Both rear wheel bearing gives up in months.Already changed 3 times within 1 year. tyre pressure is set at 27 both front and back.wheel balancing done too.

The vibration might be caused by anything connected to the road wheels. If it only happens when the car is in one of drive modes it could be something between the transmission and the tyres. Start at the wheels and work in towards the gearbox. Try this checklist.
**Note** Apply these checks to ALL 4 wheels.
-Tyres. Are they inflated correctly? Are they in good condition?
-Wheel Rims. Are they undamaged? Are ALL the wheel nuts tightened correctly?
-Tracking. Is the Toe in, camber and wheel alignment correct?
-Brakes. Are the pads and discs OK? Discs can warp and cause vibrations.
-Wheel Bearings. Worn bearings are noisy and can collapse.
-Drive Shafts. They usually need balancing when they are made.
-Suspension Mounts and Arms. Worn mounts and ball joints move creating noises. Are the springs and dampers working correctly?
The All Wheel Drive version will need the propeller shaft checked for balance and the rear differential and shafts should be checked and serviced as well.
If none of these give you the source of the problem your possibly looking at gearbox issues.

The first thing I'd check would be my tires. Then if it isn't the tires it would be in the front end. Tie Rods, Ball joints. steering linkage. or if at worst The Rack and pinion.

Needs a front end alignment

jack the front up and spin the wheel ,lay you pound to a penny the front tyre is deformed ,i blame the garage that checked the tracking and balancing for not checking the tyre first ,but as they only pay peanuts then no doubt it was only a semi skilled grease monkey you got to it for you ,change the wheels front for the rear and then it will be ok

Have drive shaft balance checked and front u-joint(s). Also a bent drive axle or worn rear wheel bearings will give same symptoms.

get under the vehicle (use ramps) and check all linkages for movement pull push on the anti roll bar links, pull push on steering rack and pinion and linkages, any excessive movement, jack each wheel at a time, using a bar check the lower wishbone joints for movement, get the bar in the gap between the wishbone and lower part of the shock. and pull down, if any movement in ball joint up and down replace. while wheel on vehicle check for movement in bearing you will feel a tiny amount not much but pull and push on wheel with opposite hands on 12 o'clock and 6 o'clock and do the same at 9 and 3. now with both wheels off the ground but with the tyres still on, have some one holed one wheel and push pull on wheels each side there should be even movement between both wheels, if everything is fine with the the steering linkages and this dose not feel or sound right then this could be the problem also to add if the inside and out side of the tyres are wearing then the tyre pressure is wrong and needs adjusting to the right tyre pressure .

If it is a tire related howl you are getting as well as the vibration through the steering wheel once you hit about 60 mph there is a number of things you need to do.

1. If you have not had a wheel alignment carried out on the vehicle in the last 6 months then have it done at a reputable suspension specialist (not a tyre dealer). Check your front tires for wear pattern in any event as uneven wear on the tyre is a sure sign of poor alignment. Bad alignment can also contribute to vibration problems. I will guarantee you that when you get the alignment checked it will be out. I am not sure if the rear alignment is adjustable on your model but if it is you will in fact need a 4 wheel alignment. (REFER point 7 also)

2. When the alignment and other necessary front end work is done check to see if the problems persists..

3. I assume your vehicle has the steel rims fitted with the plastic wheel cover. Remove the covers on the front wheels and check for the vibration. If it disappears then the out of balance condition is caused by the covers. (This would not explain the tyre howl though).

4. Remove both front wheels (clean them) and check for damage to the rims on both sides including outside scuffing. (Check tyres also.)
If the steel rim is bent or warped it will not run true and you will get vibration and the tyres will tend to be noisy on the road. It is not always easy to identify a warped steel rim from a visual check. Spinning the wheel on a wheel balance machine should normally show this up though.
If you have alloy wheels fitted these tend to crack and break rather than bend or warp.

5. Out of balance wheels.

It is possible for a wheel to be so badly manufactured that no amount of balancing on a tyre balance machine will fix it. This is a particular problem with cheap alloy wheels but even good quality wheel manufacturers will occasionally let a bad alloy wheel slip past their quality control .

6. Tyres.
If you buy budget tyres you are generally buying poor performance and potentially poorly constructed tyres. Tyres can be produced with inbuilt heavy spots that will make them impossible to properly balance. You will forever have a balance problem (and hence vibration) with such tyres. A good manufacturer will not allow such tyres to slip through quality control. Others are much less fussy. It is always a bad decision to purchase tyres in the lower price ranges.
In your case it is quite possible that if your wheels are ok the tyres are badly constructed and it is not possible to balance them properly. (This would not explain the tyre howl though).

7. Given the age of your vehicle you should have the front suspension and steering components inspected. It is possible that wear in critical components could be the source of the problem. When you take the car to the suspension specialist for the wheel alignment you need to have the front end fully checked over first and any problem areas attended to.

Without test driving and pysically inspecting the vehicle it is not possible to identify the source or sources of the problems. My best estimate is that there are significant wear problems in front end components and that your front end aligment is also out.
However , I hope this helps.

The 1st thing to get looked at is the wheel balance.Have them checked.At the same time,if the tyres are o.k. have them rotated.This means you swap the tyres from the front to the back.Always keep the tyres on the same side of the car.So left rear goes to left front and the same on the righthand side.Also,a wheel alignment should be done.These are a tyre shop job.Cheap and doesn't take that long.If these don't correct the problem,the next thing to get looked at are the front wheel bearings.Get the tyres done 1st.This is the 1st step and also the most common problem.Hope this helps

IT HAS TO BE BALANCE if it was shocky related or loose wheel bearings it would have been in evidence before the tyre change ---I would recommend you take it to one of the better tyre only establishments and ask them to balance your 2 front wheels both inner and outer please let me know the result, imay learn something------------------------but I doubt it

Hi I am Vortash the main things that cause wheel Vibration are
1/ wheel balancing ( thrown weights mostly )
2/ wheel bearings
3/ susppension arms
4/ ball joints
5/ track rod ends worn
6/ steering shims loose
7/ damaged cv joints or drive shafts (transverse engines )
8/ Prop shaft missalignment (rear wheel drives )
9/ and this is the most popular one tyres not fitted correctly (twisted )
10/ unlikely but more common than you might think Buckled wheels pot hole at 40mph do a lot of damage ..
hope this gives you some ideas and good luck with finding a solution regards Vortash