"lumpy" tyres?

[Bane]

Has anyone ever heard of tyres getting "lumpy"?
My OH said that her MK4 Golf was noisy and felt odd when she was driving it.I took it for a run and immediatly thought that there was a worn wheel bearing as it sounded like there was one on the way out and it had that mild vibration in the steering wheel.
So she got a garage to look at it and they reported that they had checked the bearings and there was nothing wrong, so they took it out and heard the noise and were a bit puzzeled until someone suggested swapping the wheels front/rear.They too it out again and the noise/vibration had stopped.
They then took a closer look at the tyres and noticed that they had a slightly mis-shapen look around the tread.
When they told me this,I initially didn't believe what they were telling me as I had never heard of this before and these wre not cheap brand tyres...they were Good Year Opti grips less than two years old.
But I ran my hand over the tyres and yep,there was definately a corrugated feel to the tread,more noticeable on the outer edge blocks.
I suspect it might be a wear thing,but the guy at the garage said he had seen it on some Good Years before.
I'm not going to go to the expense of changing them as there is loads of tread left on the tyre and they seem to be in good overall condition apart from this,but I just wondered if anyone had seen this before?

[Deako]

Could be dangerous. Ensure the lumps don't turn into balloons. I'd swap them if it was me.

[Stevepd]

Yep I've heard of that before. My sons Polo was on the drive for ages and when it came to drive it was wobbly as hell, but being thin ones we replaced them = no noise/vibration

[tony_danza]

My old MK5 had turned its rear tyres into 50ps when I got it, geo badly out scrubbing them.

[Golfgirl]

My last set of tyres (Toyos) went like that.  When I went to get some new ones they said it's common on Golfs, A3 etc.

[JoeDarKa]

Could be incorrect tyre pressures? Is the car lowered? One of my old tyres went what was described as "sawtoothed"

[mw-wax]

Hi, I had the same problem thought my wheel bearing had gone, had my mate look at it for me who is a tech he said rear shocks are weak so told him to replace. When he removed found coil spring had broken so new coil springs as well. Plus new rear tyres and four wheel alinement. Problem solved he said comon fault on vw.

[SkyJawa]

They do go a bit flat if they aren't driven for a while, find this when car has been sat and not moved for ages, but always goes off after use and up to temp.....

[Greeners]

Same problem on the wifes Tiguan! VW dealer said its common on certain brands. Commonly known as 'saw tooth'.

[bigmig95]

Running a pair of Uniroyal Rainsport over the winter on my 17"Monzas.  Took my summer wheels off with Goodyears on and couldn't believe the noise difference with Uniroyals.  It does sound like a wheel bearing has gone.  The tread as you go over the sidewall is at slightly different heights around the wheel, hardly noticeable but enough to give a nice humming noise down the road.  Started with these on the front then put on rear and it's definitely tyre noise.

[Saintsteve]

Same problem on the wifes Tiguan! VW dealer said its common on certain brands. Commonly known as 'saw tooth'.

Dunlop Sportmax suffered badly with this, leading to horrendous tyre roar in the cabin.

[tony_danza]

I will add once I'd had the geo set to my preferred (no rear toe) it never 'saw toothed' another set.

[Andy]

i see it a lot at work on different makes of tyres but the worst or should i say most common were pirelli

[rich83]

Goodyear F1 GSD3 were bad too. In the end I got new rear shocks and it sorted it out on my old mk5. My GTI has been fine though 

[Human Joist]

Our cars suffer with it. The rear suspension king fails and wears and so in turn wears they tyre as the alignment goes out. Mine were like it when I bought the car. It's referred to as saw toothing. If you look under the car from the back between the wheels you will see two large figure 8 bushes that link the suspension to the chassis in the middle of the car at the back. They fail and will need replacing followed by four wheel track and alignment. The parts are around £90 and take an hour or so to replace.