K, dumb question.
When first driving my Monte, after sitting more than 24 hrs, the tires act out-of-balance. At 40-50 mph I have noticible shudder and wheel movement. Can a radial tire get flat spots? After 10 minutes or so, the shudder and out-of-balance feel goes away and all is good.

 

[align=center][/align][align=center]Hi Tom,[/align][align=center][/align][align=center]What type/size are your tires ?[/align][align=center]How many miles are on them ? Have you hit a pot hole ?[/align][align=center]Have you checked the balance on them ?[/align][align=center]Have you run your hand over the tire thread to see[/align][align=center]if you can feel a uneven spot.[/align][align=center]Did you look to see if a balance weight fell `off ?[/align][align=center][/align][align=center][/align][align=center]Have they been aligned/Balanced?[/align][align=center]Do you have the correct air pressure in tires ?[/align][align=center]When a tire heats `up, it increases your air pressure in the tire.[/align][align=center]If this car was setting in the same spot for a long time it is very possible the tires did develop flat spots. The rubber in tires are in a constant state of curing throughout the tires life. [/align][align=center]Below link is information on tires.[/align][align=center][:-][/align][align=center]http://en.wikipedia.org/wiki/Tire[/align]

 

The tire is not going to get a flat spot from sitting just 24 hours. Most likely the weight just fell off. My car sits out all weekend without moving and have never had a flat spot.

 

[align=center][/font]The Causes Of Irregular Wear
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[/align][align=center]Many types of irregular wear can be prevented if you understand what causes it.[/align][align=center]
Irregular tire wear is a big concern to anyone who purchases his or her own tires. You want to squeeze the last mile out of every tire you buy, and strange wear patterns can rob you of tire mileage and increase your operating costs.
Irregular wear patterns are caused by abrasion that is concentrated in one area of the tire tread instead of across the entire footprint. Side forces created by turning, off tracking, incorrect toe, etc. can drag or slip the tire across the pavement and concentrate wear on one side of the tire or one side of the ribs. Out-of-balance conditions and brake skids can make the tire bounce or skip down the road rather than run smoothly and in contact with the road surface. Naturally, every time the tire lands in a certain spot, it wears faster there. Tread pattern design and tire construction determine where the pressure on the footprint is concentrated. If it is not spread fairly evenly across the tire’s footprint, irregular wear patterns will result.
There are many sources of irregular wear; some you can control, some you can’t. The ones you can’t control are road hazards and operating conditions. Tears, cuts, embedded stones and brake skids distort the tread and make the tread squirm in new ways. These road hazards can initiate irregular wear. Road crown, road surfaces, terrain, weather, loads, and other unique operational factors can start tire conditions such as overall fast wear, rib depression/punch wear (really weird and ugly wear) and rapid shoulder wear.
Vehicle maintenance has a great effect on tires, and this is one area you can take control of. Equipment that is poorly maintained and suffers from misadjusted airbags; worn shocks, worn and bent suspension and steering components; and bent or broken parts that contact the tire can set up irregular wear conditions and even out-of-service conditions that can reduce tire life. Irregular wear conditions such as erratic depression wear, alternate lug wear and one-sided rapid shoulder wear can result.
Alignment has a tremendous effect on irregular wear and is probably its biggest cause. Out-of-alignment drive axles and trailer axles that are not perpendicular to the frame or parallel with one another are usually the primary sources of irregular wear, followed by incorrect toe on steer axles. Alignment should be checked regularly to avoid conditions such as full shoulder wear, feather wear and one-sided wear.
Of course, tire maintenance is responsible for many irregular wear conditions. Lack of good inflation pressure maintenance, failure to match duals within [/color]2627[/font]/[font="georgia, times new roman,times"]28[color=#660000]30[color=#660000] and 5 psi air pressure, nonuniform tire mounting and unbalanced tire and wheel assemblies will set up irregular wear conditions. However, tire rotation can reduce the growth of irregular wear patterns. Conditions such as cupping/scallop wear and heel/toe wear are just a few that are created by poor tire maintenance.
Some irregular wear conditions are not really a problem, although they may not look right. River or channel wear has been commonly found in line-haul operations since radial tires were first introduced. However, this condition does not

 

there's more than likely nothing wrong.most tires today that are 35 series and smaller will do this simply because of temperature change and sidewall compound and thickness. im sure it goes away in 10-20 minutes or less of driving. 20's n up really enhance it too because of the extra rotating mass. nitto's, nexxen, toyo , yoko's, generals.. some that i've had on various rides and they all do it. if the sidewall is 40 series or larger it seems tonot be a factor. one more thing,........ when you run those35 and smaller series tires... when they are installed new with a fresh mount and balance the majority of them will need rebalancing within the first 1500 miles.they tend to settle in similar to a break in period. the local goodyear store where i live recognizes the problem and does the extra re-balancefor free. hope this helps!

 

Here is a GM Technical Bulletin with some interesting tire info on this very topic.............

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Subject:
Tire/Wheel Characteristics (Vibration, Balance, Shake, Flat Spotting) of GM Original Equipment Tires #03-03-10-007C - (09/21/2007)[/align]
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Models:
2008 and Prior Cars and Light Duty Trucks (Including Saturn)[/align][align=left]




2008 and Prior HUMMER H2, H3[/align][align=left]




2005-2008 Saab 9-7X[/align]

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This bulletin is being revised to include additional information and model years. Please discard Corporate Bulletin Number03-03-10-007B (Section 03 - Suspension).
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The purpose of this bulletin is to help explain that , under certain circumstances, a customer may notice a slight tire shake within the first few miles/kilometers of vehicle operation.
Tires may be designed with a nylon overlay configuration engineered to enhance the tire's integrity at high speeds. This allows the tires to be driven at higher speeds without excessive heat buildup.
Important:Before measuring tires on equipment such as the Hunter GSP 9700, the vehicle MUST be driven a minimum of 16km (10mi) to ensure removal of any flat spotting. (The tendency to "flat spot" is less likely as the tire accumulates mileage.)
When parked overnight, or for a period of time, the tires may set (flat spot) and require a few miles/kilometers before heating up to their normal operating temperature. Until the tires warm up, a slight tire shake may be felt but should subside quickly.
Important:DEALERS SHOULD REFRAIN FROM ATTEMPTING REPAIRS OR REPLACING COMPONENTS.




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.


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