As king of the custom, there are infinite customizations that can be done to your Harley. One major overhaul to your bike is to change the front suspension setup. An Old School move is to swap to a springer front end. With that, though, you are choosing style over performance. If performance is your goal, an inverted fork suspension may be what you’re looking for.
What are Inverted Forks
Inverted or upside-down (USD) forks are just what their name implies. On an inverted fork, the outer slider (the thicker tube) is clamped into the triple tree. The inner fork tubes or stanchions are located down by the axle. They are essentially the same system as your standard forks, just upside-down. The principle operation of the fork stays the same. The internal components are often the same or at least very similar as well.
You may be asking yourself, “Why the heck would that make any difference? Is this just a goof to trick people into spending more money?”
And those are valid thoughts. Ones I’m sure onlookers had when they first saw race teams do the same thing to their competition bikes in the late 80’s. But soon after, the results were enough to convince all the teams to follow suit. Now, production street bikes that were homologized for racing purposes are equipped with inverted forks right from the factory. Even a select Harleys are equipped with USD forks.
The biggest advantage that the inverted fork design provides is added stiffness and strength at the lever point of your front suspension. When the front brake is applied on a motorcycle and the tire begins to stop, all the weight of the motorcycle is forced upon the forks, right below the triple tree. Having the thicker end of the forks mounted to the triple tree adds strength to this lever point of the motorcycle. The rigidity also produces great feedback for the rider and the wheel will respond quicker to the movement made at the helm.
The length of the larger diameter tube also tends to make up more of the overall length of the fork on the inverted design. This is important because it is made up of a much lighter material than the steel stanchions. Less weight in the front suspension leads to less unsprung weight and better handling. The rider gains a better feel for the handling of the front wheel to the pavement.
All of the positives sounds great, but it’s not all roses. There are a few disadvantages that you need to consider.
First and foremost, inverted forks are not cheap. They do require a bit of investment. While that is true for all fork assemblies in general, inverted tend to be more. The prices do range quite dramatically between brands. Do some research between them to find what fits your needs. A new set of performance cartridges may treat you better if looks are not of concern.
Another issue to consider deals with maintenance. Inverted forks lack drains, which leads to a more tedious fork oil change job. It can be a bit messy without the drains. Some units are charged with nitrogen and require special tools for servicing.
The location of the fork seals also makes service more immediate. Oil sits above the fork seal in the inverted design. If that seal leaks, the oil can escape more rapidly and will fall onto your brake components and tires. This can lead to dangerous braking conditions and reduced traction. This is an accident waiting to happen if not immediately attended to.
So do you need to go out and install the latest set of inverted forks on your Harley? The short answer is no, you don’t need to. For the majority of riders, the standard fork can handle the everyday forces that are applied to it. Standard forks have made it this far and will still be installed on many new generations of motorcycles to come. They just flat out get the job done.
But if you like to push the limits of your Harley’s intended uses, or if you want the best tech available, or even if you just want to be different, inverted forks are out there. It’s not an inexpensive upgrade, but you may find the difference to be a gamechanger in performance and in style. Aggressive bagger riders (yes, they exist) may really see the benefits. The advantages of the inverted fork may help you get through the twisties with a bit more ease.
They also have a unique look and appeal. A custom builder who is looking for something different in looks while also adding performance could find that the inverted forks are a perfect addition. The springer and girder styles harken to the past, while inverted look towards the future.