Possible causes of sidewall bulge?

[Kermit power]

Morning all,

Yesterday afternoon, a guy pulled up next to me at some traffic lights and told me I'd got a large bulge on the inside sidewall of my offside rear tyre.

My initial thought was whether this was Superman, as I couldn't imagine being able to see a sidewall wall bulge at that sort of distance with the tyre still fitted to the car, but of course I checked the tyre to see.

This is no ordinary sidewall bulge!!



There is also a small "regular" sidewall bulge, further round the tyre. In 26 years of driving, I've only ever had this happen once before, and that was on an outside edge, and next to a spot on the rim which I'd clearly kerbed.

This, however, is unlike anything I've ever seen. The bulge is a good 8 inches long. There's absolutely no marking of any sort on either the rim or the tyre itself, and I'm sure I've not hit anything. Quite apart from anything else, just how much effort would you actually have to put in to hit something with the inside edge of the offside rear tyre???

Anyone got any thoughts on causes?

[Monkeylegend]

Can't help you with the tyre but respect to you if you have an 8" bulge.

[timbob]

Pothole maybe? Or possibly just good old fashioned tyre failure?!

[RizzoTheRat]

Probably a pothole

[morgrp]

Most likely a pothole - broken the nylon in the sidewall - risking a blow out driving on that at speed

[Kermit power]

morgrp said:

Most likely a pothole - broken the nylon in the sidewall - risking a blow out driving on that at speed

Fear not, there's no chance I'm driving on that at any speed now I know it's there!

I would've been inclined to agree with pothole if it had been almost anywhere else on the car, but this is the most protected bit of any tyre on the car, plus there's the second, smaller bulge on the other side of the sidewall too.

I'm starting to think it's a manufacturing error, which makes me wonder about the other tyres fitted.

[bencollins]

as the chap says above, cords broken, replace the tyre (preferably both sides)

[Ed.]

Repeated hitting of worn speed cushion?

[iguana]

Is it an Avon?

I've had this & a pal also, both on an Avon van tyre, a bad batch of construction perhaps, were pretty new when they both did it, couple of months tops.

[Kermit power]

It's a Hankook.

What is a worn speed cushion?

[GuinnessMK]

Kermit power said:

It's a Hankook.

What is a worn speed cushion?

[Donboy]

A couple of years ago my other half was driving home from work , drove through a very deep pothole , and out popped a bulge ,
Got it replaced on black circles ( barum think it was)
Fast forward a week later , reversing out the drive she ripped the side wall on our driveway edging ,replaced tyre again,
Then another week later did the same again !!(tyre number 3 )
She now reverses in the drive and is more observant about potholes

[tim2100]

I had that a few weeks ago. I had two bulges on the inside edge on both rear tyres.

These were OEM Run Flats with supposedly stiffer sidewalls. No idea what I have hit.

[Leins]

tim2100 said:

I had that a few weeks ago. I had two bulges on the inside edge on both rear tyres.

These were OEM Run Flats with supposedly stiffer sidewalls. No idea what I have hit.

RFTs seem to be particularly bad for this in my experience