BMW i3 2014-present Suspension Bolt Torque Specifications & Fastener Values
BMW i3 2014-present

BMW i3 2014-present Suspension Bolt Torque Specifications

Detailed torque specifications for suspension bolts on the 2014-Present BMW i3. Includes front and rear suspension components.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

Search Specifications

Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

Front Strut Assembly

Torque specifications for the components of the front strut assembly, including mounting points to the chassis, steering knuckle, and upper mount.

1

Strut to Steering Knuckle Pinch Bolt

M14 x 1.5
Torque Value
77 ft-lbs (105 N·m)
Important Notes
Secures the steering knuckle around the bottom of the strut. Critical for front suspension integrity.
2

Upper Strut Mount Nuts to Body

M8 x 1.25
Torque Value
32 ft-lbs (43 N·m)
Important Notes
Secures the upper strut mount to the vehicle body. Typically uses three nuts.

Front Control Arm

Torque specifications for the front control arm, including mounting points to the chassis/subframe and ball joint.

1

Control Arm Bolts to Chassis/Subframe

M12 x 1.5
Torque Value
111 ft-lbs (150 N·m)
Important Notes
Secures the control arm to the vehicle's chassis or subframe. Critical for maintaining suspension geometry.
2

Ball Joint Nut

M12 x 1.75
Torque Value
52 ft-lbs (70 N·m)
Important Notes
Secures the ball joint to the control arm or steering knuckle. Ensure proper seating before tightening.

Front Steering

Torque specifications for steering components including the tie rod end.

1

Tie Rod End Nut

M10 x 1.25
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Secures the tie rod end to the steering knuckle. Critical for steering alignment and responsiveness.

Front Subframe

Torque specifications for the front subframe mounting bolts.

1

Front Subframe Mounting Bolts

M14 x 2.0
Important Notes
These bolts mount the subframe to the chassis. Use new bolts for reassembly. Torque to spec, then tighten an additional 90 degrees. One time use bolts.

Rear Suspension

Torque specifications for the rear suspension, including the shock absorber and control arm.

1

Rear Shock Absorber Lower Mounting Bolt

M12 x 1.5
Torque Value
81 ft-lbs (110 N·m)
Important Notes
Secures the lower end of the shock absorber to the control arm or chassis.
2

Rear Control Arm Inner Bolt

M12 x 1.5
Torque Value
111 ft-lbs (150 N·m)
Important Notes
Secures the inner mounting point of the rear control arm to the chassis. Critical for proper wheel alignment.

Sway Bar

Torque specifications for the sway bar links and mounting brackets.

1

Sway Bar Link Nut

M10 x 1.5
Torque Value
37 ft-lbs (50 N·m)
Important Notes
Connects the sway bar link to the sway bar and control arm/strut assembly. Correct torque ensures proper sway bar function.
2

Sway Bar Mounting Bracket Bolts

M8 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Secures the sway bar to the chassis via the mounting brackets. Ensures the sway bar is properly secured for optimal performance.

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

Common Issues

Bolt stretching, stripped threads, uneven torque patterns

Loose Components

Symptoms:
  • Rattling or vibration noises
  • Visible movement in components
  • Uneven panel gaps
Solutions:
  • Clean threads and mounting surfaces
  • Replace damaged fasteners
  • Apply proper torque in sequence
  • Use thread locker if specified

Stripped Fasteners

Symptoms:
  • Unable to achieve proper torque
  • Fastener spins freely
  • Visible thread damage
Solutions:
  • Use thread repair kit if appropriate
  • Install thread insert (HeliCoil)
  • Replace component if threaded hole is damaged
  • Upgrade to higher grade fastener if recommended

Overtightened Components

Symptoms:
  • Cracked or deformed parts
  • Broken fasteners
  • Compressed gaskets or seals
Solutions:
  • Replace damaged components
  • Use new fasteners
  • Follow proper torque sequence
  • Verify correct torque specifications

Diagnostic Steps

Visual inspection, torque verification, thread assessment

1

Visual Inspection

Inspect the affected area for any visible signs of damage or wear

  • Check for cracks or deformation
  • Look for signs of excessive wear
  • Verify proper fastener installation
2

Torque Verification

Verify the torque applied to the fasteners

  • Check the torque wrench calibration
  • Verify the torque specification
  • Compare the applied torque to the specification
3

Thread Assessment

Assess the condition of the threads

  • Check for signs of thread damage
  • Verify the thread type and size
  • Check for proper thread engagement

Prevention Guidelines

Best practices, maintenance tips, tool care

Best Practices

  • Always follow the recommended torque specification
  • Use the correct type and size of fasteners
  • Verify the torque wrench calibration regularly

Maintenance Tips

  • Regularly inspect the affected area for signs of wear or damage
  • Replace damaged or worn-out components promptly
  • Keep the work area clean and organized

Tool Care

  • Regularly clean and maintain the torque wrench
  • Store the torque wrench in a dry and secure location
  • Verify the torque wrench calibration before each use

Frequently Asked Questions

Find answers to common questions about torque specifications

Q1

Why is using the correct torque specification so important for suspension bolts?

Using the correct torque specification ensures the suspension components are securely fastened without being over-tightened or under-tightened. Over-tightening can stretch or damage bolts and mounting points, potentially leading to failure. Under-tightening can allow components to shift, causing excessive wear, noises, and ultimately, a loss of control. For example, improperly torqued control arm bolts could cause suspension misalignment and premature tire wear.

Q2

Can I use a general torque value if I don't have the specific specification for a bolt?

No. Using generic torque values is highly discouraged for suspension components. Each bolt is designed with specific material properties and tolerances, requiring precise torque specifications outlined in the vehicle's service manual. Using an incorrect value could lead to component failure or damage. Always refer to the BMW I3 specific torque specifications for each bolt.

Q3

Do I need to use new bolts when working on the suspension?

In many cases, BMW recommends replacing certain suspension bolts during disassembly. These are often stretch bolts, designed to yield slightly during initial tightening. They should not be reused as their original strength and clamping force may be compromised after being loosened. Always consult your vehicle repair manual or a reputable repair resource to confirm if bolts should be replaced, or reused. Example: Control arm bolts or bolts near rubber bushings should be replaced.

Q4

Should I torque bolts with the suspension loaded or unloaded?

Generally, suspension bolts should be torqued with the suspension in a 'loaded' state, meaning the vehicle's weight is on the wheels and suspension is at its normal ride height. Torquing at other positions can result in stresses on bushings, reduced component life and poor suspension behavior. This is because some bushings are designed to be compressed and aligned in a specific position and torquing with suspension unloaded can cause binding in the system. For example, lower control arm bushings should always be loaded before final torquing to prevent binding and bushing failure.

Q5

What should I do if I suspect I over-torqued a suspension bolt?

If you suspect a bolt has been over-torqued, it is crucial to replace it, as the structural integrity of the bolt and/or mounting point may be compromised. Check for any damage or deformation of the bolt or its mating surfaces. Retorque any previously loosened bolts correctly using new bolts where specified.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

Temperature Effects

Includes: High Heat, Cold Weather, Thermal Cycling

Temperature can significantly impact torque values and fastener behavior

Cold Weather

Effects:
  • Increased material brittleness
  • Higher torque required due to thread contraction
  • Reduced thread lubricant effectiveness
Recommendations:
  • Allow components to warm to room temperature when possible
  • Consider using winter-grade thread lubricants
  • Check torque values more frequently during winter months

Hot Weather

Effects:
  • Thermal expansion of components
  • Decreased friction in threads
  • Accelerated lubricant breakdown
Recommendations:
  • Check torque when components are at normal operating temperature
  • Use temperature-resistant thread lockers
  • Consider re-torquing after heat cycles

Humidity and Corrosion

Covers: Rust Prevention, Salt Exposure, Moisture Control

Moisture and corrosion can affect fastener integrity and torque values

High Humidity

Effects:
  • Accelerated corrosion formation
  • Reduced friction coefficient
  • Potential thread seizing
Prevention:
  • Use corrosion-resistant fasteners
  • Apply appropriate anti-seize compounds
  • Maintain proper protective coatings

Salt Exposure

Effects:
  • Rapid corrosion development
  • Thread damage
  • Seized fasteners
Prevention:
  • Regular underbody washing
  • Use of sacrificial anodes where appropriate
  • Application of protective coatings

Seasonal Maintenance

Spring, Summer, Fall, and Winter maintenance schedules

Spring

  • Inspect for winter damage
  • Clean and protect exposed fasteners
  • Check torque on critical components

Summer

  • Monitor heat-affected components
  • Check expansion-related loosening
  • Inspect cooling system mounts

Fall

  • Prepare for winter conditions
  • Apply corrosion protection
  • Verify all fasteners are properly torqued

Winter

  • More frequent inspection of critical fasteners
  • Check for salt damage
  • Monitor suspension component torque

Related Resources

Tools, service procedures, and technical bulletins

Recommended Tools

Torque Wrench (1/2 inch drive)

A calibrated torque wrench to apply precise torque values to fasteners.

  • Click-type mechanism
  • Wide torque range (20-200 Nm recommended)
  • Easy-to-read scale
Learn more

Torque Wrench (3/8 inch drive)

A smaller torque wrench for lower torque specifications.

  • Click-type mechanism
  • Lower torque range (5-80 Nm recommended)
  • Easy-to-read scale
Learn more

Socket Set (Metric)

A set of metric sockets covering a range of sizes.

  • Various sizes (10mm - 24mm recommended)
  • 6-point design for secure grip
  • Durable construction
Learn more

Socket Extensions and Universal Joint

Extensions and a universal joint to access hard-to-reach fasteners.

  • Varying lengths of extensions
  • Durable construction
  • Smooth operation
Learn more
Service Procedures

Front Strut Assembly Bolt Torque Procedure

Procedure for tightening the bolts associated with the front strut assembly of the BMW i3.

  • Locate the upper strut mounting bolts (typically three).
  • Using a 3/8 drive torque wrench, torque to 27 Nm + 90 degrees.
  • Locate the lower strut pinch bolt.
  • Using a 1/2 drive torque wrench, torque to 110 Nm.
  • Locate the sway bar end link bolt to the strut housing
  • Using a 1/2 drive torque wrench, torque to 80Nm.
View full procedure

Rear Trailing Arm Bolt Torque Procedure

Procedure for tightening the bolts associated with the rear trailing arm of the BMW i3.

  • Locate the trailing arm to body bolts (typically two).
  • Using a 1/2 drive torque wrench, torque to 110Nm + 120 degrees.
  • Locate the trailing arm to wheel carrier bolt
  • Using a 1/2 drive torque wrench, torque to 110 Nm + 120 degrees.
  • Locate the sway bar end link to the trailing arm bolt.
  • Using a 1/2 drive torque wrench, torque to 80 Nm.
View full procedure

Rear Shock Absorber Bolt Torque Procedure

Procedure for tightening the bolts associated with the rear shock absorber of the BMW i3.

  • Locate the upper shock mount bolt.
  • Using a 3/8 drive torque wrench, torque to 27 Nm + 90 degrees.
  • Locate the lower shock absorber bolt
  • Using a 1/2 drive torque wrench, torque to 110 Nm.
View full procedure
Technical Service Bulletins

BMW I3 Suspension Bolt Torque Update

2017-05-15

A service bulletin detailing a revised torque specification for the front lower strut pinch bolt due to reports of loosening.

2014-2017

Resolution: Replace the original bolt and torque to 110 Nm and use the appropriate torque procedure.

Rear Suspension Noise Investigation

2019-11-20

This bulletin addresses a reported noise from the rear suspension traced back to improperly torqued trailing arm bolts.

2014-2019

Resolution: Ensure trailing arm bolts are torqued to 110 Nm + 120 degrees and perform a test drive.

Front Sway Bar End Link Inspection

2021-03-01

This bulletin advises a check of front sway bar end link bolts after suspension work due to a potential for noise.

2014-2021

Resolution: Check torque of sway bar end link bolt to the strut housing, torque to 80 Nm.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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