What is the estimated cost to replace a motorcycle's suspension? Can I replace it myself?

What is a Motorcycle Suspension?

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A motorcycle's suspension is a crucial component that affects both its ride quality and performance. By adjusting the suspension appropriately to your weight and riding conditions, you can enjoy a more comfortable ride.

This section explains the "basic functions" and "types" of motorcycle suspensions. If you wish to deepen your knowledge about suspensions, please refer to this information.

Functions of a Suspension

A suspension has three main functions: supporting the load on the motorcycle, absorbing shocks from the road, and keeping the tires in contact with the road to generate traction.

Without a suspension, you would feel every bump directly, leading to an uncomfortable ride. Also, the force pressing the tires against the road would be weakened, making it harder to maintain grip.

Suspension and Shock Absorber

A suspension consists of a spring and a shock absorber.

The shock absorber's role is to dampen (control) the continuous oscillating motion of the spring after it encounters road imperfections. This damping force is called "damping."

Increasing the damping force results in a harder, quicker handling feel that directly translates road imperfections, making it suitable for sport riding. Conversely, reducing the damping force provides a softer, milder handling experience over road bumps, making it ideal for city riding.

Types of Front Suspensions

The front suspension is handled by the front fork, which typically features a telescopic design with a slender inner tube inside a wider outer tube (cylindrical part).

Telescopic forks primarily come in two types: conventional front forks and inverted front forks, and one of these is typically used today. In the past, however, single-sided front forks also existed.

Conventional Front Forks

A conventional front fork is one where the outer tube extends from roughly above the fender to the axle shaft at the center of the brake disc.

The advantages of conventional forks are their simple structure, flexible movement, and low cost, leading to their adoption in a wide range of models, from scooters to large motorcycles.

BMW's "Telelever" and "Duolever" systems incorporate an additional suspension between the front fork and the fuel tank. Their role is to suppress the nose-dive effect during braking that cannot be fully controlled by the front fork alone.

Inverted Front Forks

Inverted front forks are mainly adopted for sport bikes, with the outer tube positioned above, contrary to conventional forks.

Inverted forks have the outer tube at the top, followed by the inner tube, and a short bottom case connected to the axle shaft, making the difference from conventional forks immediately apparent.

While inverted forks generally offer higher rigidity and durability compared to conventional forks, increasingly, models are adopting inverted forks not for their stiffness, but for their cool aesthetic.

Single-Sided Front Forks

A single-sided front fork supports the front wheel with just one fork, as opposed to the usual pair of two. Famous examples include the Elf X, unveiled in 1978, and the Moto Elf, which appeared in the motorcycle manga "Futari Taka."

Elf held the patents for single-sided front forks and swingarms, but Honda acquired all vehicle patents from Elf in 1980, which later led to the introduction of single-sided swingarms (frames supporting the rear wheel) on the VFR400.

Types of Rear Suspensions

Motorcycle rear suspensions primarily serve to increase grip by pressing the rear wheel against the ground, and to absorb impacts from road irregularities encountered by the rear wheel.

The two main types of rear suspensions are mono-shock, which uses a single suspension unit, and twin (dual) shock, which uses two.

Monoshock

A monoshock is a suspension fixed between the pivot of the swingarm and the underside of the seat.

As the name "mono" implies (meaning "single" in English), having just one suspension unit reduces weight and simplifies adjustments, as there's no need to balance left and right.

A drawback is that on some models, the monoshock is located in a hard-to-reach position, making preload adjustment (initial adjustment) and inspection difficult.

Twin (Dual) Shock

Twin shocks (or dual shocks) consist of two independent suspension units, one on each side of the tire.

Compared to monoshocks, adjustments like preload need to be set to the same level on both, but because they are exposed on the outside, they are easier to maintain and adjust.

When is the right time to adjust your motorcycle's suspension?

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Adjusting your motorcycle's suspension to match your weight and riding situation can make for a more comfortable ride, but when exactly is the best time to do so?

The main instances for adjusting a motorcycle's suspension are as follows:

When carrying a heavy load or riding with a passenger.
When feeling strong impacts from the road or the bike bouncing.
When having difficulty cornering or feeling a lack of road contact.
When the rider's weight is too light or too heavy.

When carrying a heavy load or riding with a passenger

When carrying a lot of luggage on your motorcycle for long tours, or when riding with a passenger for long distances or durations, adjusting the suspension can significantly improve comfort.

If the load on the motorcycle increases, the rear suspension will sag. If your bike has preload adjustment, set the preload firmer. If it has damping force adjustment, set the damping force firmer.

If the suspension is too soft for the load, it can bottom out on road bumps or make cornering difficult, so be sure to make adjustments.

When feeling strong impacts from the road or the bike bouncing

When riding on rough roads, if you experience strong impacts from road irregularities or feel the bike bouncing excessively, set the preload to a softer setting.

Softening the preload helps absorb impacts from the road and reduces the direct impact and bouncing sensation. Adjust it if road irregularities are bothersome.

When having difficulty cornering or feeling a lack of road contact

If you feel difficulty cornering, such as drifting wider than your intended line on winding roads, try softening the preload and observe the results.

Softening the preload allows the suspension to compress more effectively, ensuring the tires maintain proper contact during braking, thus stabilizing cornering.

However, adjusting haphazardly can sometimes make riding more difficult. Therefore, it's recommended to make gradual adjustments, testing after each small change, rather than making drastic changes all at once.

When the rider's weight is too light or too heavy

Japanese motorcycles are typically adjusted at the factory for a rider weight of approximately 65kg to 70kg. Therefore, if your weight is significantly above or below 65kg, adjustments tailored to your body weight are necessary.

If your weight is more than 10kg heavier than 65kg, increase the preload. Conversely, if you are more than 10kg lighter, decrease the preload.

Motorcycle Suspension Replacement Procedure

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This section explains the procedure for replacing a motorcycle's suspension. If you're considering replacing it yourself or are interested in the process, please refer to it.

Replacing the rear suspension is not overly difficult, but it does require lifting the seat area slightly during installation. Therefore, if you lack confidence in your physical strength or replacement skills, it's recommended to have a professional do it.

Rear Suspension Replacement

The procedure for replacing the rear suspension is as follows:

Support the motorcycle with a stand.
Remove surrounding suspension parts as needed.
Remove the old suspension.
Install the new suspension, one side at a time.
Check for proper operation and reattach removed parts.

Step 1. Support the motorcycle with a stand.

If your motorcycle has a center stand, deploy it. If not, and you have a rear stand, use that.

Without a stand, the motorcycle may lose balance and tip over as soon as the rear suspension is removed.

While it's possible to replace the rear suspension without a stand, using one improves work efficiency and stabilizes the bike, so it's best to use one if possible.

Step 2. Remove surrounding suspension parts as needed.

If the suspension's removal or installation seems likely to interfere with surrounding parts like the muffler, or if there isn't enough space for tools, remove the surrounding parts first.

Even if there's no interference with the muffler, removing the seat or seat cowl can sometimes improve workability, so ensure sufficient workspace as needed.

Also, it's a good idea to protect the surrounding area by placing cloths or towels around the suspension to prevent scratches during removal and installation.

Step 3. Remove the suspension.

The suspension is secured by two bolts (typically 17mm for Japanese cars) at the top and bottom. Removing these two bolts will allow you to take off the suspension.

Once the suspension is removed, the tire will drop, and you won't be able to install the new suspension without lifting it back up. Therefore, before removing the suspension, wedge some magazines or similar items, about 1cm to 2cm thick, under the tire.

The removal sequence is as follows: first, remove the lower suspension mounting bolt, then the upper bolt, and finally, detach the suspension from the motorcycle.

Step 4. Install the suspension one side at a time.

Install the new suspension one side at a time (for twin shocks).

Contrary to removal, first secure the upper bolt, then the lower bolt. When installing the lower bolt, you'll need to lift the tire slightly while inserting the bolt.

Be careful not to overtighten the bolts, as this can strip the threads or even break the bolt in the worst case.

Step 5. Check operation and reattach removed parts.

Once the suspension is installed, double-check that it is securely fastened. If any surrounding parts were removed, reattach them to their original positions.

After all installation work is complete, sit on the motorcycle and perform a test ride while observing its behavior. Adjust the suspension (preload and damping force) based on the ride comfort and amount of sag.

Estimated Cost for Motorcycle Suspension Replacement

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If bringing it to a motorcycle shop

If you bring your own suspension to a motorcycle shop for replacement, the average labor cost is around 12,000 yen for genuine front suspensions and about 18,000 yen for aftermarket ones.

For the rear, monoshocks typically cost from 5,000 yen, and twin shocks from 8,000 yen. For American motorcycles with monoshocks, the average is around 9,000 yen.

Additionally, for bikes with fairings or models that require more time for replacement, an extra labor charge of 1,000 to 3,000 yen may apply.

If requesting an overhaul

Some suspensions can be overhauled (disassembled for inspection and replacement of worn parts). The labor costs including overhaul are as follows:

Estimated overhaul labor cost for front forks (including cost of consumables)

Conventional Front Forks	24,000 yen~
Inverted Front Forks	26,000 yen~
For Cartridge Type	Add +5,000 yen~ to above labor cost

Estimated overhaul labor cost for rear suspensions (including cost of consumables)

Monoshock	24,000 yen~
Twin Shock	32,000 yen~
American Bike Monoshock	35,000 yen~

If replacing it yourself

If you replace the suspension yourself, the only cost incurred is for the new suspension itself; no labor costs apply.

For rear suspension replacement, the difficulty decreases if your motorcycle has a center stand. Even without one, if you have a stand that can lift the rear tire, the replacement time can be shortened.

Motorcycle stands with a simple structure can be purchased starting from around 5,000 yen. However, a single-support maintenance stand carries a risk of tipping over, so choose a stand that contacts the ground at two points (left and right).

FAQ on Motorcycle Suspension Replacement

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This section summarizes frequently asked questions and their answers regarding motorcycle suspension replacement.

If you are considering replacing your suspension or are interested in the process, please refer to this information.

Can I replace the motorcycle's rear suspension without a jack?

For twin shocks, you can replace them one at a time without a jack, but you'll need some force to lift the seat area slightly when pulling out the suspension mounting bolts and when securing the new suspension.

When removing the suspension mounting bolts, if the hole isn't straight, the bolt can get stuck and be difficult to remove. So, you'll need to lift the bike slightly while pulling out the bolt.

Similarly, when installing the new suspension, you'll need to lift the bike slightly to insert the securing bolts straight. If you can manage that, replacement without a jack is possible.

How long does a suspension last?

Suspensions typically last for 50,000 to 70,000 km in terms of mileage, or 7 to 10 years in terms of service life.

However, if the suspension frequently receives strong impacts from road irregularities, or if it was impacted in an accident and seems fine but is still in use, it may experience a "loss of damping."

A "loss of damping" means the shock absorber has difficulty dampening the spring's movement, leading to prolonged bouncing. When this occurs, it's time for replacement or overhaul.

How to check for sagging in a motorcycle's suspension?

Sagging in a motorcycle's suspension, which indicates it's time for replacement, might be present if you notice symptoms such as "road bumps are no longer absorbed as effectively," "the tire's contact with the road feels weaker," or "it's harder to corner."

Also, check for oil leaks. Experienced riders might also notice issues by pushing on the suspension and observing an "unusual return timing" or "excessive sag for the applied load."

If your foot reach to the ground has improved even though your tire pressure is the same as before, it could also indicate sagging in the rear suspension.

Summary

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We've covered motorcycle suspensions, from basic explanations of their roles and types to how to replace them.

You can determine when to replace your suspension based on mileage or the time since it was first used, but it's generally best to consider replacement when you notice a loss of damping or sagging.

When considering having a shop replace your suspension, we've also provided estimated costs, so please refer to that information as well.