Alignment causing out of round tyres?
Discussion
Took my GTM Libra for its MOT this week - always a bottom clenching time the first time a car is in your ownership! (At least for me, even after doing the basic checks).
Passed with a couple of advisories (catalytic converter is snagged, which I knew about and it's unnecessary so will be replaced with a decat pipe), very slight oil leak (my own fault and sorted today), but the one that surprised me was that the inside edge of the front tyres are out of round.
I'd noticed a slight vibration through the steering wheel at a bit more than my usual motorway speeds, but put it down to slightly out balancing. Tester (who was brilliant, would recommend them to anyone near Southampton) suggested it was due to slightly out camber alignment.
I can understand uneven wear across the face of the tyre due to poor alignment, but out of round? How does that work?!
Also, suggestions to resolve? It's going to have a full alignment at a Libra specialist in a month or two along with a few other bits and pieces - should I replace the tyres, or will they resolve themselves with proper alignment?
As said, it's only noticeable in driving I rarely do, under usual conditions there's nothing untoward at all, so want to be fairly pragmatic about it, without impacting the ride/handling/safety.
Cheers!
Passed with a couple of advisories (catalytic converter is snagged, which I knew about and it's unnecessary so will be replaced with a decat pipe), very slight oil leak (my own fault and sorted today), but the one that surprised me was that the inside edge of the front tyres are out of round.
I'd noticed a slight vibration through the steering wheel at a bit more than my usual motorway speeds, but put it down to slightly out balancing. Tester (who was brilliant, would recommend them to anyone near Southampton) suggested it was due to slightly out camber alignment.
I can understand uneven wear across the face of the tyre due to poor alignment, but out of round? How does that work?!
Also, suggestions to resolve? It's going to have a full alignment at a Libra specialist in a month or two along with a few other bits and pieces - should I replace the tyres, or will they resolve themselves with proper alignment?
As said, it's only noticeable in driving I rarely do, under usual conditions there's nothing untoward at all, so want to be fairly pragmatic about it, without impacting the ride/handling/safety.
Cheers!
littleredrooster said:
Worn ball-joints or bushes can cause this.
This & toe out.The toe out wears the inside edge of the tyre, full circle. Any wear in any steering or suspensions components will allow the thing to grip alternately on either wheel. This will generate a scalloped wear pattern on the edge of the tread.
If your wobble is small magnitude high frequency it will be due to balance. If it is due to toe out, it will be larger magnitude, low frequency.
The tester may well be correct. This can be caused by excessive negative camber - quite common on Mk1 Audi TT rear tyres which have a pronounced negative camber. When people lowered their suspension the negative camber increased out of spec and the inner edges of the tyre began to wear the individual tread blocks unevenly - the font of each tread block wore more than the rear of each tread block giving a 'feathered' and 'out of round' appearance.
I would suggest a full suspension alignment check/adjustment is in order.
I would suggest a full suspension alignment check/adjustment is in order.
Garvin said:
When people lowered their suspension the negative camber increased out of spec and the inner edges of the tyre began to wear the individual tread blocks unevenly - the font of each tread block wore more than the rear of each tread block giving a 'feathered' and 'out of round' appearance.
That's quite a common wear pattern even on non-lowered cars, some tyres are more susceptible to it than others. However it doesn't cause the tyre to go out of balance, it just makes an annoying droning noise that sounds like a wheel bearing.Uneven circumferential wear can be caused by knackered dampers or worn suspension joints/bushes as others have mentioned.
The other possibility that shouldn't be ignored is the wheels themselves being bent.
Edited by Mr2Mike on Saturday 28th June 12:27
Mr2Mike said:
Garvin said:
When people lowered their suspension the negative camber increased out of spec and the inner edges of the tyre began to wear the individual tread blocks unevenly - the font of each tread block wore more than the rear of each tread block giving a 'feathered' and 'out of round' appearance.
That's quite a common wear pattern even on non-lowered cars, some tyres are more susceptible to it than others. However it doesn't cause the tyre to go out of balance, it just makes an annoying droning noise that sounds like a wheel bearing.Uneven circumferential wear can be caused by knackered dampers or worn suspension joints/bushes as others have mentioned.
Interesting chaps, thanks.
I'm fairly certain it's not dampers - they're only 18k miles old and appear in perfect condition.
Bushes I'd be surprised about, for the same reasons.
Still worth some investigation though.
The Libra uses custom fabricated wishbones, and is normally mounted with 14-16" wheels. Due to the size of my front brakes, it's running 17",with pretty much zero clearance between caliper and wheel (MGF Trophy AP Racing four pots, with I think 320ish mm discs. I wonder if the wheel size is causing an increase in camber?
As said, alignment is on the cards in a couple of months time (I will only use Dudley the Libra guru for that sort of job). Perhaps if it is the wheels I could get new wishbones made up to correct the geometry...
Food for thought, will have the front clam open this afternoon so will have a look and take some pics for your opinions.
I'm fairly certain it's not dampers - they're only 18k miles old and appear in perfect condition.
Bushes I'd be surprised about, for the same reasons.
Still worth some investigation though.
The Libra uses custom fabricated wishbones, and is normally mounted with 14-16" wheels. Due to the size of my front brakes, it's running 17",with pretty much zero clearance between caliper and wheel (MGF Trophy AP Racing four pots, with I think 320ish mm discs. I wonder if the wheel size is causing an increase in camber?
As said, alignment is on the cards in a couple of months time (I will only use Dudley the Libra guru for that sort of job). Perhaps if it is the wheels I could get new wishbones made up to correct the geometry...
Food for thought, will have the front clam open this afternoon so will have a look and take some pics for your opinions.
Sway said:
. . . . . I wonder if the wheel size is causing an increase in camber . . . . . . .
I can't see how the wheel size would change the camber! I doubt very much that you need new suspension arms made up. Does it have fully adjustable suspension? If so a simple adjustment should do the job.It's a widespread problem, often on rear tyres and may be more common on VAG cars than others. Lots of internet references to it: https://www.google.co.uk/webhp?hl=en&tab=iw#hl...
Garvin said:
Sway said:
. . . . . I wonder if the wheel size is causing an increase in camber . . . . . . .
I can't see how the wheel size would change the camber! I doubt very much that you need new suspension arms made up. Does it have fully adjustable suspension? If so a simple adjustment should do the job.Cheers! As you may have noticed by now, I have little clue regarding suspension geometry, which I should probably rectify!
As long as it goes well round corners and rides well, I'm happy. The difficulty (which I've probably created for myself) is that as it's a bit unusual I only want to take it to those with knowledge and experience of them. Engine/electrics etc. then I have far more comfort in a decent mechanic.
As long as it goes well round corners and rides well, I'm happy. The difficulty (which I've probably created for myself) is that as it's a bit unusual I only want to take it to those with knowledge and experience of them. Engine/electrics etc. then I have far more comfort in a decent mechanic.
Sway said:
Cheers! As you may have noticed by now, I have little clue regarding suspension geometry, which I should probably rectify!
As long as it goes well round corners and rides well, I'm happy. The difficulty (which I've probably created for myself) is that as it's a bit unusual I only want to take it to those with knowledge and experience of them. Engine/electrics etc. then I have far more comfort in a decent mechanic.
I would venture that 99.9% of the motoring public have absolutely no clue when it comes to suspension geometry so I can assure you that you're not in a minority! If you have a well respected local expert then, as you appear to be doing, leave it to them - particularly for kit cars. Describe the problem and I'm sure he'll sort the car out for you.As long as it goes well round corners and rides well, I'm happy. The difficulty (which I've probably created for myself) is that as it's a bit unusual I only want to take it to those with knowledge and experience of them. Engine/electrics etc. then I have far more comfort in a decent mechanic.
BTW, a properly set up suspension does more for handling than almost anything else! Coupled with excellent brakes, which yours appears to have, is the best way to spend money to get from a to b quicker.
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