Sidemount Weight Systems Compared
Weighting is one of the easiest parts of a sidemount configuration to overlook. It shouldn’t be. Where you put your weight can have a significant effect on trim, stability, cylinder position, and how naturally your body sits in the water. The amount of weight matters, but where that weight goes can matter just as much.
There isn’t one universally correct sidemount weight system. Different systems place weight along the spine, around the waist, on a backplate, in dedicated pockets, or on the cylinders. Some are fixed. Some are removable. Some combine several methods.
The right system depends on the configuration you’re building and, more importantly, on what you’re trying to accomplish with the weight. A weight system should help you achieve proper balance without becoming another piece of equipment that interferes with your cylinders, restricts your movement, or creates problems when your configuration changes.
Why Weight Placement Matters in Sidemount
The Main Sidemount Weight Systems
Spine-Mounted Weight Systems
Waist-Mounted Weight Pockets
Backplate-Mounted Weight
Shoulder-Mounted Weight Systems
Weight Belts
Cylinder-Mounted Weights
Hybrid Weight Systems
Ditchable vs. Non-Ditchable Weight
Don’t Put All Your Weight in One Place Just Because It Fits
Weighting Should Not Be Used to Fix Cylinder Problems
Your Weighting Should Work With Your Wing
Steel and Aluminum Cylinders Change the Equation
Drysuits Can Change Everything
Weight Placement and Trim
How I Approach Weight Placement
A Practical Comparison
What I Look For in a Sidemount Weight System
The Right Weight System May Change Over Time
Don’t Chase Perfect Trim by Moving Weights Forever
Final Thoughts
Why Weight Placement Matters in Sidemount
In sidemount, your center of gravity and center of buoyancy need to work together. If your weight is too high, too low, too far forward, or too far back, you may find yourself constantly correcting your position underwater.
That can lead to:
- Difficulty maintaining horizontal trim
- Excessive movement of the legs
- Cylinders that don’t sit where you want them
- Increased reliance on the wing
- Difficulty maintaining a stable position
- Unnecessary drag
- Greater workload during a dive
The temptation is often to fix these problems by adding or removing weight. But the amount of weight isn’t always the problem. Sometimes the problem is where the weight is located. This is why I look at weighting as part of the entire sidemount configuration rather than as a separate piece of equipment.
The Main Sidemount Weight Systems
There are several common approaches to carrying ballast in sidemount.
The major categories include:
- Spine-mounted weight systems
- Waist-mounted weight pockets
- Backplate or plate-mounted weights
- Shoulder-mounted weight systems
- Weight belts
- Cylinder-mounted weights
- Hybrid systems using more than one location
Some commercial harnesses incorporate dedicated weight systems, while others allow the diver to add pockets or plates to a modular harness. There are also significant differences in how much weight can be carried and whether that weight is ditchable. That distinction becomes important when evaluating a system for technical or cave diving.
Spine-Mounted Weight Systems
A spine-mounted system distributes weight vertically along the diver’s back. Dedicated sidemount harnesses commonly use some variation of this concept. For example, the XDEEP Stealth 2.0 uses a modular weight system with substantial capacity, while other systems use several smaller pockets distributed along the spine. The appeal is straightforward. The weight is positioned close to the diver’s centerline rather than hanging off one side.
Advantages
- Centralized weight distribution
- Good potential for balanced left/right loading
- Low-profile configuration
- Weight can be distributed vertically
- Works well with many dedicated sidemount harnesses
- Can provide substantial capacity for drysuit configurations
Disadvantages
The biggest limitation is that much of the weight may be non-ditchable. That doesn’t automatically make the system inappropriate. It does mean the diver needs to understand exactly what happens if the primary buoyancy system is lost.
Some systems combine fixed internal weight with separate ditchable pockets, giving the diver both centralized ballast and an emergency-release option.
Another consideration is adjustment. A spine-mounted system may give you several positions for distributing weight, but you still need to determine where those weights belong in your particular configuration.
Waist-Mounted Weight Pockets
Another common approach is putting weight pockets along the waist strap. This is one of the most flexible options because you can often move the weight forward or backward to change your balance. Commercial systems are available that attach to the waist or lumbar strap, and some are specifically designed to allow the diver to redistribute ballast between locations.
Advantages
- Easy to adjust
- Relatively simple
- Can provide ditchable weight
- Useful for fine-tuning trim
- Can work with many different harness configurations
- Easy to add or remove capacity
Disadvantages
Weight around the waist can become crowded quickly.
You already have:
- Cylinder attachment points
- D-rings
- Harness webbing
- Stage equipment
- Reels and spools
- Other accessories
Adding large weight pockets can interfere with those attachment points or make the waist area unnecessarily bulky.
There is also a difference between putting weight near the sides of your waist and placing it directly along your centerline. That difference can be noticeable underwater.
Backplate-Mounted Weight
A backplate can provide another convenient location for ballast. This is particularly useful for divers who prefer a more traditional harness configuration or who need additional weight capacity. Some sidemount systems, such as the Toddy System, use a dedicated backplate or plate-like structure that provides a central location for ballast. Other systems allow weights to be attached directly to the plate.
Advantages
- Centralized weight
- Good left/right symmetry
- Low profile
- Can provide substantial capacity
- Keeps some weight away from the waist area
Disadvantages
The major concern is whether the plate itself fits the configuration. In cave sidemount, especially when entering restrictions, anything added to the back needs to be evaluated for profile. A plate that works perfectly for one type of diving may be unnecessary bulk for another.
You also need to consider whether the weight is removable and how it affects the system if your exposure protection or cylinders change.
Shoulder-Mounted Weight Systems
Shoulder-mounted weight systems take a different approach to distributing ballast. Instead of concentrating weight around the waist, lower back, or spine, these systems place some or all of the ballast higher on the diver’s body, near the shoulders. The biggest advantage is moving weight higher in the configuration without adding it directly to the cylinders. This can be useful for a diver who needs additional ballast but is trying to avoid putting too much weight low on the body.
Advantages
Shoulder-mounted weights can provide several benefits:
- Move ballast higher in the configuration
- Help balance a diver who is naturally head-light/foot-heavy
- Keep some weight away from the waist and lower back
- Provide another option when conventional weight pockets are already crowded
- Allow weight distribution to be adjusted independently from cylinder rigging
And, if located in the front of the rig:
- Provide a diver with a ditchable weight option
- Push the chest D-rings out 1 inch/2.5 cm making them easier to locate
For some divers, this can be an effective way to fine-tune the overall position of the body in the water.
Disadvantages
The location also creates some potential drawbacks. Adding weight near the shoulders can change how the harness feels and how the diver moves. If too much weight is placed there, it can create an undesirable loading on the shoulders or alter the diver’s natural balance.
There is also the question of equipment interference.
The shoulder area is already busy with:
- Harness webbing
- Shoulder D-rings
- Regulator hoses
- Inflator routing
- Cylinder attachment points
- Stage equipment
- Lights and other accessories
A weight system that adds bulk in this area needs to be evaluated carefully. In an overhead environment, profile matters. A shoulder-mounted weight system should not create unnecessary protrusions or interfere with equipment access.
When Shoulder-Mounted Weights Make Sense
I would consider shoulder-mounted weights primarily as a configuration-specific solution, rather than a reason to automatically move all of your ballast higher. For example, if your basic weighting is appropriate but you consistently find that your upper body is too light, moving a portion of the ballast toward the shoulders may help achieve better balance. But if you’re adding shoulder weight simply because you don’t have enough capacity elsewhere, I’d stop and look at the entire configuration first. Ask why you need the additional weight and whether it can be distributed more effectively.
Ditchable vs. Non-Ditchable
As with any sidemount weight system, you also need to know whether the shoulder-mounted weight is ditchable. Don’t assume that a weight pocket is ditchable simply because you can access it. If the weights are integrated into the harness or positioned in a way that makes them difficult to release (behind the shoulders), treat them as non-ditchable and understand what that means for your overall buoyancy strategy.
The Important Question
The question isn’t whether shoulder-mounted weights are better than spine-mounted, waist-mounted, or other systems.
The question is: Does putting weight here solve a specific problem in your configuration?
If the answer is yes, shoulder-mounted weights can be a useful tool.
If you’re using them to compensate for poor cylinder positioning, excessive weighting, or an incorrectly configured harness, they may simply be masking the real problem. As with every other weighting system, the goal isn’t to find somewhere to put the weight. The goal is to put the right amount of weight in the right place.
Weight Belts
The simplest system is also one of the oldest. A conventional weight belt can still work with sidemount. There is nothing inherently wrong with using one if it allows you to achieve the required weighting and doesn’t interfere with the rest of the configuration.
Advantages
- Simple
- Inexpensive
- Easy to adjust
- Ditchable
- Doesn’t require a specialized harness
- Easy to change between different diving configurations
Disadvantages
A weight belt concentrates a lot of weight around the waist. That can become uncomfortable during long dives. It can also interfere with other equipment and may not provide the fine control over vertical weight distribution that a dedicated sidemount weight system can provide.
For some divers, however, simplicity wins. There is no requirement that a sophisticated harness must have an equally sophisticated weighting system.
Cylinder-Mounted Weights
Cylinder-mounted weights are another option. These allow the diver to put ballast directly on the cylinder and adjust its position along the cylinder. This can be useful for fine-tuning cylinder position and buoyancy.
Cylinder-mounted weights can be used as an option for fine-tuning weight position by loosening and sliding the weight along the tank. This can be particularly useful when the goal isn’t simply to make the diver heavier. You’re changing the relationship between the diver and the cylinder.
Advantages
- Fine adjustment of cylinder buoyancy
- Can influence cylinder position
- Useful for addressing specific cylinder behavior
- Weight travels with the cylinder
Disadvantages
Cylinder-mounted weight isn’t a substitute for properly configuring the entire system.
Adding weight to a cylinder because the cylinder is floating or sitting incorrectly may mask a different problem involving:
- Cylinder selection
- Rigging
- Bungee tension
- Attachment points
- Gas distribution
If you find yourself adding more and more weight to a cylinder to make it behave correctly, stop and reassess the configuration.
Another consideration, especially if you dive in caves or wrecks, is the possibility of cylinder-mounted weights interfering with restrictions. Cylinder-mounted weights create protrusions in an otherwise smooth surface. Guidelines can also become trapped between the weight and the cylinder. This can be especially troublesome if it happens while moving through a restriction.
Hybrid Weight Systems
For many divers, the best solution isn’t one system. It’s a combination.
You might have:
- Centralized fixed weight
- A small amount of ditchable weight
- Cylinder-mounted trim weights
- Additional waist pockets for specific configurations
This allows you to separate two different jobs. Primary ballast provides the majority of the weight you need. Trim weight allows you to make smaller adjustments to balance the configuration. That’s an important distinction. You don’t want to use every available weight location simply because you can. Each weight should have a purpose.
Ditchable vs. Non-Ditchable Weight
This is one of the most important differences between weight systems. A weight pocket that can be released is fundamentally different from weight that is permanently attached to the harness.
Some sidemount systems use large amounts of non-ditchable weight. For example, the Hollis Katana 2 manual describes a 20-pound internal weight system and explicitly identifies those pockets as non-ditchable. Other systems offer optional droppable pockets in addition to their fixed weight capacity. The XDEEP Stealth 2.0, for example, lists optional droppable weight pockets alongside its modular weight system.
Neither approach is automatically right or wrong. But you need to know which weights you can actually remove. Don’t assume that a pocket is ditchable simply because you can reach it.
Don’t Put All Your Weight in One Place Just Because It Fits
A large weight capacity can be tempting. If your harness will hold 25 pounds/11.5 kg, that doesn’t mean you should automatically put all 25 pounds/11.5 kg into that location.
The question is: Where does that weight need to be to make the configuration work?
For example, putting everything along the lower back may produce a different result from distributing some weight higher on the spine or closer to the waist. You need to evaluate your actual trim. This is where experimentation in the water becomes much more valuable than simply following a manufacturer’s diagram.
Weighting Should Not Be Used to Fix Cylinder Problems
This is one of the most important points in this entire article. If a cylinder is floating, don’t automatically add weight to it. If a cylinder is riding too low, don’t automatically move your body weight around. If your sidemount configuration is unstable, don’t automatically add ballast.
First determine why the problem exists.
A cylinder’s behavior can be affected by:
- Cylinder material
- Cylinder size
- Gas volume
- Regulator configuration
- Rigging
- Attachment points
- Bungee tension
- Harness geometry
- Weight placement
Adding weight may change the symptom without correcting the cause. You can end up carrying unnecessary ballast simply because the underlying configuration was never properly addressed.
Your Weighting Should Work With Your Wing
Your wing is there to provide buoyancy. Your weights establish the relationship between your mass and the water. Those two systems need to work together.
If you find yourself carrying a large amount of gas in the wing simply to maintain a particular body position, look at your weighting. This is especially important because buoyancy and trim are not the same thing. You should not use wing gas as a substitute for properly positioning your weight. A properly balanced configuration should remain manageable without depending on an excessive amount of gas in the wing.
Steel and Aluminum Cylinders Change the Equation
Cylinder choice has a major effect on weighting. Aluminum cylinders generally become more positive as gas is consumed. Steel cylinders tend to remain more negative. That means the amount and placement of ballast required can vary significantly between configurations.
If you switch from aluminum to steel cylinders, don’t assume your existing weighting system will automatically work the same way. Just as your wing and harness may work with both types of cylinders, they aren’t necessarily ideal for both systems. The same applies to weighting systems. Shoulder-mounted weights may be necessary for trim with steel cylinders. With aluminum cylinders, they may create a head heavy/foot light position in the water.
The same applies when adding stages. Your configuration is changing, so your weighting needs may change as well. This is why I don’t recommend choosing a weight system simply based on how much weight it can hold. Choose it based on how well it allows you to manage the configuration you’re actually diving.
Drysuits Can Change Everything
Drysuit divers often require substantially more ballast than warm-water wetsuit divers. That makes weight capacity important. But the solution shouldn’t simply be “find the harness that holds the most weight.” More weight means more responsibility for where that weight goes.
With a drysuit and substantial undergarments, you may need additional ballast while still maintaining a streamlined configuration. This is one reason modular weight systems can be valuable. You can adjust the amount and distribution of ballast as your exposure protection and cylinder configuration change.
Weight Placement and Trim
The goal of weighting isn’t to force yourself into a particular position. It’s to establish a configuration where your natural position in the water is appropriate. If you constantly need to kick, arch your back, or manipulate your wing to remain horizontal, something deserves investigation. Move the weight. Change the cylinder position. Look at the harness. Look at the exposure protection. Look at the cylinder rigging. Then evaluate the result again.
Don’t make one adjustment and assume you’ve solved the problem.
Sidemount is a system. Changing one component can affect several others. This is why you always make one adjustment at a time.
How I Approach Weight Placement
I prefer to start with the minimum amount of weight necessary to achieve the required buoyancy. Then I look at where that weight needs to go. I don’t want to carry extra ballast simply because a pocket is available. I also don’t want to use weight to compensate for equipment that isn’t configured correctly.
Once the amount of weight is established, I can start looking at distribution.
- Is the weight too high?
- Too low?
- Too far forward?
- Too far back?
- Is it affecting cylinder position?
- Is it interfering with the harness?
- Does it remain appropriate as the cylinders become lighter?
Those questions are much more useful than simply asking how many pounds your harness can carry.
A Practical Comparison
| Weight System | Main Advantage | Main Limitation | Best Use |
|---|---|---|---|
| Spine-mounted pockets | Centralized, distributed weight | Often non-ditchable | Dedicated sidemount configurations |
| Waist pockets | Adjustable and versatile | Can crowd the waist | Flexible configurations and trim adjustment |
| Backplate weights | Centralized and low profile | Depends on plate design | Technical configurations needing additional ballast |
| Shoulder weights | Moves ballast higher in the configuration | Can crowd the shoulder area or affect balance | Divers needing additional upper-body ballast |
| Weight belt | Simple and ditchable | Concentrates weight around waist | Simple or transitional setups |
| Cylinder-mounted weights | Fine cylinder adjustment | Can mask other configuration problems | Cylinder-specific trim adjustments |
| Hybrid | Highly configurable | More complexity | Divers with changing configurations |
The “best” system is the one that lets you achieve proper weighting and trim while keeping the configuration controlled and streamlined.
What I Look For in a Sidemount Weight System
When evaluating a weight system, I consider:
1. Capacity
Does it hold enough weight for your actual configuration?
Don’t size it for a hypothetical configuration you will never dive.
2. Distribution
Can you put the weight where you need it?
Capacity isn’t useful if all of the weight has to sit in the wrong place.
3. Ditchability
Which weights can you remove quickly?
Know the answer before you need it.
4. Profile
Does the system add unnecessary bulk?
Anything that protrudes from your configuration deserves scrutiny in an overhead environment.
5. Adjustability
Can you move or redistribute weight when your configuration changes?
A non-adjustable system may prevent you from addressing configuration and trim issues.
6. Accessibility
Can you actually manipulate the system while wearing your normal exposure protection and gloves?
This is only applicable to certain systems. Spine-mounted and backplate systems are excluded.
7. Compatibility
Does it work with your harness, wing, cylinder attachment system, and stage configuration?
There are several systems available. There’s no need to make more modifications to your configuration just to accommodate a particular weight system.
8. Stability
Most importantly, does it allow you to establish a stable, balanced configuration without constantly correcting yourself?
If you’re constantly fighting to maintain trim and buoyancy, then you need to consider a different system.
The Right Weight System May Change Over Time
Your ideal weighting system today may not be the ideal system five years from now. Your diving changes.
You may move from:
- Aluminum to steel cylinders
- Warm-water wetsuits to drysuits
- Two cylinders to multiple stages
- Recreational diving to technical diving
- Open water to cave exploration
Your equipment evolves. Your weight system may need to evolve with it. That doesn’t mean you need to replace your entire harness every time something changes. A modular system can be useful because you can adapt it rather than starting over.
Don’t Chase Perfect Trim by Moving Weights Forever
There is a point where adjustment becomes counterproductive. If you find yourself moving half-pound weights around endlessly, stop and look at the bigger picture.
Ask whether the underlying problem is actually:
- Cylinder position
- Harness geometry
- Exposure protection
- Equipment configuration
- Gas distribution
- Excess ballast
Sometimes the best weight adjustment is removing weight rather than moving it. Weight is not a trim tool. It is part of the system that establishes your balance.
Final Thoughts
There is no single best sidemount weight system. A dedicated spine-mounted system can provide excellent centralized ballast. Waist pockets can give you flexibility. A backplate can provide additional centralized capacity. A weight belt can keep things simple. Cylinder-mounted weights can provide fine adjustment. And a hybrid system can combine several of these approaches.
The important question isn’t which system is most popular. It’s which system lets you put the right amount of weight in the right place for the configuration you’re actually diving.
Start with the minimum weight necessary. Then establish where that weight needs to be. Make sure it doesn’t interfere with your cylinders, harness, or other equipment. Know which weight is ditchable and which isn’t. And don’t use weight to compensate for a configuration problem that should be solved somewhere else.
In sidemount, good weighting should be almost invisible. You shouldn’t spend the dive thinking about your weights. They should simply allow the rest of your configuration to work the way it was designed to work.
The goal isn’t to carry weight. The goal is to be properly balanced.
For a complete overview of how these elements work together, see The Complete Guide to Sidemount Diving Configuration.
Readers of this article can receive $10 off the book Sidemount Diving or $5 off the book Recreational Sidemount Diving when purchasing directly from the website.
Use code WEIGHT10 for the Sidemount Diving Guide and WEIGHT5 for the Recreational Sidemount Diving Guide during checkout.
Related Reading
The Problem Isn’t Always Your Trim. It May Be Your Weighting
How to Set Up a Sidemount Harness
How to Properly Trim Out in Sidemount
Why You Can’t Stay Horizontal in Sidemount
Why Your Sidemount Cylinders Are Floating