2. Metal Disc
Metal clutch discs are usually made up of cast iron or high-carbon steel. This type of clutch disc that allows easier driving without fully engaging the clutch is known as half-clutching. The half-clutch driving technique keeps the vehicle from rolling back in bumper-to-bumper traffic or mountainous terrain. In the half-clutching technique, the driver engages forward or reverse gear (depending on the situation), keeps the brake pedal held, and slowly releases the clutch until the vehicle vibrates. This point is known as the biting point.
The disc's outer edge is light, resulting in a less inertial moment and improved clutch responsiveness at high engine speeds. Cast iron or high carbon steels are highly durable materials that enhance the clutch disc service life. These metals have good thermal properties and resist fading, so even if the clutch is frequently used in half-clutch conditions, the performance is not affected by high temperatures. When the clutch is only half depressed, it rubs against the flywheel, generating heat.
How To Select The Correct Clutch For Your Vehicle
Choosing an aftermarket clutch for your vehicle requires you to be very careful. Compatibility between your vehicle and clutch is crucial and selecting the wrong clutch can harm both the clutch and your precious transmission. In this article, we are going to explain everything you need to know to make that selection.
Clutches are one of the most important parts of your vehicle. If you own a vehicle but are not an enthusiast and never wanted to test your vehicle’s limits or throw some punish it, then you probably won’t have to worry about it. The OEM clutch that came with your vehicle is gonna do fine for a long time.
However, if you are an enthusiast, owning anything from stock or basic bolt-on to a heavily race modified car and intend to test it on the tracks in various capacities, then this article is for you.
How to select the correct clutch?
This sounds like a difficult question to answer and you are probably expecting a lot of confusing technical jargon en route to your curious mind. Worry not! We are gonna explain everything you need to know step by step.
So, what clutch should you choose for your vehicle? It depends on both your vehicle and the way you intended to use it. The combination of these two factors is very important.
Here at Action Clutch, based on the intended use and the modifications done on the vehicle, we have grouped our clutch kits into several stages.
Heavy Duty Street Use and Light Track Use: Stage 1 Clutch Kit with Reinforced Organic facing
If your car has stock configuration or even some basic bolt-ons, your OEM clutch will do fine in street use, giving you long service life and a smooth driving experience. However, anything north of typical street use is gonna be a problem for your OEM clutch to handle. This is where our Stage 1 Clutch Kit comes.
Our 1OS Stage 1 Clutch Kits are perfect for heavy-duty street use and can take a bit of punishment that comes with light track use. These kits are engineered for cars that have stock-build or basic bolt-ons like in header, exhaust, or intake.
If your vehicle fits in this category, you basically need a clutch kit that gives you more holding power than your OEM clutch offers while maintaining that OEM-like smooth engagement and pedal feel.
So how does our Stage 1 Kit do in this regard?
Stage 1 clutch kits have reinforced steel-backed Copper Kevlar Organic facings. This, coupled with a single diaphragm heavy-duty pressure plate, makes sure that the clutch plate attains a 70% more holding capacity than your stock clutch. Here we should mention that the holding capacity percentage increase is based on crank horsepower rather than wheel horsepower.
Like all our single disc kits, Stage 1 Kit features Ductile Iron Friction Plate, 4-stage heat-treated diaphragm spring, reinforced heavy-duty drive straps, and are 100% dynamic spin balanced.
The 4-stage heat-treated diaphragm spring not only produces high clamping pressure but also ensures that the pedal effort approximates a stock clutch pedal. You will have no discernible extra effort while operating it.
The reinforced organic material in the facing is ideal for smooth engagement as they allow just the right amount of slippage during take-off. On top of that, it is a sprung kit, meaning the hub has coil springs that absorb the vibration caused by engine power fluctuations and clutch engagement and provides you with a smooth ride.
We want to assure you regarding the coil springs too. These are fully enclosed within spring retainers to make sure that a spring doesn’t pop out from the housing and wreak havoc in your transmission. This feature is present in all our Sprung Kits.
Before going further, we are gonna take a detour and discuss something very important, something called Break-In.
What is Break-In and why do you need it?
Okay, this is something very important when we talk about clutches. There are many theories about the break-in and the proper way to do it. Some say break-in is a myth and not necessary at all while others recommend completely incorrect ways to break in your clutch.
So, here’s the truth: Yes, breaking in is absolutely necessary. Here’s why:
Your clutch rubs against two friction surfaces, that of the flywheel and the pressure plate. It is easy to achieve a proper surface finish with these components and hence, they don’t have unevenness on their surfaces. However, due to the nature of the friction materials and how they sit on the backing plate, it is almost impossible to create a perfectly even surface on the friction disc. That means, when you install a new clutch kit, all of its surfaces are not in contact with the flywheel and pressure plate, and hence, it simply does not have the full capability to withstand the rated torque.
If you drive your vehicle at full potential during this time, meaning at high RPM, in full throttle, making hard launches, and so on, the small patches on friction disc that are in contact, are doing more work than they can handle and ultimately going to overheat and wear out much faster, causing failure to the whole disc.
Hence, You need to make sure that the entire surface on the friction material is properly seated in and is in contact with the flywheel and pressure plate surface evenly to handle the intended torque. This we achieve by breaking in the clutch.
So, what’s the proper way to break in a clutch that you just bought? The general process is to drive your car in city streets with a lot of normal take-offs and shifting, driving at moderate RPM and throttle (4500 RPM max and no more than 50% throttle). Driving on the highway on weekends just to put down the miles is never gonna do it.
You might be wondering about the break-in procedure of our Stage 1 Clutch Kit at this point. It’s simple, take it easy for the first 500 street miles. No hard launches, no hard acceleration, no more than half throttle, and no boost (if applicable). We recommend keeping the RPM under 4500.
Heavy Duty Street Use and Occasional Track Use: Stage 2 Clutch Kit with Kevlar® facing
The 1KS Stage 2 kit from Action Clutch uses our full-face Kevlar® Friction material instead of the reinforced organic one in Stage 1. This brings in some major differences. First of all, Kevlar® provides more friction than organic facings, meaning it can grab onto the flywheel much better and hence can handle more torque. At 110% increased holding capacity, this clutch allows a larger holding power than our Stage 1 Kit does.
Secondly, Kevlar®’ has exceptional lifespan (in many cases twice as much life as other materials) and great heat dissipation capabilities, which means that this is perfect for handling the occasional abuse that will come with the 110% increased holding capacity.
Our Stage 2 kit has an almost similar use case scenario as Stage 1, but it allows more horsepower in your vehicle. The reinforced Kevlar® sprung disc is designed for vehicles with basic bolt-ons or a naturally aspirated vehicle with headwork, such as cams, or very low boost or Nitrous setup.
And now you might be wondering, how does it do in terms of engagement and pedal feel? Let us assure you, it does exceptionally well. Kevlar® fibers have low static to dynamic friction coefficient. Paired with the sprung hub, this provides easy and smooth engagement that you desire for your daily driving, stop-n-go, or off-road driving.
Stage 2 Clutch Kit retains the structural goodness from Stage 1 kit. The steel back makes sure our kit has great burst strength. The springs are fully enclosed as well, assuring you the safety of your transmission. Our signature rivets also ensure structural integrity despite the intended rough use.
The break-in period for our Kevlar facing is more rigorous. We recommend 1000 street miles at 4500 RPM, with no more than half-throttle and no boost (if applicable)
Heavy-Duty Street use and Medium Track Use: Stage 3 Clutch Kit with MIBA Sprung Ceramic Disc
The 1MS Stage 3 Kit is engineered for low and mild horsepower vehicles. At 170% increased holding capacity, this clutch kit is suitable for heavy-duty street use as well as more frequent drag, road, or drift racing.
What sets the Stage 3 Clutch Kit apart from the previous ones is the extremely durable, high-performance MIBA Sprung Ceramic Disc in a 4 or 6 puck configuration. The segmented configuration produces greater pressure for clamping power while also reducing weight.
If you have drag racing or drifting in mind and have decently modified your vehicle to put some decent numbers, go for the 4-puck configuration as it has more aggressive, quicker engagement of the two configurations.
It’s a universal fact that segmented configurations naturally come with more clutch chatter than full-faced kits. Although a proper break-in will bring it down to a minimal level, some clutch chatter and gear rattle are normal for these types of clutches.
Our 1MS Stage 3 clutch kit features a single diaphragm heavy-duty pressure plate with reinforced drive straps for increased durability. This kit also retains our fully enclosed spring retainers and American-grade rivets.
Should I use Ceramic Discs for Street Use?
We don’t recommend using Ceramic discs for your daily driving. Ceramic-based clutch discs are intended for greater holding capacity and resistance to abuse rather than increased life expectancy. Typical street use will cause clutch slip and harsher engagement, leading to premature wear of the clutch kit. These configurations are not suitable for your typical daily drive to the grocery in your stock or lightly modified vehicle.
Heavy-Duty Drag/Road/Drift Racing: Stage 4 Clutch Kit with High-Performance MIBA Unsprung Ceramic Disc
If you want something exclusively for racing purposes, then the 1MD Stage 4 Clutch Kit is for you. This kit uses high-performance MIBA ceramic discs, but the disc hub is rigid or unsprung, meaning the engagement is instant, like an on-off switch. While offering the same 170% increase in holding capabilities as our Stage 3 kit, its lighter weight makes the shifting smoother and quicker.
This kit features a single diaphragm heavy-duty pressure plate with reinforced drive straps for increased durability. Just like our Stage 3 Kit, it comes with 4 and 6 puck configurations with the 4 puck being more aggressive than the latter one.
The combination of segmented configuration and the rigid hub means that there will be some clutch chatter and gear rattle. However, a proper break-in can bring it down to a fairly minimal level. We recommend 500 street miles while not crossing 4500 RPM and half-throttle. Avoid boost too, if applicable.
Should I use Rigid or Unsprung Hub Discs for my Stock Car?
Unless you have a dual-mass flywheel, you should strictly avoid Rigid/Unsprung Hub Discs for your typical street use. Our Stage 4 Clutch Kit with an unsprung hub should not be used on a stock or lightly modified vehicle that you use for daily driving. Unsprung clutch kits are not designed for daily/street use or any constant on/off engagement environment. Doing so might break the rivets on the clutch disk hub and cause premature failure.
Race Application and Heavy Track Use: Stage 5 Clutch Kit with High-Performance MIBA Sprung Ceramic Disc
With 200% increased holding capacity, our Stage 5 2MS Clutch Kit means business. Like the Stage 4 Kit, this one also uses High-Performance MIBA Ceramic Disc, but the hub is Sprung, not Rigid.
Another major difference is that it features a dual clamp load heavy-duty pressure plate, offering near double the clamping force of our Stage 3 and 4 kits. This means it offers more torque holding capacity. If you are using tires with more tractions, such as drag-radials or slicks, they are gonna hook up hard on the track during take-off, putting a greater load on your clutch. The dual clamp load heavy-duty pressure plate will provide enough clamp pressure to handle that extra load.
However, extra clamp pressure means that the pedal feel will be heavy with aggressive engagement.
Stage 5 Kit has 4 and 6 puck configurations with 4 puck being the more aggressive of the two. Break-in requires 500 street miles under 4500 RPM with no more than half throttle and no boost ( if applicable). After the break-in is done properly, the clutch chatter and gear rattling will be fairly minimized.
Stage 5 Clutch Kits comes with all the usual goodness that Action Clutch offers, i.e., Full Enclosed Spring Retainers and American Grade Rivets.
Heavy-Duty Drag/Road/Drift Racing: Stage 6 Clutch Kit with High-Performance MIBA Sprung Ceramic Disc
The 2MD Stage 6 Clutch Kit has the same features as the Stage 5 kit, except the hub. Stage 6 Kit has a Rigid or Unsprung hub that adds instant aggressive engagement with the 200% increased holding capacity, making it a serious Drag/Road/Drift Racing vehicle.
Apart from the hub, the rest of the Clutch Kit is similar to our Stage 5 Clutch Kit, including the break-in procedure.
Ironman Sprung and Unsprung Clutch Kit: Sintered Iron Disc for Track Use Application only
If you have a vehicle with insane horsepower and God-knows-how-much torque and you want to abuse it like there’s no tomorrow, then you need Sintered Iron. Sintered Iron has an almost unmatched heat resistance and an insanely high coefficient of friction. These two properties make sure that you can let your vehicle loose in the track and basically do whatever you want.
Here come our Ironman Sprung and Unsprung Clutch Kits. Our legendary Ironman Kit features extremely durable American Sintered Iron friction material. This kit is suited for those who are not yet ready to upgrade to a multi-disc option but want something close to that insane high torque capacity at an affordable price. Paired with the super abrasive sintered iron goodness, our dual clamp load kit ensures a crazy high torque capacity. As mentioned above, the Ironman Kit is available in both sprung and unsprung versions.
One great thing about The Ironman Kit is that it offers some slippage on take-off, which champs this kit as a go-to kit with its repeatability and endurance. However, we advise you to learn how to slip a clutch before doing it to avoid damage to the clutch.
Designed with exclusively high-powered race vehicles in mind, the clutch engagement is very aggressive, rendering an instantaneous on/off feel. The clutch will not introduce clutch chatter but will have light engagement noise and some gear rattle.
For break-in, we advise 500 street miles under 4500 RPM with no more than half-throttle and no boost.
Multi-Disc Kits (Twin Disc and Triple Disc): Ultimate choice for Racing Applications
Multi-disc kits are the latest trends in clutch technology. Multi-discs design have multiple smaller disks than one larger disk, which means more surface area and consequently, more torque capacity. Add that to the sintered metals as disk materials and you’ll get something that will chew up everything that you’ll throw at it.
Action Clutch multi-disc clutches feature multiple sintered metallic race discs, formulated in the USA. These 0.25-inch-thick rigid discs have a superior wear resistance and heat capacity because of their unique friction mix and Ventilated 6061-T6 Billet Aluminum clutch cover design.
Thanks to the increased surface area and sintered metal facing, The Twin Disc Kit has 800TQ holding capacity while Triple Disc Kit flaunts a whooping 1000TQ holding capacity.
One of the great features of our Multi-Disc Clutch is its superb engagement characteristics. They offer smoother engagement than any other disc in the market right now. Moreover, our Multi-Plate assemblies offer an increase in clamping force without requiring twice the pedal pressure.
Multiple smaller discs instead of a single larger disc reduces weight, resulting in quick throttle response and an overall quick engagement to get you off that line as fast as possible.
The Multi-Disc Kits feature high-strength Steel alloy and pressure and floater plates. Our unique design offers less rotational mass and minimal deflection during quick shifting. Each unit is individually inspected before releasing, hence quality control is never compromised.
A summary on how to choose the right clutch
Action Clutch has the perfect Clutch Kits for all use case scenarios. In the below table, you’ll find some crucial information about our entire clutch lineup, which will help you to decide which clutch is right for your vehicle:
Clutch Kit
Recommended Use
Increase in Holding Capacity (based on factory power output)
Hub Type/Facing Configuration
Friction Materials
Pedal Feel & Engagement (after a proper break-in)
1OS Stage 1
Heavy-Duty Street Use and light Track-Use
70%
Sprung/Full Face
Organic
OEM-like pedal feel and a smooth engagement
1KS Stage 2
Heavy-Duty Street Use and mild Track-Use
110%
Sprung/Full Face
Kevlar®
OEM-like pedal feel and a smooth engagement
1MS Stage 3
Heavy-Duty Street Use and Medium Track-Use-Circuit / Time Attack / Road Racing
170%
Sprung/4-Puck,6-Puck
Ceramic
Light / Medium pedal feel with Aggressive Engagement
1MD Stage 4
Heavy-Duty Drag/Road/Drift Racing.
Street Use is not recommended.
170%
Unsprung/4-Puck,6-Puck
Ceramic
Light / Medium pedal feel with Aggressive Engagement
2MS Stage 5
Strictly Race Application/Heavy Track Use
200%
Sprung/4-Puck,6-Puck
Ceramic
Heavy pedal feel with Aggressive Engagement
2MD Stage 6
Strictly Race Application/Heavy Track Use
200%
Unsprung/4-Puck,6-Puck
Ceramic
Heavy pedal feel with Aggressive Engagement
Ironman
Specifically designed for track use applications only
250%
Sprung, Unsprung
Sintered Iron
Heavy pedal feel with Smooth Engagement
Multi-Disc (Twin and Triple Disc)
Racing Applications with Serious Horsepower
Twin-Disc: 800TQ Holding Capacity
Triple-Disc: 1,000TQ Holding Capacity
Unsprung
Sintered Metal
Reasonable pedal feel with Smooth Engagement
Apart from the ones on the table, the below features of our clutch kits make them a great choice for your vehicle:
Pressure Plate Features (All Single Disc Kits–stages 1-6 + Ironman)
ALL Sprung Kit Features (Stages 1, 2, 3, 5, Ironman Sprung)
ALL Kits
Still can’t decide which clutch to choose?
Purchasing the wrong type of clutch kit for your specific engine power output can result in premature clutch failure, damage to the transmission, and void warranty eligibility. If you’re unsure what kit is right for you, please DM us on any of our social media channels or through our General Inquiries form.