Preload is the adjustment you make to your suspension spring, while sag is the measurement that shows how much your suspension compresses under weight. Adjusting preload changes your sag measurement, helping you find the sweet spot where your suspension performs best. Understanding both lets you properly set up your adventure motor for better handling, comfort, and control on any terrain.

What exactly is preload and what does it do?

Preload is the initial compression you apply to your suspension spring before any weight sits on the bike. You’re not making the spring stiffer when you adjust preload, you’re simply changing how compressed the spring is at rest. This adjustment affects your ride height and determines where your suspension starts working from.

Think of it this way: your spring has a specific stiffness (spring rate) that doesn’t change. When you increase preload, you’re compressing the spring more before you even sit on the bike. This raises the bike’s ride height and changes the starting position of your suspension travel.

On adventure motors, preload adjustment typically works through a threaded collar or adjuster ring on your shock or fork. Turning this collar compresses the spring against the suspension body. Most adventure bikes have easily accessible preload adjusters, often with numbered settings or visible threads that show how much adjustment you’ve made.

The practical effect is straightforward: more preload raises your bike and reduces how much the suspension compresses under your weight. Less preload lowers your bike and allows more compression. But here’s the important bit, you’re working with the same spring throughout. If you find yourself maxing out preload adjustments and still not getting proper suspension performance, you probably need a different spring rate altogether.

What is sag and why does it matter for adventure riding?

Sag is how much your suspension compresses under the weight of your bike and rider combined. It’s measured in millimetres and tells you whether your suspension is set up correctly for your weight and riding style. Proper sag ensures your suspension can move both up and down from its normal riding position, giving you the full range of performance.

You’ll hear about two types of sag. Static sag is the compression with just the bike’s weight, no rider. Rider sag is the compression with you aboard in your normal riding gear. Rider sag is what matters most for setting up your adventure motor, though checking static sag helps confirm you’ve got the right spring rate.

Why does sag matter so much for adventure riding? Your suspension needs room to extend over bumps and compress into dips. If you have too little sag (suspension too stiff or too much preload), your bike sits high and the suspension can’t extend properly over rough terrain. You’ll feel harsh impacts and lose traction because your wheel can’t follow the ground contours.

Too much sag means your suspension sits too deep in its travel. You’ll run out of compression travel on bigger hits, bottom out frequently, and your bike’s geometry changes in ways that affect handling. On adventure motors tackling varied terrain, proper sag keeps your suspension working in its optimal range whether you’re on tarmac, gravel, or technical off-road sections.

What’s the difference between preload and sag?

Preload is the tool you use, sag is the result you measure. You adjust preload to achieve the correct sag measurement. Understanding this relationship is what lets you properly set up your suspension instead of randomly turning adjusters and hoping for improvement.

When you increase preload by turning that adjuster collar, you compress the spring more. This reduces sag because the suspension doesn’t compress as much under your weight. Decrease preload, and you get more sag. The spring itself hasn’t changed, you’ve just altered its starting position.

Here’s where many riders get confused: adding preload doesn’t make your spring stiffer. The spring rate (how much force it takes to compress the spring a certain distance) stays exactly the same. You’re simply changing the initial compression, which affects ride height and sag measurement. If you need a genuinely stiffer suspension, you need a spring with a higher spring rate, not just more preload.

This matters because you can’t fix a wrong spring rate with preload adjustment alone. If you’re cranking preload to maximum and still getting too much sag, your spring is too soft for your weight. If you’re backing off all the preload and still have too little sag, your spring is too stiff. Preload fine-tunes things, but the spring rate needs to be in the right ballpark first.

How do you measure and adjust sag on your adventure bike?

Measuring sag requires a measuring tape or ruler, a marker or tape, a helper, and your normal riding gear. The process takes about 15 minutes and gives you the information you need to set up your suspension properly. You’ll measure both the rear and front suspension, though most riders start with the rear since it carries more weight.

Here’s how to measure rear sag on your adventure motor:

• Put your bike on a stand so the rear wheel is off the ground and the suspension is fully extended
• Measure from the rear axle to a fixed point on the bike directly above it (a bolt, panel edge, or seat rail)
• Record this measurement as your fully extended length
• Take the bike off the stand and have someone hold it upright with the suspension settled
• Measure the same distance again, this is your static sag
• Get on the bike in your riding gear, bounce gently a few times to settle the suspension, then sit in your normal riding position
• Have your helper measure the same distance while you’re aboard, this is your rider sag

For adventure motors, you’re looking for 30-40mm of rear sag typically. Front sag should be around 25-35mm. These ranges work for most adventure riding, though you might adjust slightly based on whether you’re loaded with luggage or riding more aggressively.

To adjust sag, you’ll change the preload. If you have too much sag, increase preload (compress the spring more). If you have too little sag, decrease preload. Make adjustments in small increments, then remeasure until you hit your target range.

What if you can’t get proper sag even with preload adjustments? If you’re maxed out on preload and still have too much sag, you need a stiffer spring. If you’ve backed off all the preload and still have too little sag, you need a softer spring. Static sag also tells you something important: if it’s less than 5mm or more than 10mm, your spring rate probably isn’t right for your bike, regardless of what rider sag shows.

Need help getting your adventure bike suspension dialled in?

Getting preload and sag right is the foundation of good suspension performance, but it’s just the starting point. Once you’ve got proper sag measurements, you can fine-tune damping adjustments and really optimise how your adventure motor handles different terrain and riding conditions.

We specialise in custom suspension solutions for adventure motors, from proper setup and tuning to complete suspension systems built for your specific riding style and weight. Every rider is different, and your suspension should reflect that. Whether you’re sorting out basic sag settings or looking for a complete suspension upgrade, we can help you get your bike working the way it should.

Our suspension products are designed specifically for the demands of adventure riding, with full adjustability and serviceability built in. Not sure what you need or want to discuss your current setup? Get in touch and we’ll talk through your options. Proper suspension setup transforms how your bike rides, and we’re here to help you get there.

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