One of the things I love about competing in the SCCA® is constantly meeting new friends who have the same passion about #funwithcars that I do.
In 2023 at the 50th running of the Tire Rack SCCA Solo® National Championships in Lincoln, NE, I had the honor of competing against the host of the Inside the SCCA podcast, Brian Bielanski. Based on our car numbers, me 38 and him 43, we were gridded alongside each other awaiting our turns, each of us driving Hondas in the H Street class. Hanging out together during the event, we made an instant connection. Then, after the second of six runs, he and I were book-ending the results. One of us was in first place at Nationals and the other was…well, that person was last. It’s not my place to say who was who, the point was, we became fast friends.
After the event (spoiler alert: neither of us won the National Championship…darn those pesky orange cones), Brian and I kept in touch. After a few months of getting to know each other, Brian finally popped the question to me: “Rob, will you…mind telling me if I should buy a swaybar, tires, or shocks first if I want to go faster in autocross?”
I was caught off guard. I wasn’t expecting the question. It was a fascinating inquiry, though, prioritizing modifications made to a car based on a bang-for-your-buck concept and ease of installation in hopes to improve autocross times. I told Brian I wasn’t ready yet. He would have to wait for my answer.
If you ask folks who are successful at motorsports, “What is the first modification you should make to your car,” they will usually tell you to adjust the nut behind the wheel. Or, put nicely: seat time, seat time, seat time.
Sure, that’s good advice – but a lot of us want to “add to cart” a few performance parts to make ourselves faster while having fun tinkering. Also, bolting on racy bits is way easier than the humility of self-improvement.
So, forgetting the big nut behind the wheel, here’s how I’d prioritize modifying an autocross car for SCCA’s Street category (which, it should be said, has very limited rules for changing parts).
1. Tires
Every single thing you do with a car is done through the interaction of the tire patch (the small portion of the tire in contact with the ground) and the surface itself. The car won’t accelerate, brake, or turn without tires interacting with what’s beneath it. Because this is how all things are done with a car, you can see how important tires are in a sport like autocross where cars accelerate quickly, take tight turns, and use brakes heavily.
The size of the tire (wider is usually better), the tire compound (softer is usually better), and the sidewall construction (stiffer is usually better) are all factors that affect how a tire interacts with the ground – and it’s that successful interaction that will allow your car to go quicker around a course and also allow you to feel what the tires are doing through the steering wheel and the pedals. That feedback will help your brain decide what you should do: more gas, more brake, or more steering? Put another way, tires are everything. And since they’re everything, they’re also priority number one when modifying a car, especially since any other modifications you make to the car has to go through the tires in order to work.
In other words: Tires...get ‘em!
(SCCA Solo Street category rules dictate the minimum treadwear number on tires used in competition. They must have a treadwear number of 200 or above. Photo by Rob Krider.)
But which brand and model tire is right for your Street category application? In Street, where you have to run a minimum 200 treadwear tire (a Uniform Tire Quality Grade, or UTQG, rating loosely based on the softness of the rubber of the tire), you want a good extreme summer tire with exactly a 200 treadwear rating. There is quite the tire war happening in the 200 UTQG world, with numerous manufactures building faster and faster tires. To figure out your brand and model tire, check out any National Solo result sheet (where the brand of tire that was used by the competitors is listed), make a note of what others in a similar car are competing on (and having success with), then give Tire Rack a call and get yourself the same sticky rubber. Depending on the size of your wheels (Chevrolet Corvettes cost more to put tires on than Honda Civics), you are looking between $600 to $1,400 on this modification. And the mod is easy to do, because unless you own your own tire machine, the folks at any tire shop will do it for you.
2. Swaybar
Once you have your new sticky tires mounted up (your stock wheels are perfectly fine to put these tires on), I would suggest your second modification be a swaybar change.
A swaybar, or anti-swaybar or stabilizer bar (they’re all the same thing: a big bar that connects the left side of the suspension to the right side), helps a vehicle limit its lean in a corner. The more a car leans, the smaller the contact patch between the tire and the surface becomes and the car won’t want to turn well (I told you tires were important, and it’s important how tires are angled with the roadway). To fix this, you can increase the size of the swaybar to limit the amount of the car’s lean to keep the tire patch mashed into the surface and as large as possible.
On Street category cars, oversized swaybars are popular options because cars come from the manufacturer with an engineered “push” (meaning if you go too fast in a corner, the front of the car will go straight as opposed to the rear of the car coming around and causing you to spin out). But in autocross, we want cars to rotate (bring the back around) to quickly get through the coned course. This adjustment is often done with a larger swaybar.
One detail about this modification: The Street category rules say you can only change one swaybar on the car, either the front or the rear. Generally (and there are a lot of caveats with that “generally”), front-wheel-drive and all-wheel-drive competitors add a larger rear bar, while rear-wheel-drive competitors add a larger front bar.
(You can modify/change/remove one swaybar within the SCCA Solo Street category, so choose your own adventure. Change the front or the rear, but not both. Photo by Rob Krider.)
I prioritize a swaybar change second because swaybars are relatively inexpensive (around $150-$600) and are usually easy to install (give yourself a handful of hours, depending on the vehicle). I like to choose an adjustable swaybar, where you can change the position of the end-link attachment, thus adjusting how stiff the bar is – this way you can fine tune the car to your liking or the surface you’re competing on.
3. Dampers
The final priority is upgrading the vehicle’s dampers, otherwise known as shocks and struts. Street category rules don’t allow the changing of springs – you must use the OEM spring rates regardless of how soft they are. You can, however, change the vehicle’s dampers.
A vehicle with springs and no dampers attached will bounce up and down for a long time until gravity and friction take over, which is not optimum for driving. Shocks and struts, meanwhile, limit the amount of bouncing of the springs, and the stiffer the damper the quicker the bouncing comes to a stop. Too stiff of a shock, however, won’t let the springs do their job, which is to let the car’s chassis go along its path unhindered by bumps in the road.
Upgrading the dampers on a Street category car can help improve the handling, as the dampers can limit the lean of the car longitudinally and laterally, helping keep the tire contact patch where you want it: on the ground. Some aftermarket dampers have adjustments to dial in the stiffness (compression) and adjustments for the speed of the release (rebound) of the shock. Autocrossers often use aggressively adjusted shocks and struts to overcome a vehicle that has soft springs.
(Dual adjustable dampers are allowed in the SCCA Street category and allow you to improve the handling of your car. By simply clicking a knob on the shock or strut, you can easily change the compression or the rebound. Photo by Rob Krider.)
Dampers can vary in price from around $400 for a set all the way to $10,000-plus per set.
Installing upgraded struts requires a spring compressor and a fair amount of labor, which is why they’re third on my list of items to update when modifying a Street category car.
Add to Cart, Then...
So that’s the list in order of priority: tires first (you’ve got to have them, and it’s the single greatest modification you can make to any car), a swaybar second (cheap and easy), and dampers third (expensive and more work to install).
Enjoy adding those items to your cart and then attaching them to your Street category vehicle. Once everything’s bolted on, it’s then time to start working on that big nut behind the wheel because while these three mods will improve your time, there’s even more time to be had in tuning that nut.
(About the author: Rob Krider is a national champion racer, the author of the novel Cadet Blues, and is the host of the Stories and Cocktails podcast.)
Lead photo by Perry Bennett
