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: 66,800 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.
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.
Visitor, 2007 Mazda Mazda3
Between 55 and 60 there's a vibration in the front end. Had one way worse before (made the steering column vibrate too) but ended up being a rotor issue. This front end vibration is more annoying than anything else and a front end alignment did nothing.
Visitor, 2007 Mazda Mazda3, 126,000 mi
have noticed for about last 10,000 miles - started as very faint vibration noticed with highway driving
After a rear end collision at 14450, then again at 28000 miles, engine mounts failed, rotors were damaged, axles and wheel bearings needed replacement as well. This time the vibration is felt from 10-80mph. New wheels & tires don't help.
Haven't yet replaced sway bars, but figure that and coilovers ought to do it.
At that point, I will have spent the cost of the car making it safe [and fun to drive] again. Any other tips to help me decide if I should go ahead or maybe just get a sturdier car?
Visitor, 2005 Mazda Mazda3, 40,000 mi
Front brake flutter when lightly applying brakes. Turned rotors problem went away.