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January 2009

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Goodyear

Tires

sponsored by Goodyear


Tim Miller

Tim Miller
Marketing Communication Manager
Goodyear

(330) 796-7922

Tim Miller has been with Goodyear for over 30 years. He spent 8 years as a tire design engineer before taking positions as a technical representative to original equipment customers Freightliner...more»»


Featured Question

Effect of Underinflation on Traction
Posted by Larry from Waterford, VT, US on July 17, 2008

Michelin has a commercial playing in Canada (passenger tires) &

they state that an “underinflated” tire will cause a loss of traction turning a good braking vehicle into an under performer”…

Now my question…and I am thinking more about truck tires. If you want higher traction…like in sand…you lower the pressure which gives you much better traction.

But Michelin is claiming that an underinflated tire will cause LOSS of traction…am I missing something?????

I have not seen this commercial but I suspect the statement is more like " underinflation CAN cause a loss in traction". Testing on dry pavement our test track, we find that, depending on the amount of underinflation and the speed of the vehicle, braking traction can be better or worse than the same tire set at the recommended pressure. Technically, this is caused by a reduction in cornering stiffness and lateral stiffness and also changes footprint length and pressure distribution across the footprint.


Featured Question

Wide Base or Fuel Max
Posted by Kristi from Louisville, KY, US on July 1, 2008

What are the pros and cons of wide base vs. Fuel Max duels?

Fuel Max
Pros - Improved fuel economy, same wheels/rims, no change in vehicle track width, replacement tires widely available, steer, drive and traier tires all the same size (easier tire/retread management) no change in vehicle trade-in value.
Cons - No reduction in tire/wheel weight

Wide Base Tires
Pros - Improved fuel economy, reduced tire/wheel weight
Cons - New wheels required, wider axle to retain current track width, limited tire replacement availability, steer tires different size than drives and trailer tires (what to do with worn steer tires?), trade-in value of vehicle may be compromised due to "non-standard" tire/wheel/axle sizes.


Featured Question

Tire Wear on Set Back vs Set Forward Steer Axles
Posted by dolan from cookeville, TN, US on January 29, 2008

Werun trucks with set back ster axles and set foward axles, the set back axle truck wears tire out faster that the forwards do. We run the same tire on both. Can you tell me why this happens?

I forwarded your question to Mike Beckett, President of MD Alignment. Mike knows more about tire wear than anyone I know.

"First you get a more effective transfer of loads to the steer axle with a set back vs a normal axle set. This does not mean more than about 500 lbs per tire in load but it is a more consistent transfer and this will have some minor effect. The larger effect is the turning angle on set back front axles. Most set forward axles turn 20 to 25 degrees as compared to 30 to 50 degrees on set back axles.

This increase in steering angle increases the "ackerman" effect on Toe when the vehicle in in a turn. A sharper steering angle and more toe on turns causes the vehicle to turn shorter circles and therefore it is more maneuverable but it does this at the expense of tire life. In my experience, on line haul trucks the net difference in tire life is about 10 to 15% between the two.

If you want to change this, adjust the steering stops on the axle to reduce turning angle and see how much you save. Just remember that the truck will require larger areas to turn around."


Featured Question

Wheel Nut Torque
Posted by Erwin from NANJING, OT, CN on October 27, 2007

What is the specified torque for a wheel nut of a 11R22.5 OR 295/75R22.5 heavy truck tire wheel?

I don't know if you have steel or aluminum, hub piloted or stud piloted wheels. To be safe, you should checked the website for the brand and type of wheels you are running. I check one manufacturer's website and found a chart that gave wheel nut torques for the various wheels that they make. If you are still confused, contact the manufacturer through their website.


Tire maintenance
Posted by James from Sidney, BC, CA on January 5, 2009

At what tread depth do you recomend taking off drive tires so they can still go for either Casing credit or retread? Also at what difference in tread depth should drive axles be before they should be rotated?

The industry standard for minimum tread depth for drive tires is 1/32 inch for any two, adjacent major grooves. I would suggest removing at something greater than 1/32 inch due to the potential loss of traction in winter condtions and the fact that the casing is more likely to have damage if the tread depth is low. I would remove drive tires at 3/32nds for these resons. I would rotate tires when the differences are 4/32nd's or more.


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