The Path of Harley-Davidson Performance Personified

Since 2019 the H-D bagger frame has also been evolving from a pig of a motorcycle to something that is agile, and feels much lighter than what the scale says. With that said, the path to true performance can be a rocky road with lots of style and cool guy pitfalls that leave a person wondering if this whole performance Harley thing is getting to be style over substance. As of 2018 the H-D Softail went from a heavily-outdated design to a platform where this model of motorcycle could be built into a performance powerhouse. This mainly is achieved by two factors; the mono-shock frame is 34-percent stiffer and 35-pounds lighter than any Softail frame before it. And the new rendition of the H-D Softail features the liquid-assisted strategic cooling eight-valve fully-balanced Milwaukee Eight engine. A pretty monumental combination indeed. But there is always room for improvement from the aftermarket. With that said, the key to any performance bike upgrades are really pretty simple. Make the bike lighter, faster, handle better, and have it stop like a Superbike. Its how you attain these go-fast goals is where it all gets so very complicated. Lets go over some basics.

No matter how well a performance-based bike accelerates and stops if it cannot do it in a comfortable or efficient manner, when why even spend the money? Yes, ground clearance on a performance motorcycle is a big factor. But a better handing sport-specific suspension does not really need to be sky-high to do its job well. Plus many times jacked-up suspension looks cool, but it throws off the geometry of the bike immensely. I suggest getting adjustable front and rear suspension and riding many miles adjusting it to your liking. You can talk to all your friends, chat endlessly with the suspension guru online or at the dealership and watch every YouTube video made on H-D suspension, but those people aren’t you and that is not your bike. We are all different shapes and sizes and have different riding styles as well as wants and needs from both your motorcycle and its suspension. So trial and error over a few weeks is the key to predicable performance suspension.

Better braking is a cornerstone of performance and one that I suggest being done secondarily if incremental performance additions are being done. Think of it this way. If your are planning to build a faster motorcycle, it needs to stop better too. More pistons in your calipers are an advantage no matter what. So look for four or six piston brakes. The debate about radial over axial brake calipers is ongoing, but I feel that radial brakes will be the norm in American V-Twin bikes in the near future. Their radial design is superior, adjustments are easier, and its cheaper to manufacture. Bigger brake rotors have a larger surface area in which larger brake pads can engage and bigger brake rotors also have a larger surface area making it cool much better than the smaller factory brake rotors. I would also suggest to use a floating rotor as well due to the fact that the rotor has the ability to conform to the brake pads giving maximum rotor-to-pad contact. This happens even when a relatively small amount of force is applied. Floating motorcycle brake rotors often lead to more consistent and predictable braking.

The big performance power players are of course adding big inches to your engine or some sort of forced induction system. Nick Trask of Trask Performance is the godfather of the modern V-Twin Turbo. He has been in the forced induction business longer than anyone and has made turbos powerful, yet safe forms of big horsepower and torque. How much you ask? From all of them I have installed and dyno tuned over the past two decades, I have consistently seen 45-50% more power depending on the how the motor was built. I really like the Milwaukee Eight motor over the Twin Cam. Why you ask? Compared to the Twin Cam 103 and 110, the Milwaukee-Eight's increased displacement, higher compression ratio and four-valve cylinder heads provide 50-percent more intake and exhaust flow capacity, result in 10-percent more torque across the board with room to grow. If you decided that there is no replacement for displacement S&S Cycle is always a good way to go. Whether it be with one of their motor kits or a big-inch replacement motor. 

If you want another swap that is a big deal then try the addition of the BST carbon wheels, which are 1/3 lighter than the stock wheels. Lighter wheels require less energy to get to speed, turn, and slow down. So keeping the weight off the wheels of any motorcycle greatly increases braking and acceleration. Also when you lower a wheel’s weight like the usage of a carbon fiver rear sprocket you lower the unsprung mass on a motorcycle aiding in a more tunable suspension. The rule of thumb is for every pound you shave off your motorcycles rotational weight (wheels, tires, brake rotors) is equivalent of 8.4 pounds of static weight. And thats a lot of savings when calculated.

You may want to start your addiction to carbon fiber bodywork, which weighs immensely less than the factory steel, fenders, dash, and side covers. Carbon fiber has several advantages over steel and even aluminum; high stiffness, high tensile strength, high strength to weight ratio, high chemical resistance, high-temperature tolerance, and low thermal expansion. Carbon fiber is now a good choice for lightning up your Harley as there are many manufacturers making quality carbon. And like I mentioned before lighter is always good path to performance. And all that carbon fiber looks good too. 

This along with the usage of aluminum parts over the stock steel stuff helps this big bike’s weight crisis. Using windowed cnc-machined aluminum on Boosted Brad’s rear fender brackets and a Trac Dynamics swing arm these upgrades are easily half the weight of the OEM offerings. Aluminum is renowned for its lightweight nature in stark contrast to steel, which is notably heavier. This weight discrepancy in steel arises from its elevated carbon content. The abundance of carbon within an alloy directly correlates with its heaviness. Aluminum does not  possess that much carbon making it inherently lighter.

Another way to reduce weight and add power to any Harley-Davidson motorcycle is by swapping out the factory rolled and formed steel exhaust, which houses a very weighty catalytic converter to a free-flowing stainless steel or titanium 2-into-1 exhaust pipe. 

This upgrade can take 11 pounds off a bike in most cases. One of the most popular metals in countless industries is stainless steel. Engineers, scientists, architects, and more all use stainless steel to create strong equipment. Stainless steel is not only strong but also easy to maintain and corrosion resistant. Titanium is as strong as regular steel, but it is 45-percent lighter and it is non ferrous. A performance exhaust coupled with a high-flowing intake and a proper dyno tune can and will get you some real-deal power. 

And believe it or not, even something so simple as changing out your seat to a design with far more lumbar support and a more rounded side profile such as a Saddlemen Step-up seat will be one solid upgrade that will allow you to be in the proper performance riding position whether it be in the canyon carving curves or wide open throttle straight-line drag racing. 

When upgrading your bike to perform its best there are so many major factors. But with my many years of personal trial and error in building fast and dependable Harley-Davidson motorcycles these are a few of the many ways to make your bike to be a beast. I hope this feature and it photos can add some clarity and will aid you in some way with your own personal performance motorcycle build. 

Forced induction such as this Trask Performance turbo system is a great way to add some major horsepower on either a stock or built-up motor

Aluminum swing arms like these Speed Dealer offerings are both lighter and stronger that the factory steel offerings and can easily take additional horsepower and torque.

Parts like these windowed aluminum seat struts from Speed Dealer are a great way to add major rigidity without having the weightiness of steel. 

Carbon fiber wheels like these from BST are stiffer and much lighter than any spoke or aluminum wheels. This equates to more power to the ground and less force to stop.

Larger brake calipers with multiple pistons like these from Beringer Brakes coupled with floating brake rotors that have a larger braking surface area is a tried and true performance combination. 

Upgraded and adjustable rear suspension like these from Fox means that you can adjust the same shock for different riding characteristics and varied terrain.

Having proper front suspension is critical for a performance harley build. This assemblage of parts from Race Tech, Slyfox, Alloy Art, Speed Merchant, and Pro1 has all the bells and whistles including adjustable compression, proper valving for big bikes, as well as preload, and rebound damping means you can fine-tune your suspension for your own personal riding style. 

A well made seat like this Step Up from Saddlemen can give you both comfort when you are riding many miles and be supportive when riding aggressively.

Switching to a lighter lithium battery like these from AdvanBlack over the stock heavy one can save you 9 pounds or more.

Yes, titanium is hitting the V-Twin market big time with pipes, bars, and bolt kits being the major lightweight players. 

Word & Photos Jeff G. Holt