[Jim19939]

I guess this must apply to the Sienna with all its computerized controls. They do point out that Tire Rack will sell you a shaved tire to match the remaining tires.

Here’s Why Your AWD Vehicle Needs Four Tires When One Is Damaged | Torque News

One of your tires was damaged and cannot be repaired. Your tire shop says you need four tires, not just one. Here’s why they are correct.

www.torquenews.com

 

[EricD]

I wonder if this actually matters for the AWD Sienna since the front and rear axels are not connected in any way. There is growing consensus among Tesla drivers that you only need to replace pairs (both front, or both rear) but having differing wear on front vs back isn't going to cause mechanical problems as there is no mechanical linkage between them.

 

[Jim19939]

I wonder if this actually matters for the AWD Sienna since the front and rear axels are not connected in any way. There is growing consensus among Tesla drivers that you only need to replace pairs (both front, or both rear) but having differing wear on front vs back isn't going to cause mechanical problems as there is no mechanical linkage between them.

Since they sense the speed of each wheel, different tire diameters can affect ABS, TRAC and VSC systems. It must also affect the AWD controls if the front and rear diameters differ. The question is how much does it affect them. Toyota does emphasize routine tire rotation to maintain even wear.

 

[BlueRidgeMark]

Since they sense the speed of each wheel, different tire diameters can affect ABS, TRAC and VSC systems. It must also affect the AWD controls if the front and rear diameters differ.

Exactly. It's not about a mechanical linkage, it's about the whole system responding to the different wheel speeds.

The question is how much does it affect them.

That's the $64 question. What fools a lot of people is that it takes time for the damage to become evident, so they don't connect the dots.

 

[DKH]

I just can't imagine it being that bad. Everytime you turn the steering wheel your tires rotate at different speeds. And in almost every case, spare tires are different diameter than the standard tires.

Maybe if you had super handling awd that drive torque to the outside wheel then it might cause it to wear down a bit faster, but the system is literally designed to do that.

My old 04 sienna awd went 230k miles with no issues with drive train and I've replaced only a single time every time.

 

[EricD]

Yeah, there might be some issues but it is nothing like the concern of mechanically linked AWDs where the front and rear planetary gears rotating at different speeds is going to cause serious wear.