FRONT WHEEL INSTALLATION
Installing your front wheel is easy but it can be a clumsy procedure, it is also easy to do it wrong. Sadly, doing it wrong is quite common and can adversely affect the way your suspension works. An incorrectly installed from wheel can actually cause the forks to bind. This binding creates a harsh stiff feeling as the forks go through the stroke.
Installing the front wheel correctly will ensure no binding occurs, be sure to consult your service manual for the correct torque settings, they are lower than most people realize.
Below is the process we follow.
- Ensure the brake pads have enough space to accept the disk (someone may have pressed the brake lever when the wheel was off:).
- Align the front wheel disk(s) with caliper(s) and the axle lugs.
- Slide the axle through forks and hub (this is the clumsy part) and tighten the nut (to O.E.M torque spec) leaving the axle pinch bolts loose.
- Remove the bike from the stand and compress the front suspension 3-4 times. Do this by pulling in the front brake lever and pushing down on the handlebars. This action will center the axle in the fork lugs.
- Tighten the axle pinch bolts to the manufacturer’s torque specification (having a helper tighten the bolts is always nice).
There are a lot of variations of this procedure depending on the bike. Once you gain access to the chassis follow the simple steps below. This procedure will ensure there is no binding in the linkage or in the heim joints on KTM’s. Always consult your owner’s manual for proper torque settings.
- Feed the shock into its position and insert the upper and lower mounting bolts (do not torque).
- Once installed take the bike off the stand and put it under load (bounce up and down).
- Torquing the bolts to specification.
Tires are part of your suspension – about 2″ !!! Too much air pressure will contribute to a harsh ride and cause your wheels to deflect off of things, this can feel like a harsh fork or stiff shock. Deflection creates that unbalanced feeling know-one likes, it’s most noticeable in rocky and rooted out trails. Tire pressures can be a personal thing but a good starting point is 10-14 PSI. Off-road riders tend to be at the lower end of the scale (looking for traction) and motocross racers tend to be a little higher (trying to avoid pinch flats). Adventure bikes require a little more conversation depending on the type of riding you are doing.
Find a friend and check your sag! Sag is the most overlook setting but one of the most important things you can do to make your bike handle well. Follow the steps below to check your sag. Ensure you have all of your gear on including anything you may carry with you on a regular basis i.e.) camelback, tool bags, etc.The numbers used in the calculations below are for demonstration purposed only, consult your owner’s manual for bike specific values.
Follow these steps:
- Place the bike on a stand with the suspension fully extended.
- Make a mark on the rear fender directly above the rear axle nut.
- Measure from the center of the axle vertically to the mark on the fender. Record this measurement as L1 (eg. 630mm).
- Remove the bike from the stand.
- Have some hold the bike and measure the distance from the center of the axle to the mark on your fender. Record this measurement as L2 (eg. 600mm).
- Subtract L2 from L1 (30mm) from is your Static Sag number i.e.) Static Sag = Sag of the bike under its own weight
- With the bike off the stand and the rider aboard standing in a neutral riding position, bounce up and down on the bike.
- Let the bike settle and measure the distance from the center of the axle to the mark on the fender and record this as L3 (eg. 530mm).
- The Rider Sag (sag of the bike with the rider on it) is determined by subtracting L3 from L1 (eg. 100mm). This is typically between 90 and 105mm.
- If the Rider Sag is out of range you will need to increase or decrease the amount of preload on the rear spring.
- To decrease the amount of sag (smaller number) increase the spring preload.
- To increase the amount of sag (larger number) decrease the spring preload.
- Repeat the procedure until you get the proper Rider Sag number.
- Static sag should be between 30 and 40mm (for big bikes).
- Static sag rules of thumb, if after setting the rider sag your static sag is: Greater than 40mm your spring rate may be too stiff for your weight
- Less than 30mm the spring rate may be too soft for your weight
- A spring that is too soft requires so much preload to achieve the proper race sag that the rear suspension is always close to topping out, this is not good for internal components.
- One revolution of the spring preload adjuster is approximately 2mm.
- A change in rider sag as little as 2mm’s has a considerable affect on the how your bike handles.
- There are different ways to check sag, this is how we like to it, what’s most important is that you are consistent in how you do it.