Basic Suspension Tuning: Getting Started!

Discussion in 'Getting Started in Sim Racing' started by Fullhouse, Mar 11, 2018.

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  1. Fullhouse

    Fullhouse Armchair Racer

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    Suspension tuning can be quite difficult. Some changes that work well on one car may not work well on another. Getting a good suspension tune is crucial, as it can mean the difference between winning a race or hitting a wall. Hopefully this guide will help you understand the basics of how a car handles and make tuning a bit easier. Remember, there is no right or wrong tune! Every person has a different idea of how they want their car to handle, so set up your vehicle to work best for you!


    Ride Height: This is pretty self-explanatory. It’s how high your car sits off the ground. Generally you want a fairly low ride height, this brings the car’s centre of gravity closer to the ground, resulting in better balance, less leaning in corners, and a pretty cool look too! Even better than that, you can adjust how the car handles by raising or lowering the front and rear ride heights separately. Be careful when doing this though, lower ride heights can cause the suspension to bottom out (the springs run out of travel) and body damage if the track is bumpy. The best advice I can give is to leave adjusting ride height to the end, once everything else is sorted. Then you’ll know how much suspension travel you’ll need.


    Spring rates: These adjust how stiff your overall suspension is. In most cases, running a stiffer spring rate will help the car corner better. However, setting it too stiff will make it difficult to transfer weight, and on particularly bumpy courses, it can cause the car to bounce around. Different cars react to spring rate adjustments differently, but as a general rule the springs are stiffest where the most weight is. For example, a front wheel drive car will have stiffer springs, but a mid-engined car will likely have stiffer rear springs. Ultimately, it’s a case of personal preference so be sure to experiment.


    Dampers: Dampers are designed to reduce (or dampen) suspension oscillations. They are often referred to as shock absorbers. Ever see videos of old cars from the early 1900’s bouncing around after hitting a bump? The reason modern cars don’t do that is because modern suspension incorporates dampers to keep the springs from bouncing around after absorbing a bump. (something they didn’t have back in the early 1900’s) Newer cars are quite heavily damped, and generally this is what you want when tuning your car. Like spring rates though, different cars respond to damper adjustments differently.


    Anti-roll bars: These do exactly what their name suggests; they reduce body roll while going around corners. These are a great way to adjust how your car handles, a stiffer anti-roll bar in the front will encourage understeer, whereas a stiffer anti-roll bar in the rear will cause more oversteer. Almost always, the front bar is set higher than the rear one to make the car stable, but feel free to adjust according to what you need!


    Camber: Camber is a little trickier to explain than the things above, but think of camber as the amount a wheel is vertically tilted. Ever seen pictures of tuners or show cars with wheels that look like they’re about to fall off? That’s a very extreme case of camber. When a car goes around a corner, it leans onto its outside wheels. If the car has some camber, the car will lean more onto the rest of tire, generating more traction. Too much or too little camber will cause quite a bit of traction loss, so it’s important to get right. Most road cars have a little bit of camber from the factory to help cornering and stability, but not enough to cause excessive tire wear. If you plan to race these road cars though, adding camber may prove beneficial. If you’re stuck on where to start, I personally set my rear-wheel-drive cars to around -2.0 degrees camber in the front and -3.0 degrees in the back, then adjust based on what the car needs. I almost never adjust the camber past -4.0 degrees, and if you are having to do so, chances are there’s something else set up wrong in your suspension. If you’re planning to run an endurance race, you may want a little less camber than usual to help the tires wear more evenly, but again it’s a case of personal preference.


    Toe: This adjusts the amount the front of your wheels point in towards the car (toe in) or away from the front. (toe out) An easy way to remember this is to use your toes, pointing your feet inwards is toe in, and pointing your feet outwards is toe out. When a car has its wheels toed in, the spinning of the wheels is pushing into the car slightly, making the car more stable. Toe out has the opposite effect. Almost any road car you’ll drive has toe in on either the rear wheels or all four wheels, so the car tracks straight instead of wandering around and hitting the neighbour’s dog. Adjusting toe can completely change the way a car drives, turning an understeering mess into an oversteering one, but be careful with how much toe you use, as excessive amounts cause more heat and wear on the tires. As with all other forms of tuning, mess around with it until you find something you like. (Here’s a hint, if you’re trying to make a really pushy front-wheel-drive car turn better, adding some toe out in the back can help you swing it in better)


    Differential: Ok, it’s not technically part of the suspension, but it’s a very important part of tuning that many people overlook. The differential is a device between the driven wheels that can allow one wheel to spin faster than the other as a car goes around corners. While I won’t explain how it goes about doing this, I will say that an average differential (known as an “open differential”) will always try to send power to the wheel with the least resistance. On the road, a driver will likely never run into an issue with this, but on a track it can become a major issue. It’s very hard to launch a high powered car with an open diff because the engine will often just end up spinning one wheel while the other does almost nothing, ruining acceleration and possibly tires too. To get around this issue, racers use a “Limited Slip Differential”, often simply abbreviated to LSD. (Ya, I know it’s a bad abbreviation) An LSD lets the wheels spin at different enough speeds to go around corners, but it prevents one wheel from taking all the power from the other. There are many types of LSD, but the one that’s most common is a geared differential. It has 2 different adjustable variables, locking when accelerating and locking while coasting (or braking). Feel free to mess with these to your hearts content!


    Transfer Case: If you’re planning on running all-wheel drive cars, then you’ll need to know what a transfer case is. Thankfully, understanding what it is really isn’t to difficult. It simply transfers power from the transmission to the front and rear axles. Many cars allow you to adjust the amount of power sent to the front axle versus the rear, which gives you options for adjusting how your car handles on power. That said, many modern cars are starting to use built in computers to automatically adjust this on the go, and often they do this very well. Personally, when it comes to stuff like Nissan GT-R’s or newer Mitsubishi Evo’s, I let their computer controlled transfer case do the work as opposed to tuning it myself.
     

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