Commercial Technical Presentation – Tire Wear

Thank you for inviting Yokohama Tire to your meeting this evening.

This presentation was developed by Yokohama Tire’s Technical Department with assistance from the Commercial Sales Division. We also received guidance on the Tire Wear Section from Mike Beckett of MD Alignment in Altoona, IA.

This presentation will review some common factors, which affect Tire Wear. Most of the emphasis will be on Steer , since that is the area of greatest sensitivity for most fleets and drivers.

@Tire Wear Basics • Factors Affecting Tire Wear • TMC – Quick Alignment Check

@Six Main Factors which Affect Tire Wear. We will assume vehicle is mechanically sound. Meaning the frame and axles are not bent. • Air • Loose Bearings • Improper Toe Settings • Mis-Aligned Drive Axles • Improper Camber Settings • Speed in Excess of Tire’s Design Speed

@Factors Affecting Tire Wear • Air Pressure - The easiest to check and adjust, but still often neglected

@Tire Footprint • Maximum tire mileage depends on the tire rolling smoothly though the footprint. This RY637 ran well for our Customer. But, a number of details must be right for this kind of steer tire performance. Most basic is air pressure.

@Affect of Air Pressure • How a tire wears depends on the forces that act upon the of that tire as it meets the road. Therefore, it is important to maintain proper inflation pressure.

@Over Inflated for Load – contact patch (Speakers note: Pay attention to the ‘yellow’ in the shoulder vs. the center rib) • Short shoulder rib contact area • This causes much more scrubbing action and wearing away of the shoulder rib.

@Over Inflated for Load - photo This type of shoulder wear is often seen on trailers with light loads and high fleet recommended air .

@Air Pressure Matched to Load - contact patch • Square footprint shape. • The shoulder rib contact area is very long, about the same length as the center ribs. • As the tire rotates, contact with the road is good. This tire has a good chance of wearing smoothly.

2 @Under inflated for the Load - contact patch • Shoulder Rib Contact Area Longer than Center Rib • Under-inflation by 20%, decreases tire life by 30% (TMC RP233). This situation is actually fairly common for steer tires. Many fleets set the fleet air pressure at 100 psi for all tires. As I will show in a few minutes, this may not be enough air pressure for steer tires and too much for dualled tires. The problem of under-inflated steer tires is further aggravated as the weather cools from summer heat into cool autumns and cold winters. A decrease of 10 degrees in ambient temperature causes a 1-psi drop in inflation pressure. (RMA – Care and Service of Light Trick and Truck Tires @1998 Page 37.)

@Under inflated for the Load - photo • River Type Rib Wear is aggravated by under-inflation. This tire had a small puncture, see inset .

@Under inflated for the Load – Drive Type Tire • Heel and Toe Wear, with sharp block edges may occur in under-inflated lug tires. This tire had a small sidewall injury, which may have caused it to run under-inflated for some time.

When a tractor has a matched set of drive tires and only one is wearing ‘funny’, low air pressure is the likely cause. I can almost guarantee it will be an inner dual.

@Mis-matched Tire Circumference will also affect Tire Wear • Mis-matched Air pressures is the primary type of Mis-matched Tire Circumference. • Tires with different remaining tread depths – The radius of the tires should be matched within 1/8” or a 4/32nds difference in remaining tread depth. (RMA – Care and Service of Light Truck and Truck Tires @1998 Page 37.) Matching within 2/32nds would be even better! (Tire Life article – Aug., 2003) • Same size tire from different manufacturers • Mis-matched tire size Even though an 11R22.5 and a 285/75R24.5 tire are close in size, this is a likely mis-match.

@Under inflated for the Load In Addition to Irregular Wear, Under Inflation causes a number of Tire Durability problems, including Zipper failures.

@There are two methods for d etermining Correct Tire Inflation Pressure • Industry Charts from the Tire Manufacturer or The Tire and Association. • Using Actual Vehicle Loads - Most vehicles carry standard axle weights. But, extremely heavy or light fleet loads might require using this method. This method should also be used with fleets experiencing a excessive number of tire durability related failures.

3 @Determining the Correct Inflation Pressure – Using Industry Charts. Typical Chart For a standard, over the road vehicle, using the charts in the Yokohama Tire Truck and Bus – Sales and Reference Guide

An Example Recommendation for an 80,000 lbs. GVW operation Vehicle: 6 X 4 tractor, 53 foot long box trailer

Steer Drive Trailer 12,000 lbs. 34,000 lbs. 34,000 lbs.

@Determining the Correct Inflation Pressure – Typical Inflation Chart Yokohama Tire Corporation Recommended Cold Inflation Pressures - requires truck to be parked 3-4 hours Tire Size Steer Drive Trailer Single Duals Duals ______

295/75R22.5 (14PR) 110 psi 90 psi 90 psi 285/75R24.5 (14PR) 110 psi 90 psi 90 psi 11R22.5 (14PR) 105 psi 90 psi 90 psi ______

11R24.5 (14PR) 95 psi 90 psi 90 psi ______Steer tires in the first three examples are set at max. cold inflation. In all examples, the drive and trailer duals are set at 80 psi, plus 10 psi for compensation between airing. NOTE: Never bleed excessive air from a ‘hot’ tire

@Determining the Correct Inflation Pressure Setting a vehicle’s tire to the recommended , - requires truck to be parked 3-4 hours.

@Note: The top 3steer tire sizes are set at Max. air pressure, which is higher than 100 psi, which may fleets use as their fleet spec.

@Determining the Correct Inflation Pressure In all examples, the drive and trailer duals are set at 80 psi, plus 10 psi for compensation between airing. Which is lower than the 100 psi, most fleets set as their dualled tire spec.

@Determining the Correct Inflation Pressure

4 Using Actual Vehicle Loads • Weigh Similarly Loaded Vehicles • Divide Axle Weightings by Number of Tires per Axle

@Determining the Correct Inflation Pressure • Use the actual load per tire (per axle) to determine the cold inflation pressures for the tires by size, ply, and type.

@Determining the Correct Inflation Pressure • If the actual tire loads are heavier than the ply rating of the chosen tire, it may be necessary to install a tire with a higher ply rating.

@Protect your Work • An important part of air pressure maintenance involves the use of high temperature, metal valve caps. • The use of inflate-through caps, or ‘alligators’ is a labor saving choice, which is suitable for many on-highway fleets.

Construction fleets, waste haulers and other off the road operations may need standard metal caps.

@Factors Affecting Tire Wear • Loose Wheel Bearings

@Loose Wheel Bearings • Loose Wheel Bearings often Cause Cupping Wear on Steer Tires

@Loose Wheel Bearings • Loose Wheel Bearings often Cause Inner Shoulder Wear – Drive and Trailer Tires. • Loose bearings can be checked by jacking up a corner of the truck. • Placing a under the tire and bumping the tire iron up and down. • Any movement or noise indicates excessive looseness in the bearings.

@Factors Affecting Tire Wear Improper Toe Settings

Improper Toe Settings Rubbing your hand back and forth across the tread of a steer tire, can tell you a lot about the vehicle’s overall alignment. • Smooth in – Toe in • Smooth out – Toe out

5 @Factors Affecting Tire Wear - Mis-Aligned Drive Axles What you felt when you rub your hand across the steer tires can also tell you about the truck’s drive axle alignment.

@If the drive axles push the truck right • Shoulder wear occurs on the right side (inboard) side of the left front tire – Smooth Out • Shoulder wear also occurs on the right side (outboard) side of the right front tire – Smooth In

@Right Thrust – This diagram shows one type of drive axle mis-alignment, which could cause a Right Thrust. The axle alignment is in a cone pattern. Which will cause the truck to drift right. ( This effect can be demonstrated with a Styrofoam cup rolled across a table.).

@Left Thrust – With a left Thrust- the feathering begins on the outboard shoulder of the left steer tire. And the inboard side of the right steer tire.

@Combination Wear - Right Thrust – Toe In Have you ever had a situation where only one steer tire has feathering. Of course the driver insists the truck is in perfect alignment. This is often caused by combination wear. A combination of Drive axle Mis-alignment and a Toe problem.

This diagram shows Right Thrust and Toe In. The left front tire will wear smoothly, but the Right front tire will show significant Toe In wear. This vehicle may be ‘in spec’ according to the truck driver’s alignment shop Printout!. The only problem is; trucks tires can’t read. The wear patterns they develop are caused by the way they roll on the highway, not alignment shop print-outs.

@Combination Wear - Right Thrust – Toe Out This next example shows the same Right Thrust, but this time with Toe Out. Now, the Right steer tire will wear smoothly and the Left Steer tire will naturally have significant Toe Out Wear.

Note: Right Thrust is a bigger aggravation in the United States, due to the crowning of our highways.

@Drive Axles not centered under the Truck’s Frame. In addition to Drive axle mis-alignment, axles not properly centered under the frame can cause Thrust problems, which will result in irregular steer tire wear. In this diagram, the axles are jacked to the left. This condition would cause a right thrust.

6 @Factors Affecting Tire Wear Improper Camber Settings

Camber Wear – On newer trucks, Camber wear should not be a major problem. Heavy Duty trucks leave the factory with zero to slightly positive camber. Unless, the tire and wheel assembly tilt is visibly obvious - it can be disregarded. Since, correcting camber involves either bending the front axle, which voids most manufacturer’s warrantees, or replacing the axle.

The only vehicle manufacturers which permit axle-bending are the makers of some small imported trucks, like Mitsubishis.

If an alignment shop print-out indicates, that camber is out of spec. The front bearings should be checked. This looseness may contribute to this out of spec camber reading.

@Excessive Positive Camber – ( Note: Diagram looking at the front of the vehicle) Wheel is tilted outward at the top Result is Smooth Fast wear on the outer half of the Steer Tires

@ Excessive Negative Camber - ( Note: Diagram looking at the front of the vehicle) Wheel is tilted inward at the top Result is Smooth Fast Wear on the inner half of the Steer Tires

@Factors Affecting Tire Wear Speed in Excess of Tire’s Design Speed

@Speed in Excess of Tire Design • Speeds in excess of a tire’s designed capability, lengthens the footprint. • This lengthening will cause premature wear on the shoulders of the tires Today, most linehaul tires are designed to perform at 75 mph. These speed ratings are now listed in product catalogues.

However, most fleets would experience less irregular wear and greater overall tire durability, at lower average highway speeds . Studies suggest that overall original tread life may be reduced as much as 20% when a truck’s average speed increases from 55 to 75 mph.

@ Air Pressure and High Speeds – Now, we are back to the beginning – Air Pressure. For fleets which choose to run high speeds, near the upper limits of the tire’s design capability. The importance of proper air pressure maintenance increases.

7 • References: • RMA – Care and Service of Truck and Light Truck Tires • TMC – RP233 – Guidelines for Tire Inflation Pressure Maintenance • TMC – Guidelines for Total Vehicle Alignment • The Tire Life: A Tire Expert offers the Best Way to Extend Tire Life – Driver’s magazine. August 1, 2003 • Truck Wheel Alignment – A Common Man’s Guide, by Mike Beckett

Thank you for attending

Show – TMC Alignment Video (DVD)

Commercial Tire Technical Presentation – Tire Quiz

Thank you for inviting Yokohama Tire to your meeting this evening.

This presentation was developed by Yokohama Tire’s Technical Department with assistance from the Commercial Sales Division. We also received guidance in the Tire Wear Section from Mike Beckett of MD Alignment in Altoona, IA.

This presentation has 3 parts

• Tire Basics – has information on tire sizes, mounting and tire construction • Tire Conditions – is a review of common tire conditions and their causes • Tire Wear – A quick review of common tread wear conditions and their causes.

9 @Tire Basics

@What does 22.5 indicate in Tire sizing? A. Rim Diameter B. Rim Width C. Wheel manufacturer D. Max air pressure

@What does 22.5 indicate in Tire sizing? Rim Diameter

@What does ‘285’ in Tire size 285/75R24.5 indicate? A. Rim Diameter B. Rim Width C. Tire’s Section Width D. Max air pressure

@What does the‘285’ in Tire size 285/75R24.5 indicate? Tire’s Section Width Measured in millimeters

@What the‘285’ in Tire size 285/75R24.5 indicates. Section Width. • Measured in Millimeters for metric sizing 285/75R24.5 • Measured in inches for Conventional sizing 11R22.5

@The ‘75’ in Tire size 285/75R24.5 is the Aspect Ratio.

@Aspect Ratio in Metric Sizing Aspect Ratio = Section Height Section Width.

Aspect Ratio equals The Section Height Divided by the Section Width. In this case the Ratio is 75%.

In Conventional sizing the ratio is about 90%, but this is not indicated on the sidewall

@What are the TMC approved Bead Lubricants A. Animal and Vegetable Soaps B. KY Jelly C. WD 40 D. Draft Beer

@What are the TMC approved Bead Lubricants A. Animal and Vegetable Soaps

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@The yellow paint dot on the sidewall indicates? A. This tire was made in Japan B. The Light Spot on the tire C. We ran out of black tire paint D. Checked by inspector 13

@The yellow paint dot on the sidewall indicates? B. The Light Spot on the tire This marking is common for many tire manufacturers.

@How do you use this dot in tire mounting? A. Spot should be cleaned off so customers don’t see it. B. It means nothing C. Align it with the valve D. Contact your sales rep for an adjustment

@How do you use this dot in tire mounting? C. Align it with the wheels valve This is a type of match-mounting, which aligns the light spot of the tire with the assumed heavy spot of the wheel, due to the weight of the brass valve.

@Tire Components This drawing shows the basics of tire construction: the body plies including the turn-ups, which wrap around the beads. There are 3 working belts that give the casing strength and help provide a flat footprint. The 4 th or top belt is a protector ply, which is primarily for protection of the 3 working belts.

@Tire Components. – This cut away view of a Yokohama RY637, which shows this tire’s components in more detail.

Tread - Yokohama and all Tire manufacturers will change their tread compounds for different tire applications. For example – a 315/80R22.5 RY103 or 773 – waste hauler tire, will have a dense chip resistant tread compound. Whereas, an RY637 will have a different compound designed to provide long wear. But, it will have less chip resistance.

Under tread – This rubber layer has low heat properties. These compounds keep the casing cool and protect it from heat related belt edge failures. Sometimes, this rubber will be exposed as a tire wears down.

Liner – Retains air to ensure long casing life.

@Tire Conditions – The next section is tire conditions. As you will notice from the following slides- many of these conditions are due to under inflation.

11 @Tire Conditions – will be covered in this order A. Tread B. Sidewall C. Beads D. Liner

@Tire Conditions First, we will review tread conditions

@What caused this tire to fail? A. Poor Rubber Adhesion B. Delamination C. Brake Lock up D. Road Rage

@What caused this tire to fail? D. Brake Lock up – This was caused by a severe skid. The dual tire next to it was probably in a similar condition.

@What caused this tire to fail? A. Poor Rubber Adhesion B. Delamination C. Tread Cut D. Road Rage

@What caused this tire to fail? D. Tread Cut – in this example there are many cuts in the tread rubber. But the steel belts did their job and protected the casing from air-loss.

@Tread Area Rust Damage • Excessive Tread Wear May Expose Belt Material to Air and Moisture and leave the casing unable to be retreaded.

@Tread Area Rust Damage • Tread Damage May also Cause Belt Rust and result in unretreadable casings

@Tire Conditions – now we move on to Sidewall Conditions

@Sidewall Conditions Manufacturing related Sidewall conditions are rare in Yokohama Truck Tires. Part of the inspection process includes X-raying each tire.

@Sample of Tire X-Ray The inspector will reject tires with spread body ply cords, dog-eared belt splices or other tires with manufacturing anomalies. In this photo, you can see the sidewall and number 2 belt. Speakers note: Going from right to left Here, you can see the cross thatching of the number 2 and 3 belts

12 @How can you tell if a sidewall condition is a cut? A. Ask the Truck Driver B. Find evidence of an entry point C. Locate the object which caused the damage

@How can you tell if a sidewall condition is a cut? B. Find evidence of an entry point

@This Star pattern is evidence of Air Migration Through the liner. The liner of any tire with a sidewall bulge or blister, must be carefully inspected to determine how air migrated through the liner, between the body plies to the outer sidewall rubber.

In this case, a rock lodged between dualled tires repeatedly worked against the Shoulder of the tire. Finally, this flexing broke the liner and air traveled between the body plies and formed a sidewall blister. This blister later burst, resulting in the “Star” pattern seen here.

@Sidewall condition caused by a repair failure. Here a sidewall repair failed, allowing air to migrate through the body plies and form a blister.

@This Sidewall Bubble was due to liner damage. This is a good example, showing the body ply spacing is fine, but air migrated through the damaged liner.

@Liner Damage – due to liner fire. (Interior view of previous condition) This could actually be classified as mounting damage. The tire installer had difficulty seating the beads, so a flammable substance, like ether was used to “blast” the beads. Since this is a floatation tire with lots of air in the air chamber. There was plenty of oxygen, so the fire burned for a while and and destroyed this brand new tire.

@Sidewall condition related to an improper repair. Radial repair units have reinforcing material embedded in them. This reinforcement must flex with the radial body plies in the tire, This is why radial repair units have bead aligning arrows. In this photo the arrows are not aligned to the beads.

@Sidewall Snag This started as a small sidewall snag and progressed to a significant and unrepairable injury.

@Sidewall Conditions • May be the Result of a Tread Injury. This tire had a fairly small puncture. Over time and continued use resulted in this large damage area.

13 @Sidewall Condition - Interior View The small area of the initial penetration is circled.

@What should a State inspector find next to this repair related sidewall bulge? A. Chewing gum B. A blue Triangle patch indicating a repair area C. A $50 bill D. Nuthin

@What should a State inspector find next to this repair related sidewall bulge? B. A blue Triangle patch indicating a repair area .

Sidewall repair related bulges up to 3/8 of an inch are permitted in truck tires. But the tire repair facility must place a blue triangle patch in the area. So a road side inspector, knows it is a repair related bulge, not just a damaged tire. The inspector might shut the rig down for repairs if he does not see the blue triangle.

@What is the primary cause of Zipper Failures? A. Lot Lizards in Rest Areas B. Impact Damage C. Tires under-inflated by 20%, or more D. Bead Mounting Damage

@What is the primary cause of Zipper Failures? C. Tires under-inflated by 20%, or more . The industry guidelines are any tire found in service, which is under-inflated by 20%, or more is to be removed from service and inspected/repaired by a full service tire repair facility.

@ The repair facility may use these techniques, when inspecting this tire. • The repair facility must be advised that the tire was more than 20% under inflated at removal. • The inspection will likely include – looking for a Rippled sidewall. This can be done with a grazing light technique, which highlights the rippled sidewall. This sidewall rippling indicates body ply strands are broken. • The tire inspector may also listen for a Crunching sound when pressing against the sidewall.

@Other Evidence a tire may have damaged body ply cords • Discoloring in the liner. Truck tires do not show this discoloration as dramatically as passenger or light truck tires, but this sign of excessive tire flexing is often seen. Liner discoloration should cause the inspector to look very carefully at the casing prior to repair or retreading.

@Long Term under inflation may cause significant Liner Damage In this case part of the inner liner has worn away due to excessive tire flexing from running under-inflated. Obviously, this tire is junk.

14 @Further Evidence of Tire Under-inflation/Overload? • Deformation of the Beads – rather than having the familiar 15 degree taper, they will flatten out, sometimes looking more like tube type tire beads. • Bead Chafing – which is wear and abrasion in the rim flange area.

@This Detachment of belt and tread material from a casing, is likely due to: A. Bad retreading. B. Trailer Mis-Alignment C. A maintenance problem D. Puncture Run Flat Condition

@This Detachment of belt and tread material from a casing, is likely due to: E. Puncture Run Flat Condition The tread portion of this tire would have been a big hunk of roadside debris, if the driver had not saved it for warranty consideration. This type of roadside debris is often blamed on retreaded tires. This debris may be from a retreaded tire, but rarely is the retreading at fault for the failure. When the roadside debris or ‘alligator’ has steel belt material and tread rubber, the cause of the failure will be related to under-inflation or injury.

@TMC (Technology & Maintenance Council) TMC Tire Air Pressure Study - May 2002 In 2002, the Technology and Maintenance Council of the American Trucking Association issued a Task Force Report. • This task force was created with the purpose of reducing the incidence of tire debris littering the nation's highways and preventing regulations that restrict retreading. To accomplish these objectives, the Task Force conducted surveys and analysis of tire road debris to ascertain its cause.

Tire Engineers from the major rubber companies, including Yokohama Tire assisted in this work. The road surveys were done on selected stretches of highway, in Texas, Arizona and Ohio. Road crews collected the tire scraps and brought them to safe inspection sites. The Engineers then proceeded to classify the reason for failure of the scraps. A later survey involved Engineers visiting Truck Jamborees and checking air pressures. Finally, air pressure surveys were conducted at large fleet locations.

@ - The Findings - TMC (Technology & Maintenance Council) TMC Tire Air Pressure Study - May 2002 • 90% of the tire failures examined were caused by under inflation, which had either existed for a substantial period of time or had been caused by road hazards.

@Tire Conditions - Beads

@Bead Mounting Damage

15 • Possibly due to Lack of Proper Bead Lubrication @Bead Mounting Damage • Possibly due to Lack of Proper Bead Lubrication. • Followed by Air and Moisture rusting Body Plies Note: Sidewall Bulge

@This type of bead failure is due to? A. Broken Bead Wires B. Under-inflation C. Excessive Brake Heat D. Mounting or Dismounting Damage

@This type of bead failure is due to? C. Excessive Brake Heat

@Evidence of Brake Heat Bead Damage • Only one bead is affected • Condition often affects two tires Typically where tires are bolted to the drum • Bead material is melted and brittle

@Tire Conditions - Liner

@What is this SMILE in the Liner evidence of? A. Tube Failure B. Impact Break C. Tax Cuts D. Open Liner Splice

@What is this SMILE in the Liner evidence of? B. Impact Break This tire had a shoulder blister, indicating the liner was broken, at initial impact. Air migrated through the body plies. Over time, the casing continued to come apart as the driver rolled on down the road.

@In addition to the SMILE in the liner. There is often other evidence of an impact?

@This concentric circle of torn rubber will help pinpoint the initial area of impact.

@Is a proper plug/patch Combination?

@NO! All injuries should be filled and patched from the inside, but this isn’t the right idea. Actually, this tire was repaired with a patch, but not filled. Debris got in the injury and punctured the patch. This time the flat was repaired with a road plug. A road plug is never an acceptable repair on truck tire, a light truck tire, or even a passenger tire.

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@What condition was this tire was submitted to Yokohama for?

@Was it? A. Vibration B. Foreign Material C. Thin Liner D. Bead Mounting Damage

@What condition was this tire was submitted to Yokohama for? A. Vibration !!!!! According to our Dealer - Honest Bob Somebody. The tire still held air. Which is possible, since the innerliners of tubeless tires are designed to seal around injuring objects to protect the tire from run low damage.

@Tire Wear Our final section addresses Tire Wear and Tread conditions

@What is the most likely cause of this tread condition? A. Electrical Discharge Damage B. Chain Damage C. Rubber Worms D. Off Highway use of an On Highway Tire

@What is the most likely cause of these tread conditions? A. Off Highway use of an On Highway Tire This photo shows an area of stone retention damage and rust in the belts. This tire has a fairly large area of belt rust. So, how do a couple of small punctures result in a large area of belt rust.

@How water on the road is drawn into the casing. A bulb Syringe demonstrates this well. The weight of the vehicle compresses the tread in the footprint area. As the tire rolls through the footprint the tread rubber decompresses. The small hole acts as a siphon when the punctured area is rolling out of the footprint area. Basically, drawing (or sucking) water from the road into the casing. If with water is mixed with road salt or brine, well you can imagine the effect on the steel belts.

@What caused this tire wear pattern. A. Tread separating from belts B. Brake Lock up C. Tires under-inflated by 20%, or more D. Out of Balance

@What caused this tire wear pattern. B. Brake Lock up which spotted the tire

17 @Brake spotted tires often occur in Pairs. • Clocking the flat spots 180 degrees can minimize the vibration and permit these tires to remain in service longer.

@Irregular wear on only one of a dual tire set, usually indicates? A. Mis-matched tire circumference B. A broken Axle C. This is normal D. Loose nut behind the wheel

@Irregular wear on only one of a dual tire set, usually indicates? A. Mis-matched tire circumference

@Common Causes of Mis-matched Tire Circumference include: • Mis-matched Air pressures • Tires with different remaining tread depths • Same size tire from different manufacturers • Mis-matched tire size Even though an 11R22.5 and a 285/75R24.5 tire are close in size, this is likely a mis-match.

@What is a likely cause of this inner dual inner shoulder wear? A. A broken Axle B. Loose wheel bearings C. I never had this until; I got an Air Ride suspension D. Improper dual spacing

@What is a likely cause of this inner dual inner shoulder wear? B. Loose wheel bearings This can be checked by jacking up a corner of the truck. Placing a tire iron under the tire and bumping the tire iron up and down. Any movement or noise indicates excessive looseness in the bearings.

@How would a tire with Toe in Wear Feel? A. Perfectly smooth B. Dirty C. Smooth in – Toe In D. Hot to the touch

@How would a tire with Toe in Wear Feel? B. Smooth in – Toe In Similarly, a tire with Toe Out – Smooth Out – Toe Out.

@Thank you for attending Yokohama Tire’s Commercial Tire Technical Presentation.

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