DEVELOPMENT OF A SEAT PAD SUITABLE FOR MEASURING

DEVELOPMENT OF A SEAT PAD SUITABLE FOR
MEASURING MOTORCYCLE SEAT VIBRATION
Neil J Mansfield and James P Irvine
Department of Human Sciences
Loughborough University
Loughborough
Leicestershire
LE11 3TU
UK
Abstract
Standard methods of measuring seat vibration have been developed with
automotive applications in mind. The pad specified in standards for measurement of
vibration on seats is a proven and accepted technology for conventional and
suspension seats found in, for example, cars, trucks and off-road machinery.
However, the pad is not suitable for measurements on motorcycles. The posture on
motorcycle seats introduces some degree of uncertainty as to where to locate the
pad and riders complain that the pad is uncomfortable. This paper describes the
development and validation of a revised pad designed for motorcycles.
1. Introduction
Traditionally, rider comfort on motorcycles has been seen as unimportant, as most riders saw the
vibration as part of the biking experience. However, the increase in professional riders (e.g. police,
paramedics, breakdown recovery, traffic congestion reporters, delivery and couriers) and therefore
exposure time has been accompanied by a demand to improve comfort. For example, Bike Magazine
(July 1998) included a comfort self-help guide:
"…try and avoid just sitting like a sack of spuds - you can end up putting too much weight
through the base of your spine and your backside will hurt more than King Edward II’s by
the time you’ve done a hundred miles. Spread the weight, taking some through your legs
and feet, some through your arms and the rest through your butt. Try and keep your back
fairly straight in normal riding (you’ll automatically bend over as you go faster or crouch out
of the wind, but do it all the time and you’ll get backache). The same goes for bending your
back the other way - a surprising number of people ride like this and it can lead to lower
back problems. It’s usually a symptom of an inability to relax, backed up by straight arms
and hunched shoulders, and you often see it in less experienced riders."
In a similar article in Motorcycle News (30 May 2001):
"…we regard a bit of suffering as part and parcel of biking - a badge of hardness that sets
us apart from flabby, cosseted car drivers…few of us realise that in certain
circumstances, simply sitting on our bikes could also be harmful to our health."
It is clearly not satisfactory to leave issues of health in the realms of self-help articles in magazines and
newspapers. However, standard techniques for assessing other vehicles are not necessarily applicable
to motorcycles.
th
Presented at the 36 United Kingdom Group Meeting on Human Responses to Vibration, held at Centre
for Human Sciences, QinetiQ, Farnborough, UK, 12 - 14 September 2001
Previous research on vehicle vibration has focussed on cars and off road machinery. This has been
due to these sectors either having a large market share or that they are perceived to be problematic
regarding vibration exposure. It is therefore natural that techniques are optimised for these vehicles.
The measurement of vibration at a seat requires that the transducers (e.g. accelerometers) are located
between the body and the seat. The accelerometers must move with the interface, they must not alter
the dynamic properties of either the seat or the body and they must offer little impedance to movement
over the frequency range of interest. The two most common faults appear to be the use of devices
which cause abnormal compression of the seat (or even require the cutting away of material from the
seat cushion) and failure to recognise that the seat must be loaded with the impedance of the body.
There are currently two generally recognised seat pad designs, one originally defined by the Society of
Automotive Engineers (SAE, 1973), and another known as the SIT-BAR (seat interface for transducers
indicating body acceleration received, Whitham and Griffin, 1977).
There currently exists no
specialised design of seat pad for use with a motorcycle although the SAE pad is generally used on
conventionally shaped seats in most vehicles (cars, lorries, agricultural equipment, etc.) and has also
been used to test vibration on the seats of motorcycles.
Previous studies of vibration exposure on motorcycles are rare, although hand-arm vibration has been
considered by Tominaga (2000) as has vibration at the feet (Doria and Cossalter, 2000). Measures of
vibration on motorcycle seats have been reported (Seaman, 2001) where an SAE pad was used, but is
was identified as 'very uncomfortable', did not fit to the profile of many motorcycle seats and riders
found it difficult to sit normally on the seat with the seat pad in place.
Likewise, in reference to
ISO2631, Rafl and Korbel stated (1989):
"To apply to motorcycles, it would be necessary to develop a new measurement
methodology."
This paper reports the design process of the development of a pad suitable for mounting accelerometers
on the surface of motorcycle seats and initial validation.
2. Specification of a specification
The seat pad is purely the means by which the accelerometers are protected from damage by the seat
occupant and the means by which the seat occupant is protected from discomfort from the
accelerometers. The pad must also be flexible to enable it to fit many different seat designs. The pad
must be comfortable for the user in an effort to minimise the distraction from the task of controlling the
motorcycle, as this could affect the way the machine is used or be dangerous due to distraction.
Current seat pads are designed with a conventional seat in mind (car seat/chair) and thus the flexibility
of these seat-pads is minimal. Indeed, a requirement of the SIT-BAR is that it is a rigid structure such
that rotational movement can be detected. Such properties would be unacceptable for a motorcycle
seat pad as the pad has to fit a much more diverse range of seat designs that occur on motorcycles and
not on cars. Current seat-pad designs do not need to be secured in position as the subject is physically
pressing it in position by sitting on it. The pad position is also stable due to the concave shape of the
seat. Motorcycles generally have convex seats so a pad will need to be secured to the seat, either by
2
friction or a dedicated securing device.
The pad will also be exposed to different environmental
conditions to those that occur inside a car. The conditions that the motorcycle seat pad could have to
endure include sunlight, oil, petrol, water, grease, grit/dirt, low and high temperatures.
The requirements of a seat pad for motorcycles are listed in Table 1.
Table 1. Requirements for a motorcycle seat pad
1.
Must fit all motorcycles
2.
Must be flexible to mould to all seat shapes
3.
Must not alter vibration on the seat surface
4.
Must be durable
5.
Must protect accelerometers from the physical environment
6.
Must be comfortable for the rider
7.
Must accommodate triaxial accelerometer set
8.
Must be low cost
The current SAE-pad meets requirements 2, 3, 4, 5, 7 and 8 listed in Table 1. However, a redesigned
shape for the pad might affect the vibration on the seat surface. Therefore, this study has focused on
points 1 (fit to all motorcycles), 3 (reliability of the vibration measurement) and 6 (comfort for the rider).
3. Survey of motorcycle seat dimensions
3.1 Method
The dimensions of 58 motorcycle seats were measured. A standardised proforma was used to log the
motorcycle type, seat type, subjective seat hardness, and seat dimensions. Seat type was classified
into 'single', 'dual' and 'split'. Subjective seat hardness was classified into 'v. hard', 'hard', 'firm', 'soft'
and 'v. soft' and was assessed by the experimenter by sitting on the motorcycle. Seat hardness was
therefore a general impression of the seat rather than an objective measure.
The dimensions of the seat were measured using a tape measure and for the plan of the seat included:
front width, narrowest width, rear width, greatest length and front width to narrowest width. For the
profile of the seat the front relative depth, greatest relative depth and extent of curvature depth were
measured. Measured seat dimensions are illustrated in Figure 1.
58 motorcycle seats were measured and included commuters, touring bikes and sports bikes.
3.2 Results and discussion
The dimensions for the 58 motorcycle seats are listed in Table 2. Seat depths ranged from 290 to 510
mm; front seat widths ranged from 70 to 320 mm and rear seat widths ranged from 180 to 430 mm. The
narrowest seats (CCM 604e and Gilera GSM50) were for specialist off road motorcycles where the
motorcycle is designed to be ridden whilst standing on the foot pegs. Widest seats (BMW K1200,
Kawasaki VN1500 and ZX6R) were found on touring bikes where long term comfort is a consideration.
3
A: Front width
B: Narrowest width
A C: Rear width
D: Greatest length
E E: Front width to narrowest width
B F: Front relative depth
G: Greatest relative depth
H: Extent of curvature
F
G
C
H
D
Figure 1. Seat dimensions measured in motorcycle seat survey.
th
The narrowest width of the seats was less than the 5 percentile male distance between ischia centres
(99.4mm, Peebles and Norris, 1998) which could result in discomfort if riders sat on the seat for
extended periods of time. However, 84% of the seats were wide enough at their narrowest point to
accommodate both ischia of a 95th percentile male (136.5mm).
The relative dimensions give an idea of the overall geometry of the bike, whether it is an extreme
curvature from front to back or a slight curvature on the cross section of the seat. The data can be
interpreted by using a difference of the rear width of the seat to the narrowest width, the greater this
difference, the more triangular the shape is. This sort of characteristic is typical of scooters and 'easy
rider’ style bikes (such as Harley-Davidson).
Conversely the opposite end of the scale exhibits
characteristics that link to bikes with a more rectangular shaped seat. Bikes such as off-roaders which
have generally narrow seats to complement the narrow nature of the bike, but also including bikes
which could be considered as ‘all-rounders’ (these are bikes that are sports based but have added
comfort for long distance riding). It is also worthwhile to notice that manufacturers tend to have similar
seat geometries on bikes that are in the same product range. This is especially evident in Kawasaki’s
ZX range of bikes.
4. Design of the motorcycle seat pad
4.1 Motorcycle pad shape
The ideal seat pad must be ergonomically designed for the rider, but must also be suitable for the
motorcycle. The survey of motorcycle seat dimensions indicated a broad range of seat shapes and
sizes. One strategy for design would be to make a pad that fits onto the smallest top surface of the
motorcycle seats surveyed. However, this would require a narrow pad with a width of less than 70 mm
and a length of less than 300 mm resulting in a device that may not be stable on the surface of the seat
that could also increase localised pressure on narrow seats, where localised pressure may already be
an issue.
4
Narrow
Width
Rear
Width
Max.
Length
Soft
Hard
Firm
Soft
Firm
Hard
Hard
Hard
Firm
Hard
Soft
Firm
Firm
Firm
Firm
Hard
Firm
Firm
Firm
Soft
Hard
Firm
Hard
Soft
Firm
Firm
Firm
Soft
Firm
V Hard
Hard
Soft
Hard
Firm
Firm
Hard
Firm
Hard
Firm
Firm
Firm
Hard
Hard
Soft
Firm
Soft
Firm
Firm
Firm
Firm
Firm
Firm
Hard
Hard
Firm
Hard
Firm
Hard
x
200
130
190
250
190
190
70
260
220
240
200
100
220
230
190
300
300
250
200
270
180
270
150
160
180
230
200
240
140
120
260
220
320
280
220
150
230
260
160
120
250
320
130
240
240
170
240
190
120
150
240
160
250
240
130
190
120
x
200
130
190
250
190
190
70
210
210
230
190
100
220
220
190
260
280
250
200
260
180
270
150
160
180
230
200
240
140
120
230
220
270
240
220
150
230
260
160
120
240
320
130
240
240
170
220
190
120
150
240
160
220
230
130
190
120
370
310
320
430
330
320
320
190
210
320
280
350
180
290
300
320
330
300
330
290
260
350
300
290
290
280
320
250
430
410
340
370
310
400
430
370
330
340
370
380
280
340
320
280
360
350
270
300
290
320
310
290
230
370
300
300
290
250
x
300
420
510
490
480
480
400
420
320
410
430
510
360
440
370
410
490
460
360
420
320
400
400
340
380
410
460
460
420
360
450
360
460
410
300
300
300
360
490
350
390
480
360
350
290
360
380
350
450
490
360
300
360
420
430
460
510
5
0
0
0
0
0
0
0
0
210
90
10
10
0
0
90
0
150
210
0
0
50
0
0
0
0
0
0
0
0
0
0
150
0
260
120
0
0
0
0
0
0
100
0
0
0
0
0
110
0
0
0
0
0
80
80
0
0
0
0
10
-5
50
-20
80
80
40
10
60
70
60
-30
10
50
10
50
60
40
40
80
20
30
60
40
-10
40
-90
10
-10
40
70
80
110
30
50
40
20
70
20
-10
60
30
80
0
10
40
10
90
30
10
70
20
30
20
40
-60
-60
0
10
5
150
40
80
80
30
30
60
90
80
30
60
55
90
60
60
50
40
80
20
60
70
45
70
100
20
80
10
50
80
85
115
30
50
40
20
70
20
-10
70
30
90
15
10
50
10
95
32
20
80
20
30
20
50
100
30
Curvature
Front
Width
Dual
Single
Split
Split
Dual
Dual
Dual
Dual
Dual
Split
Dual
Dual
Dual
Dual
Dual
Dual
Dual
Dual
Dual
Split
Single
Single
Dual
Dual
Dual
Dual
Dual
Dual
Split
Single
Dual
Dual
Dual
Single
Split
Split
Split
Split
Single
Dual
Dual
Dual
Dual
Dual
Single
Single
Split
Split
Split
Dual
Dual
Dual
Split
Split
Split
Dual
Dual
Dual
Front Narrow
Width
Front
Rel.
Depth
Max
Rel.
Depth
Hardness
Aprilia
GP Sonic
Aprilia
RSV Mille
Aprilia
SR Sport
BMW
K1200LT
Cagiva
Navigator 1000
Cagiva
Raptor
Cagiva
V Raptor
CCM
604e
CCM
604RS
Ducati
748 BP
Ducati
Monster 750
Gilera
DNA
Gilera
GSM50 Super Motard
Honda
CB500R
Honda
CB600F
Honda
CB750
Honda
CBR1100XX
Honda
CBR600F
Honda
Deauville
Honda
Fireblade
Honda
VTR1000
Honda
VTR1000SP1
Honda
X11
Kawasaki
Eliminator
Kawasaki
ER5
Kawasaki
GPZ500
Kawasaki
GTR1000
Kawasaki
KLR650
Kawasaki
VN1500
Kawasaki
VN800
Kawasaki
W650
Kawasaki
ZR7S
Kawasaki
ZRX1200
Kawasaki
ZX12R
Kawasaki
ZX6R
Kawasaki
ZX7R
Kawasaki
ZXR400
Laverda
750s
Moto Guzzi
V11 Sport
Peugeot
Speedfight 2
Piaggio
PX125
Suzuki
Bandit 600
Suzuki
Estilect
Suzuki
GN125
Suzuki
GSXR1300R
Suzuki
GSXR600
Suzuki
Marauder
Suzuki
SV650
Triumph
T955i
Yamaha
100 Neos
Yamaha
AeroX
Yamaha
Fazer
Yamaha
FZR400
Yamaha
R1
Yamaha
R6
Yamaha
SR125
Yamaha
TDM 850
Yamaha
TW Trailway
Seat
Type
Model
Make
Table 2. Dimensions of 58 motorcycle seats.
180
80
140
250
260
190
190
180
130
80
200
210
170
180
220
190
110
250
220
130
180
110
290
190
190
190
230
140
70
30
90
200
190
210
120
120
110
130
190
210
130
220
250
200
120
140
210
150
130
190
220
210
80
110
180
230
240
170
Uniform (does not alter seat profile) Sloped (increases seat angle)
Domed (could cause discomfort
for anterior leaning postures)
Figure 2. Diagrammatic representation of effect of profiling the seat pad.
An alternative strategy is to design the pad to be flexible such that it wraps around the seat edge. This
has the advantage that it would not increase pressure at the edges of the pad and that it would be
suitable for the diverse range of seat designs.
4.2 Motorcycle pad profile
Taking into consideration the nature of motorcycle seats from the point of view of their general shape, a
different concept is required to that of the existing SAE seat pad. This difference is because of the
overall profile of a bike seat compared to that of a car. If the pad was to slope from front to back on a
seat that naturally tends to slope forward, the pad would make this angle of slope even more extreme,
altering the seat geometry such that it may affect the rider, in that they may be aware of the pad or
perhaps even distracted by it (Figure 2). Similarly, a design which incorporates a dome, as for the SAE
pad, could cause discomfort for male riders sitting astride the saddle leaning forwards due to increased
pressure on the sex organs. The benefits of a more uniform cross-section than for the SAE pad offset
the disadvantages of the increased seat depth.
The depth of the profile is mainly determined by the size and number of accelerometers that need to be
accommodated. The design requirement 7 (Table 1) stipulates that a tri-axial accelerometer set must
be contained within the pad. Therefore, the pad must contain a cavity deep enough for orthogonally
orientated accelerometers.
4.3 Design conclusions
From the discussion above, one can identify a number of major considerations that need to be made for
the design of a seat pad to measure vibration on a motorcycle. These are as follows:
•
The seat pad must exhibit a uniform cross section in the x-axis.
•
The seat pad must be able to accommodate accelerometers in an orthogonal set up.
•
The seat pad must be made of a material that will remain in the correct orientation during use.
•
The seat pad must be able to mould to the contour of the seat to provide minimal distraction to the
rider.
•
The seat pad must be suitable for use on all of the motorcycles that have been measured.
6
For the pad to exhibit a uniform cross section in the x-axis it is crucial to ensure that the depth at the
front of the pad is the same as the depth at the back of the pad.
For the pad to accommodate the available Entran accelerometers it must have a 12mm cavity in the
centre where the accelerometers will be positioned. As for the SAE pad, these should be mounted on a
rigid disc to ensure good coupling with the seat. A disc width of 75mm would enable good coupling for
all seats surveyed at the position where the accelerometers are mounted.
4.4 Design solution
The design for the seat pad is shown in Figure 3. The fit of the pad was tested on a variety of
motorcycle seats and it fitted all tested (e.g. Figure 4).
5. Validation of the motorcycle seat pad
5.1 Method
To provide some indication of the validity of vibration measurements made with the motorcycle seat
pad, tests were carried out using the new motorcycle pad and two different SAE pads (new flexible
rubber, old semi-rigid resin).
The same three orthogonally mounted accelerometers were used with each pad.
Entran EGAS
accelerometers were used with the pads. Signals from the accelerometers were amplified using battery
powered custom built strain gauge amplifiers containing anti-aliasing filters set at 1000 Hz. Filtered
signals were acquired at 4096 samples per second to a portable computer running National Instruments
LabVIEW 5.1 via a ComputerBoards PCM-DAS16S/12 DAQ card. The equipment was mounted into a
tank bag that was located in front of the riders.
Two motorcycles were used for the tests and were ridden by their respective owners. The test bikes
were a 500cc Honda CB500R 180° parallel twin and a 600cc Yamaha XJ600 in-line four. Each bike
was ridden over the same section of country road in the same direction for each seat pad. Each
measurement lasted 50 seconds, although the analysis was only carried out on the last 30 seconds of
data, to ensure that the motorcycle was travelling at a constant speed.
Five riders were also asked to judge the comfort of each pad on a 5-point scale (painful, uncomfortable,
neutral, comfortable, very comfortable) whist the motorcycle was stationary.
The safety and ethics committee of Loughborough University approved the experiment.
5.2 Results and discussion
Power spectra of the vibration measured on the seats of the motorcycles using the three seat pads are
shown in Figure 5. The power spectra demonstrate that the pads all perform in a similar manner as the
general shapes of the spectra are similar. However, some differences are clear, particularly for the
vertical measures at non-dominant frequencies. These could be attributed to a number of factors such
as an internal resonance of the seat pad material, a localised resonance of the accelerometers
7
Figure 3. Design of new motorcycle seat pad.
8
Figure 4. Pad fitted to six different motorcycles including off road, scooter, easy rider, 2 x sports
and touring bikes.
mounting, or an electromagnetic shielding problem that the material of the pad provides which may
affect noise.
Weighted vibration magnitudes for the six measurements are shown in Table 3 and Figure 6. Measures
of vibration using the three different mountings showed similar results. However, there were some
small discrepancies between the three sets of data, primarily in the x-direction. For vibration in the xdirection the motorcycle pad consistently measured slightly higher vibration magnitudes than measures
using the SAE pads.
XJ600
CBR500R
Table 3. Weighted vibration magnitudes measured using the three pads on the two motorcycles.
Frequency
Motorcycle Transducer
Direction
r.m.s.
Total r.m.s.
VDV
Total VDV
Weighting
x
Wd
0.787
2.824
Motorcycle
1.614
3.960
y
Wd
0.522
1.925
pad
z
Wb
1.308
3.603
x
Wd
0.685
2.520
Resin SAE
1.469
3.915
y
Wd
0.544
2.067
z
Wb
1.180
3.644
x
Wd
0.586
2.042
Flexible
1.454
3.943
y
Wd
0.557
2.146
SAE
z
Wb
1.208
3.776
x
Wd
0.979
3.355
Motorcycle
1.607
4.061
y
Wd
0.545
2.125
pad
z
Wb
1.151
3.342
x
Wd
0.557
1.906
1.266
3.964
Resin SAE
Wd
0.557
2.178
y
Wb
0.990
3.812
z
2.694
x
Wd
0.734
Flexible
1.439
4.002
y
Wd
0.530
2.031
SAE
1.119
3.697
z
Wb
For the static comfort of the pads, all riders reported that the new motorcycle pad was either ‘neutral’ or
‘comfortable’, whilst the SAE pads were described in all cases as ‘painful’ or ‘uncomfortable’.
9
1 .000
0 .100
0 .010
0
10
20
30
Frequency (Hz)
0 .010
50 0
1 .000
40
10
20
30
Frequency (Hz)
CB SAE y
CB resin y
CB moto y
Power spectral density
Power spectral density
1 .000
0 .100
0 .001
0 .001
0 .100
0 .010
0 .001
40
50
XJ SAE y
XJ resin y
XJ moto y
0 .100
0 .010
0 .001
0
10
20
30
Frequency (Hz)
40
50 0
1 .000
10
CB SAE z
CB resin z
CB moto z
Power spectral density
1 .000
Power spectral density
XJ SAE x
XJ resin x
XJ moto x
CB SAE x
CB resin x
CB moto x
Power spectral density
Power spectral density
1 .000
0 .100
0 .010
0 .001
20
30
Frequency (Hz)
40
50
XJ SAE z
XJ resin z
XJ moto z
0 .100
0 .010
0 .001
0
10
20
30
Frequency (Hz)
40
50 0
10
20
30
Frequency (Hz)
40
50
Figure 5. Power spectra of motorcycle vibration measures on two motorcycles using three
different pad types.
Considering the measurements of vibration on the surface of the seats of the motorcycles, there are
problems in interpreting vibration magnitudes or spectra.
As there is currently no ‘gold standard’
method of measuring vibration on the seat of a motorcycle there is no reference measure of vibration
that can be taken as reliable. The SAE pad is the most common pad used for measuring on seats and
so this might be considered as a ‘target’ measurement. However, the discomfort from the pad might
cause the riders to ride in a different way or in a different posture that could affect the results more than
the differences between the pads. For these tests, then, any one of the three pads could be taken as
the ‘correct’ measurement. It might therefore be appropriate to select the ‘best’ pad using other criteria
than whether it reproduces the vibration measured using the SAE pad.
A further problem with comparison of measures taken with the different pads is that the exact route that
a motorcycle traverses is impossible to repeat. Therefore, the detail of the road profile at the wheels
would be different each time producing different results at the seat surface. Such differences are
always present for vehicle measurements and would also be expected for the ‘gold standard’ measuring
pad. One way to eliminate this problem would be to conduct testing in the laboratory rather than on the
road, thereby controlling the input to the seat / motorcycle combination.
10
CBR500R
5
y
z
to tal
4
Vibration magnitude
3
2
1
3
2
1
Flexible
SAE (VDV)
Resin SAE
(VDV)
Motorcycle
pad (VDV)
Flexible
SAE
(r.m.s.)
(r.m.s.)
Motorcycle
pad (r.m.s.)
Flexible
SAE (VDV)
Resin SAE
(VDV)
Motorcycle
pad (VDV)
Flexible
SAE
(r.m.s.)
(r.m.s.)
Resin SAE
0
Motorcycle
pad (r.m.s.)
0
4
Resin SAE
Vibration magnitude
x
XJ600
5
Figure 6. Weighted vibration magnitudes measured using the three pads on the two motorcycles.
A final issue with interpretation of measurements on motorcycle seats is in the application of frequency
weightings and treatment of multi-axis signals. Frequency weightings were developed using subjects
sitting in an upright posture on a standard seat type. However, on a motorcycle, riders frequently lean
forwards up to 45°. Therefore, vertical vibration at the seat will not be axial to the spine. This would be
expected to influence the comfort and health considerations for multi-axis vibration. It is currently
unclear whether signals should be (true) vector summed in the time domain such that co-ordinate
systems can be aligned with the spine or whether it is acceptable to use seat based co-ordinate
systems.
6. Summary
Considering the design requirements in Table 1, one can conclude that an appropriate design has been
achieved.
•
The pad fits all motorcycles currently available
•
The pad is flexible
•
The pad vibration measurements on the seat surface are valid
•
The material of the pad is durable and protective
•
The seat pad is comfortable
•
The seat pad accommodates a triaxial accelerometer set
•
The seat pad is low cost
It is recommended that future tests of vibration on motorcycle seats uses this alternative to the SAE
pad.
The seat pad might also be suitable for use with other saddled vehicles such as push-bikes, some
boats, quad bikes, horses and snow-scooters.
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7. References
Anon (1998) Rider comfort and posture. Bike Magazine, July 1998.
Anon (2001) Bend over - this won't hurt a bit. Well, maybe a little… Motor Cycle News, May 30 2001,
28-31.
Society of Automotive Engineers (1973) Measurement of whole-body vibration of the seated operator of
agricultural equipment - SAE J1013. Society of Automotive Engineers, SAE recommended practice
J1013.
Whitham EM and Griffin MJ (1977) Measuring vibration on soft seats. Society of Automotive Engineers,
SAE paper 770253
Tominaga Y (2000) A report for Japanese mailmen who used motorbikes daily. Proceedings of 8th
International Conference on Hand-Arm Vibration, 9-12 June 1998, Umeå, Sweden.
Eds., Ronnie
Lundström and Asta Lindmark.
Doria A and Cossalter V (2000) Riders sensitivity to motorcycle vibrations. Paper presented at the 2nd
International Conference on Whole-Body Vibration injuries, 7-9 November 2000, Siena, Italy.
Seaman RA (2001) The development of a motorcycle vibration measurement procedure. Final year
MEng Systems Engineering project report, Department of Human Sciences, Loughborough University.
Rafl J and Korbel Z (1989) Measurement and evaluation of motorcycle vibration acting on the driver as
part of improved safety in operation.
Proceedings of the 5th international pacific conference on
automotive engineering, Nov 5-10, 1989.
Peebles L and Norris B (1998) Adultdata. The handbook of adult anthropometric and strength
measurements - Data for design safety. Department of trade and industry, DTI publication
2917/3k/6/98/NP URN 98/736.
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