Schumacher Cat XLS Manual

The Schumacher Cat XLS is a high-performance competition electric touring car chassis designed for 1/10 scale racing. Featuring a lightweight yet rigid carbon fiber chassis, adjustable suspension geometry, modular motor mount system, and precision ball differentials, it is built for competitive club and national level racing. Below are key sections covering specifications, assembly, setup, maintenance, and troubleshooting.

Features at a Glance

Key components: Carbon fiber main chassis, adjustable aluminum shock towers, modular motor mount, front & rear ball differentials, universal drive shafts.

Feature	Description
Chassis Material	2.5mm 3K carbon fiber for optimal stiffness and weight
Motor Mount	Modular system for short/long can motors; adjustable gear mesh
Suspension	Double wishbone with adjustable camber, caster, and toe
Differentials	Precision ball diffs front and rear with adjustable preload
Drive Shafts	Universal CVD joints for smooth power transmission
Shock Towers	7075 aluminum, multiple mounting positions for ride height and roll center
Battery Mount	Adjustable strap system for shorty or standard LiPo packs
Steering	Bell-crank system with adjustable Ackermann and bump steer
Weight	Approximately 1450g ready-to-run (without battery)
Wheelbase	Adjustable 257-262mm to suit different touring car bodies

Unpacking & Contents

Carefully unpack and verify all components against the parts list.

1. Carbon fiber chassis (main plate)
2. Front and rear aluminum shock towers
3. Suspension arms, hinge pins, and pivot balls
4. Ball differential assemblies (front and rear)
5. Universal drive shafts and outdrives
6. Motor mount module and hardware
7. Shock absorbers (4x) with springs and pistons
8. Hardware pack (screws, nuts, washers)
9. Decal sheet and assembly manual

WARNING! Small parts present choking hazard. Keep away from children. Inspect all parts for damage before assembly.

Chassis Assembly

Follow step-by-step instructions for proper assembly.

1. Install front and rear bulkheads to chassis using provided screws.
2. Assemble suspension arms with hinge pins and pivot balls; attach to bulkheads.
3. Mount shock towers to bulkheads; note orientation (front/rear, left/right).
4. Install ball differentials into gearboxes; set preload with shims.
5. Attach universal drive shafts to diffs and wheel hubs.
6. Install motor mount; align pinion and spur gear with proper mesh.
7. Assemble shocks with recommended oil weight (35wt front, 30wt rear).
8. Mount shocks to shock towers and suspension arms.
9. Install steering bell-crank and tie rods; adjust for zero toe.
10. Fit wheels and tires; balance if necessary for competition.

CAUTION! Use thread lock on metal-to-metal screws. Do not overtighten carbon fiber parts.

Technical Specifications

• Scale: 1/10 electric touring car.
• Chassis: 2.5mm 3K carbon fiber.
• Motor: 540-size brushless or brushed (modular mount).
• Drivetrain: Shaft-driven 4WD with ball diffs.
• Suspension: Independent double wishbone, oil-filled shocks.
• Adjustability: Camber, caster, toe, ride height, roll center, wheelbase.
• Battery: Shorty or standard 2S LiPo (7.4V).
• Radio: 2-channel minimum (steering & throttle).
• Dimensions: Length 400mm, width 190mm (adjustable).
• Weight: 1450g (without battery).

Suspension Setup & Adjustments

Fine-tune handling characteristics for different track conditions.

Camber: Adjust via upper suspension ball stud positions. Typical: -1° to -2° front, -0.5° to -1.5° rear.

Caster: Modified by front upper arm inner pivot location. More caster increases high-speed stability.

Toe: Front toe-out 1-2°, rear toe-in 2-3° for baseline.

Ride Height: Adjust shock mounting positions on tower and arm. Measure under chassis at front and rear.

Roll Center: Change via ball stud positions on shock towers and arms.

Anti-Squat & Anti-Dive: Adjust rear suspension arm angle for traction and braking.

Drivetrain Installation

Install motor, differentials, and gears for optimal performance.

1. Select motor (brushless recommended for competition).
2. Mount motor to modular plate; align with spur gear.
3. Set gear mesh: paper strip method; slight backlash acceptable.
4. Assemble ball diffs: pack with grease, adjust preload via shims.
5. Install drive shafts: ensure smooth rotation without binding.
6. Lubricate all bearings with lightweight oil.

Tip: Use gear calculator to determine final drive ratio for track.

Electronics Installation

Mount ESC, receiver, and servo for clean wiring layout.

1. Mount steering servo to chassis using provided hardware.
2. Install ESC on side plate; secure with double-sided tape or zip ties.
3. Place receiver in protective case; mount away from power wires.
4. Connect servo to channel 1, ESC to channel 2.
5. Route wires neatly; use cable ties to avoid interference with moving parts.
6. Install battery with strap; ensure secure connection to ESC.
7. Bind transmitter to receiver per manufacturer instructions.

WARNING! Ensure all electronics are compatible with your battery voltage. Check polarity before connecting.

Setup Tips & Tuning Guide

Baseline setup for medium-grip asphalt track.

• Shock Oil: 35wt front, 30wt rear.
• Springs: Medium stiffness front and rear.
• Camber: -1.5° front, -1.0° rear.
• Toe: 1.5° front out, 2.5° rear in.
• Ride Height: 5mm front, 5.5mm rear.
• Diff Preload: Medium front, slightly looser rear.
• Anti-Roll Bars: 1.2mm front, 1.0mm rear (optional).

Adjust for high-grip: stiffer springs, more camber, tighter diffs. Adjust for low-grip: softer setup, less camber, looser diffs.

Maintenance Schedule

Regular maintenance ensures longevity and performance.

After Every Run: Clean chassis with compressed air; check for loose screws; inspect tires for wear.

Weekly (or 5-10 runs): Re-lubricate bearings; check diff preload; clean shock shafts; inspect drive shafts for wear.

Monthly (or 20-30 runs): Rebuild shocks with fresh oil; replace worn hinge pins and pivot balls; check gear mesh; replace damaged parts.

CAUTION! Use only recommended lubricants. Do not use WD-40 on bearings or plastic parts.

Warranty Information

Schumacher Racing Products offers a limited warranty on manufacturing defects for 12 months from date of purchase. Warranty does not cover wear and tear, crash damage, improper assembly, or modifications. Proof of purchase required. For warranty claims, contact your local authorized dealer or visit www.racing-cars.com. Keep original packaging for possible returns.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Car pulls to one side	Uneven tire wear, binding suspension, incorrect toe	Check tire diameters; free up suspension; adjust toe settings.
Excessive traction roll	Too stiff anti-roll bar, high ride height, hard tires	Soften anti-roll bar; lower ride height; use softer compound tires.
Poor corner entry	Front diff too tight, excessive front grip	Loosen front diff preload; reduce front camber; soften front springs.
Poor corner exit	Rear diff too tight, insufficient rear traction	Loosen rear diff; increase rear camber; adjust rear toe-in.
Motor overheating	Gear mesh too tight, high gearing, insufficient airflow	Reset gear mesh; use smaller pinion; ensure motor fan is working.
Shocks leaking	Worn O-rings, damaged shafts, loose caps	Rebuild shocks with new seals; replace damaged shafts; tighten caps.
Differential noise	Insufficient grease, worn balls/outdrives	Disassemble, clean, re-grease; replace worn components.
Steering not centered	Trim setting, servo horn position, linkage binding	Adjust transmitter trim; re-center servo horn; check steering linkage.

Support: For technical assistance, contact Schumacher Racing at +44 (0)1283 217330 or [email protected].