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Annoying vibration

Hi guys, I am hoping someone with experience can tell me what to do next. I developed a bulge/bubble on my front passenger tire about a month ago. I have a 2015 mercedes benz cla, I do not have run flats. I bought 2 new front tires (Nankang NS-20 Performance Radial Tire - 225/40R18 92H) and had them replaced and balanced at pep boys. My original tires were pirrelli, same size, and the 2 originals are sill on the back of the car.

After installing the new tires on the front, The tire tech told me I have a small bend in my rim and that may have caused the tire bulge. I could see how this might have happened, because I hit a small pole laying across the road a few months back, but never had any vibrations.

After having the new tires installed, I took the car on the highway a few days later and noticed a vibration at high speeds, 60 mph +.  The steering wheel gas pedal and even inside door and seat vibrate.  I can feel the vibration in the steering wheel only at lower speeds 35 mph, only if I squeeze the wheel tight.  

I took the car in to have the bent rim fixed, but a week later I still had the vibrations.  I went back to pep boys and they explained I had a small bend in the drivers side rim as well.  They also explained that the tires needed to be rebalanced.  They insisted that when I had the rim fixed it was not rebalanced.  So I balanced all 4 this time and had a full alignment. 

Considering I still had the vibration I had the drivers side rim fixed the following week, as well. At this time I still have the vibration in all areas I mentioned. Should I go back to pep boys or maybe my regular car mechanic to see if it is not related to tires and rims. Should I go to mercedes if it is not the tires? Please let me know what else should be checked. Considering I never noticed the vibration before the new tires, can one of the new tires be bad? I would expect pep boys to tell me that though. Thank you for your time.


Not a fan of Pep Boys which I believe is owned by someone else now. The accepted practice is when only getting two new tires they go rear of vehicle no matter front, rear or all wheel drive. Most places will have you sign a waiver if you insist they go on front. I suspect your front suspension has damage or the repaired wheel needs replaced.

You may be expecting too much from the folks at Pep Boys. You own an expensive German performance car. At the very minimum you want to be dealing with a tire shop that does nothing but tire and wheel work. Or a shop that does nothing but work on German performance cars. Or a tire shop that shop recommends.

Does anyone else find the post where you have to use a scroll bar to read what is being said annoying?


I suggested new tires on front because my rear tires are still very good, with thread on them. I asked them if rotating front to back in 5k-8k miles made sense. they said that was fine.

if i has suspension damage wouldnt i have had the vibration before the new tires were put on?

My guess is that either one of your new tires is out of round or a tire is out of balance. I bought 4 new tires and had a vibration at highway speeds. The tire dealer moved the tire about 45 degrees on the rim and rebalanced that tire. That took care of the problem.

All I wanted was them to change two tires, then they told me i had a bent rim, then i got this vibration, then they told me i had another bent rim, and i still have the vibration…

Just trying to figure out if i should go to my reg mechanic or mercedes to see if the problem is covered under warranty.

i cut and paste the message no clue where that came from… interesting option though.

Yes, that’s what you should do.

which one?

And another reason to avoid pep boys.

Either one, provided your mechanic has Mercedes or at least German car expertise.

Didn’t anybody catch that part where OP mentioned both of his front rims are bent . . . ?!

Bent rims can and do result in wicked vibrations

The impact with the pole caused both the damage to the tire and the bent wheels. When this was discovered you should have had the wheels replaced or straightened by a wheel repair service. If the wheels are straightened the wheel/tire must then be balanced once again.

Rotate the tires front to back - doesn’t matter what pattern, this is a test. Did the vibration move?

First, if the front tires/wheels are involved, the vibration should be in the steering wheel before the rotation. If so, then the vibration ought to change after the rotation to the back.

If that is the case, take the car to someone with a Hunter GSP9700 balance machine for further diagnosis. That machine can detect (to a large degree, it’s not perfect) an out of round tire and a bent rim. The tech may need to dismount the tire to be sure it is the rim.

You can find such a machine here:

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Thanks guys I really appreciate the responses! My mechanic called me and said the drivers side front rim is bent. Should I attempt to have it fixed AGAIN or replace the rim?

I had to think long and hard about this. Repaired once and did not last. just replace it.

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Very annoying.

It wasn’t actually fixed the first time. Someone whacked away at it and though MAYbe that would be enough.

Replace the rim. Stop going to Pep Boys with your Mercedes.

Also, stop buying the abSOlute cheapest (Nankang!) tires available. Premium cars should have premium tires. I admit I am a “tire snob” because those 4 black rubber bits are the only thing that keeps you on the road.


I google rim repair, the place has positive reviews i take it there!
Im not a mechanic, i dont know how rims should be fixed.

Pep boys is a tire shop, they cant be trusted changing and balancing tires?

The reviews for these tires are very good, why shouldn’t I buy them? I am not a tire specialist either.