A General Guide To Setting Up Sidemount Diving Gear
A sidemount diver who is fighting trim at 20 metres usually has the same problem as one struggling on the surface, It all lies in how the gear was assembled. That is why learning how to set up sidemount gear matters so much. Small changes in the fit of the harness, cylinder attachment, hose routing, and weighting can turn a cluttered, uncomfortable rig into one that feels stable, streamlined, and easy to manage.
Sidemount was never meant to be a fixed or "one all, be all" configuration. Cold water UK diving, warm water travel, aluminium cylinders, steel cylinders, single-stage recreational diving, and technical decompression dives all place different demands on the system. The goal is never to copy somebody else's rig bolt for bolt. The goal is to build a setup that matches your body, your cylinders, and the type of diving you actually do.
Start with the right sidemount setup
Before adjusting anything, make sure the wing and harness are suitable for the diving you have planned. A lightweight travel-focused system can work brilliantly with aluminium cylinders in warm water, but may be less ideal when used with heavier steels tanks, drysuit or when you need to carry more accessories. Likewise, a larger wing built for technical use can feel excessive if your normal diving is simpler and more streamlined.
Harness design matters as much as the amount of lift your wing generates. Some sidemount systems offer extensive adjustment so that it can be adjusted to divers who require more attachment points or a have a particular body type, while others are more fixed in terms of the adjustments. Neither approach is automatically better. Divers with very specific fit requirements often benefit from more adjustable systems. Divers who prefer a simpler setup may prefer a more minimalist design. If you are building from components, compatibility between the harness, bladder, cambands or tank attachment points, and weighting options should be checked early rather than corrected later.
How to set up sidemount gear from the harness out
The sidemount harness forms the foundation of the Sidemount bc. If it sits too low, cylinders hang badly and dump valves become awkward to reach. If it sits too high or too loose, the whole system can shift during the dive. Start by fitting the waist belt so it sits securely around the hip bone rather than riding up the torso. The shoulder straps should be snug enough to keep the harness stable, but not so tight that they restrict movement or make it difficult to don.
The crotch strap should stabilise the system without pulling uncomfortably. Too loose, and the harness can float upwards. Too tight, and surface comfort disappears quickly. This is one of those areas where a drysuit, undersuit bulk, and body shape make a real difference. A setup that feels correct in a thin wetsuit may need to be readjsuted for drysuit diving especially with thicker undergarments.
D-rings should be positioned where you can actually use them. Shoulder D-rings need to be easy to reach for clipping stages or accessories. Waist D-rings are even more critical in sidemount because they influence where the cylinders sit along the body. If those lower attachment points are too far forward or back, cylinder trim suffers.
Cylinder attachment and trim
Most sidemount frustrations show up here. If the tops of the cylinders flare away from the body, the lower clips may be too far forward, the bungees may be too loose, or the tank valves may be positioned poorly relative to the shoulders. If the bottoms of the cylinders drop low, the lower attachment point usually needs adjustment.
Steel and aluminium cylinders behave differently, especially as gas is used. Aluminium cylinders often become more buoyant towards the end of the dive, which means rear trim may need more active management through clip position or bungee tension. Steel cylinders are generally easier to keep in place, but they can make the whole rig heavier and less forgiving if weighting is not thought through.
Begin with symmetry. Set both cylinders up identically, then make one change at a time in the water. Trying to correct everything at once usually creates confusion. It is also worth remembering that what looks slightly odd on land may sit perfectly once submerged.
Regulator and hose routing
Clean hose routing is not just about appearance. It reduces snag risk, keeps second stages where you expect them, and makes shutdowns and gas sharing more predictable. In a standard two-cylinder sidemount setup, one regulator usually carries the long hose and the other the backup second stage on a necklace. SPGs should be clipped where they are accessible but not dangling.
The exact hose lengths depend on body size, cylinder position, and whether the setup is for straightforward no-stop diving or more complex technical use. Too-short hoses create tension and pull second stages out of place. Too-long hoses leave loops and clutter. There is no prize for forcing a standard length if it clearly does not suit the diver.
First stage orientation matters as well. A tidy sidemount regulator set often comes from turning the first stage so each hose leaves in the most natural direction. This varies by regulator design and cylinder valve position. What matters is that hoses route close to the body and remain easy to deploy, donate, and stow.
Weighting a sidemount system properly
A poor weighting strategy can make a well-built sidemount rig feel terrible. The usual mistake is treating sidemount weighting like jacket BCD weighting. In sidemount, where the weight sits can matter as much as the total amount.
If you are feet heavy, moving some weight higher on the harness may help. If the upper body floats high and the cylinders sink low, weight placement may need to come down or spread differently. Divers in drysuits often need to balance suit gas management with trim weight placement, while wetsuit divers may have fewer variables but still need to account for cylinder buoyancy characteristics.
Keep the system as simple as possible. Start with the minimum weight required for a proper stop at the end of the dive with near-empty cylinders, then adjust placement to refine trim. Adding extra lead to mask poor trim nearly always creates more work.
Fine-tuning in the water
This is where a sidemount setup becomes personal. Pool sessions or shallow confined water dives are ideal because they let you test changes without task loading. Hover horizontally and check whether the harness stays fixed, whether the cylinders remain parallel to the body, and whether hose routing still looks sensible after a few valve drills and regulator switches.
If one cylinder consistently sits differently from the other, do not assume your body position is to blame. Check that both tanks are rigged the same way, the bungees are equally tensioned, and the lower clips sit at matching points. Small asymmetries in hardware placement can create surprisingly obvious differences underwater.
Breathing characteristics, exposure kit, and even fin choice can also influence your impression of trim. That does not mean the setup is wrong. It means sidemount is a system, not a collection of isolated parts.
Common mistakes when setting up sidemount gear
One common mistake is over-tightening everything on land. Divers often make the harness very tight because it feels secure in the changing area, only to find it restrictive once in the water. Another is copying a cave or technical configuration without considering whether it fits the actual diving being done.
There is also a tendency to chase perfection immediately. In reality, good sidemount setup is iterative. You fit the harness, test the cylinders, adjust the bungees, move a D-ring, dive again, and repeat. Experienced divers do this too. Better equipment helps, but no sidemount system is genuinely plug-and-play.
Another issue is mixing components without thinking through the whole configuration. A wing with one style of attachment, cylinders rigged another way, and regulator hoses chosen around a different setup can all work against each other. This is where a custom-built approach is genuinely useful. Matching the parts from the start saves a lot of compromise later.
When a custom setup makes more sense
If you are between standard sizes, changing exposure systems across the year, or using less common cylinder types, an off-the-shelf answer may not be the best one. The same applies if you need a sidemount system that can move between recreational use and more advanced diving without becoming awkward in either role.
That is why many divers benefit from building the setup around their actual use case rather than buying to a generic specification. At Deep Dive Supplies, that usually means looking beyond the wing alone and considering harness geometry, weighting options, hose lengths, bolt snaps, bungee style, and cylinder choice as one integrated system.
Sidemount rewards patience. Set it up carefully, change one variable at a time, and judge the result in the water rather than in front of the mirror. When the configuration finally clicks, the difference is obvious - better trim, cleaner movement, and far less effort spent managing your kit instead of enjoying the dive.
The best sidemount setup is the one that makes you feel like you are not wearing one especially when you leave the surface.
