Tire Impressions Flashcards
(39 cards)
Stance
Different name for Track Width
4 Methods of Track Width
Outside to Inside
Inside to Inside (plus tread width)
Center to Center
Outside to Outside (minus tread width)
Another name for after market wheels
OEM
Length of full rotation of a tire
Rolling circumference, the linear distance traveled in one revelation by an inflated tire under load
How long should a cast be?
3-4 feet the entire impression can and should be done, minimally 3 ft in length
Dental Stone
need to place something at each end of tire impression using a large bucket, do not pour directly onto the impression
Snow impressions- “not the normal way”
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
For elimination purposes at the scene, you can do this…
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
Ideal dental stone P:W and PSI
100:30 meaning a consistency of 30 and a PSI of 8,000-9,000
Before removing a tire from a suspects vehicle you should…
Note which tire is where, i.e. left front, left rear, right rear, and right front
In comparisons, what should you be making your comparisons against
the actual tire
What happens if you put too much ink down, what happens to the block edges…
inks presses out to the edges of the tread block possibly enlarging their actual size
Do you use brakes when making exemplars
NO
How do you take exemplars from duel tires
full circumference impressions should be made, do not remove the tires
how can you see underneath the paint of a retreaded tire
using a uv light
Regroove, is it regulated or not
National Highway Safety Administration has advised, it’s only permitted on tires labeled “Regroovable”
Window of acceptability, what is it
all tires must fit into this, some parameters might excel in a certain tire and must still meet standards
Tread block, what is it
shapes of tread that make up the design of the tread
Noise treatment, what is it
efforts to reduce noise using a mixture of tread block sizes
Rib, what is it
row of solid rubber or disconnected tread blocks that run around the tire to form the tread pattern
Tread pattern can be divided into 3 categories, what are they
Non-directional Symmetrical tread design, Directional tread design, and Asymmetric Tread design
Typically there are even or odd number of ribs on a tire
**need to find info on
Characteristic of a high performance tire
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
Tread Wear Indicator bars, what do they look like
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
