Tire Impressions

Question 1

Stance

Answer 1

Different name for Track Width

Question 2

4 Methods of Track Width

Answer 2

Outside to Inside
Inside to Inside (plus tread width)
Center to Center
Outside to Outside (minus tread width)

Question 3

Another name for after market wheels

Answer 3

OEM

Question 4

Length of full rotation of a tire

Answer 4

Rolling circumference, the linear distance traveled in one revelation by an inflated tire under load

Question 5

How long should a cast be?

Answer 5

3-4 feet the entire impression can and should be done, minimally 3 ft in length

Question 6

Dental Stone

Answer 6

need to place something at each end of tire impression using a large bucket, do not pour directly onto the impression

Question 7

Snow impressions- “not the normal way”

Answer 7

Dry Casting- a fine layer of stone powder, mist water offer the powder done 2 more times and then a normal mixture of dental stone of the top

Question 8

For elimination purposes at the scene, you can do this…

Answer 8

digital photography of the tread design with positions of the tire on vehicles, manufacturer, brand, and size of tire or white adhesive lift of tire design

Question 9

Ideal dental stone P:W and PSI

Answer 9

100:30 meaning a consistency of 30 and a PSI of 8,000-9,000

Question 10

Before removing a tire from a suspects vehicle you should…

Answer 10

Note which tire is where, i.e. left front, left rear, right rear, and right front

Question 11

In comparisons, what should you be making your comparisons against

Answer 11

the actual tire

Question 12

What happens if you put too much ink down, what happens to the block edges…

Answer 12

inks presses out to the edges of the tread block possibly enlarging their actual size

Question 13

Do you use brakes when making exemplars

Answer 13

NO

Question 14

How do you take exemplars from duel tires

Answer 14

full circumference impressions should be made, do not remove the tires

Question 15

how can you see underneath the paint of a retreaded tire

Answer 15

using a uv light

Question 16

Regroove, is it regulated or not

Answer 16

National Highway Safety Administration has advised, it’s only permitted on tires labeled “Regroovable”

Question 17

Window of acceptability, what is it

Answer 17

all tires must fit into this, some parameters might excel in a certain tire and must still meet standards

Question 18

Tread block, what is it

Answer 18

shapes of tread that make up the design of the tread

Question 19

Noise treatment, what is it

Answer 19

efforts to reduce noise using a mixture of tread block sizes

Question 20

Rib, what is it

Answer 20

row of solid rubber or disconnected tread blocks that run around the tire to form the tread pattern

Question 21

Tread pattern can be divided into 3 categories, what are they

Answer 21

Non-directional Symmetrical tread design, Directional tread design, and Asymmetric Tread design

Question 22

Typically there are even or odd number of ribs on a tire

Answer 22

**need to find info on

Question 23

Characteristic of a high performance tire

Answer 23

Generally wider, and lower profile, higher speed rating, , primarily for sports or luxury cars and designed for speed, acceleration, braking, cornering and made with a softer tread compound

Question 24

Tread Wear Indicator bars, what do they look like

Answer 24

raised bar of rubber raised 2/23 inch above the bottom groove, may not be seen in an impression if the tire isn’t worn down, the type of substrate the impression is in, short impression left at scene, poor impression

Question 25

What is cupping and camber and what is the difference

Answer 25

Cupping-

Camber- inward or outward tilt of the tire, negative cambers tilt inward, positive cambers tilt outwards

Question 26

Toe in

Answer 26

Looking at the tires location from above, toe in are closer in and toe out is father apart than the rear tires

Question 27

Spare tire

Answer 27

can be a full sized tire, usually smaller with only a small amount of millage on it, not intended to use for longer periods of time

Question 28

Order of doing a comparison

Answer 28

**long process need to look up

Question 29

Mold number on the side of the tire

Answer 29

contains mold design number and specific mold

Question 30

Directional noise treatment

Answer 30

Noise treatment on one side of the tire is not the same on the other side

Question 31

How to detect directional noise treatment

Answer 31

cannot be seen just looking at the tire

Question 32

Different types of tire molds

Answer 32

Shell and segmented mold

Question 33

Where the molds join together, what is it called

Answer 33

parting line

Question 34

When are vent holes added to the tire, the process

Answer 34

can be made with tiny holes drilled through the surface of the tire mold, also ventless molds with interconnecting pieces, like a puzzle with small holes drilled into the sidewall plates

Question 35

Two ways to retread a tire, name them

Answer 35

pre-cure and mold-cure

Question 36

In retread, when they splice it together, what do you get

Answer 36

possible individual characteristics, staples or misalignment of tread design

Question 37

Pre-cured stock, what do you find on it, what you won’t find on it

Answer 37

sometimes have the manufacturer’s name and molded number

Question 38

What is the Ring tread process

Answer 38

**listen again may not be ring tread

Question 39

How do you know if a tire has been re-grooved

Answer 39

Its done free hand so there won’t be straight cut lines, unevenness along the groove and numerous individual features