SPEC Answers The Most Common Performance Clutch Questions

There is nothing quite like banging through the gears in a fast car with a manual transmission. You are connected to the performance and in complete control of its application. However, the clutch that joins your engine to that transmission is a wear item. Whether it is a stock or a high-performance unit, you will eventually need a new one.

It’s not just peak numbers that matter — how and where the car is driven plays a huge role… — SPEC Clutch

Often, the need for a new clutch springs up at an inopportune time, which might limit the time you have available to research the subject. To make sure you are ready to pick the proper performance clutch for your project, we reached out to the experts at SPEC Clutch, a company known for its high-performance single- and twin-disc clutches. The team at SPEC Clutch, shared the most common inquiries the company receives and provided feedback to help you make a clutch decision.

Will this clutch hold my horsepower?

SPEC: Before we can confidently answer that, we always ask for the full build specs — not just horsepower, but torque, the car’s weight, intended use (street, strip, autocross, etc.), tire setup, and gear ratios. A clutch rated at 500 lb-ft might hold just fine on the street with street tires, but the same setup on slicks at the drag strip could easily overpower it. It’s not just peak numbers that matter — how and where the car is driven plays a huge role.

Do I need a twin-disc clutch for my build?

SPEC: Not necessarily. Twin-disc clutches are ideal for cars that make higher torque or ones that see a mix of street and track use. They’re especially helpful in maintaining reasonable pedal effort while offering high torque capacity. But for milder builds or daily drivers, a quality single-disc clutch may be more appropriate. We often steer customers toward the simplest clutch that will reliably hold their power without compromising drivability.

Is this clutch streetable?

SPEC: That depends mostly on the friction material. Organic and Kevlar options tend to be much more forgiving — they offer smoother engagement and better modulation, which is great for stop-and-go driving. On the other hand, puck-style or ceramic clutches can be more aggressive, with harsher engagement and a greater likelihood of chatter. We always ask how often the car is driven on the street vs. track so we can make a recommendation that won’t beat up the driver in traffic.

Can I reuse my flywheel?

SPEC: Only if it’s in good shape and properly resurfaced. We check for heat checking, cracks, hotspots, or excessive wear. Warped or glazed flywheels can cause chatter, poor engagement, or even premature clutch failure. In some cases — especially with lightweight aluminum flywheels — they may not be serviceable at all. Replacing the flywheel may seem like an extra cost up front, but it can save a lot of headaches in the long run.

Do I need to break in the clutch?

SPEC: Absolutely. For most organic or Kevlar clutches, we recommend 500 miles of normal stop-and-go driving with no aggressive launches, clutch kicks, or dyno pulls. This lets the friction surfaces fully seat and ensures even wear. Skipping the break-in period or driving too hard too soon can glaze the disc or cause uneven contact, leading to chatter, slipping, or a much shorter service life.

Do I need a new slave cylinder or throwout bearing?

SPEC: In most cases, yes — especially if the setup is hydraulic or has high mileage. These components are often overlooked, but they play a huge role in clutch operation. A worn throwout bearing can quickly ruin a new pressure plate, and a failing slave cylinder can cause engagement issues or fluid leaks. We recommend replacing them during a clutch job to avoid tearing the car back apart later.

So there you have it. These are some useful data points you can use to select the proper clutch for your project, whether it is an everyday street car, a multi-purpose performer, or an all-out race car.

Naturally, SPEC can help you through the process for your specific application and recommend one of its clutches that fits the bill. The company offers single- and twin-disc clutches for a wide range of vehicle applications and performance ranges, including torque outputs as high as 1,500 lb-ft. If you need help selecting the right clutch for your application, you can reach out to their in-house experts here.