Tires

 

 

Tire Balance

 

Static balance – up and down

 

Dynamic balance – both up/down and side-to-side

   *Preferred way

 

Dual plane –

·        A Static imbalance causes a wobble band and forth

·        Just because you have weights on inside and outside, doesn’t mean it is balanced

·        Weights should be all together, use as little as possible

 

 

Tire Rotation

Modified X pattern of rotation, rotate the drive wheels straightforward or rearward and cross the non-drive wheels.

 

                                   

 

 

 

 

 

 

 

 

Aspect  Ratio – height over width (pg. 246)

  Height = tread to rim

  Width =

 

  70 Series = height is 70% of width

  60 Series = height is 60% of width

 

P          235                    75                         R                          15

             ­                        ­                        ­                           ­

          mm.cross-sectional         aspect                                         radial                                 15” rim

                     width                     ratio

 

 

 

 

Tread wear indicator – shows up at 2/32, mouth parts around tread

 

Tread wear number – the higher the better, used to be good at 300, now numbers a e up over 500

 

Tread Blocks – used to all be the same size, not anymore; different size to prevent whines

 

Speed Rating – stiffness should be about equal all around

 

Radial force variation – could be a stiffer or looser part of tire; will make it “hop” a bit – reflected to steering wheel

 

Radial run cut – measured at center.  Tread of tire.

 

When belts slip – effects radial force variation and rolling resistance and makes tire wobble

 

 

Types of Movement: axial, radial, lateral

·        Radial runout on tire is mounted on tread                            

·        Movement 90 degrees to axis

·        Axial – movement along axis

·        Lateral – always side-to-side

·        Lateral run out on tire – side wall

 

 

 

 

 

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