCG; and (4) E-Type for use with e-type front derailleurs. Santa Cruz Nomad Carbon uses ISCG-05 type.
Install the chain tensioner with the allen bolts supplied together with the chain guide. Grease the bolts before installation. The chain tensioner should be adjusted to prevent the pulley from hitting the bash guard and the bike frame. Ideally, the chain tensioner's roller should be installed as near to the larger chain ring as possible to provide optimum chain tension. If your Front Derailleur has been adjusted correctly before installing the MRP LRP chain guide, you will not require to adjust the Front Derailleur again. If you convert 3 chainring into dual chainring to fit the chain guide, you will need to adjust the high limit screw on your front derailleur so it cannot shift the chain up onto the guide ring. Do not change the height of the derailleur, its ramps are designed to work at a certain height, and if you deviate from that placement, it will not function correctly.

4. Installed the complete crank assembly into the BB
The chain position on the roller will follow the chain ring you are currently using. When the chain is at the larger chain ring, the chain will rest on the groove of the pulley. When the chain is at the smaller chain ring, the chain will step up onto the inner part of the pulley, resting against the shoulder. The MRP LRP fits the Nomad Carbon perfectly, without the need to tweak the tension arm to achieve the optimum position. I am not able to speak for other bike frame.

Tested the MRP LRP Chain Guide on muddy and rocky trails, did jumps and drops on both trail and urban ridings without a single chain drop. Both the chain guide and bash guard were tightly fitted on the frame, no sign of loose fit after some hard hits. Surprisingly quite and stiff, feel more confident than without it. Some may complain the plasticky feel of the bash guard, but I think is a good balance between weight and toughness. Highly recommended.  


How to Overhaul XTR Rear Derailleur RD-M980

The best way to see if your rear derailleur need major servicing is look for sign of slack chain when the bike engages the smallest gears for both the chain ring and the sprocket. Refer to the above photo, despite the installation of chain tensioner, the chain slacked like a dead noodle. The problem lies on the rear derailleur, where the spring tension has been weakened over time. The only way to rectify the problem was to overhaul the rear derailleur by dissemble the whole unit into pieces, then clean & lubricate thoroughly before putting them back together. If the Tension Spring loss its tension characteristic over long usage, the XTR rear derailleur has a second hole on the Pulley's Arm where the Tension Spring can be further stretch to increase its tension. Hence, it is worthwhile to invest in good component which can last for a long time.
When I discovered the chain slacked at the smallest sprocket and chain ring despite having a chain guide and chain tensioner, it was an alarm that my XTR rear derailleur (RD-M980) needed a complete overhaul. The XTR rear derailleur has attached to me through thick and thin, faithfully serving three different bikes of mine; namely Jamis hardtail, Trek Fuel EX, and Santa Cruz Nomad Carbon. It has gone through countless battles under rain and shine, on trails, rock gardens and streams. Besides regular lubrication on the outside after each ride, no major servicing has been done. Finally, the time has arrived for a thorough overhaul!

1. REMOVE THE CHAIN


Before removing XTR rear derailleur, there are two components that need to be dissembled; the chain and shifter cable. To remove Shimano's chain, you need a chain tool, which can be purchased in any good bike shop. Personally, I prefer SRAM chain as it can be easily de-linked by simply using your hands to unlock the links. I think all chain should make that way. The pain to de-link Shimano chain does not end here, the nightmare starts when you try to link the chain. I will come to that later.

2. REMOVE THE CABLE


Removing the gear shifter cable is simple. Use the 5mm allen key to loosen the nut, then pull out the cable gently. If the cable has a cable end cap, remove it with a cable cutter. Otherwise, the cable end cap will jam at the cable-guided hole, which will prevent the cable from pulling out of the XTR rear derailleur. For the benefit of maintenance, it is a good practice to leave about 2.5 cm of extra cable at the end, as it will be shortened after each maintenance.

3. REMOVE THE XTR REAR DERAILLUER


Once the chain and cable have been removed, the XTR rear derailleur can be safely removed from the hanger by unscrewing the bolt with a 5mm allen key. If the rear derailleur has not been removed for servicing for a long time, you will need a great effort to unscrew the bolt, especially if the bolt has not been lubricated properly.

The photo illustrated the two main components removed from the bike: the chain and XTR rear derailleur. I suggest using degreaser to thoroughly clean the chain, then lubricate it with silicon lubricants (dry type). I used FINISH LINE dry teflon lube to grease the chain.

4. DISSEMBLE THE XTR REAR DERAILLUER


To dissemble the XTR rear derailluer, you must strictly dissemble the unit according to the following sequence: Inner Plate; Guide & Tension Pulley Units; Outer Plate Assembly; P-Axle Assembly; and P-Tension Spring. It is easy to strip the XTR rear derailluer into pieces, as long as you have the patient and interest. To dissemble the Tension Pulley Unit, remember to remove the Stop Ring (above photo:lower left) before unscrewing the bolt with a 3mm allen key. Once the Tension Pulley Unit is dissembled, unscrew the bolt on the Chain Guide Pulley Unit. Take note that the two Pulleys are supported by washers on each side (total 4 x washers). At this stage, the Inner Plate Assembly can be detached from the main unit. If needed, the bearings of the Guide and Tension Pulleys can be easily removed for cleaning and lubricating.

Once the Tension Pulley Unit and Chain Guide Pulley Unit are removed from the Axle Unit, the P-Tension Spring inside the Axle Unit can be taken out by unscrewing the bolt from the P-Axle Assembly. Remember to hold tight the P-Axle Assembly while unscrewing the bolt, as the P-Tension Spring may bounce the outer-plate away. This photo display the dissembled P-Tension Spring and Outer Plate Assembly. Remember this, how well the XTR rear derailleur work depends on how thorough the P-Tension Spring, P-Axle Assembly and the Outer Plate Assembly are cleaned, lube and installed. Take gentle care not to damage the P-Seal Ring, as it is easily bent. I recommend investing in high quality grease, as it will ensure smooth and long lasting movement and tension. I used FINISH LINE teflon grease, which has high pressure rating, lower wear rating and excellent grade in salt water rust and corrosion test.

Lay all the components orderly is the manner as shown in the following photo. It will give you a visual image of the whole assembly, and to minimize the possibility of losing the tiny bolts and washers. The above photo illustrated all the dissembled components of XTR Rear Derailleur before they are cleaned and greased. The photo below illustrated the cleaned and greased components of the XTR Rear Derailleur.

The photo above illustrated the cleaned and greased components of the XTR Rear Derailleur before they were assembled. To assemble the XTR Rear Derailleur, assemble according to the following sequence: P-Tension Spring; P-Axle Assembly; Outer Plate Assembly; Guide & Tension Pulley Units; and Inner Plate.

The above photo illustrated the chain and rear derailleur after it was overhauled. The chain was well tension despite the gears being engaged in smallest gears for both the sprocket and chain ring. The gear shift was quick and precise, as good as new! It took me half a day to overhaul the XTR rear derailleur, including removing it from the bike and installing it back after overhaul.

Sunday, October 23, 2011

Jamis X3


This is the only hardtail mountain bike I have. The stock RST front fork was replaced with Fox 100mm RLC Fit front fork.

Trek Fuel EX


Frameset (Sizes: 17.5)
Frame: Alpha Red Aluminum w/ABP Convert, Full Floater, E2 tapered head tube, magnesium EVO Link, oversized pivot bearings, replaceable derailleur hanger, 120mm travel. Front Suspension: Fox 32 F-Series RL w/air spring, rebound, alloy steerer, 120mm travel. Rear Suspension: Fox Float RP-2, "trail tuned" w/XV air can, ProPedal, rebound; 7.0x2.0". Wheels: Hope Pro II hubs; Sten’s ZTR rim. 32-hole rims. Tires: Kenda Nevegal 2.35 Tubeless. Shifters: Shimano XT, 10 speed. Front Derailleur: Shimano XTR. Rear Derailleur: Shimano XT. Crank: Shimano XT, 42/32/22. Cassette: Shimano XT, 10 speed. Pedals: Shimano PD-M770 Deore XT. Saddle: Bontrager Evoke 2, chromoly rails. Seat Post: Thomson Elite.. Handlebars: Raceface Next Carbon. Stem: Thomson, 31.8mm, 90mm, 10 degree. Headset: FSA NO.57E, E2, ACB sealed bearings. Brakeset: Shimano XT disc brakes. 12.5kg.

Santa Cruz Nomad Carbon


Frame: Santa Cruze Nomad Carbon (Medium)
Shock: CCDB coil (Ti-Spring 2.5 x 350 lbs)
Fork: Fox Talas 36 TALAS FIT RLC Kashima
Handle bar: Deity Dirty30 handlebar
Stem: Point One Split-Second
Seatpost: KSi950R
Saddle: WTB Rocket saddle
Headset: Chris King Headset
Hubs: Chris King
Rims: ZTR Flow Wheelset
Tires: Hans Dampf 2.35 Tubeless (Front), Nobby Nic Evolution UST 2.25 (Rear)
Brake: XT Brake set
Groupset: XT Groupset
Chain guide: MRP mini G2 SL
Pedal: Point One Podium
Weight: 30.84 lbs (14kg)

Essential Specifications
BB: 73mm (SM-BB70)
Chainline: 50-51mm
Chain guide: ISCG05
Chainring: MRP 32T Single Chain ring
Cogs(CS-M771-10): 11-36T (36/32/28/24/21/19/17/15/13/11)
FD: 34.9mm top swing (low clamp)
Seat collar: 34.9mm
Seat post: 30.9mm
Shock: 8.5" x 2.5" 8mm hole
Rear hub: 135 x 10mm

Suspension Setting
Shock sag: 30%
Fork sag: 30%
Fork rebound: 8 clicks anti-clock
Fork high speed: middle
Fork low speed: middle