A vibration felt at 55 mph may not be a tire problem. Mazda has revised motor mounts available which may help remedy this problem.Google+
Car Problem Reports
Mazda Mazda3 Vibration Felt at 55 mph
Mazda Mazda3 Problem
Engine Affected: 2.0L 4 Cylinder
Average Mileage: 66,775 mi (15,000 mi - 130,000 mi)
Visitor, 2005 Mazda Mazda3, 55,000 mi
heavy vibration begins over 60 and gets worse as speed increases - bought new tires, didn't help, double checked balance and alignment at two shops - didn't help - new front rotors and pads - didn't help. Next step is checking mounts -
Driving at around 60 MPH I feel that the body (not the steering wheel) vibrates. Al 4 tires repalced and balanced including dynamic (on the car) blancing and still the problem not fixed.
Visitor, 2005 Mazda Mazda3, 90,000 mi
We picked up a shimmy/vibration at 70 mph, and it was intermittent, sometimes to the point of slowing down to 20 mph to get it to stop. We thought it might be the roads, but we got all 4 tires replaced and the alignment done and no change. It's really bad in a side wind (this could be wind getting under the hood and yanking it around), but we're tired of spending money on it. Our tires also had severe wear on the outsides.
Visitor, 2011 Mazda Mazda3, 2.0L 4 Cylinder
viabration at 55mpr
Visitor, 2007 Mazda Mazda3, 70,000 mi
shaking at 55mph....5 different mechanics swore it was my tires
did the front and rear shocks/struts
balanced tires 5x and aligned the car
HOPING it is the motor mounts!
Visitor, 2007 Mazda Mazda3, 50,000 mi
Rumbling coming into steering column starting at about 60mph. Still searching for the cause.
Visitor, 2008 Mazda Mazda3, 80,000 mi
Vibration right 60 mph and gets worse as speed increases. Rebalanced tires three times with no change.
I am too feeling the vibration at speed of 60mph
Visitor, 2006 Mazda Mazda3
vibration at 55 mph,had tires ballanced and re-ballanced. Dealer cannot say for sure engine mounts will solve the problem. Said, best to live with the problem.
Visitor, 2007 Mazda Mazda3, 71,000 mi
Felt like R. Front strut not working- like oversteer or sway more to R. than L.
but no vertical rebound with compression. Replaced strus anyway. Felt
a little better but then noise like CV joint loose- intermittent rattle worse turning
to left. Then noise suddenly got very bad, loud grinding, went immediately to shop,
driveability not affected! Was a failed R. motor mount, approx $200.00 (records
in storage). Now 115750 mi & no other problems with motor mounts.