All bikes come off the showroom floor set up for no one in particular. Then riders grab the clicker settings recommended by a magazine, set the sag however a mate told them, throw in some fuel and head for the track.
Seriously, at this point the bike will only handle as well as its factory spring rates happen to suit the rider.
I have shown many times on the Mountain Race Shop Facebook page—using the LABA 7 spring dyno—how far measured spring rates can be from the numbers stamped on them. That is a discussion for another day. For now, assume that a stamped rate is a claim until it has been tested.
To put the problem into a real-world context, let's use the 2026 KX250F and look at why adjusting the clickers cannot fix one direct problem: incorrect spring rates.
The stock fork springs are nominally 5.1 N/mm with 5 mm preload. The shock spring tested at 51 N/mm, although it was stamped 54 N/mm. That difference is exactly why measuring matters.
Who is the bike really aimed at?
The 250F class attracts a broad spread of riders: teenagers, lighter adults, women, C-grade riders and veterans who do not want the power or weight of a 450. In practice, that can mean riders around 65–75 kg at one end and 95–110 kg at the other.
The required spring rates therefore vary substantially. A lighter rider may only need fork springs. A heavier veteran may only need a shock spring. Many riders in between will need both ends corrected.
What normally happens next
For the most part, riders wind preload into the shock until they achieve the recommended sag number, then reach for a screwdriver and soften the fork clickers because the bike “feels stiff”.
The problem is that suspension has different components doing different jobs. We can change those job descriptions depending on the rider and the use, but we cannot make one adjustment perform every task.
The jobs inside a suspension system
The tuneable elements include low-speed compression damping, high-speed compression damping, rebound damping, oil height, oil viscosity, gas pressure, air and ICS spring rates, main spring rates and preload.
It is a lot to take in. For most riders, the sensible starting points are spring rate, ride height, clickers and fork oil height.
Oil height and clickers do not replace the spring
Fork oil height mainly influences roughly the final 50–75 mm of travel by changing the trapped air volume and end-stroke progression—provided the main spring rate is already suitable for the job.
A clicker controls a bleed path. Open the adjuster and more oil can bypass the main damping circuit; close it and less oil can pass through that bleed. Clickers fine-tune damping force. They do not change the main spring rate, correct the chassis geometry or create the missing mechanical support.
What the spring actually does
The main spring has the critical job of supporting the chassis. It establishes ride height and therefore influences steering geometry, straight-line stability, cornering attitude and weight transfer.
A spring also stores energy during compression and releases that energy as the suspension extends. Damping controls the rate of that motion; it should not be used as a substitute for the correct spring force.
With a shock spring that is too soft, more compression damping is often added to hold the bike up and resist bottoming. The same setup may then need less rebound damping than ideal so the under-sprung shock can return quickly enough. The result is a compromise at both ends of the stroke.
Think of preload as a ride-height adjuster
Forget calling it a preload adjuster for a moment. Think of it as a ride-height adjuster.
When different-rate springs are preloaded until the same laden ride height is achieved, they can produce the same spring force at that single sag point. But they do not produce the same force everywhere else in the travel.
Near full extension—such as when the rear wheel unloads over a jump or crest—the softer spring may carry more installed force because extra preload was required to reach the same sag. That extra initial force can make the suspension reluctant to begin moving and can be felt as harshness.
Once the suspension moves beyond the sag point, the softer spring builds force more slowly than the correct spring. The bike then drops deeper into the stroke, bottoms more readily and loses chassis control. Adding compression damping to compensate raises impact force and often makes landings and sharp bumps harsher.
What the correct spring gives you
A correctly selected spring lets the wheels move over the ground while keeping the chassis in the intended attitude. The result is better tyre contact, more traction—particularly in corners—less false harshness and a much wider useful clicker range.
There is no downside to using spring rates selected for the rider's weight, speed, style and intended use. It is all roses and teddy bears.
Mountain Race Shop Takeaway
- Clickers fine-tune damping.
- Springs determine support, geometry and stored energy.
- Preload changes installed force and ride height—it does not change spring rate.
- Matching one sag number does not make two different spring rates behave the same.
- If the spring is wrong, you can spend all day chasing clickers.
Stop guessing. Get the suspension diagnosed properly.
Mountain Race Shop tests spring rates, measures chassis balance and selects springs for the rider's weight, speed, style and intended use.