Tech Talk with Mike Parliament | Presented by MP1 Suspension
By Mike Parliament
SPRING FORKS vs. AIR FORKS
As we all know, the AIR FORK has been on many production motocross bikes since 2013. And since that day the question has been, “Are air forks any good?”
Well, depending on what you read online or in the chat forums, the answer has always left us wondering. Without getting super-technical, let’s take a quick look at the differences in both fork systems.
The conventional SPRING FORK has a mechanical spring in one or both fork tubes. The Showa SSF fork that is equipped on some KXF 250, RMZ 250 and 450 models has one steel spring in one fork only. The other, and most common system, has two springs — one in each fork.
The purpose of the spring is to carry the weight of the bike and rider. In both systems, there are chambers of oil that contain the damping control system. These types of forks have been around for a very long time, work very well, are reliable, and have a consistent feel for the rider throughout a long moto.
So, we ask ourselves: “If these forks work so well, why did the manufacturers produce an air fork?”
It is quite simple — WEIGHT and ADJUSTABILITY.
For most racers and riders, the thought of saving just a bit weight on your motorcycle doesn’t really cross our minds, but at the factory racing level, it’s a huge deciding factor. And nothing really ends up on a production motorcycle without going through the race division first.
Enter, the air fork.
There are a few different air fork types: KYB has their version. Showa has their version. WP has their own also. But the concept is similar in each of them.
For starters, there is no mechanical spring in an air fork. This makes the fork quite a bit lighter. Every person that has ever held an air fork in one hand and a spring fork in the other is amazed at the difference in weight. However, there are also some misconceptions that people have. The air in a fork does not replace the damping system. Air only replaces the spring, they ALL still have a damping system in them. This system works the same way it does in a spring fork. All air forks can be re-valved to suit rider size and ability.
The other advantage to the air fork is that, unlike a spring fork, it can be adjusted for different track conditions very easily with a tool that fits in your tool box.
In my opinion, some of the negativity the air fork receives comes from the lack of understanding the air pressures. Having the accessibility to change pressures in your fork doesn’t mean that it’s the only thing to do. Always reaching for the air pump to try to have a different feeling and not a screwdriver to adjust COMPRESSION or REBOUND ends up making the situation worse, leading people to say the air fork doesn’t work.
Education is the key to understanding. We need to understand that if you own a bike with air forks, you will always have to check and set the air pressure. It must be done, period. Gone are the days of just pulling your bike off the truck and riding — performance suffers, and the dislike for the air fork increases.
Hello, plot twist!
The release of the all-new 2017 Honda CRF 450R with the news of returning to the spring forks has definitely created a buzz in the industry. Does that mean Honda admits a mistake? No, I don’t think so. I believe Honda wants to provide a product that you can just go ride and enjoy. They released a new version of an old design. No more checking air pressure before you ride just to realize you left your pump at home. Just gear up, start up and moto. Happy customers.
While all Red Riders are pumped to have a spring fork, all our fellow KTM and Husqvarna riders are welcoming the decision to abandon the 4CS spring fork and bring on the WP AER forks. I feel that the situation is again the same. The WP AER fork is a light, easy-to-use air fork that is equipped on KTM and Husky motocross bikes, including the 65cc bikes.
The PROS List
Spring forks: Once the correct spring rate is installed, there is no need to recheck it. Easy to use. Just ride your bike. Very predictable feeling.
Air forks: Very light compared to spring. Very adjustable to create a spring feel that you like or for different track conditions.
The CONS List
Spring forks: They are heavy compared to air. No adjustability.
Air forks: Air pressure can change with temperature. Air pressure must always be checked and adjusted. They can seem frustrating trying to understand what the air pressures are doing.
So, there you have it. There is no right or wrong answer. A lot of the decision will come down to personal preference, or what you choose to believe. We need to understand that the air pressure is just replacing the mechanical spring. Whether spring forks or air forks, if you want your suspension to have a custom set up, a professional re-valve may need to be performed.
Here is some food for thought…
If you look around, teams like Factory Honda, RCH Suzuki, Factory Yamaha and Factory Kawasaki with riders Ken Roczen, Cole Seely, Justin Bogle, Chad Reed, and Eli Tomac are all running the AIR FORK in Supercross. Although they are using WORKS components, the air is still the spring.
If you would like more information or help with your suspension, contact Mike Parliament at MP1 Suspension: firstname.lastname@example.org