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View Full Version : Rollin on 18s...egg shape style



Anon
16-04-2009, 07:26 PM
So...I thought I'd share this weeks little dilema.

For a while I've had this persistent vibration in the rear. It's been slight but getting worse and worse. Sometimes it was worse then others. Previously I had a tyre wear unevenly on the rear, as in wore more on one spot of the tread than anywhere else. I had the rears replaced, the old fronts put to the rear and new tyres put on the front. I thought perhaps the same thing was happening and was beginning to suspect a warped disc catching on one part of the rotation, thus causing more resistance and a slight drag, so more wear. As things get progressively worse slowly over time, you get immune to what should be normal so I thought a lot of the vibration was just the harder springs going over the high frequency bumps in the road. Even though I had looked my tyres all thoughout this, they looked fine. I was just looking for uneven wear. Yesterday I just caught the tyre at a certain angle...and what I saw scared the **** out of me. The right rear tyre had 'bubbled' or 'ballooned' out on a portion of the tread. The bubble ran for about 1/5 of the circumference of the tyre, and ran to the centre line of the tread. Looking at the tyre facing along the line of the tread, the inner half of tread would be straight, at the centre line it stepped up about 15mm to where it ballooned out, and was reasonably flat again out to the edge.

I went straight to the place I bought the tyres from and had them look at it. They too had a 'wtf' response and rang the rep and said to come back tomorrow so the rep can look at it. So today I went back and the rep was there. He looked at it and even though he didn't speak to me or give his opinion on what could have happened (quite rude really) he was obviously of the opinion that something wasn't right. The tyre chalk came out and the bubble outlined was traced. I pointed out that the other side doesn't look too good either, and sure enough the same had happened to the other side, but to a lesser degree (the step was perhaps 7mm and 1/6th of the circumference, but the same area from the the outside edge to the centreline of the tread). Since they were some what worn (they assessed 50%), they gave me a 50% discount of the value of the old tyres on the replacements. While the tyres were off and I wasn't interested in driving on them any further, I got two new Ecstas put on (same as the front).

I asked the the guy at the tyre shop whether he had seen it before, and he said 1 was rare, but never 2. He said the rep reckoned I had punished them and been 'drifting' given the rubber was burring/balling on the edge of the tyre. My response was...wtf...its a front wheel drive, how can I drift. wtfbbq..its a ****in Magna!! The tyre is sold as a 'performance' tyre, and yes I do push it to understeer every now and then (not too hard on that tyre, a lot more effort is needed on the Ecstas. How can they sell a tyre as a performance tyre, then whinge when its used for its purpose.

Anywho, the vibration rock n rolling is fixed, and literally feels like I'm driving on carpet. Only with gone do I released how bad it was. It will be interesting to see how the new tyres fair on the rear.

MadMax
16-04-2009, 07:35 PM
The rubber has let go of the underlying belts. Tyre pressures may have something to do with it, or they may just have been crap tyres, or good tyres ruined by incorrect manufacturing temperatures or materials. There was a whole batch of Chinese made tyres imported into Australia in the news a while ago where the manufacturer had skimped (ie left out) some important process or material - can't remember the exact details. Try running the new tyres (and old) at the recommended pressure for the tyre.

AND STOP that naughty drifting you have been doing!

Anon
16-04-2009, 07:53 PM
All tyres are running at 40psi, which I believe is about right for that rim size and tyre.

Actually, I left the handbrake on for 15,000km..silly me.

EZ Boy
16-04-2009, 08:24 PM
Actually, I left the handbrake on for 15,000km.. And was probably still slaughtering falcodores

MAD35L
16-04-2009, 09:08 PM
And was probably still slaughtering falcodores

ease up!

Alan J
17-04-2009, 03:40 PM
This sort of issue with tyres "egging" is more common than tyre shops let on. Even some very good brands do it quite badly. I phoned Bob Jane a few weeks back looking for a particular size Maxxis and there were no stocks, but they could get Goodyear F1 GS-D3 in that size. I asked if they were Japanese or German made. Answer German. OK next question "how many have you had go out of round recently?" Answer "we've had a couple". If they had been Japanese then I knew they would have been OK. I've never had a Japanese tyre go eggy, nor a Maxxis (don't know about the Chinese ones, but Maxxis from Taiwan/Thailand never had a problem) nor Michelin.

A quick test for eggy tyres is to put your hand across the tread after a normal drive. Any tyre that is much hotter will have eggs, that's assuming the pressures are OK.

The eggs happen due to poor carcass quality. The tread piles start tearing apart, so the tyre goes out of shape. If you pull the tyre off the wheel you will find inside it feels mushy rather than stiff in the eggy areas.

Cheers,
Alan

HyperTF
17-04-2009, 04:16 PM
I think the rep should count himself lucky that you didn't take the matter further, but of course the first thing to do is deny accountability :roll:

A company rep saying "Hey, it looks like you have been drifting to me" knowing fully well that you haven't would be enough for me to snub that maker and poo poo them to other people

whereas saying "That shouldn't happen with our quality control standards, we'll give you free replacements and I will check it out and let you know what I find." would restore my faith in their commitment to their products and make me want to commend their service to others.

Replacing a couple of tyres out of goodwill would be nothing to them... what a joke.

EZ Boy
18-04-2009, 02:33 PM
:stoopid: