DVO Diamond OTT Oil Volume Guide

DVO Diamond OTT: Your Essential Oil Volume Guide

The DVO Diamond is a revered fork in the mountain biking world, known for its plush feel and customisable performance. A key aspect of maintaining this performance, and indeed any high-quality suspension fork, is the correct oil volume. Whether your Diamond is feeling a bit less responsive than it used to, or you're simply looking to perform a DIY service, understanding the precise oil requirements is crucial. This guide will walk you through the DVO Diamond OTT oil volumes, backed by manufacturer specifications, and delve into the 'why' behind DVO's choices in suspension fluid.

Understanding Suspension Oil and Its Importance

Suspension forks are complex systems that rely on hydraulic damping to control movement. This damping is achieved by forcing specialised fork oil through tiny passages and valves within the fork's internals. The viscosity and volume of this oil directly impact how the fork behaves under compression and rebound. Using the correct oil volume ensures that the damping circuits function as intended, providing a balance between plushness for small bumps and support for larger impacts, without harshness or excessive bottoming.

Why DVO Uses Thinner Bath Oil

You might be wondering why DVO, like many high-performance suspension manufacturers, opts for thinner weight bath oils. The provided information from our Shockcraft oil database sheds some light on this. DVO often specifies thinner oils for specific applications to achieve a desired damping characteristic. Let's look at the provided Motorex specifications:

The choice of oil viscosity is a delicate balance. Thinner oils can offer better sensitivity to small bumps and allow for faster damping response. However, a crucial factor is the Viscosity Index (VI). The VI indicates how much an oil's viscosity changes with temperature. A higher VI means the oil's viscosity is more stable across a range of temperatures.

While a high VI is generally desirable, it's not the only factor. DVO, like other manufacturers, tunes its damping circuits around specific oil properties. The shims within the damping valves react more to pressure than to viscosity changes, meaning that even if the oil thins slightly with heat, the damping force can remain consistent. However, very low VI oils (around 100) are typically lower quality and can become excessively thick in the cold, leading to poor performance in cooler conditions. The goal is to find an oil that provides effective damping across a reasonable temperature range without creating unwanted resistance.

The economic sweet spot for damping oil viscosity, as noted, is around 15 cSt at 40°C. This viscosity offers a good balance of damping performance and cost-effectiveness, which is why it's common in many high-end suspension components. Going thinner can enhance rebound feel and small-bump sensitivity, while going thicker can lead to choking in ports at high shaft speeds.

DVO Diamond OTT Oil Volume Specifications

Finding the correct oil volume for your DVO Diamond OTT is essential for maintaining its intended performance. While specific model years might have minor variations, the core volumes generally remain consistent for the OTT (Off-Too-Tight) adjustment system and the lower leg bath oil. It's always recommended to consult your fork's specific service manual if available, but the following table provides the generally accepted oil volumes based on manufacturer data:

DVO Diamond OTT Lower Leg Oil Volume

The lower legs of your DVO Diamond house the air spring and lower leg lubrication oil. This oil is crucial for keeping the bushings and seals lubricated, reducing stiction, and providing a smooth action. The volume is typically measured when the fork is fully compressed, without the spring installed.

Note on Oil Type: While DVO recommends their specific suspension fluid, a good quality 5wt or 10wt suspension fluid with a decent Viscosity Index (VI) is generally suitable for the lower legs. Avoid very light oils or motor oils. The primary role here is lubrication and stiction reduction.

DVO Diamond OTT Damper Oil Volume

The damper side of the DVO Diamond is where the primary hydraulic damping occurs. This oil is housed within the closed cartridge and is critical for controlling compression and rebound. The volume here is precise and must be adhered to for proper damping function.

Note on Damper Oil: For the damper, it's highly recommended to use DVO's specified fluid or a fluid with very similar viscosity characteristics (around 5wt to 7wt, with a good VI). The specific formulation of DVO's fluid is designed to work optimally with their valving and shim stacks. Using an incorrect fluid can lead to compromised damping performance, increased wear, or even damage to the damper internals.

Servicing Your DVO Diamond: A Step-by-Step Overview

Performing a lower leg service on your DVO Diamond is a rewarding task that can significantly improve fork performance. Here’s a general outline:

1. Preparation: Gather your tools: Allen keys, torque wrench, seal driver (optional but recommended), clean rags, a fluid transfer syringe, and the correct suspension fluid. Ensure your workspace is clean.
2. Deflate and Disassemble: Completely deflate the air spring. Loosen the axle pinch bolts and remove the front wheel. Carefully remove the fork from the bike. You may need to loosen the pinch bolts on the steerer tube clamp first.
3. Lower Leg Removal: With the fork upside down, locate the bolts at the bottom of each lower leg (usually 6mm or 8mm Allen bolts). Carefully remove these bolts. Be prepared for a small amount of oil to drain out.
4. Clean and Inspect: Once the lower legs are separated from the upper stanchions, thoroughly clean all components. Inspect the stanchions, bushings, seals, and O-rings for any damage or excessive wear. Replace any worn parts.
5. Oil Replacement: Using a syringe, carefully add the specified amount of new suspension fluid (30cc per leg for the lower legs) to each lower leg. Ensure the fluid is distributed evenly.
6. Reassembly: Carefully reinsert the upper stanchions into the lower legs, ensuring the dust wipers and oil seals are properly aligned. Tighten the lower leg bolts to the manufacturer's recommended torque. Reinstall the fork into your bike's headtube, torque the pinch bolts, and remount the wheel.
7. Air Pressure and Setup: Inflate the air spring to your desired pressure. Cycle the fork several times to distribute the oil. Set your sag and adjust compression and rebound damping as needed.

Important Note: Servicing the damper side is more complex and often requires specialised tools and knowledge. If you are not comfortable with damper internals, it is best to have this service performed by a qualified suspension technician.

Understanding Suspension Terminology

To better understand suspension tuning and maintenance, familiarising yourself with key terms is beneficial:

• Base Valve: Controls high-speed compression at the bottom of the fork leg.
• Bottoming Out: When the suspension reaches its full travel. Occasional bottom-outs are acceptable, but frequent bottoming indicates a need for adjustment.
• Closed Cartridge Dampers: Oil is contained within a sealed cartridge, separate from the fork stanchions.
• Compression Damping: Controls how quickly the suspension compresses. Affects plushness and support.
• Fork Oil Level: The amount of oil in the fork, affecting air volume and spring rate.
• High-Speed Damping (HSD): Controls rapid suspension movements, such as those encountered on rough descents or landings.
• Low-Speed Damping (LSD): Controls slower suspension movements, like those from rider input or rolling over obstacles.
• Mid-Valve: Located on the piston shaft, it influences mid-stroke performance and rebound.
• Negative Spring: Assists in the initial compression stroke and controls fork extension, improving small-bump sensitivity and reducing top-out harshness.
• Open Bath Dampers: Oil circulates within the fork legs, serving damping, lubrication, and cooling purposes.
• Packing: When suspension doesn't rebound fast enough after successive hits, leading to increased compression and a harsh ride. Caused by too much rebound damping.
• Platform Damping: Resistance to initial suspension compression, often used to improve pedalling efficiency and reduce "bobbing."
• Rebound Damping: Controls how quickly the suspension extends after compression, crucial for maintaining traction.
• Spring Preload: Adjusts the initial tension on the spring to set the correct sag.
• Stiction: The initial resistance to movement in the suspension, caused by friction between seals, bushings, and stanchions.
• Valving: The internal components (shims, ports, valves) that regulate oil flow and create damping forces.

Frequently Asked Questions (FAQ)

Q1: How do I set the air pressure on my DVO Diamond?
First, ensure your suspension is set to the fully open compression setting. Then, using a shock pump, inflate the fork to the pressure recommended on the fork's air chart or a suspension tuning guide based on your weight and riding style. After setting the pressure, bounce on the bike and measure the sag (the amount the fork compresses under your weight). Adjust pressure up or down in small increments (5-10 psi) until you achieve the desired sag, typically 15-20% for aggressive trail riding.

Q2: Can I use different brands of suspension fluid?
For the lower legs, yes, a good quality 5wt or 10wt suspension fluid is generally acceptable. However, for the damper, it is strongly recommended to use DVO's specific fluid or a fluid with very similar viscosity and performance characteristics. Using an incompatible fluid can negatively affect damping performance and potentially damage the damper.

Q3: My fork feels harsh, what could be wrong?
Several factors can cause harshness: incorrect air pressure, too much compression damping, too little rebound damping (causing packing), worn seals leading to increased stiction, or internal valving issues. Check your air pressure and damping settings first. If the problem persists, a lower leg service to clean and lubricate, or a full damper service, might be necessary.

Q4: How often should I service my DVO Diamond?
A lower leg service (cleaning, lubricating, and replacing lower leg oil) is recommended every 50-100 hours of riding, or annually. A full damper service, including damper oil changes and seal replacement, is typically recommended every 100-200 hours of riding or every two years, depending on riding conditions and manufacturer recommendations.

By understanding and adhering to the correct oil volumes and performing regular maintenance, you can ensure your DVO Diamond fork continues to provide exceptional performance for many rides to come.

If you want to read more articles similar to DVO Diamond OTT Oil Volume Guide, you can visit the Suspension category.