Strange vibration

rat

Joined
Dec 10, 2006
Messages
361
Location
Michigan
2015 Focus SE with a manual trans. 99k miles. Thursday I decided it was time for new tires, tech installed them and we replaced the thermostat at the same time. I live roughly an hour away from work, and noticed a vibration on the way home at highway speed. I assumed maybe the balance was a little off and I'll have him look at it again when I go back to work. This time I asked him if he could do a road force balance just to make sure. He literally spent over 2 hours making sure that they were spot on balanced. Now the vibration is worse. Seems to get worse with more speed. Seems fine at 25-30 mph, and idles fine. Could it still be the tires?
 
I don't think he REALLY did a road force balance. Out of round tires would have shown up immediately. If tires are the only thing you changed, then your question is already answered, Yes, it's the tries.
Oh yeah, I see the thermostat was done too. But I don't think anything short of a misfire would cause your issue. You have ruled that out, I think.

Did you get the results of the road force balance? Properly done on a Hunter machine usually comes with a printout. I like mine to be below 10# of road force for a smooth ride.
 
He did actually do the road force balance. I watched him doing it. I watched him reposition the tires on the rims as the screen instructed. I didn't ask for a printout because assumed it would have been perfect after all that.
 
Before condemning the tires if this car has alloy wheels take them off and clean the hub and the back of the wheel mounting area.
This is common in the salt belt, all 4 wheels are removed, tires mounted and reinstalled then vibration occurs. use a wire wheel carefully on a drill and only get the crud off so its clean.
Sometimes it can be the car drives smoothly but shudders like crazy under braking that was previously smooth for the same reason.
 
Rust on the hubs can be a funny thing.. Rotated wifes tires and cleaned up hubs no more shuddering during braking.
 
Originally Posted by rat
Could it still be the tires?


It could. There is one brand I avoid, because I've never had an example of that brand that I was pleased with.

Assuming the machine was calibrated, the wheel properly centered with the correct cone or lug-centric adapter, the operator truly knew how to use the machine, a tire or wheel with poor uniformity or excessive runout or 'roadforce' should be identifiable.
 
I had this faint vibration that felt like all over the car. This was after new Michelin tires. I think it was Premier but never had any issues with the previous Michelins ...
Balanced it 2 or 3 times and finally gave up. it got better with time but it still does it if I focus on it. It's not in the steering wheel and I've asked others if they feel it and they say no.
 
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