Technical product information
Flying Spur - Steering shimmy/vibration - 21 inch wheels only - ROW
Hongkong-Macau (5HK),Russische Föderation (5RU),Australia E04 Bentley rest Asia and Australia (6E04),China 796 VW Import
Comp. Ltd (Vico), Beijing (6796),Germany E02 Bentley rest Europe (6E02),Japan E03 Bentley Japan (6E03),Russian Federation
935 Volkswagen Group RUS (6935),United Kingdom E01 Bentley UK (6E01),United States E05 Bentley USA and rest America
(6E05)
Bentley

Topic
Market
area
Brand

Transaction
2045082/1
No.
Level
EH
Status
Approval
Release
date
New customer code
Object of complaint
Complaint type
Position
Running gear -> Wheels, tyres, tyre pressure monitoring -> Tyres -> Tyre tread visual appeal / surface -> bump
> not specified <
Running gear -> Steering, power-assisted steering -> Steer
Noise, vibration -> vibrate
Running gear -> Steering system
functionality
Running gear -> Steering system
Noise, vibration
Running gear -> Wheels, tyres, tyre pressure monitoring -> Tyres
component / consumables -> incorrectly built
New workshop code
Object of complaint
Running
Running
Running
Running
Running

gear
gear
gear
gear
gear

->
->
->
->
->

Wheels,
Wheels,
Wheels,
Wheels,
Wheels,

Complaint type
tyres,
tyres,
tyres,
tyres,
tyres,

tyre
tyre
tyre
tyre
tyre

pressure
pressure
pressure
pressure
pressure

monitoring
monitoring
monitoring
monitoring
monitoring

-> Tyres
-> Tyres
-> Tyres
-> Tyres
-> Tyres

component
component
component
component
component

/
/
/
/
/

consumables
consumables
consumables
consumables
consumables

Vehicle data
Flying Spur
Sales types
Type MY Brand Designation Engine code Gearbox code Final drive code
4W2* 2014 E
4W2* 2015 E
4W2* 2016 E

Documents
Document name
master.xml

*
*
*

*
*
*

*
*
*

Position
-> unbalanced
-> unbalanced
-> unbalanced
-> unbalanced
-> incorrectly built

rear right
front right
rear left
front left
> not specified <

Technical product information

Transaction No.: 2045082/1

Flying Spur - Steering shimmy/vibration - 21 inch wheels only - ROW

Customer statement / workshop findings
This TPI is only applicable to Flying Spur vehicles fitted with 21 Inch wheels, should 20 inch Bentley approved wheels be fitted please raise a DISS
query and await further instruction from Product support before commencing with any other work.

Before carrying out any work please check that this TPI is the latest available document by searching in Elsa Pro, you must ensure
that the applicable VIN is used when searching for any technical information.
Should a customer complain of steering wheel shimmy/vibration constantly and the condition does not improve when driven please proceed with this
TPI. Steering shimmy/vibration is most evident at 90 km/h
Before commencing with this TPI - Refer to the applicable vehicles repair history in Elsa Pro to check that the latest level steering rack wagner valves
have not already been fitted or may not be required

Technical background
Due to environmental conditions involving large changes of ambient temperature, condition can occur after a very short stationary period where flat
spots are created as the warm tyres cool down. The tread surface of the tyre forming the footprint on the road surface retains the relatively flat form
when driven and does not immediately restore to a constant radius. Hence the name of flat spotting which is generally given to this condition.
Flat spotting should not be confused with out of balance, out of round or radial force variation. It is very important that the diagnosis and correction
of these different conditions are not confused with each other. Attempting to correct flat spotting by rebalancing the assembly will not correct the
problem and worse still, when the flat spots are removed the tyres will be out of balance.
EXPLANATIONS AND DEFINITIONS
Radial force variation (RFV)
The radial force is the force with which a tyre is compressed.
Tyres have softer and stiffer areas along their circumference. In Figure 1, the softer and stiffer areas are illustrated by different size springs.
If this wheel rolls on a level road with constant wheel load (Figure 1, point 1), the centre of the wheel rises and falls by the amount (x) because of the varying
spring hardness. The change by the amount (x) can be felt in the vehicle as vibration or shaking of the steering wheel.
The change of the compression force of the tire is the radial force variation.

Figure 1
Harmonic vibrations
The wheel force variations during the turn of the wheel can be mathematically divided into individual harmonic vibrations.
For an objective of tyre stiffness, the first harmonic (basic vibration) is used
The basic vibration or first harmonic is the share of the RFV that causes the strongest vibrations
The first harmonic (RFV) must be 85N or less
NOTE: it is imperative that the first harmonic result is used (Figure 2) please ensure your vibration balancer always shows the first harmonic result, Do
not use the Total Indicated Reading (TIR) only the first harmonic result should be used - Refer to the vibration control balancer handbook for further
details.

Figure 2
During this TPI the Workshop manual is quoted to help in carrying out various tasks, it is recommended that the procedures referenced are checked
by the operative as the process within the Workshop manual may have changed since last viewed.

Production change
-

Measure
1. Check all wheels and tyres for damage/distortion. NEVER fit tyres to rims which are damaged/kerbed or distorted, tyres can be damaged/cut
during the fitment process if the rims are damaged/kerbed on the outer edge of the rim
- Check the tyres are of correct Bentley approved specification including date code otherwise this TPI does not apply
- Check that Bentley 21 inch approved wheels are fitted
- Check the front and rear suspension for any damage and wear - Refer to Workshop manual
- Check all steering components for damage and wear - Refer to Workshop manual
- Check all wheels for distortion/buckles whilst the car is on the ramp
2. In ambient workshop temperature and ensuring the engine and tyres have cooled down to ambient temperature adjust all tyre pressures to
‘Normal’ pressure (see tyre pressure label on B-post)
The next part of this process requires the vehicle to be road tested to allow the tyres to warm up sufficiently, on return the vehicle
must be raised from the ground within two minutes, please ensure you have a wheel free ramp available on return from road test
Should the vehicle not be raised within a maximum of two minutes after returning from road test the tyres will begin to flat spot
resulting in the need to repeat the road test procedure
3.
ROAD TEST - Conduct an initial road test, the vehicle should be driven until the flat spots come out or the flat spotting condition improves,
drive the vehicle for a minimum of 30 km at 120 kp/h (where permitted) to allow the tyres to warm up to running temperature and allow the flat
spots to run out, the most sensitive speed for shimmy/vibration is 90 km/h during the road test you should also drive at this speed to validate
steering shimmy/vibration to allow the driver to make an accurate assessment.
IMPORTANT Within a maximum of two minutes after returning from the road test, raise the vehicle off the ground
4. Allow the wheel assemblies to cool for 20 minutes before removal
- After 20 minutes has elapsed remove all four wheels
- The wheels should be left to cool down positioned lying flat as shown in Figure 3 ensure the rim of the wheel is protected to prevent damage when
lying on the floor WARNING Do not allow the wheels to cool down standing upright as shown in Figure 4

Figure 3

Figure 4

- Using a digital infrared thermometer check the temperature of the tyres
- The RFV process should only be conducted once the tyres are within 10% of ambient workshop temperature this is to allow and confirm the tyres
are at the correct temperature

For Example – If the Workshop temperature is 25°C the tyres should be 27.5°C before commencing with the RFV process otherwise do not
commence until the tyres have cooled to correct temperature

5. The next part of this process requires the use of the Hunter GSP9712 (VAS 6230) vibration control balancer (or similar)

IMPORTANT: Please ensure your vibration control balancer is calibrated and is in full working order.

Self calibration (excluding service contract calibration is highly recommended every 3 days to ensure correct and accurate measurements) – please
refer to manufacturer’s instructions relating to self calibration
Please refer to the instruction manual of your particular vibration control balancer for all relevant information

• If your vibration control balancer has a Smart weight function Do Not use this function when balancing Bentley wheel assemblies

please only use traditional balancing technology

• Ensure Smart weight is not selected please refer to the manufacturers operating instructions
Does the vehicle have accessory tyre valve caps fitted as shown in Figure 5? If Yes please ensure the force match and balance
process is always conducted with the accessory valve caps fitted
If No and the wheels are fitted with plastic valve caps these should still be fitted during the force match and balance process

Figure 5
IMPORTANT: Apply a thin smear of silicon based grease for example Dow Corning high vacuum grease to the external threads of the valve stem
prior to fitting the accessory valve cap. Grease should be applied any time the cap is removed and the grease is not evident
If during the RFV process you are prompted to measure the rim run out due to an out of specification assembly please adhere to all points below
Please refer to workshop manual Rep.Gr 44 Tyres – checking condition and replacement – Radial Force Variation – Best fit practice to ensure the
following are confirmed and rectified
•

The wheel rim run out measurement is as per specification

• The wheel rim run out process is strictly adhered to as per the manufacturers vibration control balancer operating instructions
•

It is recommended to measure the bare rim for accurate run out readings

Referring to Figure 6 (Point A) - After force matching and balancing the assembly must not exceed 85N (first harmonic)

Figure 6
Ensure after balancing the screen shows as (Point B) do not fit an assembly which does not show OK – OK for the inner and outer
balance weight adjustment
- For Hunter GSP 9712 (or similar) use the White faced adaptor cone with identification code 154 F+ shown in Figure 7, NOTE: If your workshop
does not have this particular adaptor please contact your local Hunter representative

Figure 7
6. The cone must be fitted on the spindle as shown in Figure 8 ensuring the white face of the cone is facing towards the end of the spindle

IMPORTANT NOTE: Should the initial first harmonic reading be above 85N this does not necessarily mean the assembly cannot be adjusted to the
specified tolerance, please ensure that the force matching process is adhered to as instructed within the workshop manual Rep.Gr 44 – Tyres –
checking condition and replacement.
All four tyres must not exceed 85N after force matching and balancing, should this not be achievable replace the applicable tyres - Refer to Workshop
Manual Rep.Gr 44

Figure 8
IMPORTANT: When conducting the wheel and tyre force matching process or the tyres require replacing, a specific tyre fitting lubricant should be
used. The lubricant is Rema Tip Top Anti Gliss Lube with the Bentley Part Number of RH 14530. On drying the Anti Gliss has adhesive properties that
increases friction between the tyre and wheel rim to prevent slippage. Please Refer to Workshop Manual Rep.Gr 44 Tyres - Checking Condition and
Replacement - Radial force variation - Best fit practice.
• Using a clean brush apply to the entire circumference of the upper and lower tyre beads
• Anti Gliss must also be applied to the entire circumference of the upper hump of the wheel rim (Figure 9 shows the upper hump and where the Anti
Gliss should be applied)

Figure 9
•

Every time the bead is broken any remnants of “Anti –Gliss” MUST be cleaned off the wheel rim and the tyre bead

•

Ensure that all original balance weights and balance weight adhesive is completely removed from the wheel rim

Failure to remove weight adhesive could result in the application of the new weights in the same place resulting in poor contact
between the weight and rim, the weight can become detached from the rim which will affect the balance of the assembly

It is recommended to wear eye protection
- To seat the tyre beads to the wheel rim inflate to a min of 3.5 Bar max of 4.2 Bar with the valve core removed (Figure 10), the removal of the
valve core allows the assembly to be inflated quicker than with the core fitted, which helps to seat the tyre bead to the rim evenly

Figure 10
Once satisfied that the tyre beads are seated correctly refit the valve core and readjust to the RFV measuring pressure of 3.0 Bar – Refer to workshop
manual Rep.Gr 44 and also observe the following key points
-Referring to Figure 11 The assembly high spot is identified with a brown dash the first harmonic result (RFV) is shown in this example as 45N

Figure 11
-Rotate the assembly on the spindle until the high spot is at 12 o’clock and the brown dash turns to Green (Figure 12)

Figure 12
-Mark the RFV high point with a paint pen or similar (Figure 13) this will be required when refitting the wheels

Figure 13
In the event that any parts are required to be replaced using the latest specification they should be fitted at this point prior to
refitting the wheels
12. Refit the road wheels refer to Workshop manual Rep.Gr 44 Tyres – Checking Condition and Replacement – Radial force variation – Best fit
practice
.- Carry out a full front and rear geometry check and adjust as required - Refer to workshop manual - Rep.Gr 44 Wheels, tyres. axle align
IMPORTANT: The geometry check and adjust process is crucial to the whole process please ensure the process is fully adhered to including ‘S’ Point
adjustment (Raised toe adjustment)
Vehicle model
Flying Spur

‘S’ Point toe constant
5' ± 2'

Toe - in
10' ± 2' positive (per
side)

13. Adjust the tyre pressures to ‘Normal’ pressure (see tyre pressure label on B-post)
IMPORTANT: In the event that brand new tyres have been fitted you must carry out procedures 14 to 16
•

If the original tyres were used it is only a requirement to carry out procedure 16

• The second road test on fitment of new tyres is only applicable when conducting this TPI and should not be conducted if a customer requires new
tyres for a non steering shimmy/vibration complaint
14. NEW TYRES ONLY Conduct a second road test to evenly seat the beads to the rim, drive the vehicle for a minimum of 30 Km at 120 kp/h (where
permitted) this process is essential to allow the tyres to warm up to running temperature
15. NEW TYRES ONLY On return from the second road test repeat Section 1 procedures 1 to 6 to confirm the RFV and balance is within specification
- When refitting the wheels - Refer to Workshop manual Rep.Gr 44 Tyres – Checking Condition and Replacement – Radial force variation – Best fit
practice
16. NEW AND ORIGINAL TYRES Reassess the vehicle, the vehicle should be driven for a minimum of 20 Km at 90 kp/h (where permitted) 90 kp/h is
the most sensitive speed for steering shimmy/vibration validation
NOTE: It is recommended the tyre pressures are adjusted to ‘Normal’ pressure (see tyre pressure label on B-post) on return to the customer
The customer should be made aware that should they require to drive at higher speeds than recommended for Normal pressure the pressure should
be adjusted accordingly

Warranty accounting instructions
Time to carry out the initial flat spot recovery process and force match and balance all four assemblies
Warranty Type

910 or 110

Labour operation code

44 40 94 00

Damage Service Number

44 40

Damage code

00 13

Time

Shop Time

Time to check and adjust the front and rear vehicle geometry without ACC
Warranty Type

910 or 110

Labour operation code

44 95 03 00

Damage Service Number

44 95

Damage Code

00 13

Time

80 Time units

Time to check and adjust the front and rear vehicle geometry with ACC
Warranty Type
Labour operation code

910 or 110
44 95 03 10

Damage Service Number

44 95

Damage Code

00 13

Time

150 Time units

Road Test
Warranty Type
Labour operation code
Damage Service Number

910 or 110
01 21 00 00
01 21

Damage Code

00 13

Time

50 Time units

Parts information
Description

Part Number

Quantity

Anti Gliss

RH 14530

1 x 500 Gram tin can be
used for multiple applications

All regions applicable to this TPI must be source tyres locallyRep.Gr please ensure the new tyres are of correct specification as detailed within the
Workshop Manual Rep.Gr 44 – Tyres - Checking, Condition and Replacement

Customer information
Bentley branded Tyre Cradles are available as an approved accessory – Part number JNV 018 927
The tyre cradles have been designed and manufactured specifically for Bentley providing simple and effective tyre protection.
Tyre flat spotting can be caused by medium to long term storage or from parking after a long drive, especially where the tyre experiences large
changes in temperature.
To prevent flat spotting, tyres need to be cooled in a controlled manner to enable the tyre to restore to a constant radius.
Made from a unique polymer that moulds to the shape of the tyre the new Bentley Tyre Cradles maintain the tyre shape whilst cooling and in storage.
The tyre cradles are easy to use, simply drive the car onto them in the desired parking area.
NOTE: It is recommended the tyre pressures are adjusted to ‘Normal’ pressure (see tyre pressure label on B-post) on return to the customer
The customer should be made aware that should they require to drive at higher speeds than recommended for Normal pressure the pressure should
be adjusted accordingly