Replace just one tire?

[JCH13]

I still don't understand the matched tire crap. I do match tires when shit happens but if one tire has lost 1/8" of tread on wheels that are 5' apart, we are talking about the axle (and tires) being 0.119 degrees out of level.

Or think of a tire that is 8" wide. We are talking about the left/right edge of the tire being off by 0.0166".

Perfect? no. Signficant? I don't think so.

It's not about sitting off-level, it's about spinning the differential all the time because of a rotational speed difference.

Question: what qualifies you to make a judgement call as to what is significant or not when it comes to this subject?

 

[IHateMyJob2004]

It's not about sitting off-level, it's about spinning the differential all the time because of a rotational speed difference.

Question: what qualifies you to make a judgement call as to what is significant or not when it comes to this subject?

Engineer? The differential isn't an issue. That's the whole point of their design. If it were a straight shaft, sure. The whole point of a the differential is to allow for the wheels to spin at different rates.

For every day drivers, the issue seems moot. For people that go to the track or drive like idiots, ya it might be an issue.

 

[Elganja]

it accelerates the wear of the clutches and differentials if the wheel speeds are different ... the larger the difference the quicker it wears

it's in your best interest to match them if possible, esp when tire shaving cost like $20 bucks from tire rack... it's not astronomical and will save you more money in the end

 

[JCH13]

Engineer? The differential isn't an issue. That's the whole point of their design. If it were a straight shaft, sure. The whole point of a the differential is to allow for the wheels to spin at different rates.

For every day drivers, the issue seems moot. For people that go to the track or drive like idiots, ya it might be an issue.

So you're a powertrain engineer?

Differentials allow the speed difference to occur, but they wear and create heat when doing their job. Reducing that wear is important to long drivetrain life.

If the difference is great enough the ABS/DSTC system or TPMS (for those that use wheel speed) might not function properly.

 

[IHateMyJob2004]

In a 4wd car, it matters. I'll never believe any 2WD vehicle with non locking diffs will care about mismatched tire sizes.

 

[JCH13]

In a 4wd car, it matters. I'll never believe any 2WD vehicle with non locking diffs will care about mismatched tire sizes.

So you'd drive a 2WD car with a $1k LSD that's constantly wearing to save $20 on shaving a tire?

It's good to know that you refuse to consider any evidence or reasoning contrary to your own.

 

[RLGL]

Read the owners manuals for the AWD vehicles, ALL of them have a specification for the amount of tire diameter difference.
No two specifications are the same!!!