Width Matters: Part 2

While wheel weight might affect the performance of your car, wheel size can affect both the performance and the safety of your car. This article could frankly save your life or the life of someone near to you.

 

Unfortunately, there are a number of enthusiasts out there that by following typical forum/magazine myths about wheel sizing, have put us all in danger. Many of these myths have been around for literally decades.

 

“You see, what I’ve found is that if enough people say something long enough and loud enough, everyone begins to accept it as fact even if it’s not necessarily true.”

 

This is certainly true of the general rules of wheel size selection that you get on forums and even in magazines.

 

Here are some of the myths you probably have been led to believe:

 

  • Larger rims with lower profile tires handle better
  • Wider tires give better grip and thus better handling

Both of these are (for almost all enthusiasts) entirely incorrect.

 

In this particular article, we’re going to discuss wheel width. Next time we will talk about wheel diameter.

 

“But how could this be? Of course wider wheels handle better! The tire is wider so you’ve got more rubber on the road!” I hear cried from a member of the peanut gallery.

 

Another member of the forum certified expert crowd shouts: “All supercars have super wide tires and low profile tires, if they’re doing it – of course it works!”

 

Unfortunately, both are only true in limited circumstances, and for most people reading this, they’re never true.

 

The point that both of these claims miss is that the cars they are looking to and learning from, were designed with those wheel sizes in mind, before hand. It’s not so much that wider tires do not give more grip – it’s that if you do not also have the suspension to match, you may actually be creating a very dangerous situation indeed.

 

Think about it, have you ever seen a factory tuned car that came with significantly wider wheels or significantly larger wheels? You may have seen an inch or just over added, but no factory tuner worth their salt has ever gone much more than that – without also altering the suspension.

 

The primary reason, is fitting a car with a wheel or tire combo that has a different offset or width will affect camber, toe, and caster angles in the suspension. Lowering a car will also have a similar effect. These changes have significant impact on the handling of the car and can even make it downright unstable.

 

Even where the alignment is corrected, there can be significant changes in the scrub radius of the vehicle and unfortunately, in almost all production cars, scrub radius cannot be directly adjusted.

 

In order to compensate for the change in the suspension geometry you introduced with the new size wheels, you would need to completely revisit the suspension geometry and this would require extensive modifications in most cases, far outside the resources of the average home mechanic. To correctly address these changes, you would literally need access to an alignment rack and the ability to fabricate custom control arms, and other suspension pieces.

 

Danger of Wheel Width

 

Which brings me to the first main point of this article. Given most people’s suspension tuning abilities and resources – straying far from the original tire and rim size will result in worsened handling and acceleration. In some cases, even downright dangerous handling characteristics at the limit , or in the event of a tire blow out or single wheel brake failure.

 

I’ll go ahead and brace myself for the “but Nathan!s”, but stick with me and I’ll explain why getting this point will put you miles ahead of everyone else on the street – and even save you a good bit of money and possibly even your life.

 

Wheel Width

 

Simply put, this is where everyone goes wrong. The actual tire width isn’t as important as the OFFSET of the wheel in this case however. Small changes in tire width are sometimes acceptable, though they still alter scrub radius, a key figure that determines how stable your car is, or isn’t at the limit.

 

You see, in order to fit wider wheels, typically folks use smaller offset wheels to accomplish this. The lower the offset, the closer the wheel face is to the hub. The opposite applies for those who fit larger offset wheels to push the tire edge out towards the fender.

 

In both cases, the scrub radius of the car is altered. It either becomes smaller or larger. Both can create dramatically different handling characteristics at the limit, and for the street especially, all of those are highly undesirable.

 

Symptoms of modified scrub radius include the tendency for the steering wheel to ‘rip’ out of the hands of the driver during hard braking or turning. The wheels will also tend to react violently to imperfections in the road surface, especially when being pushed.

 

Aside from safety, it should also be noted that given a stock suspension setup, or a simply lowered one, you will not gain any additional rubber on the road

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Think for a moment about an inflated balloon. When it is sitting on a table, there is no weight on the balloon and the air pressure inside the balloon is constant. If you let air out of the balloon, more of the balloon will touch the table. If you put more air in, less and less will touch the table. Think of that as tire pressure. Then, apply pressure with your hand. You’ll notice that you get more balloon on the table, the harder you press.

 

The point of this illustration is to illustrate that the rubber on the road is mostly a function of air pressure and weight on the tire. The actual tire size matters minimally.

 

Disclaimer: Tires are infinitely more complex than a balloon. While the physics are at the very basic level the same, due to the complex construction of a tire, the basic physics are not a great model of what happens in the real world. It would take an extremely complicated simulator to even approach accurate predictions of tire width’s effect on a car especially at the limit. That said, the suspension geometry argument holds water. Contact patch is a little more debatable but from the data I’ve seen and from first hand experience, it seems that wider tires give more contact patch to a point, but then it goes backwards (less grip). It also is not easy to model or predict. The best method to find out if you’re competing is TRIAL AND ERROR, period. There’s no free lunch or general rule here. If you are not competing, then the advice given in this article is probably as close to accurate as it can be.

 

How can that be? Well, when a vehicle is sitting at rest (easiest to illustrate) , regardless of the size of the tire, the same amount of tire will be in touch with the ground, given the same vehicle weight and tire pressure. The only difference will be the SHAPE of the contact patch. This is an oversimplification and yes there are other factors such as tire construction that play a role – but stick with me.

 

Wider wheels will give you a more rectangular patch, while thinner wheels will give you a narrow yet longer more square patch. The thinner wheels will therefore be better (and of course there are extremes in both cases) for straight line acceleration and braking. The wider ones, because of the direction of the forces on the tire tread in the corners, will be better for cornering at the expense of some straight line acceleration. Unfortunately, it’s not quite that simple for say road racing as whatever gains you get in cornering, you’ll probably give up in the ability to get back on the throttle early. Something you would need to test and tune for sure, no guaranteed rule of thumb there.

 

In other words, wider wheels do not always net an increase in actual grip, but they can under the right circumstances with the correct suspension to go with.

 

As a matter of fact, the number one place you can pick up GRIP is in the tire tread and compound you choose. A 6″ wide tire, if it is appropriately sized and chosen for the application can handle over 1g of force if you use the right tire. You do not need a 14″ wide tire to achieve that kind of grip.

 

We’ll talk at another time about other ways that grip can be increased, just know for now that raw grip is not directly (and sometimes not at all) related to the width of the tire. Especially when we’re dealing with modified production cars.

 

As a bonus, thinner wheels tend to be lighter as well. You can gain a lot of wheel and tire weight by going wider.

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Wheel Weight Slows You Down: Part 1

Wheels are wheels right? Just pick whatever wheels look sweet on your ride and you’re off. Oh, and the bigger they are – the better, right?

 

Unfortunately, wheels are one of the major places that many enthusiasts completely ruin their car’s potential performance. They have an enormous impact on ride quality, acceleration, handling, and also to a smaller degree, braking.

 

Choosing the correct size and paying careful attention to weight will improve your car’s ride and ability to tear it up at the track and on the street.

 

Wheel weight is one factor that many enthusiasts are aware of. However, I still see so many people picking wheels for their car that weigh a LOT. Some enthusiasts select the right wheel, but blow it on the size they chose to run.

 

Let’s talk about weight first and then we’ll talk about one of the more controversial and surprising topics of wheel size in the next part.

 

Why does wheel weight matter? Wheel weight, if nothing else, is part of the vehicle’s weight and will need to be carried along with the car’s mass everywhere it goes. It Is one of the cheaper and easier items to change on a car, especially when it comes to weight. It’s free to lose weight by removing items, but replacing components with lighter weight parts is usually expensive. Wheels, are multipurpose items and they can usually be the source of quite a few pounds of weight loss at a much better value than carbon fiber hoods and the like.

 

They are also a special sort of weight. Wheels turn (obviously) and therefore they are rotational weight. If you pick up a 30lb weight it may feel a little heavy in your hands. However, if you attach that same weight to a piece of chain or rope and begin to swing it, you’ll find out quite quickly that it is much harder to spin a 30lb weight than to simply hold it. It is also requires more and more energy the further out you let that weight slide from you. So, if you spin a 30lb weight on a 2ft piece of chain, it’s a lot easier than even a 3 ft section of chain.

 

The same goes for your car. A 30lb weight sitting on the floor is easier for your engine to pull down the road than a 30lb spinning wheel is.

 

It’s not as simple as saying (as some people do) that a lb off the wheels is worth 2x, or even 10x what a lb off the interior of the car is worth. The reasons are complex. For one, the weight of the wheel is distributed over a large area. Some aftermarket wheels have quite a lot of their weight focused at the center of the wheel (at the hub of the wheel), whereas others may have more of their weight focused on the rim of the wheel. It all depends on the material, construction, and style of the rim you’re using.

 

Also, the weight of the tires and where that weight is relative to the center of the wheel, is also important. We’ll talk more about that when we talk about sizing. For now, just understand that the further the weight is from the center of the wheel, the more it matters.

 

Now, the wheel is also one other special type of weight, which is UNsprung weight. On your car, there are two types of weight. One is sprung (or held up by the springs), the other is unsprung weight. Which, in most cars includes things like the brakes, the control arms, the wheels, tires, and so forth.

 

UNsprung weight is another complicated topic so I’ll try to keep it simple for this discussion. As you drive down the road, the road is pushing up and down on the suspension (the car is also doing the same, but let’s save that discussion for high school physics class). Other forces are at work too, when you corner for example, the weight transfer from turning puts a force on the suspension and relieves a force on the opposite side.

 

The suspension (aptly the springs and shocks) have to control both the weight of the car, and the unsprung components of the car. The lighter either component is, the easier job they have.

 

When you reduce the wheel weight, for example, whenever a wheel moves, the spring can more easily bring that wheel back to where it needs to be. In effect, it has a similar effect of fitting stiffer suspension springs or dampers. The reason is that the wheel has momentum wherever it’s traveling. Momentum is the objects desire to keep moving in a certain direction unless another force acts upon it.

 

Momentum is best ‘felt’ or demonstrated by thinking about pushing a light grocery cart and then trying to stop, versus pushing a several hundred pound cart and trying to stop. The heavier object has more momentum and is therefore harder to control.

 

Handling is all about controlling weight. Sway bars help control weight transfer, springs help control weight transfer, shocks control weight  and help absorb shock.

 

Unfortunately, I don’t have the space to go much deeper here. However, hopefully you’re starting to understand at least at the most basic level why wheel weight is important.

 

The bottom line is, the lighter your wheels (preferably with the majority of their weight focused at the center of the wheel), the easier your suspension can keep the tires planted firmly on the ground.

 

Lighter wheels also allow more torque to be available to push the car down the road. Turning a wheel requires TORQUE, so in smaller engines, lighter wheels really do make a difference.

 

There are two other side effects of lighter wheels that I don’t have time to talk about much here: better gas mileage (in the city only, no effect on highway mileage), better ride quality. The first comes from there being less weight to spin up every time you run through the gears. We’re not talking about huge MPG gains here, but I’ve seen 1-2mpg in the city before on certain vehicles. The other comes from the suspensions ability to respond to road imperfections better, and, the wheels’ weight is less significant so it upsets the chassis less when it moves around. It’s kind of like having a big sack of cement in the trunk versus your laptop – one actually makes the car feel different, the other does not.

 

Finally, lighter wheels can be stopped faster. In the real world, you may see a slight decrease in stopping distance (as-in, slight), and a slight decrease in the amount of heat you see at the brake rotor due to less energy being absorbed thanks to your lighter wheels.

 

In closing, whenever choosing parts for the unsprung portion of your car, always try to minimize weight whenever possible. There are some times when an increase in unsprung weight can be warranted, but as a general rule – the lighter, the better.

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Nitrous Oxide

Nitrous, or Nitrous Oxide is a power adder that provides incredible “Bang for the Buck” but for a number of reasons that we’ll explore today, almost never gets used, and that’s a shame because there’s really no better way to get a reasonable boost in power for peanuts.

 

Nitrous has a bad reputation for blowing up engines and is often even called “cheating.” Additionally, it gets a bad rap for not being “always available” and for needing refills to keep the power going.

 

All of these rumors have some basis in fact but as with almost anything, when used correctly, the benefits of nitrous are HUGE, especially for the target audience of this site: daily driven performance enthusiasts.

 

The biggest benefit of nitrous is that it provides enormous “bang for the buck.” You can purchase a nitrous kit, brand new for around $500 with everything you really need to start using it, maybe as much as $700 if you get all the bells and whistles, and instantly strap on 15, 35, 55, 65, 75, 125 or even 150 horsepower. The kits are usually pretty straight forward to install and the nitrous re1fills are about $40-50 or so at the time of this writing.

 

In a naturally aspirated engine, gaining 35-55 horsepower can be tough with any amount of money, and typically it costs more than the “fully loaded” nitrous kit (plus several bottle refills) to get even 15-20 horsepower out of your car. In most cars, a 10-20% improvement with bolt-ons can be had, but even a very low shot of nitrous can be worth significantly more, especially in otherwise low performance cars.

 

If you buy a second hand kit from someone, you have an even more price competitive solution. For example, I once bought a second hand “Zex” brand kit for about $200 locally which was good for a 55-75hp gain depending on jet settings and tuning. That’s enormous “bang for the buck”

 

So why don’t more people use nitrous?

 

Well, one of the rumors out there is that nitrous destroys your engine. However, this is completely untrue. Nitrous oxide is no more damaging to your engine than any other modification by itself, but like a turbo kit or add-on supercharger, the potential for blowing your engine goes up significantly due to the enormous amount of additional stress being put on your engine and the chances of running lean or experiencing pre-ignition due to heat.

 

You see, your engine can burn as much air/fuel as you can jam into the cylinders. The limitations are fuel delivery, spark plug/combustion chamber design and the physical strength of the engine itself to withstand cylinder pressures that can become quite high with forced induction solutions like nitrous, turbos, and superchargers.

 

However, nitrous is no more dangerous than a turbo or supercharger. To understand why, I’ll have to unpack what nitrous is a bit.

 

Nitrous is Nitrous Oxide, a gas which you may have been given if you’ve ever had surgery. It’s “laughing gas.” In the medicine field, it’s used to relax patients before procedures and is actually abused by some people for its euphoric effects. In an engine, nitrous is an oxidizer and to some degree a chemical/physical compressor of the air charge.

 

Oxidizers, for the purposes of this article, are compounds which provide dense amounts of Oxygen molecules to a reaction (such as the combustion of gasoline and air). Essentially nitrous serves as compressed air that is far more oxygen dense than the air around us. It is itself, not flammable, but under intense pressure and heat provides enormous “fuel to the fire” in your engine. Any time you detonate (not burn) a fuel like gasoline with an oxidizer, the resulting explosion is impressively powerful (for example, the combination of diesel fuel + ammonium nitrate, a different oxidizer are popular for demolition work and unfortunately also improved explosives in terrorism).

 

As we know, the more oxygen we can pack into a cylinder with the appropriate amount of fuel, the more POWER we can produce. Nitrous also super cools the air going into the engine as it is sprayed into the intake tract, this further allows more air and fuel to be packed into the engine with each rotation. In effect, this super chilling of the air is similar to the effect of compressing air by mechanical means (such as with a turbocharger).

 

The danger with nitrous, is the same as a turbocharger or supercharger, if you pack way too much air/oxygen in with not enough fuel, temperatures can sore inside the cylinder and cause components to melt/warp. To avoid that problem, we simply make absolutely sure that the air/fuel mixture is relatively rich (lots of fuel to keep things cool) and we do everything we can to avoid pre-ignition by running conservative ignition timing of either stock values or slightly “retarded” values

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The reason that engines fail with nitrous are the same that engines fail with boost. There is nothing particularly dangerous about nitrous, other than that people don’t often treat it with the respect that they do a turbo for example. Treat it with respect and keep your power gains reasonable and you shouldn’t have any troubles with nitrous.

 

Next is the idea that nitrous is “cheating.” I suppose it is if it’s against the class rules in your racing class, but for a street car, it’s absolutely not cheating. In a street car, or an occasional “for fun” dragster or something, I don’t see any problems with it. If the end goal of a high performance street car is to give the driver some enjoyment for a minimum outlay of cash, then nitrous might be a great way to do that.

 

As for the “not always available” argument, that’s very true. If your bottle is empty, you will have to refill it, that is true. However, if your gas tank is empty or you have no oil in your engine, it doesn’t matter how much power you have normally, your car still isn’t winning a race now is it? Same is true for nitrous, it’s just an additional “fuel” that you need to run the car at its optimum performance level, no big deal.

 

The thing about nitrous that makes it unique compared to other forced induction solutions as well as all motor techniques, is that it produces torque (POWER) – instantly. Whereas a turbocharger produces variable amounts of additional torque based on how much boost it’s producing, nitrous instantaneously adds torque with no lag. For this reason, even in high powered turbo cars you’ll often see nitrous added to make up for turbo lag caused by the enormous turbocharger and get the car into boost faster.

 

It doesn’t matter if you’re at 2500rpm or 8000rpm, you’ll still get gobs of torque with nitrous. Typically, this means that given the same peak power output, the nitrous car will beat the all-motor or turbo/supercharger car, all else being equal and traction dependent.

 

As for long term cost effectiveness, it depends on how much power you’re looking to add. If you’d be happy with a 35-75 horsepower gain (which is usually somewhat conservative), then a 10lb bottle in a daily driver can last for MONTHS depending on your driving habits, jet settings, and if you have it always ON or if you only use it when you really just want a laugh. Refills aren’t that expensive in the grand scheme of things and there are a lot of refills before you buy a comparable turbo kit even when you consider the kit cost.There A LOT more refills before you build a comparable “all motor” build.

 

Once you go over 75hp or so, I begin to see the cost effectiveness argument, but it depends on the expected use of the car and the cost of the comparable turbo/supercharger components to get there. With 75-150hp settings you can always install a second bottle to get more time before refills, the 25 pounds for the entire kit are highly offset by the 75-150 hp gain, are they not?

 

If a fully loaded (all the gizmos, bottle heater, rpm window switch, etc) “basic” kit costs around $800, let’s say. Then let’s say you can get an awesome deal on a complete turbo kit (that’s actually complete and not just some eBay “some modification” required kit) for $2000. There is a $1200 spread there. There are 24 bottle refills between the two options if a refill costs $50. The odds are good that no matter how much you drive hard, you won’t go through 24 bottle refills in the time you own your car.

 

Bottles of nitrous do go fast at the drag strip, typically you’ll see a bottle last about 8-10 solid runs at a lower nitrous setting (around 55hp), or roughly about as many runs as you can get at a typical test-n-tune event anyway. The thing is, very few people actually go WOT for a full quarter mile on the street, so the length of time the nitrous will last is actually quite significant, especially if most of your “WOT runs” are on on-ramps and to pass people on the highway.

 

Nitrous can be used with nearly any build. It works great with other power adders (such as turbos and superchargers) and it is not incompatible with most “all motor” setups.

 

Nitrous kits are also nearly universal, in other words, if you buy a 4-6 cylinder kit, it can be used with nearly any 4-6 cylinder car you ever purchase. Of course, that’s not true of nearly any other power adding solution, so you can keep your kit and upgrade your kit from car to car. In the long run, this makes it significantly less expensive than other options, even if you add in the cost of nitrous refills.

 

Safety and legality is one concern that needs addressing. Nitrous is not without risk. Compressed gas has to be treated with respect. A punctured compressed gas container can become a rocket, and excessive heat can cause a compressed gas container to literally explode. The amount of heat needed can only come from an external source, but it’s important to understand this risk and do everything you can to mitigate it. If you are going to use nitrous, the bottles should be in the trunk. Check your local laws because in some states it is illegal to have nitrous in the vehicle, in others it’s legal with certain rules (can’t be open/hooked up), and in others there are no regulations on the books at all. I am a safety fanatic, so with nitrous I believe it should always be very firmly mounted in a place unlikely to be damaged during an accident (close to the trunk firewall, towards the center of the car, for example). There should always be a plate of steel that separates the bottle from the passenger compartment. When wiring bottle heaters and other electronics related to your nitrous, always follow directions.

 

One important note is to always ensure that all nitrous components are on switched 12v sources so that they are only turned on when the engine is running. This is particularly true of bottle heaters. Bottle heaters have safety mechanisms implemented into them, however, always have additional fail safes. Ideally, a switched 12v source powers the electronics but additionally requires the user to activate them for them to turn on.

 

I think it’s always a good idea to have a fire extinguisher in your vehicle anyway, it’s particularly true when running power adders of any kind. If a fire should ever occur, only attempt to put it out if it’s small and the source is known. Otherwise, get away from the car immediately. Cars can be replaced, you cannot.

 

The only reason to perhaps consider only one bottle instead of two, is safety. Less oxidizer in the car and fewer bottles do reduce the odds of an accident occurring.

 

Finally, nitrous has essentially no effect on fuel economy. Sure it uses more fuel when you’re using it, but only when you’re using it. Turbos are also great about producing great power without negatively effecting daily driving fuel economy. However, nitrous is ONLY activated at wide open throttle, so it only activates when you’re asking the engine for all available power. Turbos however will use more fuel anytime you tip the throttle far enough to get into boost. That’s a fine trade off for most people, but it is a plus in the nitrous corner.

 

So, while some common sense safety measures are necessary with nitrous (or really any significant power adders), it’s actually a pretty cost effective way to add some fun to your daily driver.

 

If all your looking for is a nice “bump” in your car’s performance, then honestly it’s hard to beat it.

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Strut Bars and Braces

No matter what car you drive, there are a number of suspension braces available to supposedly improve handling. People shell out hundreds, even thousands of dollars on strut bars, under body braces, suspension member braces, fender braces, and frankly braces that attach to just about anything that has a bolt in it.

 

But what do these bars really do, if anything? Are all braces the same or are there important differences between them?

 

In today’s article, I hope to begin to decode a little bit about each of these extremely important questions. While everyone just assumes they wouldn’t be so popular if they didn’t “work”, I am here to tell you that there are far more bad products on the market than good ones – especially when it comes to chassis braces.

 

I am going to limit my discussion here to strut braces as they are generally the most effective and common. However, aside from placement, all other braces you can fit to your car are going to have a similar function.

 

What is a strut bar?

 

A strut bar is a simple metal bar that connects the left and right strut tower. The idea is that by tying them together, you reinforce the frame of the car and therefore you reduce chassis flex. It’s the same idea as adding an cross beam stud to a wall in your house.

 

The placement of the strut bar is particularly important as it is tying two of the most stressed points together and helping to prevent the body of the car from flexing due to a strong force to one side or the other.

 

For example, when you go over a raised bump with your right tire, the spring compresses as the wheel pushes up on the body. This force, if high enough, can actually cause the metal body of the car to move and twist. When this occurs, especially during high speed cornering, it can affect the suspension’s alignment temporarily and actually make the car feel less stable and predictable.

 

What do chassis braces DO?

 

Well, strut bars, contrary to popular belief, are not going to measurably increase your G-force handling in the corners. They won’t even measurably increase your cornering speed. They may, in some cases, improve your transitional speed (ie, your slalom speed, or perhaps in better layman terms – the speed at which the car changes directions). However, their primary contribution to your car is to HANDLING (or feel).

 

Now, I am just as guilty as anyone for using the term handling and grip interchangeably. However, they are quite different. Handling really refers (at least in my mind and for the purposes of this article) to how the car feels to the driver, how well it communicates what is going on to them, and also how stable it is – especially at the limit of grip.

 

There are many cars that I’ve driven that were extremely fast through the bends, but not exactly confidence inspiring. Because of their vague handling, they were very difficult to drive to the limits of the car and they were also somewhat frightening to drive rather than “fun to drive”.

 

A strut brace will often improve the handling of the car, but understand that handling is highly subjective. As a general rule, the stiffer the chassis, the more predictable the handling, the longer the life of the chassis (especially if being raced), and the easier the car will be to drive at the limit.

 

Poor handling cars are not necessarily lacking in grip, they are lacking in feel or transitional response. Hopefully this illustrates what I’m on about.

 

Finally, chassis braces do two other things that I won’t talk too much about in this article because they are more theoretical. They are however important to understand. The first is that the chassis is basically just as much a spring as the springs in your suspension. Though, the chassis is more like the sway bars in your suspension in that it acts as a torsion spring.

 

This is why you’ll often hear people say that sway bars increase torsional (twisting) strength of the chassis. Anyhow, all this means is that as you go down the road or turn into a corner, the steel body of the car will bend with the forces applied to it by the suspension and things like centrifugal force. Obviously it doesn’t flex much, even in factory form, or you’d not only notice but you’d have a rather dangerous vehicle.

 

Modern vehicles especially are quite stiff from the factory, if for no other reason than it generally makes them hold up better in accidents. The other reason is letting the suspension do its job. You see, when the body is twisting, it’s changing the location and angles of the suspension as well. This messes with the alignment of the wheels in a corner or going over a bump. The body’s flex is also difficult to monitor so it can lead to troublesome suspension tuning. In other words, if the body is flexing about, it’s much harder to tune out undesirable suspension traits because it’s much harder to pinpoint what’s causing that handling problem. A stiff chassis makes it very easy to isolate suspension problems and tune them out. It also keeps the tires in the location the suspension designer intended, with the desired behavior as well.

 

So are they useless?

 

It depends. Chassis braces can be extremely worthwhile, or they can be an excessive waste of money.

 

The difference depends on what you’re trying to accomplish, the car you started with, and ultimately – what the brace is constructed of and how it’s constructed.

 

Let’s start with the goals part. A strut brace is primarily going to be an improvement to the feel of your car. If you’re trying to improve instrumented numbers (ie, g-force in corners), you probably won’t see much there. If you’re trying to improve times, you may or may not see huge improvements, depending on you as a driver – not so much the brace in use.

 

The variables are many here, but as a general rule – the strut brace allows more mortal drivers the ability to drive their cars closer to the limit by giving the car a more predictable and stable feel. A true professional driver would probably prefer a really stiff chassis, but could most likely turn similar if not identical times with and without the added stiffness (obviously there are extremes!!).

 

That said, if you want to build a fun to drive “driver’s car” or if you want to generally improve the handling and predictability of your car – a strut brace (or any brace) can really be a great addition.

 

Which Braces to Buy?

 

In most cars, the front strut brace is going to have the biggest impact of all of them. In most cars, for most drivers, this is going to be plenty. The front wheels are by far the most stressed due to the fact that they must steer the vehicle in all sorts of situations while also dealing with imperfections in the road, weight transfer, and other stresses.

 

The front wheels are usually also located roughly in the middle of or just to the rear of the largest hole in the vehicle’s chassis.  In other words, the place where the least reinforcement exists due to practical reasons – the engine is there.

 

You’ll also find that any time a factory supported tuning job is done to a car, they add a front strut bar, and only sometimes a rear one. The rear one is usually omitted because it’s of less importance and it usually comes at the expense of cargo and passenger space – something most OEMs are not really willing to give up.

 

The other braces, well, they’re possibly helpful for hardcore track and track-day cars. However, for most of you – you’re better off spending your money elsewhere. The returns are minimal from the rest of the bracing despite the hype. If you’re going to do much more than a front and rear strut brace, you should consider a roll cage as you’ll be needing one anyway if you’re pushing your car to that sort of limit.

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