Astra excessive rear tyre wear

[BrianJP]

Hi, I have an 2004 Astra convertible that has suddenly started to suffer from excessive rear tyre wear on the inner edges to the extent that the n/s tyre has almost lost its shoulder .The wear looks feathered.The vehicle has not been in any accident nor driven hard over potholed roads or speedbumps. It was recently tracked when the front tyres were replaced and at that time the rears were ok although the n/s looked as though it was just starting to go on the inside. I know I will probably have to have the vehicle checked on 4 whel alignment as I had a similar problem a few years ago on a Mondeo.But as the rear suspension of the Astra is basically a fixed set up does anyone have any ideas what the likely cause is.

 

thanks

[Tony]

Hello

Has the car been lowered...... Also is the steering position straight when driving straight?

[BrianJP]

Hello

Has the car been lowered...... Also is the steering position straight when driving straight?

Nope car has standard set up and steering is straight.

As I said previously this has just happened suddenly.

 

thanks for reply

[Tony]

Hello

Has the car been lowered...... Also is the steering position straight when driving straight?

Nope car has standard set up and steering is straight.

As I said previously this has just happened suddenly.

 

thanks for reply

 

So both rear tyres are showing signs of lateral wear but one in particular?

 

The "feathered wear" can you feel this over the entire tread area.... If no what area do you feel is feathered... 80%...50%?

[BrianJP]

Hello

Has the car been lowered...... Also is the steering position straight when driving straight?

Nope car has standard set up and steering is straight.

As I said previously this has just happened suddenly.

 

thanks for reply

 

So both rear tyres are showing signs of lateral wear but one in particular?

 

The "feathered wear" can you feel this over the entire tread area.... If no what area do you feel is feathered... 80%...50%?

 

Difficult to be accurate as car is sitting on the ground, but I would say that both tyres have feathered wear over entire circumference.n/s worse than o/s. but on both tyres particulary again on the n/s there is greater wear on about 25% of the circumference with what appears to be a groove developing on the shoulder.

thanks

[Tony]

Hello

Has the car been lowered...... Also is the steering position straight when driving straight?

Nope car has standard set up and steering is straight.

As I said previously this has just happened suddenly.

 

thanks for reply

 

So both rear tyres are showing signs of lateral wear but one in particular?

 

The "feathered wear" can you feel this over the entire tread area.... If no what area do you feel is feathered... 80%...50%?

 

Difficult to be accurate as car is sitting on the ground, but I would say that both tyres have feathered wear over entire circumference.n/s worse than o/s. but on both tyres particulary again on the n/s there is greater wear on about 25% of the circumference with what appears to be a groove developing on the shoulder.

thanks

 

Anything like one of these?

 

1>

 

2>

 

3>

 

4>

[BrianJP]

hi

 

doesnt really look like any of these at the moment but I guess if anything if left it would end up like pix 3

[Tony]

hi

 

doesnt really look like any of these at the moment but I guess if anything if left it would end up like pix 3

 

That type of wear is camber (deviation from vertical) and confined to a small percentage of the tyres total width.

 

As you know the Astra has a fixed "I" beam rear axle with independent coils and oils. The arrangement is not subject to camber gains like multi link suspension systems so we have to assume there has been some form of trauma to the axle.

 

Since the wear is on the inners then the beam cannot be bent due to a jacking error.... and since both tyres have wear on both inners then we can assume the beam is still aligned parallel to the front axle.

 

Tricky one.......

 

In the absence of any mechanical defects or explanation to why this condition exists our only option is what to do about it?

 

A Geometry will open pages to assist but in the worst case scenario the hubs can be shimmed to re-gain the camber... I really feel you need to have a Geometry test... costs around £30 and we can go from there

[BrianJP]

hi

 

doesnt really look like any of these at the moment but I guess if anything if left it would end up like pix 3

 

That type of wear is camber (deviation from vertical) and confined to a small percentage of the tyres total width.

 

As you know the Astra has a fixed "I" beam rear axle with independent coils and oils. The arrangement is not subject to camber gains like multi link suspension systems so we have to assume there has been some form of trauma to the axle.

 

Since the wear is on the inners then the beam cannot be bent due to a jacking error.... and since both tyres have wear on both inners then we can assume the beam is still aligned parallel to the front axle.

 

Tricky one.......

 

In the absence of any mechanical defects or explanation to why this condition exists our only option is what to do about it?

 

A Geometry will open pages to assist but in the worst case scenario the hubs can be shimmed to re-gain the camber... I really feel you need to have a Geometry test... costs around £30 and we can go from there

 

ok thanks for the input.

much as I have been suspecting.

added problem is that the vehicle is now in Spain and this wear has materialised during the journey out here.

I am sure I can find somewhere here to do a geometry check but obviously this is an added complication.

I may be over re-acting as the wear is nowhere near as bad as in your pix yet( although almost UK illegal) .But since the tyres will have to last for 1600mls return to UK plus mileage here I would have to replace these tyres at very least before returning home hence my reasons for trying to resolve the matter first here.

cheers

[Tony]

Sometimes all we can show is the facts, not the reason. Often customers say "I've not hit a curb or pothole", well we never said you did but the chassis is distressed whatever.

 

The situation with your Astra exists whatever so all we need to do now is form a solution.... In truth once an image of the chassis is made then the solution should be pain free

[NickT]

Wouldn't the wear in pic3 also come from a broken coil spring (near the top) causing it to drop slightly increasing negative camber, or fitting aftermarket alloys with the incorrect offset?

 

NickT

[Tony]

Wouldn't the wear in pic3 also come from a broken coil spring (near the top) causing it to drop slightly increasing negative camber, or fitting aftermarket alloys with the incorrect offset?

 

NickT

 

Broken coil no, incorrect off-set yes...... But you would expect the handling to be pants.

[BrianJP]

Wouldn't the wear in pic3 also come from a broken coil spring (near the top) causing it to drop slightly increasing negative camber, or fitting aftermarket alloys with the incorrect offset?

 

NickT

 

Broken coil no, incorrect off-set yes...... But you would expect the handling to be pants.

Hi again

I have a pix that shows wear reasonably clearly but cannot see how to upload into post.If its poss can you tell me how to do it.

cheers

Brian

[Tony]

Wouldn't the wear in pic3 also come from a broken coil spring (near the top) causing it to drop slightly increasing negative camber, or fitting aftermarket alloys with the incorrect offset?

 

NickT

 

Broken coil no, incorrect off-set yes...... But you would expect the handling to be pants.

Hi again

I have a pix that shows wear reasonably clearly but cannot see how to upload into post.If its poss can you tell me how to do it.

cheers

Brian

 

You need an external link like photo-bucket.... Or become a Gold member here

[BrianJP]

Wouldn't the wear in pic3 also come from a broken coil spring (near the top) causing it to drop slightly increasing negative camber, or fitting aftermarket alloys with the incorrect offset?

 

NickT

 

Broken coil no, incorrect off-set yes...... But you would expect the handling to be pants.

Hi again

I have a pix that shows wear reasonably clearly but cannot see how to upload into post.If its poss can you tell me how to do it.

cheers

Brian

 

You need an external link like photo-bucket.... Or become a Gold member here

Ok thanks here goes if it can be seen pix shows nsr tyre of vehicle in question from the front side.

Shoulder wear can just be seen on left of pix .see link below

http://i279.photobucket.com/albums/kk157/b...008/Misc826.jpg.

 

hopefully this still ties in with your previous opinion.

 

thanks

[Tony]

That type of wear is camber....Albeit gentle.

 

Manipulation of the tyre pressure will reduce the damage, other than that we are talking shim kits... In truth the amount of loss verses the cost of shimming the hub is an easy call.

 

I would up the pressure.... monitor the wear then once visibly worn have the tyres rotated on the rim.

[BrianJP]

That type of wear is camber....Albeit gentle.

 

Manipulation of the tyre pressure will reduce the damage, other than that we are talking shim kits... In truth the amount of loss verses the cost of shimming the hub is an easy call.

 

I would up the pressure.... monitor the wear then once visibly worn have the tyres rotated on the rim.

 

Thanks for further input Tony I will try that as I dont have much to lose. Standard pressure on rears is 28psi and max 39 so I guess somewhere midway would be a good start ?.As inner edge on n/s is already down to around 1mm in places I suppose it might be the time to have the tyres turned now but as they are directional this means swapping n/s for o/s.

thanks again and any further advice would be appreciated.

Brian

[Tony]

That type of wear is camber....Albeit gentle.

 

Manipulation of the tyre pressure will reduce the damage, other than that we are talking shim kits... In truth the amount of loss verses the cost of shimming the hub is an easy call.

 

I would up the pressure.... monitor the wear then once visibly worn have the tyres rotated on the rim.

 

Thanks for further input Tony I will try that as I dont have much to lose. Standard pressure on rears is 28psi and max 39 so I guess somewhere midway would be a good start ?.As inner edge on n/s is already down to around 1mm in places I suppose it might be the time to have the tyres turned now but as they are directional this means swapping n/s for o/s.

thanks again and any further advice would be appreciated.

Brian

 

Your welcome

[BrianJP]

That type of wear is camber....Albeit gentle.

 

Manipulation of the tyre pressure will reduce the damage, other than that we are talking shim kits... In truth the amount of loss verses the cost of shimming the hub is an easy call.

 

I would up the pressure.... monitor the wear then once visibly worn have the tyres rotated on the rim.

 

Thanks for further input Tony I will try that as I dont have much to lose. Standard pressure on rears is 28psi and max 39 so I guess somewhere midway would be a good start ?.As inner edge on n/s is already down to around 1mm in places I suppose it might be the time to have the tyres turned now but as they are directional this means swapping n/s for o/s.

thanks again and any further advice would be appreciated.

Brian

 

Your welcome

 

just one last question on this subject.

Does vehicle speed have any effect on the rate of wear with a camber problem such as this ?

The reason I ask is that when I first noticed the sudden wear on the journey to where I am now I had covered over 500mls in France at avge speeds up to 130kmh.Following this I reduced my speed to around 110kmh

mainly for safety reasons as at that stage I had no idea how much more the tyre would wear on the edges.At the start of the journey I had also increased the rear tyre pressures to 32psi as I was carrying a (although not particularly heavy) bootfull of luggage.

By the time I had arrived at my destination after a further 1000mls ,having checked the rear tyres at regular intervals the wear did not appear to have increased by a huge margin which lead me to conclude that either speed or some other factor had changed the situation.The car incidently drives and steers normally with no abnormal noises.

thanks

Brian

[Tony]

Speed would affect the camber if the suspension was multilink.

 

On your car you have a beam axle and independent coil/ oil so there are no camber gains.