What is sag and why does it matter on a motorcycle?
Sag is the amount your motorcycle’s suspension compresses under weight. It is measured as the difference between the suspension’s fully extended position and its compressed position, either under the bike’s own weight (free sag) or under the combined weight of the bike and rider (rider sag). Getting sag right ensures your suspension operates in its optimal travel range.
When sag is set correctly, your suspension has enough travel to absorb bumps and impacts without bottoming out, while still maintaining enough spring tension to rebound properly. On an adventure bike like the CFMoto 800 MT, this balance is especially important because you’re frequently switching between smooth tarmac and rough off-road terrain, often with varying loads from luggage or a passenger.
Too little sag means the suspension is too stiff. The bike will skip over bumps rather than absorbing them, reducing tyre contact with the ground and making the handling feel harsh and unpredictable. Too much sag means the suspension is too soft, causing the bike to wallow through corners and potentially bottom out on larger impacts. Both extremes compromise safety and comfort, particularly on long-distance tours where fatigue compounds the effects of poor handling.
What tools do you need to measure sag on the CFMoto 800 MT?
To measure sag on the CFMoto 800 MT, you need a tape measure or ruler, a notepad to record measurements, a helper to hold the bike upright, and optionally a sag scale or zip tie to mark reference points on the suspension. No specialist equipment is required, making this a straightforward process you can complete at home.
Here is a simple list of what to gather before you start:
- A steel tape measure or rigid ruler (at least 300mm)
- A pen and notepad or your phone for recording measurements
- A second person to hold the bike upright and steady
- Your riding gear and helmet (you’ll need to sit on the bike in full kit)
- A spanner or C-spanner if preload adjustment is needed afterwards
Wearing your full riding gear when measuring rider sag is important because your jacket, boots, helmet, and hydration pack can add several kilograms to your overall weight. Measuring without gear and then riding with it will give you inaccurate results, so always measure as you intend to ride.
How do you measure free sag on the CFMoto 800 MT?
Free sag on the CFMoto 800 MT is measured by comparing the suspension length when the wheel is hanging freely to its length when the bike rests on its own weight with no rider. Lift the rear of the bike so the suspension fully extends, measure from a fixed point, then lower the bike and measure again. The difference is your free sag.
Step-by-step: measuring rear free sag
- Place the bike on a flat surface and have your helper hold it upright without a centre stand.
- Choose a consistent measurement point on the rear, typically directly above the rear axle, measuring vertically to a fixed point on the subframe or seat unit. Mark this reference point.
- Lift the rear of the bike gently until the suspension is fully extended and the wheel hangs freely. Record this measurement (L1).
- Lower the bike so it rests on its own weight with no rider. Gently push down and release the suspension, then let it settle naturally. Record this measurement (L2).
- Calculate free sag: L1 minus L2.
For most adventure bikes, free sag should fall between 0mm and 10mm. If free sag exceeds 10mm, the spring rate may be too soft for your weight, or the preload needs increasing. If there is no free sag at all, the preload may be set too high. Repeat the same process at the front fork, measuring from the bottom of the lower leg to a reference mark on the upper tube.
How do you measure rider sag on the CFMoto 800 MT?
Rider sag on the CFMoto 800 MT is measured by taking the fully extended suspension measurement, then comparing it to the measurement taken with the rider sitting on the bike in their normal riding position wearing full gear. The difference between these two figures is your rider sag.
Step-by-step: measuring rear rider sag
- Using the same measurement point from your free sag check, record the fully extended measurement (L1) again if needed.
- Have the rider sit on the bike in their normal riding position, feet on the pegs, hands on the bars. The helper holds the bike upright so the rider does not need to put a foot down.
- Gently bounce the suspension a couple of times to help it settle, then take the measurement (L3).
- Calculate rider sag: L1 minus L3.
The target rider sag for the CFMoto 800 MT rear suspension is generally between 25mm and 35mm for road-focused riding. If you ride predominantly off-road or on rough adventure terrain, many riders prefer the higher end of this range, around 30mm to 35mm, to give the suspension more room to absorb impacts. For the front forks, a target of around 25mm to 35mm is also typical, though this can vary slightly depending on riding style and load.
If your rider sag falls outside these ranges, adjusting preload is your next step.
How do you adjust preload to correct sag on the CFMoto 800 MT?
To correct sag on the CFMoto 800 MT, adjust the spring preload on the rear shock and front forks. Increasing preload reduces sag; decreasing preload increases sag. On the CFMoto 800 MT, the rear shock typically uses a threaded collar adjuster, while the front forks may have a preload adjuster accessible from the top of the fork caps.
Adjusting rear preload
Locate the preload adjuster on the rear shock, usually a threaded ring or collar near the top of the shock body. Use a C-spanner or the appropriate tool to turn the adjuster. Turning clockwise typically increases preload (reduces sag), while turning anticlockwise decreases preload (increases sag). Make adjustments in small increments, re-measure after each change, and always adjust both sides equally if your bike has twin rear shocks.
Adjusting front preload
On the CFMoto 800 MT, front preload is adjusted at the top of each fork leg. Remove the fork cap carefully and turn the preload adjuster bolt. Again, clockwise increases preload and anticlockwise decreases it. Ensure both fork legs are adjusted by exactly the same amount to maintain balanced handling. After adjusting, bounce the forks a few times and re-measure before finalising your settings.
Once sag is set correctly, you can fine-tune rebound and compression damping to match your riding style and terrain, but always start with sag as your baseline.
What are common sag setting mistakes on adventure bikes?
The most common sag setting mistakes on adventure bikes include measuring without full riding gear, not accounting for luggage weight, measuring on uneven ground, and failing to bounce the suspension before taking readings. Each of these errors can result in sag figures that are several millimetres off, leading to poorly tuned suspension.
Here are the most frequent mistakes and how to avoid them:
- Measuring without gear: Always wear your full kit. Helmet, jacket, boots, and any hydration pack or body armour can add 5kg or more.
- Ignoring luggage weight: If you regularly ride with panniers or a top box, measure sag with your typical loaded weight. A fully loaded adventure bike can add 20kg or more, which significantly affects sag.
- Not bouncing the suspension first: Stiction in the suspension can give a false reading. Always compress and release the suspension gently before recording a measurement.
- Measuring on uneven ground: Even a slight slope will affect your readings. Always use a flat, level surface.
- Adjusting only one end: Front and rear sag work together. Adjusting only the rear without checking the front can upset the bike’s balance and steering geometry.
- Skipping free sag: Many riders only check rider sag, but free sag tells you whether your spring rate is appropriate for your weight. Both measurements together give you the full picture.
Taking the time to avoid these mistakes means your sag settings will genuinely reflect how your bike behaves on the road, giving you a solid foundation to build the rest of your suspension setup on.
How TFX Suspension helps you get the most from your CFMoto 800 MT
Setting sag is a great starting point, but the factory suspension on the CFMoto 800 MT is designed as a compromise for a wide range of riders and conditions. If you’re finding that correct sag settings still leave you with handling that doesn’t match your riding style, terrain, or load requirements, an upgrade or custom tune can make a significant difference.
At TFX Suspension, we specialise in exactly this. Our approach is built around the philosophy that no two riders are the same, and your suspension should reflect that. Here is what we offer for adventure riders looking to get more from their CFMoto 800 MT:
- Custom-built shock absorbers tailored to your weight, riding style, and typical terrain, available in our online shop
- Professional suspension service and rebuilds to restore or improve the performance of your existing suspension, handled by our experienced team via our service page
- Custom tuning where every setting is dialled in specifically for you, not a generic rider profile
- Ongoing support so you’re never left guessing after an upgrade or service
Whether you’re preparing for a long-distance adventure tour or simply want better control on mixed terrain, we’re here to help. Visit the TFX Suspension blog for more technical guides, or get in touch with us directly to discuss what your CFMoto 800 MT needs. You can also explore our full range of suspension solutions on the TFX Suspension website. Do not settle for standard.
Frequently Asked Questions
How often should I re-check sag on my CFMoto 800 MT?
You should re-check sag any time your riding conditions change significantly — for example, before a loaded touring trip, after fitting new suspension components, or when switching between solo and two-up riding. As a general rule, a quick sag check at the start of each riding season is good practice, since springs can settle and lose a small amount of preload over time. If you notice handling changes mid-season, such as increased wallowing or a harsher ride, it’s worth re-measuring before chasing other causes.
Can I set sag correctly if I'm riding two-up or with a passenger on the CFMoto 800 MT?
Yes, and it’s highly recommended if you regularly carry a passenger. For two-up riding, both rider and passenger should sit on the bike in their normal positions wearing full gear when taking the rider sag measurement. This combined weight will almost certainly require you to increase rear preload compared to your solo setting, and you may also need to revisit front sag to maintain balanced geometry. If you frequently switch between solo and two-up riding, consider noting down both sets of preload settings so you can swap between them quickly.
What should I do if I've maxed out the preload adjuster but my sag is still out of range?
If you’ve reached the limit of the preload adjuster and sag is still too high (suspension too soft), the spring rate is likely too low for your weight and riding style — no amount of preload adjustment can compensate for a fundamentally mismatched spring. Conversely, if preload is fully backed off and sag is still too low, the spring rate is too stiff. In both cases, fitting a spring with the correct rate for your weight is the proper solution, and this is exactly the kind of situation where a custom-built shock or fork spring from a specialist like TFX Suspension will make a genuine difference.
Does tyre pressure affect sag measurements on the CFMoto 800 MT?
Yes, tyre pressure has a small but measurable effect on sag readings because an under-inflated tyre will compress slightly under the bike’s weight, altering the effective ride height and your measurement baseline. Always inflate both tyres to your standard riding pressure before measuring sag, and keep that pressure consistent each time you re-check. This ensures your measurements are comparable across sessions and removes one variable from the equation.
Once sag is set, what should I adjust next to fine-tune my CFMoto 800 MT's suspension?
With sag correctly set as your baseline, rebound damping is typically the next adjustment to address. Rebound controls how quickly the suspension returns after compression — too fast and the bike feels skittish, too slow and it wallows or packs down over successive bumps. Start with the rear rebound, make small clicks of adjustment, and test on a familiar road before moving to the front. Compression damping is generally the final layer of fine-tuning, best adjusted once rebound feels right, as the two settings interact closely.
Is there a difference in how I should set sag for off-road riding versus road touring on the 800 MT?
Yes, and it’s one of the most practical adjustments adventure riders can make. For off-road or rough terrain riding, running sag towards the higher end of the target range (around 30–35mm rear) gives the suspension more available travel to absorb larger hits and uneven surfaces, reducing the risk of bottoming out. For predominantly road-based touring, the lower end of the range (around 25–30mm) generally provides sharper handling and more predictable cornering. If your riding involves a genuine mix of both, setting sag in the middle of the range and fine-tuning damping is a sensible compromise.
How do I know if my CFMoto 800 MT's suspension needs a service rather than just a sag adjustment?
If you’re measuring sag correctly and making preload adjustments but the handling still feels vague, wallowy, or inconsistent, the suspension internals may be worn or the fluid degraded — problems that sag adjustment alone cannot fix. Key warning signs include oil leaks around fork seals, a noticeably different feel between the two fork legs, excessive noise from the shock, or a suspension that feels slow to respond regardless of damping settings. In these cases, a professional suspension service or rebuild is the right next step before any further tuning.
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