rangerboy

First post here so bare with me.

My wife has a 04 RX330 AWD coils. We have had the alignment checked multiple times by different shops. All show the same specs and or close to it. Camber, Caster and toe all are good. Vehicle drives straight and steering wheel is straight.
Front and rear suspension components are all tight. No abnormal tire wear. Struts are new KYBs. Tires are new. While driving on dry roads no issues.

Our issue is when the roads are icy the back end feels like it wants to slide out. Always have to correct it. Makes my wife feel very unsafe. We have had this vehicle since it had 15k on it. It has 105k on it. We noticed this issue at about 80k and have been chasing this since.

Anything that we have over looked that that could cause this? Anything with the traction control?

tomr51

what tire pressure are you running?

rangerboy

Tried 35 psi. Tried 40 psi. Tried 30 psi. Doesn’t seem to change it.

tomr51

just a thought try 38 front and 36 rear?????

tomr51

another thought, what brand are your new tires and did the issue only become noticeable with the new tires??

rangerboy

ukrkoz

Drop 3 50 lb bags of sand into trunk. Or 4. Opposite side to driver. I used to drive with 250lb ballast this way. You are driving a vehicle that has very heavy engine and literally not enough weight on the rear end. So ballast it. Why she's not using snow mode on icy roads? And tell her to slow down. AWD is not substitute to cautious driving.

ukrkoz

New set of winter Michelins? Or, regular ones?
Is rear camber within spec? Yes, I saw what you posted in OP. Camber has huge influence on rear end stability.
Ballast rear end. 200 lb or so, opposite to driver corner. Sand bags. Dead serious. I drove like this for years. Your entire weight load is on the front end.
Any fraction of PSI you add above recommended level lowers traction.
Why is she not using Snow Mode?