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[sochermit]

How do I tell if my tires need replacing? How deep should the depth be? Under normal driving how far would you expect I could go on a 2003 325i with OEM tires? Any comments are appreciated.

[Dackelone]

There are thread wear indicators on the tire's circumference(marked by a triangle). Look on the tire's side wall for TWI (thread wear indicator), when the thread is flush with those bars - your tires are done.









In Germany, the legal limit is 1.2mm(I think?). That is the legal MINIMUM! But ADAC and most Germans will tell you to change the tires when they are at 4mm thread. Now mind you new tires only have 8 or 9mm of thread when new! But over here... the risks with aquaplaning are so great on the Autobahn that the 4mm rule is a good idea.

Also tires older than five years old should also be replaced regardless of thread depth. The the reason is tires get harder with age and loose their grip and performance - so its best to replace them before causing an accident.

Tires are often the most over looked item on a car. But they are your ONLY contact with the road... and they play such an important role in your safety.

[sochermit]

Originally Posted by Dackelone

There are thread wear indicators on the tire's circumference(marked by a triangle). Look on the tire's side wall for TWI (thread wear indicator), when the thread is flush with those bars - your tires are done.


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In Germany, the legal limit is 1.2mm(I think?). That is the legal MINIMUM! But ADAC and most Germans will tell you to change the tires when they are at 4mm thread. Now mind you new tires only have 8 or 9mm of thread when new! But over here... the risks with aquaplaning are so great on the Autobahn that the 4mm rule is a good idea.

Also tires older than five years old should also be replaced regardless of thread depth. The the reason is tires get harder with age and loose their grip and performance - so its best to replace them before causing an accident.

Tires are often the most over looked item on a car. But they are your ONLY contact with the road... and they play such an important role in your safety.

Thank you for all the valuable information. The car only has 30k miles on it so I think, from all your comments, I will replace the tires.

[sochermit]

I found on TireRack.com that when you get to 4/32in, .125in, 3.175mm you should start looking to replace your tires. If you reach 2/32in, .0625in, 1.587mm you should replace them.

The dealership said, after rotating my tires, that it is time for me to replace them. I have 4,5,8/32. The 8/32 is a replaced tire. So I am going to make one more trip and then replace them.

[1speedbike]

Measuring tire tread depth with a coin.

This is good for a quick and accurate estimate without having to go out and get a tread depth tool.

[VMRWheels]

This is what I generally go off of. Once the tires hit those horizontal lines, you should be preparing to purchase new tires, it's basically an indicator that the life of those tires are almost over.

[GaryS]

Originally Posted by sochermit

I found on TireRack.com that when you get to 4/32in, .125in, 3.175mm you should start looking to replace your tires. If you reach 2/32in, .0625in, 1.587mm you should replace them.

The dealership said, after rotating my tires, that it is time for me to replace them. I have 4,5,8/32. The 8/32 is a replaced tire. So I am going to make one more trip and then replace them.

Is it dry where you live? If it rains a lot, like here, you should replace tires around 4/32" to leave enough tread for wet roads.

If it doesn't rain a lot, you can wear them down to the legal limit, which is 2/32nd".

[sochermit]

Originally Posted by GaryS

Is it dry where you live? If it rains a lot, like here, you should replace tires around 4/32" to leave enough tread for wet roads.

If it doesn't rain a lot, you can wear them down to the legal limit, which is 2/32nd".

Rain, what is that? We are in another draught so I will not worry about the rain.

[Dackelone]

Originally Posted by sochermit

...The dealership said, after rotating my tires, that it is time for me to replace them. I have 4,5,8/32. The 8/32 is a replaced tire. So I am going to make one more trip and then replace them.

How can they rotate a staggered tire setup? All 135i's have a staggered wheel setup! Your 135i has a 7.5" wide wheels on the front and 8.5" wheels on the rear. Rotating wheels is not gonna happen!

Originally Posted by sochermit

Rain, what is that? We are in another draught so I will not worry about the rain.

It will only take it to rain ONCE and then you will see... that driving on bald tires (or low thread depth tires) is a bad idea.


I have a friend here who runs a used Porsche parts business. He loves the Fall(time) bc a lot of people don't think about flash rain storms or cold weather. He is so busy in the Fall bc so many people total their P-cars and he buys them on the cheap.

[Freon]

4/32nd with a performance tire in heavy rainful is going to start to be hair raising.

You can get a real treadwear gauge for a few bucks at the auto parts store. I have one that reads both in 32nds and mm. I don't care for the penny method.

You can't really rotate, but you can have your fronts dismounted and swapped/flipped, and rears dismounted and swapped/flipped. But that's a full mount and balance on the entire car. You can manage wear with tire pressure and proper alignment as well. Oprtimal alignment may depend on your driving habits. More aggressive drivers will probably want some extra camber in front.

[sochermit]

Originally Posted by sochermit

Rain, what is that? We are in another draught so I will not worry about the rain.

Seriously, I will be replacing my tires within the next month. I place a lot of importance on my tires. When doing 100 MPH that is the only thing between me and the pavement.

[ken1137]

I realize you already decided to purchase tires, but get one of these...

http://www.pepboys.com/product/detai...ils+Controller

I usually target 5/32 and the gauge is pretty helpful if you are selling tires.

[sochermit]

Pep Boys here I come. Thanks for the info.