OT-185 7.25″ OT-II Metallic Racing Clutches

$555$850

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Designed primarily for road racing, circle track, open wheel and formula applications, Tilton’s 7.25″ OT-II metallic racing clutches offer the low moment-of-inertia, high torque capacity and reliability necessary for the most demanding racing applications. These features have made metallic clutches the most common clutch type used in road racing and circle track racing. Metallic clutches are not recommended for street use.

Applications

  • Road Racing
  • Circle Track
  • Open Wheel
  • Formula

Design
Open, one-piece clutch cover design provides lower operating temperature, high strength and minimal deflection for quick shifting.
Engineering
Chrome vanadium diaphragm springs and an engineered pressure plate geometry provide a high clamp load-to-wear ratio, low release load, and quick shifting.
Materials
High-strength steel is used in both the pressure plates and the floater plates.
Toughness
.104″-thick friction disc withstands elevated temperatures while providing low inertia and excellent wear resistance.
Operation
Hardened steel thrust buttons provide a smooth and durable surface for pressure and floater plates.
Testing
Every Tilton OT clutch is dynamically balanced to ensure the highest level of performance.
Quality Assurance
Each OT clutch is individually inspected for proper assembly and balance, and initialed by the quality personnel as confirmation.

1-Plate Specifications:
Weight**: 5.1 lbs/2.3 kg
M.O.I.**: 44.1 lb-in2/.0130 kg-m2

Spring Color

Torque Capacity
(lb-ft/Nm)

Release Load*
(lbs/daN)

Pressure Plate
(Ratio)

White

200/272

400/180

High

"

240/326

"

Ultra-High

Buff

240/326

480/211

High

"

285/388

"

Ultra-High

Orange

280/381

560/247

High

"

335/456

"

Ultra-High

Gray

340/462

680/299

High

"

410/558

"

Ultra-High

Double Gray

380/517

760/334

High

"

455/619

"

Ultra-High

Triple Gray

415/564

800/352

High


2-Plate Specifications:
Weight**: 7.5 lbs/3.4 kg
M.O.I.**: 66.3 lb-in2/.0195 kg-m2

Spring Color

Torque Capacity
(lb-ft/Nm)

Release Load*
(lbs/daN)

Pressure Plate
(Ratio)

White

400/544

400/180

High

"

480/652

"

Ultra-High

Buff

480/652

480/211

High

"

570/775

"

Ultra-High

Orange

560/762

560/247

High

"

670/911

"

Ultra-High

Gray

680/925

680/299

High

"

820/1115

"

Ultra-High

Double Gray

760/1034

760/334

High

"

910/1238

"

Ultra-High

Triple Gray

830/1129

800/352

High


3-Plate Specifications:
Weight**: 9.9 lbs/4.5 kg
M.O.I.**: 87.6 lb-in2/.0258 kg-m2

Spring Color

Torque Capacity
(lb-ft/Nm)

Release Load*
(lbs/daN)

Pressure Plate
(Ratio)

Buff

720/979

480/211

High

"

855/1163

"

Ultra-High

Orange

840/1142

560/247

High

"

1005/1367

"

Ultra-High

Gray

1020/1387

680/299

High

"

1230/1673

"

Ultra-High

Double Gray

1140/1550

760/334

High

"

1365/1856

"

Ultra-High

Triple Gray

1245/1693

800/352

High


Tilton offers two different styles of every clutch configuration: one designed to be compatible with a step-type flywheel, and another for pot-type (“no-step”) flywheels. Step flywheels have a .100″ step for contact with the friction material of the clutch, so clutches made for this application will have a .100″ height difference between the bottom friction disc and the end of the clutch cover legs (the mounting points). Pot flywheels don’t have this step, so the friction disc and clutch cover legs will be flush on clutches designed for them.

Step-Type vs Pot-Type - Clutch Flywheel

Tilton’s 7.25″ metallic clutches are available with either a High Ratio or Ultra-High Ratio pressure plate. High Ratio pressure plates offer high clamp load over a wide wear range, while Ultra-High Ratio pressure plates provide 20% more clamp load and diaphragm spring travel (modulation). As seen on the graph below, the clamp load (or torque capacity) of the High Ratio pressure plate is relatively flat until .030″ (76mm) of wear; Ultra-High Ratio pressure plates offer a higher initial clamp load at a faster wear rate.

Pressure Plate Clamp Load Curve

High Ratio Pressure Plate Header

  • Standard pressure plate ratio for 7.25″ metallic clutches
  • Short release travel for quick engagement and shifting
  • Flat clamp load curve for longest wear range

Ultra-High Ratio Pressure Plate Header

  • 20% more release travel than High Ratio for improved modulation
  • 20% more clamp load than High Ratio for higher peak torque capacity
  • Clamp load reduced more quickly with wear than High Ratio

Tilton uses a color system for indicating the angle and weight of the clutch spring, which has an effect on release load and torque capacity for the clutch. The exact values for each color vary depending on the type of clutch, so be sure to check the Specs tab to find exact measurements.

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