As much as we enjoy making big power on an engine dyno, keeping it pointed in the right direction is just as critical.
So we sat down with our old pal Lee Grimes from Koni North America to talk all about performance suspension tuning 101. If the name sounds familiar, we actually met Lee a while back when he rumbled the Koni Mustang into the Summit Racing headquarters way back in 2018—he had plenty of advice then, and he’s got even more now.
That’s because Lee’s not just a guy who knows a lot about Koni suspension parts, he’s also serious racer with around 40 years of track experience under his tires. Suffice it to say, when he offers insight and tips on suspension tuning, we’re inclined to listen.
We recorded an entire 30 minute interview with Lee that you can hear below, and we’ll take 10 short excerpts from our chat and include them below. If you’re trying to get your suspension to that “juuuust perfect” spot, we recommend listening to his full advice in the podcast episode.
10 Suspension Questions with Lee Grimes from Koni North America
1. What Advice Do You Give Folks Who Are New to the Suspension Upgrade Process?
“Your vehicle’s suspension is going to move as the car goes straight, accelerates, brakes, and it turns corners. The weight of the car moves around a little bit. So if you can get a suspension that’s going to connect you to the road, and help with the grip, handling, and balance of the car, that’s what’s going to make the car work the best.
“And then if the car is also being used on the street, you want to make sure that it has a level of refinement and acceptable comfort to serve the needs of a daily driver.
“It’s a matter of finding a balance. So when someone comes to me for suspension advice on a particular vehicle, my first question is ‘What do you want to do with it?’
“The more we can focus in on what your needs and expectations are, then we can decide which characteristics are best going to suit you.”
2. What’s the Issue with an OE Suspension System for Performance Driving?
“Factory shocks are going to be as good as they can ultimately be for a very generalized customer. And, just the way volume manufacturing works, they’re going to do the best they can with a relatively inexpensive product—a shock may cost the manufacturer under $10.
“They’ve got to paint with a pretty broad brush and keep the bean counters happy.
“But if you’re willing to look in the aftermarket for something better, that’s higher quality, then all kinds of opportunities open up.”
3. Is there a Recipe or Logical Progression to Follow when Upgrading a Suspension?
“It’s going to change with the vehicle and the application. Ultimately if you’re in a sportier performance situation, you’ve first got to make sure your tires are appropriate, because your tires connect the car to the ground.
“The next issue, is your intention to lower the car—or not? If it’s your daily, are you willing to sacrifice comfort? Again, focus on what the expectations are. Something like Koni’s Frequency Selective Dampening shocks can be a solution. Or if you want to lower the car or do any fine-tuning, you can look to an adjustable shock.
“Determining your goal for the car up front is going to deliver the best outcome.”
4. Are There Any Common Suspension Issues That You’re Often Asked to Solve?
“People hear some buzzwords, and they think that it’s the ‘cool’ thing you need to do, but they may not understand the ramifications. And that’s especially true if they’re on a tight budget. I’ve heard from people who were just randomly buying popular parts, and have had three or four suspension systems on their car because of it.
“Coilovers are a good example. They offer a great deal of opportunity to people, changing ride heights and spring rates—but those are pretty technical and focused things. And there’s often a lot of compromise.
“A lot of coilover systems let you get really far down, but they’re also often pretty harsh riding. You don’t need to necessarily beat yourself up on the road to have good handling.”
5. How Does Lowering a Car Make it Handle Better?
“As you accelerate, decelerate, turn left or right, the weight of the car above the suspension is what’s known as the sprung weight—that’s you, the engine, the weight of the car itself.
“The more we can control that motion, and not just let it flop over, the more responsive the driving feel’s going to be. And the more consistent the tire loading is, it will help effectively maximize the grip.
“Then, the car is easier to drive. If we can refine that motion and you really feel what the car is doing, now we can push it closer to the edge.”
6. Is There a Limit to How Low You Can Go?
“Absolutely. You’ve got to work within the suspension stroke that the vehicle designers give you. And quite frankly, as a lot of cars are getting more refined and the packaging gets tighter, there may not be a large amount of stroke that you can just take away.
“Say you want to lower a car by two inches, we’ve got to make sure that you can take away that two inches and not make the suspension bottom out on a regular basis. To make it balanced, and not have a suspension that is now a solid—you need it to move.
“Some cars you may not be able to lower as much as another. You might not be able to lop-off suspension stroke for one, like you may be able to do on another. You’ve got to work within what’s already there to make sure you don’t sacrifice function for a key look.”
7. Is There a Common Culprit You Often See on an Improper Suspension Setup?
“Over-lowering is an awfully big deal—because cars look cool when they’re really down. But you may have just taken away all the suspension motion and made it too stiff. That’s probably the most common thing that we run into, especially on a car that had a limited suspension stroke to begin with.
“You want to lower it to make it look better, to be firmer for more control—but it’s still a dynamic system that rides on public roads, railroad tracks, potholes, and bumps.
“It all goes back to: What is your car, how do you use it, and where do you use it?”
8. How Important is Adjustability? Do You Have Any Recommendations?
“If someone wants to improve handling, having an adjustable shock, like the Koni Sport, you can affect the balance of the car.
“For example, front wheel drive cars have a tendency to under-steer when you’re really moving fast, pushing the tires. But if you lift off the throttle, you can also make the car snap over-steer as well. Once you’ve got some tuning pieces, like shock adjustability, now we can begin to play with the adjustments to bring the balance to where you want it to be.
“If your issue is at corner entry, then adjust your rear rebound damping. With a little more rebound stiffness, you can make the back end of the car a bit more lively, more likely to rotate. Or if the car is too snap-happy, the weight is transferring too much, in that case we’d want to soften the rear rebound.
“At the apex of the corner, the shock isn’t doing too much, and that’s really more sway bar territory. And then at corner exit, as you’re beginning to roll into the power, then front rebound is something you’re going to look at.
“Once you get a bit of adjustability into the system, now you can begin to refine it—tuning it from corner entry, to apex, to corner exit. And that’s what’s going to make you faster.”
9. Is There a Point When You Need to Stop Adjusting Things?
“Not necessarily, because you can throw-in other parts. Are you running the factory sway bars or spring rate?
“If you research, you can continue to dive down and further refine the car, make it quicker, and make it ride better.
“Everything works together; nothing operates in a void. Shocks can make a really big change on an otherwise stock car. But if you want to do springs, or maybe a different wheel and tire combo, the more adjustability that you have, it lets those pieces work together better, even if they’re from different manufacturers.”
10. Should You Consider Ancillary Vehicle Systems & Parts Too?
“You have to add tires in there relatively quickly, as they can become the weak link in the chain. Again, everything works together.
“It’s easy today to add a significant amount of horsepower. At some events I’ve been to, if you don’t have 400 to 500 horsepower, it sounds like you’re not even trying. (Laughs) But if that power’s not connected to the ground, not only does that not do you any good, it can actually cause trouble.
“That amount of power can overwhelm the driver and the suspension. So you’ve got to make sure the whole package works together. Huge power doesn’t do you any good if you can’t put it to the ground.”
You can hear more from this interview in the OnAllCylinders Podcasts section.
Better still, Lee and his team of suspension experts are happy to help talk-through your questions and guide you along your suspension upgrade path. You can start that conversation by visiting the Contact Us page at the Koni North America website.