Dyna Suspension Upgrade

Progressive Suspension 970 Series Shock Install

Dyna Suspension Upgrade - Hot Bike Magazine

01.Progressive’s 970 Series come with two shocks, a preload adjustment tool, and a bag of sleeves and collars. To set its shocks apart, Progressive came up with a signature Bronze anodize color for the 970s.

01.Progressive’s 970 Series come with two shocks, a preload adjustment tool, and a bag of sleeves and collars. To set its shocks apart, Progressive came up with a signature Bronze anodize color for the 970s.

02.Here’s Ron’s ride, a brand-new ’11 Street Bob. Ron doesn’t like to waste time; in a few months this bike will be upgraded in looks and performance.

03.Kevin started the install by slightly raising the rear tire off the lift with a center jack. He then unbolted the top and bottom of the right-side shock and set the stock hardware aside as it will be used to install the 970. He was then able to remove the shock.

05.Here’s a cutaway of the components and inner workings of the 970s.

06.The 970s come with these steel sleeves and collars which slide into the shock’s eyelets

07.Kevin slid a sleeve between the top and bottom eyelets, then pressed in the collars with a bench vice.

08.He then applied some thread locker to the stock hardware, slid the right-side 970 into position, and torqued the hardware to spec.

09.After repeating the process to install the left side, installation was complete. Next, Kevin set the sag. Ride sag is the amount the suspension compresses with the weight of the rider and/or passenger/luggage. Setting ride sag is important as it sets the shock up to properly handle bump travel and extension travel. Progressive recommends a ride sag of 1/3 of the wheel travel. For example, if a bike has 3 inches of wheel travel, the ride sag would be set at 1 inch. To set the ride sag, Kevin fully extended the rear shocks and took a measurement from the center of the axle to the center of the fender mount.

10.With the rider on the bike, he then took the same measurement. Kevin subtracted the second measurement from the first and came up with the ride sag amount.

11.He then loosened the lock ring on the preload adjuster and adjusted the preload ring until the shock was set at the proper ride sag amount. Once he had the correct measurement, he tightened the lock ring and set the other shock up to the same measurement.

12.All that was left was for the rider to go for a testride to set up the compression to his liking. The compression adjuster is dialed-in with a series of clicks adding more or less compression.

13. In less than 20 minutes the rear of Ron’s Street Bob was ready for action. After logging several hundred miles, Ron reported that as soon as he got on the bike he could immediately notice a difference in ride quality. And once he dialed-in the compression, he said the bike handled much better and was much more enjoyable to ride. The suspension was smooth over regular road inconsistencies and plush over larger bumps. When he pushed the bike into turns, he felt a positive response from the rear of the bike as the suspension kept the rear wheel hooked to the ground and the back of the bike tight under his body and not sloppy like he felt on the stock shocks.

We’re not sure if it’s the influence of Sons of Anarchy, people taking a liking to the mean look of a club-style bike, or riders realizing the performance potential of the Dyna models, but whatever it is, Dynas are hot. A friend of ours, Ron, has been hip to the styling and performance capabilities of Dynas for a while now, and the recent purchase of an ’11 Street Bob makes for his third Dyna. Ron is a hard rider who rides long distances really fast and likes to push his bikes to their limits. So when it comes to making modifications, one of the first things he does with his Dynas is upgrade the rear suspension.

When it came to upgrading the shocks on his Street Bob, Ron turned to Progressive Suspension and its new 970 Series with piggyback reservoir. Continually striving to provide riders with suspension that offers an enjoyable ride with the benefits of comfort and performance, Progressive developed the 970 Series as a de-featured race shock. Originally the company planned to only make a short run of these shocks; however, the response was so good that Progressive put them into full production and expanded the application list.

On the exterior the 970s feature a forged aluminum body, 6061 aluminum tube construction, and a hard-chrome main shaft. Like all of Progressive’s shocks, the 970s utilize progressive rate springs. They also feature damping control and adjustable preload. The combination of the progressive rate spring, damping control, and adjustable preload allow the rider to tune the ride quality and bottoming characteristics. Unlike standard springs, which compress at the same rate (amount of force required to compress the spring), progressive rate springs require more and more force as they compress. The more a progressive rate spring is compressed, the stiffer it gets, resulting in a spring that is supple enough to soak up smaller bumps, but firm enough to absorb large bumps without resulting in hard jolts. Just above the spring is the preload adjuster, which can be used to compress or uncompress the shock and allow the rider to set the shock accordingly depending on weight, cargo, or if there is a passenger. At the very top of the shock body is the piggyback reservoir, which has a compression adjustment knob. The compression adjustment knob allows the rider to adjust the damping effects of the shocks based on the riding style and expected terrain.

To further improve the performance of the shocks, Progressive utilized several friction-reducing coatings and a shaft seal designed to reduce friction resulting in a shock that can be activated with a smaller amount of force and is more compliant on the road.

Follow along as we watch Anaheim-Fullerton service tech Kevin install the 970s and properly set them up for the rider. HB


It’s What’s Best for You

According to Progressive, compression damping is all about ride characteristic tradeoffs. Damping preferences for each rider and situation will differ. Less compression can offer better rider comfort as the shock produces less resistance to movement from an impact. The shock absorbs more, so less of the impact motion is transferred to the rider. The risk of softer compression is the potential for bottoming out, or running out of stroke in the compressed direction. Too soft of compression can result in too much motion that feels mushy and disconnected from the road. Increase compression damping and the shock produces more resistance to movement on impacts and reduces the possibility of bottoming. Increased damping will provide quicker ride motions with a more connected feel to the road. The tradeoff is more of the impact energy will be transmitted to the rider sacrificing ride comfort. Different riders will be willing to give up certain benefits to achieve others, and different terrains and situations will be best suited for different damping characteristics. An adjustable compression damping feature will allow the rider to tailor the shock to the road conditions, riding conditions, and their preferences.


Anaheim-Fullerton Harley-Davidson
(714) 871-6563 | harleyfullerton.com

Progressive Suspension
(877) 690-7411 | progressivesuspension.com

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