Study of Vehicle Pulling Phenomenon and Various …
253
Table 5 Tire swapping effect on subjective vehicle evaluation ratings
Vehicle
Tire set used
New ratings
Good
T5, T6, T6, T8
3
Bad
T1, T2, T3, T4
0
Worst
T1, T2, T3, T4
0
As seen from the subjective ratings given in the table above, the vehicle V1 was
showing the best capability to maintain the straight line and the side pull was not
noticeable.
For finding the correct cause for the pull, three out of the eight vehicles were
selected for further study. Based on the total score of each vehicle we selected V1
which was considered as good vehicle, V7 as a bad vehicle and V8 as a worst vehicle.
To check the effect of tires on the vehicle pull, tire swapping was done between the
three selected vehicles and subjective ratings were given again with changed tires.
Tires were numbered for the three vehicles as T1 to T4 for good vehicle, T5 to T8,
and T 9 to T12. Numbering for the tires was from front right, front left, rear right,
and rear left for each vehicle.
Vehicles were evaluated on the same track and pulling was checked during
accelerating from 40 to 100 kmph in the 4th gear.
As shown in Table 5 it can be seen that worst vehicle rating changed to zero,
which indicates no pulling which by replacing the tires with the good vehicle and
similarly, because of replacement of tires form the good vehicle with the bad vehicle
pulling phenomenon started to occur in the good vehicle.
Figure 10 shows the change in the subjective evaluation score because of the tire
replacement between vehicles.
1
4
4
3
0
0
0
1
2
3
4
5
Good Vehicle
Bad Vehicle
Worst Vehicle
Rating Score
Old Rating
New Rating
Fig. 10 Rating comparison pre- and post-tire change (lower is better)
253
Table 5 Tire swapping effect on subjective vehicle evaluation ratings
Vehicle
Tire set used
New ratings
Good
T5, T6, T6, T8
3
Bad
T1, T2, T3, T4
0
Worst
T1, T2, T3, T4
0
As seen from the subjective ratings given in the table above, the vehicle V1 was
showing the best capability to maintain the straight line and the side pull was not
noticeable.
For finding the correct cause for the pull, three out of the eight vehicles were
selected for further study. Based on the total score of each vehicle we selected V1
which was considered as good vehicle, V7 as a bad vehicle and V8 as a worst vehicle.
To check the effect of tires on the vehicle pull, tire swapping was done between the
three selected vehicles and subjective ratings were given again with changed tires.
Tires were numbered for the three vehicles as T1 to T4 for good vehicle, T5 to T8,
and T 9 to T12. Numbering for the tires was from front right, front left, rear right,
and rear left for each vehicle.
Vehicles were evaluated on the same track and pulling was checked during
accelerating from 40 to 100 kmph in the 4th gear.
As shown in Table 5 it can be seen that worst vehicle rating changed to zero,
which indicates no pulling which by replacing the tires with the good vehicle and
similarly, because of replacement of tires form the good vehicle with the bad vehicle
pulling phenomenon started to occur in the good vehicle.
Figure 10 shows the change in the subjective evaluation score because of the tire
replacement between vehicles.
1
4
4
3
0
0
0
1
2
3
4
5
Good Vehicle
Bad Vehicle
Worst Vehicle
Rating Score
Old Rating
New Rating
Fig. 10 Rating comparison pre- and post-tire change (lower is better)