Test Conditions Before and During the Road Test
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Check all suspension components on front and rear axle for damage. |
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Check tire pressure and correct if necessary. |
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Check the tires for external damage. Holes, cuts, bulges in the side wall, flat spots from braking and/or damage to the tread. |
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Ask the customer if a tire had been damaged by a nail or similar object and perhaps repaired by a tire dealer. You may have to replace such tires. |
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Check tires for even wear and tread depth. |
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Are all tires of the same type, manufacture and tread pattern? |
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If the tires are non-directional, ensure that all DOT classifications on the tire face outwards. It may be that the vehicle's wheels and tires were already changed around at an earlier date. |
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Are the tire brands factory recommended as initial equipment? |
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For the road test, use a level, straight driving surface that does not slope off to one side and does not have ruts. |
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Perform the road test with the customer under the conditions specified above. The customer should demonstrate the problem. |
 Note There should not be any side wind when road test takes place. If the complaint is justified, it is recommend to rotate the wheels and tires as described on the following pages. Before beginning, observe the following notes, otherwise all effort will be for nothing! Note Mark tires/wheels before the first rotation, e.g. LF, RF, LR, RR. After rotating wheels or reversing the tire on its rim, observe very carefully how the vehicle behaves during the road test. Note what was replaced and how. The intensity or any possible change to the one-sided pulling should be assessed. To do this, it is absolutely essential that the road tests are always performed by the same person on the same road. It is best to drive the "test course" in both directions. Replacing a tire with a new tire does not guarantee that pulling to one side will be eliminated. Therefore, it is recommended to perform a targeted exchange of the wheels as described below. If there are large differences in the tread depth of the tires on the front and rear axles, the tires with the deeper tread should always be mounted on the front axle. |
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| Perform a road test to determine if a vehicle pulls to one side and if so, when and to which side |
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| If the vehicle pulls to one side, swap the front wheels. |
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| Road Test, Performing |
| Vehicle travels straight - END |
| Vehicle pulls opposite |
Vehicle pulls to the same side |
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| Reverse one tire on its rim on the front axle (reverse the direction of travel) |
Rotate wheels from front to back |
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| Road Test, Performing |
Road Test, Performing |
| Vehicle travels straight - END |
Vehicle travels straight - END |
| Vehicle does not travel straight |
Vehicle does not travel straight |
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| Swap front wheels and swap back wheels |
Vehicle pulls opposite |
No change |
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| Road Test, Performing |
Reverse one tire on its rim on the front axle (reverse the direction of travel) |
Check alignment of front and rear axles, adjust if necessary. |
| Vehicle travels straight - END |
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If adjustment is correct, inform Product Support. |
| Vehicle does not travel straight |
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| Swap the front wheels |
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↓ |
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| Road Test, Performing |
Road Test, Performing |
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| Vehicle travels straight - END |
Vehicle does not travel straight |
Vehicle travels straight END |
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Vehicle does not travel straight |
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Install new tires on front axle |
Install new tires on front axle |
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Road Test, Performing |
Road Test, Performing |
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Vehicle travels straight - END |
Vehicle travels straight - END |
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| Vehicle does not travel straight, inform Product Support |
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| Perform a road test to determine if a vehicle pulls to one side and if so, when and to which side |
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| If the vehicle pulls to one side, swap wheel with tire front and back. |
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| Road Test, Performing |
| Vehicle travels straight - END |
| Vehicle does not travel straight |
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| First, replace one tire on the front axle |
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| Road Test, Performing |
| Vehicle travels straight - END |
| Vehicle does not travel straight |
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| Replace second tire on the front axle |
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| Road Test, Performing |
| Vehicle travels straight - END |
| Vehicle does not travel straight |
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| Measure vehicle at front and back |
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| Road Test, Performing |
| Vehicle travels straight - END |
| Vehicle does not travel straight, inform Product Support |