Nasty swelling

[Iancider]

Today it was kind of good news bad news.

The Good news:

The reason my tin-top has developed a nasty low speed shake was was a bulge in the tyre tread - not the sidewall - the tread.  It was VERY hard to see even when rotated on the wheel balancer - which said it was in perfect balance.  Trouble was it wasn't round any more.  The tread was becoming detached from the core fabric and was fit to blow out catastrophically at any time.  It had lifted more on the outer edge so was quite violent through the steering.  Two new tyres sorted it.

The BAD news:

My garage was previously baffled by this and concluded previously that it was a driveshaft problem and the CV joint wasn't constant velocity any more.  Oops no it wasn't and it didn't cure the problem.  But only after it was fitted was it clearly NOT that. 

The wheel started life on the rear nearside and shook the car badly from the end of November.  When the front and rears were swapped the problem got worse and it pulled to the left on a left camber and went neutral on a right camber.  Swapping right and left fronts the shake became much worse and the car pulled to the right.  This indicated the wheel or tyre was at fault and my friendly wheel shop found it.

The tyre was a Michelin Economiser - don't buy this tyre.  It is an old fashioned ribbed tyre with low rolling resistance and drove well when it was new but as they wore they tracked every crack in the road and then this bulge appeared.  This was an EXPENSIVE experience!

[benchmark51]

come back C41' s all forgiven

[Moleman]

Sorry to hear this mate but glad it's all sorted now. 

[sanzomat]

Was there ever a puncture repair on the tyre? If not done entirely correctly that can lead to a delamination as water can get to the steel belt and rust it. In fact a cut in the tread that didn't actually become a puncture can do the same. Back tyres on FWD cars can last so long that age related defects can occur before they wear out.

Unusual for a Michelin to have a quality failure but then things do slip through the best of systems.

['The Gaffer']

Its always the way with odd problems like that but I bet the garage never admitted they were wrong and offered the money back

[Iancider]

Answering two in one:

The tyres have not been punctured or repaired and they are textile lay-ups.  Teh one that was troublesome did have a slow puncture though but through the rubber and not due to perforation - even worse!  Having identified one defective tyre it is now apparent that there is another that is less seriously defective at the rear - possibly both.  I still get a shake for the rear and it is variable and it is possibly when both tyres synchronise. There are clearly defective tyres and I will be complaining to Michelin.

With the garage, they are genuinely embarrassed about this and will be offering me a substantial discount on the work - a dodgy CV did seem the most like when the tyres were initially cleared as okay.  The distortion is very hard to see on the static tyre but it balloons and slaps the road as it rotates.  It is obvious when you film it with a Go-Pro but that is not an everyday type of test.

Tyre manufacturers should not be selling dodgy tyres.  These were not cheapies nor were they remoulds but they were VR rated high speed tyres.

Ian