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.