Suspension Corrected

A shop that knows a thing or two about servicing today’s suspension systems holds the key to saving on labor costs while processing more suspension repairs.

Knowing how to properly diagnose and service common suspension issues can increase your shop’s profitability by up to 2.5 hours of billable labor in some cases. Additionally, it will provide your customers a noticeable difference the next time they hit the trail. As with any repair, setting reasonable and realistic expectations while service writing will help avoid surprises and additional labor costs to the customer later, increasing their trust in your repair technicians. Here are a few easy, but important, steps to properly identify and diagnose issues before you open up the fork.

Ask Questions

The first step is to get to know your customer and their bike by asking a few key questions. Take note of the bike when it rolls in. Can you identify the trails it’s being ridden on by the type of dirt or dust on the bike? Ask the rider where they are riding and how often. Do they remember the last time the suspension had a basic service, and the dust seals and bath oil in the fork legs were changed? This will help you understand how aware they are of their suspension. One important thing to note is that the skill level of a rider is not a good indicator of how aware they are of the current state of their suspension. Seasoned riders are often the best at being able to ride through suspension that is broken or badly in need of standard service.

Visually Inspect The Bike

Before you put the bike in the stand to inspect the drivetrain and brakes, take a moment to cycle through the suspension system 10­–15 times, feeling for any underlying issues. Suspension components are dynamic, and their motion is the only real way to identify any issues with them. 

If the suspension is sticking while compressing or returning, chances are good that it’s suffering from a lack of lubrication and needs a basic spring service to add volume. Adjustment knobs are a good indicator of the health of a damper. Ask the rider for their settings. If they don’t know or don’t have them written down, take the liberty of jotting down the number of clicks or turns to one end of the range. Move the rebound knob from one extreme to the other and feel if it makes a difference in the return rate of the fork. For a RockShox fork, pull the rebound knob off (most are just held in place with friction) and inspect it for oil in the adjustment cap. If you see any beginning to pool up inside the cap, a new rebound damper and damper service should do the trick.

If you find that the knob doesn’t change the return speed of the shaft, the damper is either broken or in need of service, or there’s a lack of suspension fluid in the system. While operating the lockout, low-speed or high-speed compression will further diagnose whether the issue is with the level of fluid in the system or with a physical component. This is where experience is crucial: the feeling of properly locked out suspension differs from brand to brand and model to model. A bit of give in the lock position is normal, as it prevents internal damage by allowing fluid to bypass the lockout in an impact. If the suspension doesn’t respond to changing the adjustment on both compression and rebound dampers, a full damper service is needed to return fluid to its factory setting, but the internal components themselves may be just fine.

Get It In The Stand

At this point, it’s okay to put the bike in the stand and work through your normal process of inspecting brakes, drivetrain, wheels, and bearings. As part of this process, be sure to check the fork seals for any wear or cracking. Replacing seals and bath oil is the easiest and most regular repair you can perform. It’s recommend that these are replaced on regular intervals so it’s best to consult with the fork manufacturer on timing. Also check the stanchions for any nicks and scratches. A scratched stanchion will require a new crown, steerer, and upper tube (CSU) assembly. This is the most expensive component to replace due to a combination of parts and labor, so be sure and warn the customer if this is the case.

Check the bushings by grasping the lowers of the fork at the axle and pushing straight back to the rear wheel, and then pull the fork to you. Then grab the fork near the seals, and perform the same test. If you feel excessive play the bushings may be worn. Some bushings can be replaced, while other forks will need all new lowers to remedy this situation. While the fork lowers will be a more expensive component to replace, this will take much less time than removing and replacing bushings, and the overall cost to the customer will be similar in many situations. Grasp the stanchions, and rock these back and forth at the seal and again near the crown. If you can feel some creaking or looseness, the CSU assembly may have come loose from its factory pressing.

Clean and inspect the rear shock in the same manner. Air cans should be serviced at more regular intervals than forks for basic seals and lubrication. Check the tightness of the shock mounting hardware and pivots by grasping the wheel and rocking it side to side while feeling the shock body, and then working your hand back to the rear axle, inspecting each bearing and bushing of the shock linkage. If you are able to get creaking or feel looseness from these junctions, replacement bushings at the shock or frame pivots may be in order. If the damper body has a scratch or marring, it will need to be replaced just as a CSU would.

By now, you should now have enough of a diagnosis to help the customer determine whether it makes more sense to service the fork or replace it altogether. Talk through the cost and time estimates of each, and offer advice on the situation.

The Nitty Gritty Of Suspension

Familiarizing yourself with a few specific symptoms can be a timesaver for both you and your customers. 

Clunking while cycling air sprung suspension fork: 
RockShox: Compression damper might be broken and require replacement.
Manitou, DVO, X-Fusion, Fox: Negative spring might be broken and require replacement

Difficult to remove negative air cap on RockShox Dual Air fork: 
Air spring may be damaged and require replacement

Fork or shock is “stuck down” in the travel: 
Air has transferred from the positive to negative air chambers in the component. An air spring rebuild will be required

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