Tires/tranction/abs Issue

[bappleby]

I have an 06 IS250. I replaced the front tires about 15k ago with Continentals and just replaced the rears with Toyo Proxys 300 miles ago. All relevant tire number match and the fronts are not worn excessively. I went on a road trip and on every moderate turn of 35mph or more the traction control light came on and off, buzzer sounded and ABS engaged even though it's light didn't come on. This did not happen when I did the fronts. It behaved normally on normal roads, freeway etc. Keep in mind I wasn't cutting the turns Dukes of Hazzard style but driving easily. Come on, don't tell me you can't mix tires from back to front? Tire shop says the fronts put on by another shop were non-directional and that the rears they installed are. No one is suggesting any type of sensor malfunction. I did notice a bit of a tracking issue when they were first installed but nothing I couldn't live with. Shop is suggesting I keep all tires the same and replace two of them. They say directional/non directional are not necessary either way but must match. Has anyone run into this? I'm unemployed right now, and don't want to shell out more $$ if I'm being led down the wrong path. And yes, I just ran out of warranty.

[bartkat]

That can happen if you just happen to get the right combination of a dip or hole or bump in the road and one tire momentarily loses traction. I wouldn't be too concerned if it doesn't happen on a regular basis. I've had it happen when making a right turn on a street corner and the inside tire drops into a dip by the curb.

Directional has little to do with dry traction. The tires just need to be installed turning the right direction in order to throw water out and prevent hydroplaning.

[bappleby]

That can happen if you just happen to get the right combination of a dip or hole or bump in the road and one tire momentarily loses traction. I wouldn't be too concerned if it doesn't happen on a regular basis. I've had it happen when making a right turn on a street corner and the inside tire drops into a dip by the curb.

Directional has little to do with dry traction. The tires just need to be installed turning the right direction in order to throw water out and prevent hydroplaning.

Hmmm..for what it's worth this was a pretty well paved road, went 150 miles out to the desert. The light and ABS went on on EVERY turn, and I mean EVERY. I've had this happen on a bump or steep driveway before but not a moderately curvy, flat road...and regularly. Thanks!

[bartkat]

Sounds like the yaw sensor may be too sensitive then.

I drove my 350 for a while with diff front and rear tire types with no problems.