[ElleB]

Hi all,
 I know that I have been inconsistent......missed the chat  but... life goes on !!

  My i30 is now just out of warranty and I have been trialing Mastercraft tyres on the car, guaranteed* for 70,000Km.. I recently had them rotated, by the type centre that fitted them and there was an immediate thump thump emanating from what was the rear tyres, now in the front...it was awful.
 I took it back and they checked and said that the rear tyres had been "flat spotted" as a result of rear shock failure, thus creating the "drumming" sound from the tyres. I had my doubts,, the car is only used 2 up and never carries much weight in the back ,, it is a wagon. I queried this with the tyre centre and they said that , as a result of the back running "light weight" the rear was "bouncing"even if it was not noticeable, thus having agradual and cumulative effect on the tyres which is now  heard as the thump or drumming sound.
I had the tyres immediately put back to the pre rotation settings and that reduced the effect up through the steering column, but is still audible from the rear.

   I will need new tyres in a month or so, but has anyone else had similar issues or can they vouch for this diagnosis being correct, re the rear shocks. ?  How about you Surfer dude ? Will I need to factor in new shocks as well 

Car has now done 118K.. easy rural driving...in fact we are still on the original rotors and brake pads. Also now due for a skim and pad change.
Cheers

 Tony

[Phil №❶]

So, are you going to get 70k or has your guarantee been voided, by this amazing story.

I have no technical background, but I find all that a little hard to believe and very convenient. You may wish to mention that of 5k + members of this forum, no one else has ever mentioned the same result, after a tyre rotation AFAIK.

Our car is using Bridgestone and also guaranteed 50k, I wonder if they'll trot this one out when our turn comes.

[Surferdude]

Hi all,
 I know that I have been inconsistent......missed the chat  but... life goes on !!

  My i30 is now just out of warranty and I have been trialing Mastercraft tyres on the car, guaranteed* for 70,000Km.. I recently had them rotated, by the type centre that fitted them and there was an immediate thump thump emanating from what was the rear tyres, now in the front...it was awful.
 I took it back and they checked and said that the rear tyres had been "flat spotted" as a result of rear shock failure, thus creating the "drumming" sound from the tyres. I had my doubts,, the car is only used 2 up and never carries much weight in the back ,, it is a wagon. I queried this with the tyre centre and they said that , as a result of the back running "light weight" the rear was "bouncing"even if it was not noticeable, thus having agradual and cumulative effect on the tyres which is now  heard as the thump or drumming sound.
I had the tyres immediately put back to the pre rotation settings and that reduced the effect up through the steering column, but is still audible from the rear.

   I will need new tyres in a month or so, but has anyone else had similar issues or can they vouch for this diagnosis being correct, re the rear shocks. ?  How about you Surfer dude ? Will I need to factor in new shocks as well 

Car has now done 118K.. easy rural driving...in fact we are still on the original rotors and brake pads. Also now due for a skim and pad change.
Cheers

 Tony

Tony, many tyre "experts" diagnose shocks as the cause of uneven tyre wear. Others place the blame on wheel bearings.
But in my experience, the most common cause is misalignment at the rear.

The wear you  are describing (although pics would help), was first evident on the rear of Minis when that funny box section rear end used to get out of kilter (although not often noticed because of the short life of the 10" tyres). Then it came to the fore with Ford Lasers and for months the tyre manufacturers caved in and replaced a lot of rear tyres as "policy" adjustments, until I was over at Q Ford Springwood one day and watched them unload a trailer full of new Lasers - undoing the chains they had stretched over the rear control arms.
We started insisting they actually re-align the rears before they went out and the problem went away - at least on new cars. Still see it today on FWD cars when the rear alignment has been out for a while.

What's happening is the rear tyres are dragging sideways across the road and trying to pull off the rim. Of course this can't happen so you get a cycle of the tyre pulling back across the bitumen to straighten itself. Thus you get a diagonal depression across the thread and generally one or two smaller ones either side of the main.

Hope this all makes sense.

Yes, the shocks could be causing or accentuating the problem but at 118,000 klms I'd be surprised if they are the cause.

More money to be made in replacing shocks than just doing a wheel alignment (I didn't say that).

[Surferdude]

So, are you going to get 70k or has your guarantee been voided, by this amazing story.

I have no technical background, but I find all that a little hard to believe and very convenient. You may wish to mention that of 5k + members of this forum, no one else has ever mentioned the same result, after a tyre rotation AFAIK.

Our car is using Bridgestone and also guaranteed 50k, I wonder if they'll trot this one out when our turn comes.

Pretty sure the issue of uneven wear on the rear has come up.
But to be fair to the tyre supplier, the wear such as being described here will be obvious to the naked eye. It's certainly not a tyre fault in that form. The "mileage" warranty of necessity must apply to evenly worn tyres.

And if the tyre construction was at fault, it's be evident on all four.

[ElleB]

Hi Phil, thanks for the pronto reply !!! Wow...and Surfer dude!!!   Thanks Guys..

Up till now the tyres were fine did give great life and gave a good ride and ll round performance. They still have plenty of meat left.
 So this drumming noise is definitely coming from the tyres that were on the rear.. so something has caused that to happen. I have not as yet gone direct to the tyre makers... and was wondering if I should get a Pedders type suspension check done, where the shocks are tested and we get a print out of their performance. I could then get some recommendations from them as back up.
 I am not looking form "stouch", just to know and thus let others know of the possibility and so on, in case others find the same thing. Of course I want to solve this before new tyres are needed of fitted.

The car has regular 10K alignment checks and has not been an issue since we fitted the camber kit at the same time as these tyres were fitted. Alignment has been very stalke and has not needed adjusting... Yes I have the print outs..

I will look closely at the tyres to see if I can find any tell tale signs as described by SD...but not right now, it is plus 40 degrees at the mo. !!!

BTW   initially I thought it was a balance problem and that is why I went back to my tyre guy to have it checked and the wheels rotated as per schedule.

Any comment welcome.


 FYI the distance on these tyres now is just a tad over 60K.

[Phil №❶]

60k & plenty of meat, still. That's pretty good.