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Bulge in Tire

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.


[fixed formatting issues, moved to M/R topic - lackeyjr (moderator)]

Don’t expect Pep Boys mechanics to know much unless you are familiar with the techs there. Big chains like Pep Boys doesn’t pay well and they usually have inexperienced techs that just graduated from their first job at a quick lube shop. I’m not implying that they are stupid, just inexperienced.

I don’t think the bulge is due to damaged rims, but more likely due to the pot hole impact itself. The shock from impact that dented the rim may last have led to delmination of the inner layers of the tire. Replacing the tire was the right thing to do since you don’t want to tempt getting a catastrophic tire failure at high speed.

Have the suspension checked for damage if that was not done yet. Any wheel impact that bent the rim and destroyed the tire could have bent suspension components. This should have been seen during the alignment process though. Did you get a printout of the alignment before and after the alignment process? If so, what did it show?

Not sure what happened here. This post is identical to the one called " Annoying vibration " that the OP made 5/1. The OP has not responded to their other thread in 3 days.

@lackeyjr Did you mean to modify the other thread by this OP?

@cdaquila Carolyn, sorry to bother you but it appears we have a duplicate thread with a different heading so confusion is happening.

Same advice as before

replace bulging tires

replace bent rims

have all rims and tires balanced again, afterwards

don’t waste any more time and money having somebody attempt to straighten your bent rims

report back afterwards, please

1 Like

I’m afraid I disagree with a lot of what you’re doing here. I would take a luxury car to a real mechanic, not Pep Boys. I would never put cheap Chinese tires on any car (let alone a luxury car) because your safety depends on them. Furthermore, I would especially never mix two cheap Chinese tires with two normal tires because you want equal traction at all corners to keep the car under control in an emergency maneuver. Finally, if you have to use two new tires and two old tires, then the new tires belong on the back.

Beyond that, do what db4690 says.


+1 to everything that lion9car stated!


I just can’t get my mind around someone buying a Mercedes and taking it to Pep Boys for anything. There must be some shop in your area that specializes in wheel straightening. They would do balancing and alignment too and can probably trll you if there is anything wrong with the new tires.


It’s probably an off-lease car. You can get one for the price of a Honda Civic. Used luxury cars often bite people because they think they’re getting a $60,000 car for less than half price, without realizing how much it costs to run them. It costs me over $1,000 to put tires on my 10 year old Acura TL - I can’t imagine how much rubber for this thing runs.

OP, you need to put good tires on the car - I personally recommend Michelin - and you probably need to upgrade from normal balancing to roadforce balancing.

At least on mine, I always had vibration until I started getting them roadforce balanced, and then the vibration went away.

Michelin Pilot Sport A/S tires run about $180 each with the W or Y speed rating. An ultra-high performance tire for an Acura TL would cost about the same.

Yeah, but that’s $780 before tax just for the tires. By the time I pay for mounting and roadforce balancing and disposal fees… Not to mention $60 or so in shipping.

And the price has dropped since I put on the A/S + tires several years back. At the time it was $250/tire installed, plus tax.