Easy, Accurate, Inexpensive, Do-It-Yourself Vehicle Alignment

One of the easiest and cheapest modifications a racer can make to his or her vehicle to try to find more performance and speed is by changing alignment settings; simply adjusting camber, caster and toe can radically improve a car’s handling ability. What a normal road car that is traveling down the freeway trying to get 30,000 miles out of a set of tires requires in alignment settings is very different from what a race car trying to get 100 miles out of a set of tires needs.

Conversely, racers understand there is a lot to be gained in alignment so they change their settings quite often. But towing a race car to an alignment shop during business hours and convincing the technicians there to set the car at unorthodox racetrack alignment settings is often a challenge.

What would be much easier for racers is to have a simple portable alignment system that provides repeatable results they can use in their own shop and at the race track. Craig Watkins, working on his own Porsche race car, thought the same thing. Out of necessity he built Smart Strings and Smart Camber so he could align his own car. Then he made these tools available to everyone.

Craig Watkins invented Smart Strings and Smart Camber back in 1993. He’s sold over 20,000 units which are used worldwide by everyone from pro racing teams, to autocrossers and even aftermarket shops. here’s a unit in use in by a race team in Great Britain.

Craig Watkins is not your typical weekend racer. He is an engineer by trade and was formerly the chief engineer for Flying Lizard Motorsports. Using his Watkins Smart Racing Products tools he aligned the Flying Lizard Porsches to be fastest enough to earn a pole position at Le Mans and a victory at Daytona.

Craig Watkins knows how to setup successful racing cars and he made adjustments at the track using his Watkins Smart Racing Products tools on the Flying Lizard Motorsports Porsches.

Before he was engineering race cars at Le Mans, Craig was a desert racer competing in Baja. There he met fellow Baja racer Robby Gordon. Robby was also racing Indy cars at the time and Craig went to hang out with him at Laguna Seca for an Indy car race. There Craig saw Robby’s team using strings to align the Indy car before the race. Craig said, “It was so simple, it made sense.” Craig went home and designed Smart Strings.


Double Nickel Nine Motorsports uses Craig’s tools exclusively on their National Champion NASA  Honda Challenge cars. We are going to go through step by step how to use the tools to set an accurate performance alignment.

Most of what you see here comes directly from Watkins Smart Racing Products when you order their Smart String and Smart Camber tools.

Our recommendation is to find a nice flat surface with good lighting to begin your alignment. We like to keep things as accurate as possible so we weight the car as if the driver was sitting inside it. We can either do that by having a driver sit in the seat (a very boring job) or add weight to the seat to replicate the driver.

The easiest place to align a car is a level space with a smooth floor and lots of lighting. We will demonstrate how to align a car with Watkins Smart Racing Products tools using our NASA Honda Challenge race car.

When we align our cars we either have the driver sitting in the driver’s seat or we place the driver’s weight in the seat using workout plates. This settles the car’s suspension to the actual weight when being driven for more accurate alignment.

A Few Extra Items

In addition to what comes in the box, we suggest few other items to help with your alignment: two fishing line reels, sidewalk chalk, a yard stick, a degree wheel, a small aluminum measuring tool (in millimeters), a flat plane, and wheel center caps.

Order of Operations

When doing an alignment one setting usually affects another setting. For example camber and caster can affect toe settings. For this reason when doing alignments there is a specific order of operations:
1. Camber
2. Caster
3. Toe


There have been some really informative articles here at TURNology about what camber is. Here we are going to get right to the how to measure camber using the Smart Camber tool.

The Smart Camber tool is very easy to use. Simply hold it against the wheel and the digital display will tell you what your camber angle is set at. The chalk lines on the floor are for setting caster (we will get to that in a moment).

To see if your work space is level use the Smart Camber tool to ensure your shop floor is level. Here you can see our floor is registering 0.0 degrees.

By holding the Smart Camber tool against the wheel, you can see our wheel is at 2.9 degrees negative camber. We wanted it set at 3.2 degrees so we will have to make an adjustment.

To make camber adjustments on our Honda Challenge car we simply lengthen or shorten our Hardrace upper control arm. Two end wrenches get the job done easily here. Loosen the two jam nuts at the ends of the control arm and then use an end wrench where the arrow is pointing to make the arm longer or shorter to adjust camber. We made the arm shorter to get to our 3.2 degree negative camber goal.

Here is a quick reference guide for the Smart Camber (zeroing, calibrating, etc.) and a template for setting up for caster adjustments.

Camber settings, in my opinion, are the most beneficial in terms of cornering speed and grip. The next setting to measure and adjust in our order of operations is caster.


What caster is was covered well in TURNology before. Here is how to measure it using the Smart Camber tool.

Camber and toe adjustments are pretty easy to measure and adjust, but caster has a bit more mystery to it. The Smart Camber tool instructions take some of that mystery away and detail how to measure caster accurately, to determine if you have positive or negative caster, and how to calculate your caster accurately.

For accurate measurements for caster we want to ensure we are turning the front wheels exactly 20 degrees in each direction. We use chalk lines on the shop floor to measure the steering angle. At those different steering angles we re-measure our camber to calculate caster.

To ensure we had our car at exactly 20 degrees worth of steering angle we use a small piece of aluminum as a plane. We lean the piece of aluminum against the wheel to accurately display if our steering angle is lined up with our 20 degree steering chalk line. Here you can see we nailed it.

We use large white boards in our shop to track our alignment as we are going along. Here you can see how we determined if we had positive or negative caster and how we calculated how much caster we had. These calculations were done in accordance with the instructions on measuring caster which came with the Smart Camber tool.

For our road racing cars we try to dial in as much positive caster as the vehicle will allow us to. With positive caster the steering wheel tends to self-center while going down the track. We were able to get 5.1 degrees of positive caster on the left front (maxed out). The goal then is to get the right front at the same number. If caster is off between the left and right front sides, the car will start to wander under braking. To keep braking nice and straight we work hard to get our caster equal between both sides, even if it means dialing in a little less positive caster, so the two sides are the same.


Once our camber and caster are set it’s time to move on to toe settings. Toe is the direction the tires are pointed from longitudinal center when the steering wheel is centered straight. For a road-racing set-up on a front wheel drive car, we like toe-out (tires turned out) in the front and the rear. For a rear wheel drive car we like toe-out in the front and toe-in (tires turned in) in the rear.

Smart Strings creates a perfect parallelogram (rectangle) around the car where you can measure toe alignments by measuring from the outer rectangle to the edges of the rims. These measurements will indicate if you have neutral toe, toe-in or toe-out.

Here is what the Smart Strings tools look like once they are quickly assembled. The two separate assemblies hang off of the vehicle (one on the front and one on the rear) to create a perfect rectangle with strings.

In order to create the box around the car, Smart Strings has adjustable rigging that can adjust to almost any vehicle’s shape to hold two strings bars, one at each end of the car.

Here you can see the string bars placed into the rigging hanging off the front and rear of the car. What is handy about this setup is you can roll the car back and forth to settle the suspension with the Smart Strings rig on the car.

To find the true center of the wheels we machined some portable center caps from Delrin for our Enkei RPF1s. This allows us to do two things with Smart Strings: 1. find the height of the center of the wheel (11.75 inches) and 2. to help center the string box around the car.

The front and rear of the car each have a set of string bars, which come in two pieces. Once these pieces are threaded together they are of equal distance. Strings connecting the two string bars at the front and rear of the car create a perfectly square parallelogram (rectangle) around the car. Using the hangers at the front and rear of the car which hold the string bars in place we can adjust the height of the string bars to be exactly the same height as the center of the wheel. In our case, 11.75 inches high.

Even though the tool is called Smart Strings, we use “smart” fishing line. A couple of inexpensive fishing reels from Walmart ($12) are an easy way to quickly reel in the line and store the tools without getting tangled strings in the toolbox. We also like the thinness of the fishing line for accurate measurements.

Using our handy little aluminum millimeter ruler along with our center caps, we can determine how far from the center of the wheel our strings are. In this photo you can see we are 121 millimeters out. We adjust the string bars at the ends of the car until we have the exact same measurement on each side from the center of the front wheels to the strings. We also do the same adjustment with the back wheels. The front and back track width on cars are generally not the same so the measurement between front and rear will differ. What is important is that side-to-side the left front is the same as the right front while the left rear is the same as the right rear.

Once the rectangle around the car is created it is time to start taking measurements to determine toe-in or toe-out settings. This is done using a small ruler. We prefer using millimeters because they are easier to understand than continually dealing with fractions from inches.

Here is a close up of our measurements for the left front wheel. The lead measurement (front of the wheel) is 83 millimeters. The trail measurement (rear of the wheel) is 86 millimeters. These measurements are made from the edge of the rim at string height to the fishing line. Because the lead measurement to the outside string box is smaller, it means the left front wheel is steered slightly to the left, showing a toe-out setting. This is more than we want so we will adjust the toe-in slightly.

In order to adjust toe on the front of a vehicle you will first need to loosen the jam nut against the outer tie rod. Simply use two end wrenches (one on the tie rod, one the jam nut) and break the jam nut free. Have the steering wheel locked in place a the center (straight) position, either by having a driver in the seat holding it or with a locking tool. The steering wheel can move during these adjustments.

To adjust toe, simply turn the inner tie rod clockwise or counter-clockwise to move the outer tie rod in or out from the vehicle. The inner tie rod will have a spot where an end wrench can be used for this adjustment.

We use white boards on the shop walls to track our alignment progress. Here you can see our car has 4 millimeters of toe-out in the front (two millimeters each side) and three millimeters of toe-out in the rear (one millimeter on the right side and two millimeters on the left side). We will adjust the left side to get it down to one millimeter of toe-out to give us an even setup side to side and an overall toe-out in the rear of two millimeters out.

I’ve been asked before, “Why not just use toe plates? Why build this box with strings?” The answer is simple: Toe plates work great for setting toe at one end of the car, however, they don’t recognize what the other end of the car is doing. In order to set the thrust angle correct and have the car track straight, both the front and rear of the car need to be set relevant to one another. This is done using strings creating the parallelogram for the entire car. This way front and rear adjustments are done simultaneously on the same longitudinal plane. I will use toe plates to check a car quickly to see if it is off, but I will make final adjustments using Smart Strings every time.

The Smart Strings take a little practice in setting up on a car the first time. But after a while they get easier and easier to use. Using white boards on the wall of the shop is a very simple way to quickly track how your adjustments are changing the whole car.


To see how good Smart Racing Products alignment tools were we decided to align a car and then take it to a reputable alignment shop and compare the strings against the computer.

Using Smart Camber and Smart Strings to get our car aligned is great for doing things at the track and in your own garage, but I was curious how close and accurate we were getting our alignments. To compare our do-it-yourself method to a high-end alignment shop we aligned our C6 Z06 Corvette with Watkins Smart Racing Products tools and then took the Vette to an alignment shop to verify the settings. Answer: We were right on the money using strings!

Track Use

One of the advantages to using Smart Camber and Smart Strings is you can use them at the track. These tools are very portable (pro tip: buy the carrying bag for the tools –sold separately) and you can make adjustments in the paddock.

Autocrossers love Smart Strings and Smart Camber because they can make adjustments at the event after a long drive to an autocross race. Aggressive autocross alignments will destroy a set of street tires on a long road trip. Here we are dialing in some more rear toe-in on our Z06 after some serious over-steer issues at an event.


For Double Nickel Nine Motorsports not only do we complete our own alignments at the shop with Smart Racing Products tools we verify our settings pre- and post-session at the track. This has proven to be extremely beneficial to our team.

Race cars are driven extremely aggressively. That aggressive style of driving can cause changes in vehicle alignment during warm-up, qualifying, or racing sessions. It is important to be able to verify a car’s alignment before and after a session to ensure it is set at optimal positions for peak performance.

At our last Honda Challenge race I was qualifying and the car suddenly wouldn’t allow me to go full throttle through Riverside corner (a long high speed banked curve at Buttonwillow Raceway). I was radioing in to my spotter the car wasn’t handling right. He confirmed my suspicions based on my qualifying time of 2:04.364 which put me in P4, row two. This was an unacceptable result for our team, who is used to being on the front row. I brought the car in and we immediately set up Smart Strings on the car.

One of the greatest advantages of Smart Strings and Smart Camber are their portability. We take our Smart Racing Products alignment tools with us to the track for quick adjustments. This has proven to be extremely advantageous competitively.

We only had an hour between qualifying and the race. There was no time to put the car on a trailer and tow it to an alignment shop (not that we would find one open on a Sunday). Luckily we brought our Smart Racing Products tools. What we found after we had the car set up with the strings was that my left rear toe was off and my left rear camber was off. This made sense based on the fact I couldn’t go flat through a right hand curve (putting a lot of load on the left rear tire). The setting probably changed after bouncing off of the curbing at Buttonwillow. We made the adjustments we needed and made it to grid just in time for the race. During the race, after just small adjustments to the left rear wheel using our alignment tools, I broke the Honda Challenge 4 class track record at Buttonwillow with a lap time of 2:04.076. I also won the race all thanks to Craig Watkins and his tools.

Long story short, we will never have to rely on an alignment shop again.

Article Sources

About the author

Rob Krider

Rob Krider will race absolutely anything. He is a multi-national champion racing driver and is also the author of the novel, Cadet Blues.
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