When you hear the name Fox, in the motorcycle world, you likely associate it with off-road riding. A few years ago the company began offering suspension for the V-twin market, giving Harley-Davidson owners a chance to improve their ride with proven race-winning technology.
First, a little history. Founder Bob Fox first began making suspension parts for a Maico dirt bike before he joined his brother’s company Moto-X Fox, to run the AirShox division. Soon after, Bob’s suspension design was used to win, and place highly in multiple motocross races year after year. By the late ’70s, Fox suspension had expanded to off-road trucks, and later to on-road vehicles, winning in both AMA Superbike Championship and the Indy 500. Through the years, Fox suspension has been used in on- and off-road bikes, race cars, trucks, ATVs, and UTVs, as well as snowmobiles, watercraft, and mountain bikes.
You don’t have to ride a racebike to appreciate the real-world benefit of racing-bred suspension technology and engineering. Any rider who logs hundreds of miles each day can attest to feeling saddle sore. Many riders will attempt to fix this with an aftermarket seat, but you are far more likely to get the comfortable ride you seek by upgrading suspension. Investing in more sophisticated fork innards and shocks will not only improve your experience eating up the straight freeway miles, but will help keep your bike settled and riding smoothly through the twisties and over bumps and dips as well.
Fox has created a full lineup of front and rear suspension to fit a wide range of Harley-Davidsons, everything from a Sportster to an Iron 883 to a Road King. The V-twin suite of suspension components include RC-1 ($1,199/pair), QS3-R ($1,199–$1,299/pair), IFP ($649/pair), and IFP-R ($749–849/pair).
The bike we rode for our Fox suspension test ride was a 2017 Harley-Davidson Road Glide Special. Fox’s suspension techs installed their Grip Street Performance fork cartridge kit 49mm Standard, made specifically for Harley-Davidson touring models. The Standard fork cartridge kit ($549) is built to handle loads up to 240 pounds, which includes the rider, passenger, and any luggage you’ll have loaded on the bike. Fox offers the Grip Street Performance Cartridge Kit in 41mm and 49mm diameter fitments, and both sizes are also available in Standard or Heavy Duty (HD) for loads greater than 240 pounds. In the rear, Fox installed the Grip Street Performance Rear Shock Set IFP-R 13-inch Standard shocks. These are the mid-grade option between the higher-priced QS3-R and lower-priced IFP shocks. Fox also makes a 12-inch version for a lower ride, and offers an HD version of both sizes. Its suspension experts set up the preload for each of our bikes in the morning, based on each rider’s weight, so we could feel the maximum potential of Fox’s dedicated fork kit and shocks. With just 135 pounds of rider weight, the suspension techs set it up with just three clicks of rebound damping.
Anyone who has owned a stock Harley-Davidson will be familiar with the suspension that comes straight from the factory. The stock springs used in the fork legs have a variable rate, meaning they have varying distances between the spring coils from one end of the spring to the other. This translates to unpredictable compression and rebound damping in the corners, since you won’t know exactly which rate you are using at any given time. This often means the small bumps and ruts can feel harsh, while still allowing the front end to dive during hard braking. Companies will opt for progressive spring rates to accommodate a wide range of rider weights. But with a linear spring rate, like the springs Fox uses in its fork cartridge kits, it’s much easier to get the correct spring rate for your weight, and get a more predictable response to compression and rebound damping adjustments.
Another downfall of the stock suspension on Harley-Davidsons is the ability for the shock oil and gas to mix. When oil and air mix, it causes the oil to froth and foam (cavitate) which reduces its viscosity, making it less effective at damping compression and rebound. This can make your suspension feel better tuned at the beginning of a ride, and far worse by the end of it. Fox uses an internal floating piston (IFP) to create a hydraulic-damped shock, which keeps the oil and gas (nitrogen) separate to keep it from cavitating.
We headed out onto a wide variety of paved surface qualities for a full day of riding in the Santa Cruz mountains. There is no shortage of tight twisties through the redwoods, and there were plenty of opportunities to put Fox’s suspension components to the test. As we dipped through tight uphill corners, the front end absorbed the quick variations in the elevation, keeping the front wheel planted. This was a more spirited pace than we would normally be riding a bagger. Making our way over tree roots pushing up through the pavement, we found the front suspension compressed and rebounded with finesse, keeping the front wheel in contact with the pavement. As we glided through the redwood forest roads, tight hairpin turns came up quickly. Stabbing the front brakes of the Road Glide Special didn’t cause the front end to dive; the front end remained stable and predictable.
While we had adjusted our preload before setting out on our ride, the settings on the IFP-R shocks were still a bit harsh for our 135-pound rider weight. There were a few points where rolling over a medium-sized bump actually launched us out of our saddle about an inch, so at one of our pre-lunch stops, we added three more clicks of rebound damping. That seemed to do the trick, as the rest of the day went more smoothly; the IFP-R shocks kept the Road Glide Special’s rear end planted. The “R” of IFP-R stands for rebound, and that extra adjustability was very much appreciated, and is worth the extra $150–$200 over the standard IFP shocks.
At the end of the day, the Fox suspension proved its weight in gold, turning these otherwise vaguely wallowing baggers into more comfortable, responsive machines. Fox’s 40-plus years of suspension engineering prowess is evident in its lineup of V-twin Grip Street Performance fork cartridge kits and IFP-R shocks. If you’re itching to spend money on aftermarket parts for your Harley, you would be wise to spend that hard-earned cash making your bike more comfortable and safer to ride. The upgrade won’t be the flashiest aftermarket addition to your bike, but it will be the smartest.
Verdict: Fox Harley-Davidson Touring Suspension
Grade: A
Summary: A worthwhile investment to improve your Harley's ride.
Price: $130–$1,299
Contact: ridefox.com or revzilla.com