Help - Is there a "service bulletin" available from Audi that states that AWD cars need to have all
01-28-2005, 05:41 AM
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Help - Is there a "service bulletin" available from Audi that states that AWD cars need to have all
4 tires replaced when one blows out? My insurance co. is requesting that of me because of a recent pothole incident.
01-28-2005, 06:01 AM
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Okay. What about this? I needed to replace 2 of my winter tires...
They were older style Pilot Alpins because of the pothole. I could not find any of the older style ones anywhere I looked so I had to buy the Pilot Alpin PA2 which has a different tread pattern. Tire dealer also said that different tread patterns are a no go for winter tires.
Know if this is true?
Know if this is true?
01-28-2005, 06:49 AM
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it depends on the tread diff between tires
If you have different sized tires or tires that are not worn to the same depth on all 4 corners you stand the chance of "over working" your differentials. All three of them! chances are that you do not need to replace all 4 but if the differences are within 5mm you are likely ok. I have seen on several occasions where different sized tires where used and the differentials became so hot from working all the tiime that they cook the oil in the bearings and everythings stops!
01-28-2005, 07:23 AM
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Question...Since the front and back diff are open diffs, why do they get hot?
I can understand the brakes getting hot (from the EDL), but why would the those diffs get hot?
Just curious, not challenging. It doesn't make obvious sense to me.
Just curious, not challenging. It doesn't make obvious sense to me.
01-29-2005, 08:34 PM
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Re: Question...Since the front and back diff are open diffs, why do they get hot?
under normal driving conditions IE a straight line and with perfectly matched tires the side gears of the diff are not working, the entire gear set is moving as one piece. when you turn a corner the outside wheels have to rotate faster than the inside wheels, they are turning different arcs. in order to keep the wheels from wearing and for the ease of turning, the differential side gears allow for the slippage neccessary between the inside and outside wheels.
If you have 2 very different tires on the same axle essentially you are simulating turning a corner, perpetually. The side gears were only designed to operate during normal driving and they can not disipate the heat or supply enough oil to the gears to spin for a long time, or at high rates of speed.
hope this help a bit.
If you have 2 very different tires on the same axle essentially you are simulating turning a corner, perpetually. The side gears were only designed to operate during normal driving and they can not disipate the heat or supply enough oil to the gears to spin for a long time, or at high rates of speed.
hope this help a bit.
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