What Makes A Good Damper

After years of helping a wide variety of folks across a myriad of classes set their cars up, there are a few things I’ve learned…

IME, your average end user cares about a few things.

1. Does it properly fit the car, and install as designed. Usually, most people will prioritize ease of installation over outright performance. If you have to design or make something to get it to fit, it's a non-starter to the end user.

2. Does it ride okay over bumps? While this is easy to achieve with effort in nearly hardware quality, this is probably what most end users will think is the biggest difference between a "cheap" shock and a "good" shock. Most of this just comes down to horrifically poor valving choices for the use case in inexpensive shocks. Usually they're using a one-size-fits-all damping curve, a cheap linear piston, and something that they can make up with how mismatched it is with the adjuster most of the time to make this okay. Of course, that usually means that the best riding setting is not the best dynamic handling setting. So people consider that an either/or proposition and move to #3.

3. How many adjusters does it have? Because so many dampers come with such mismatched valving for the application / rate / use case, they need to make extensive use of the adjusters to shape the curve remotely close to being right. You'll see this in shocks that dyno the same front/rear for the same car, have identical curves for dissimilar platforms, and try to run the same shock for a street car on 200lb springs as they do on a race car with 1000lb springs. A jack of all trades is a master of none.

4. How big do those adjustments feel? By and large, people are setting their dampers based on feel, not on grip, tire loading, or pace. So feeling a HUGE adjustment, regardless of whether or not it's a useful one to make for more grip, is preferable to many.

5. The hardware needs to have no glaring flaws. Shock needs to be dimensioned sanely (not too long, not too short) for the ride height it intends to be run at. The designs needs to not contain inherent flaws that generate hysteresis or friction unnecessarily to support the rest of the demands of the shock in its application. The adjusters should be designed / quantified to work in a way that is intuitive and consistent to the end user. WRT "priority", the core here is just "the hardware can't prevent you from arriving at step 2"

6. The valving needs to be nailed. A terribly valved "perfect" shock otherwise will get outperformed by a bad hardware, poorly designed shock that has optimized valving for the use case. Adjusters are not powerful enough to overcome this, no matter how many you put on a shock. This is 100% the most important thing, and disappointingly, probably the thing that convinces people to spend more and more money on more adjusters, because while it can get you closer to a right valving, that is something better obtained with fixing the valving than it is very expensive adjusters that aren't nearly as powerful.

7. The damper needs to react very quickly, have very low hysteresis and friction. The lower the rod pressure, the more quickly and easily the damper can react to a force acted on it. The lower the friction, the less impact that friction will have on the damper forces, allowing your damper to behave much more precisely. The lower the hysteresis (largely affected by friction / flow paths that generate latency), the more consistently the damper will behave in accelerating versus decelerating velocities, which allow you to more accurately choose a damping profile that results in maximized grip. No shocks in the consumer market are good at all of the above. Some are good at some, and horrible at others. Some are great at some, good at others, and ok at best at yet others. While making a really great damper is expensive, being expensive alone does not make a great damper, and there's effectively no correlation between damper price and damper quality, beyond a floor of what seems to be around the $400/corner price. Once you're there, depending upon the amount of engineering work you can undertake, you're able to outperform shocks up until you get into extremely motorsports-focused, $2k/damper costs.