“One of the biggest mistakes we hear often is people making a wide range of changes to their vehicles all at the same time: stiffen the front sway bar, remove two clicks of rebound from all four shocks, add one click of compression on all four shocks, add more negative camber to the rear, etc.
If all the changes are made at the same time, the effect on the car will be drastic and will make it difficult to discern which change directly affected the undesirable behavior you were trying to tune around or improve. The behavior may be gone, but you may sacrifice performance elsewhere by making changes that were unnecessary. The best way to determine this is by only making one change at a time and testing its effects.
If your suspension has adjustable dampers, it’s wise to verify that your settings match from side to side.”
Frank Vasquez
Brand manager
KW Suspensions & ST Suspensions
“I talk to many people who go overboard when looking for a low vehicle. They’ll order our lower arms–a 1-inch drop–with the Pro Springs–a 1.3-inch drop–and add tall lower ball joints–a half-inch drop–all packaged around a 2-inch drop spindle. Let’s see: 1+1.3+0.5+2=4.8 inches of drop. There’s no room under the car!”
Tom Przedpelski
Specialty Products Company
“I don’t know why we get so many questions that start with, “I just put this part on my car….” Why not ask us before you go through all the trouble of acquiring and installing the parts? Ask questions first, then hit the Buy button.
Facebook groups and other online forums are full of supposed experts who love to offer advice based on what they’ve read online. (Okay, the Grassroots Motorsports forums are pretty solid for tech advice, we admit.) In our experience, the best advice will come from an experienced parts installer who works on your specific kind of car (like–cough!– Mach V Motorsports for Subarus) or from consumers who have actually been down this path.
Seek out people with the same type of car in the paddock at the race track or at your local autocross. Ask them what they run, why, and how they like it. Would they do it differently if they started over?”
Dan Hurwitz
Owner
Mach V Motorsports
“Most people don’t understand that those cool DTMs or European Touring Cars that sit really low often have massively redesigned suspension geometry and pickup points to make it work better on true racing tires in a dedicated racing situation: smooth race track without any street hazards. It is not just a stock geometry just slammed to the ground on public roads, rough surfaces, street tires, etc.
Measure the car before you lower it so you have an original reference point. Not having a ‘before’ measurement takes away real data and leads to only assumptions, and it is easy to misjudge how much it has actually been lowered. Without a starting measurement, you’ll never know if your car actually came down 2, 2.5 or 3 inches.”
Lee Grimes
Automotive product manager
Koni
“The golden rule of working on setup is to first analyze your driving to see if you may be inducing the unwanted balance issues. When we’re adjusting setup, in most cases we’re adjusting weight transfer–how much weight transfers, how quickly it transfers, etc.–because that is what affects grip. As race car drivers, every input we make affects weight transfer, too. So, step one is understanding the fundamentals of how to drive a race car quickly around the race track. That includes figuring out if the setup issue is something that’s preventing good fundamentals or something you are inducing. When you’re ready to do setup work, don’t overcomplicate it. Do one thing at a time and have a thesis for why this change should work. But if you don’t feel any difference or the result is negative, go back to where you were and try something else.”
Dion von Moltke
Co-founder
Racers360
“In the holy-grail chase for super-high caster, there may be undesirable consequences–for example, bumpsteer. If you rotate the knuckle too far back, the steering arm changes position vertically and the tie rod doesn’t stay in the correct orientation to the control arms. Backing off the caster can help how the vehicle feels. (There are some bumpsteer kits for many cars that change the height of the tie rod-to-knuckle attachment. These often replace the tie rod end with Heim joints.)”
Tom Przedpelski
Specialty Products Company
“Your amateur competition vehicle has to set up differently for each track layout, so to make sure your vehicle is competitive, you have to spend the time making the correct suspension adjustments for where you are running it.
Suspension bushings are the weakest link to the suspension system and must be addressed! The larger the rubber stock bushings, the greater the need to replace them with firmer ones. Suspension bushings made of performance-grade urethane/ polyurethane must be used. Not available for your vehicle? Sometimes, make your own sway bar end links of hard-durometer, Delrin-type material.”
Art Niese
Prothane Bushings
“The most overlooked part on IRS setups? Toe rods. IRSequipped cars have an inherent issue with the toe changing under heavy acceleration and braking. With excessive toe-in occurring in those conditions, you can experience rear-steer issues. The toe-out happens under heavy braking. Performance-tuned toe rods eliminate the deflection that the factory toe rods allow.
When modifying a suspension, there is almost always an increase in NVH: noise, vibration and harshness. The range of NVH that is tolerable differs from person to person, just like seating position. The OEM companies use soft rubber bushings to isolate NVH. So that vibration or noise was already there; it just becomes more noticeable once aftermarket parts have stiffened up the chassis.
Rod ends are great for performance by eliminating deflection and increasing articulation. The issue comes when people do not understand that rod ends are exposed bearings and are consumable items like brakes and tires. The more dirt, moisture and debris they’re exposed to, the sooner they can wear out or seize up. Keeping them clean definitely prolongs their use.
A lot of issues are created by people swapping out parts and not getting a good alignment done afterwards. A quality alignment is crucial in both straight-line racing and road course/autocross setups. Close enough is not acceptable.”
Frank Steadman
Quality assurance & returns department manager
BMR Suspension
“They call it a ‘suspension’ and not a ‘solid’ for a reason. It needs to be able to move to optimally load and work the tires and control weight transfer of the moving car. Just because Race Team X uses it or Online Parts Seller Y offers it, higher spring rates are not always better. Don’t forget that the cool race car with stiff springs may have lots of aero devices pushing down or a steady diet of fresh, super-sticky tires. Proper spring rate selection is not about online chest thumping. Mechanical tire grip goes away and ride harshness skyrockets as the tire sidewall (with its own basic internal spring rate and no damper) becomes the only remaining suspension once you take away the real suspension.
A car sitting on the bumpstops is not going to really work well, and the right answer is not just to cut away or throw away the bumpstop itself. A simple, strategically placed zip tie costing only a few cents placed on a shock piston rod can serve as a great suspension travel indicator providing real feedback on your car’s ride height, bump rubber function, etc.
Everything interacts; nothing operates in a void. You don’t drive a shock valving and a spring rate alone; it’s a car made of many parts that you are trying to optimize together on a road or track to give the driver the most confidence and performance capability. Get a basic understanding of what each type of suspension part contributes to the total equation so that you can tune and refine with what the driver feels. (And, likewise, just because a part is offered doesn’t mean that you need it.)
Is a car over- or understeering? Gripping or sliding? Is it repeatable and where in the corner is it happening–entry, mid-corner or exit? This can then help you determine what parts you need or what adjustments you can make to make it better.
Suspension operation and tuning is not black magic or smoke and mirrors. Having a basic, logical process or methodology to evaluate and tune your car will put you much further ahead, and the car will empower the driver to drive better and grow in capability. There is no single best setup that works for everyone equally, so once you have a general baseline or ballpark of parts and needs for that, it is up to the driver to understand and coordinate how they work together and how they support them.”
Lee Grimes
Automotive product manager
Koni
“A common suspension mistake is replacing OEM components such as lower/ upper control arms and doing a final torque with the suspension unloaded. Most bushings found in these style arms are fluid-filled and have a specific range of motion. If the arms are tightened at or near their maximum extension, it will place unnecessary stress on these bushings and lead to premature failure. It is always recommended to perform a final torque of suspension arms when the suspension is loaded as close as possible to what the chassis would see on the street.
We routinely field customer inquiries asking for customizations to our products with the expressed purpose of achieving a setup that will work best for a multitude of driving scenarios from daily driving to drifting, to autocross/track simultaneously. Unfortunately, there is no magic setup that would allow a certain chassis to excel in every motorsport scenario. Each discipline of motorsport requires specific chassis setup to maximize performance, and often times that same setup will underperform in a different motorsport scenario. Simply put, a competitive drift setup is not a competitive autocross/ track setup.”
Sam Bracero
Lead for tech support/R&D departments
BC Racing
“Roll is compliance and compliance maintains grip. Roll is also feedback. The driver cannot sense roll angle, only rate of roll. Less roll can feel far more confident in a car which is quick to ‘take a set.’ It can be easy to overdo this and end up with a car that sacrifices grip over every road feature.“
Rob Lindsey
Morlind Engineering
“Many consumers get hung up on shock selection: monotube or twin-tube? A twin-tube shock tends to generate more heat due to a smaller inner steel tube coupled with smaller valving. Nitrogen gas and oil are also mixed internally, which results in oil foaming. Monotube offers reduced temperatures thanks to a larger, single aluminum tube design and reduced oil foaming due to its separate nitrogen chamber. More stable temperatures and larger internal valving result in more fluid flow, increased damping consistency and reduced hysteresis.
Preload is often misunderstood. On a basic level, having enough preload is important to ensure complete shock extension. Without ample force applied to extend the shock, an unloaded inside tire simply floats across the surface, leaving nearly all cornering grip up to the outside tires. Proper preload allows the spring to continue pushing the tire into the pavement all the way up to the shock’s full extension point. This offers maximum grip and increased cornering ability.
Dedicated race vehicles are recommended to use systems harnessing divorced damping control and remote reservoirs. More shock fluid, more accurate and precise metering and fluid control, cooler shock temperatures, and more travel within the shock body offer more consistent oil viscosity, performance and precise suspension tuning.”
Cory Barker
Skunk2 Racing
“Are you struggling with the installation? Read the instructions! Most are available online now. Take a few phone pics before you begin disassembly so you can see the orientation of the sway bar.
Noisy sway bar? Grease the bushings! And grease only the bushing bore/inside, not the outer section. Use the manufacturer- supplied grease or a marine wheel bearing grease; Lucas makes a good one.
Got a new rattle from the chassis? It’s likely that there’s a loose fastener in the assembly. Check all the fasteners for torque with a torque wrench.
Be safe. Work on a smooth, level surface. Use a sturdy floor jack and good jack stands. A modern LED shop light can be a big help when you‘re burning the midnight oil.”
Jeff Cheechov
The Progress Group
“It’s easy to gradually erode your travel as you make changes to the car, so go back and check it regularly. Pulling the springs off and moving the wheels through their full travel will also help identify if you’re having binding problems or if any parts are making contact with things they shouldn’t be. I’ve seen situations where a team was chasing a braking problem that turned out to be the front tires making contact with the top of the fender well.
It’s a lot easier to feel an underdamped suspension than an overdamped one, so start off soft and start increasing. The car might move around a little more, but less damping will make it more predictable and compliant, which means you can push harder and use more of the track surface.”
Keith Tanner
Flyin' Miata
“There is no replacement for seat time. The best way to learn how a suspension works is to play with it. Make changes, evaluate, take notes. Especially when you’re dealing with things like shock and sway bar settings, it’s usually easy to make changes and test. When you’re testing, do your best to isolate the various aspects of the car’s behavior. Start with steady-state cornering and get your basic balance sorted out. Then start working on more transient behaviors, like corner entry and corner exit. Now you can start throwing bumps and curbs into the mix.
Notes are really important so you can go back to a known good setup or find out how you solved a similar problem last time. You can even try narrating what’s going on if you’re shooting video.”
Keith Tanner
Flyin' Miata
“Some people think that coil-overs will negatively affect the ride quality. In reality, with properly matched spring rates for the chassis using correct weight balance load, motion ratio and frequency of the suspension, a well-equipped, aftermarket damper can ride better than OEM in most situations.
A common misconception is that preload is affected by ride height. However, not all coil-over suspension is designed that way. For example, many suspensions have independent ride height and preload adjustments to fine-tune the suspension.”
Devin Herndon
Motorsports coordinator
Fortune Auto
“If your shocks have adjusters, they’re meant to be adjusted. But just keep in mind that this can have significant impacts on how your vehicle handles, which can be good or bad. Give yourself time to get used to new shock tunes and setups once you’ve made a change, especially if it’s a big one. Use the bracketing method. Take notes. Make incremental changes. Isolate variables. It’s an iterative process.
Reducing the sprung (chassis, cockpit, etc.) or unsprung (wheels, tires, etc.) weight of your vehicle changes the forces that your shocks need to control. To have the right amount of comfort and support, you also need to change the tune of your shocks. When you lighten your car, you need less damping; when you add weight to your car, you need more damping.
Over the lifetime of your vehicle, the oil in your engine breaks down, degrades, and needs to be swapped out. This makes sense because your engine revolves thousands of times a second.
It’s the same with your shocks. They absorb impacts hundreds, if not thousands, of times per second. Over time, the oil inside your shocks degrades from use, seals break down, and these things need to be replaced. If you’re still using your stock shocks, chances are they’re worn out and need to be replaced. Upgrade to quality aftermarket ones that can be rebuilt and retuned so your shocks can grow with your vehicle setup.”
Daniel Gillooley
Manager
Fox Academy
