scrubbing rear tyres

[alfmech]

hi guys

i have a 55plate 130ps mk2 galaxy that has chewed the inner shoulders off of both rear tyres,
the tyre pressures are/were well maintained throughout
they are both extra load tyres and the rest of the tyre is still in very good order with no lumps or deformations there are no horrible vibrations or shimmying to indicate a problem
the car handles very well as always
the car rarely carries more than a driver and occasionally a pair of labradors.
the rearmost seats are never fitted so not carrying much load
i have jacked up the car and checked for play in any direction and can find nothing not even slightly

my question is.....what am i missing???
could rear arms be bent from all the potholes in this area? (if so wouldnt that just affect the NS of the car as that takes the hammering)

there is no adjustment for caster camber angles for the rear

any ideas/suggestions would be very welcome,

P.S just in case does anyone have a known straight set of rear arms?

[insanitybeard]

Greetings!

When you say the inner shoulders have gone, can you post a picture for example to show how bad the shoulder is in comparison to the rest of the tread? What sort of mileage have they done and whose tyres are they? Are both sides worn in exactly the same way?

[alfmech]

when i say gone i mean cords showing over approx last inch of tyre compared to 6mm+ over remainder of tyre

[insanitybeard]

So that's firmly in the something majorly wrong category then.

Are both rear tyres worn exactly the same? Have they both been fitted in the same position for their entire working life and how many miles have they done? Has the vehicle suffered any previous collision damage that you're aware of?

[alfmech]

the car was bounced out of a pot hole this time last year that smashed the nsf wheel and tyre the whole car was carefully examined all over, new wheel and tyre and re-tracked afterwards.

the rear tyres were replaced about 2 years ago the old ones were worn fairly evenly down to wear marks so nothing apparently wrong at that point.

the car has done very little mileage in last 2 years mainly due to health issues and also having another vehicle to hand maybe 5,000 if that.

MOT in feb no problems i was with the vehicle and checked myself aswell so am sure it wasnt overlooked and they seemes pretty much fine then.

the car has only been used for local pottering about and taking dogs to forest since and definatly no accidents or impacts in that time

noticed last week that nsr tyre was flat removed it to put on the spare and spotted cords. checked the other side and its almost a mirror image both inside edges completly shot showing cords

[insanitybeard]

Not that it really matters, but what manufacturer's tyres are they? It's certainly not a common problem, how many miles has the vehicle done? So the previous pot hole damage only affected one of the front wheels, in which case I wouldn't expect it to have a bearing on this problem. Without being able to look at the vehicle directly it's hard to say but I'd start by checking that the rear dampers aren't knackered/ leaking, and a good check of the rear anti roll bar and trailing arm bushes, and rear suspension in general for security of all items and any damage.

Although the rear suspension may not be adjustable, I'd consider getting the geometry checked anyway to see if anything is obviously out of spec. For this kind of wear to occur something would have to be pretty bad.

[alfmech]

thanks for the tips i will re-check those bits over the weekend and try and find someone locally to check 4 wheel alignment

the tyres were pirelli but cant remember which ones

i will report my findings asap thanks again for the hints

[alfmech]

udate.

first off sorry for the delay getting back on here real life in the way as usual.

after finding nothing visably wrong anywhere we would have expected and finding all bushes intact and in good order i booked it in for 4 wheel alignment check.

the machine says the o/s/r arm is bent and in need of replacing, so now the car is out of commission while i source a replacement rather than buying new at 525+vat i have ordered one from a reputable breaker who is prepared to guarantee its straight(he is willing to refund or exchange if it isnt)

so now i wait patiently while it is delivered to me
once it is fitted i will get the car re-checked for alignment and fingers crossed i can report back some good news.

thanks for your help and advise

[insanitybeard]

I'm assuming that means one of the rear trailing arms (number 1 on this parts diagram) is bent as opposed to the actual crossmember (number 2 on same diagram). Either way, those arms are pretty meaty, it must have taken some force to bend it! Five hundred quid plus VAT for a new one, that's madness. And that's coming from somebody who was a former partsman! 

[alfmech]

finally a positive update

i replaced the suspect rear arm with one from another vehicle only to take it for re-alignment to find it was exactly as bent as before, i then purchased the rear subframe from the same vehicle and low and behold its straight again!!! yay

i did compare old to new subframe on the floor and could see absolutly no difference no impact marks or cracked paint so i have no idea what was bent i just know it was

thanks to all for the input i am now a happy(ish) galaxy driver again