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 [Alignment Guide/General Discussion], How to interpret wheel alignment number?

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dwRK
post Jan 2 2021, 03:04 PM

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QUOTE(zeng @ Jan 2 2021, 11:40 AM)
6UEST , you're absolutely right in your assessment .

However, one of the two things I don't sense 'right' (or raising some of my doubt) was about achieved angle readings in Camber .

Yes LF camber positive 0°15' and RF negative 0°15'(at border of limits) are both complying with specs .

Besides , the Cross Camber (LF minus RF) of positive 0°30' also is complying with specs .

However , the LF positive Camber in combination with RF negative Camber may or may not promote pulling left .

Considering our road crown is higher on the RHS slanting downwards towards the LHS of the road , this may further promote pulling left , or it may not ?

True enough after about a week of driving with the alignment angles , the vehicle quite consistently is pulling left on straight highway driving .

Further , it is annoying to me that this alignment job was incomplete as pointed out by you whereby the  Caster angle was not measured and displayed ......
which may or may not help to explain the pulling left .

Agree with you on toe readings , which are quite desirable .

For now, I'm a bit 'suspicious' on one aspect of the spec limits displayed though Toyota should have done extensive tests/research to come up with this limits .....
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nobody measures caster... it cannot be adjusted normally... it's only a problem if involved in a big accident

pulling left or right can be tyre related...I changed 4 new tyres, alignment done, but car pull to left...swap tyre left to right solved the problem

pulling one side can also be torque-steer problem...this affects both acceleration and to a degree deceleration

imho your alignment too neutral... easy to drift, not stable at high speed...ok for urban driving... the marginal non symmetric camber is not a problem

btw... didn't you post somewhere last time that you are not a fan of tyre alignment and rotation? anyways not important...
dwRK
post Jan 4 2021, 12:35 PM

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QUOTE(zeng @ Jan 4 2021, 11:11 AM)
Yes @dwRK I used to consider myself as being not a fan of tyre alignment and rotation till todate .

Subsequent to my previous wheel alignment 3.5 years ago post front axle tyres replacements ,about a year later my mechanic did advise me to do another wheel alignment after changing some front suspension parts (not sure whether it is cheapo absorbers or absorber links etc ) .

However as typically , I did not follow through with the alignment advice as I felt vehicle handling/cornering was ok and fine .

This may help explain why about a year ago , I began feeling unsteady/unstable steering wheel during cornering into Right ...... probably caused by and related to out of spec alignment angles .

If not for the recent 'major' front suspension parts replacement and I was troubled by the real 'lousy' right turn cornering and pulling left , I wouldn't have visited this alignment shop .

As regards current alignment values as being too neutral .... easy to drift and unstable at high speed .......
I think you could be right about it including the marginal assymetric camber angles not being a problem .

Do you think an inappropriate or less than 'ideal' non-adjustable front caster angles could lead to my current 'complaints of annoyance' ???  .

I think you are right in suggesting the 3.5 year olds 'worn' front tyres could cause pulling to one side here ......

Unfortunately caster angles are not being checked and measured here , accepting the scenario that Caster angles on Avanza can't be adjusted .

On torque-steer / acceleration/deceleration  , I would need to google to read up more about it and appreciate your highlighting of it . 

Oh no ... the pulling left phenomenon that I tested occurs at straight ahead driving at a constant road speed of 80/90/110 km per hr , not really during acceleration/deceleration , if that matters .

Quantitatively , I would say my Avanza pulling left fully occupying/blocking neighbouring lane completely in about 6-8 seconds after hands off steering wheel whilst traveling at 90 km/hr .
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no worries mate... as long as we open to learning and get smarter...

don't worry about caster angle, by process of elimination...it wasn't a problem before wink.gif ...and it won't change unless car got banged up... caster angles affects steering feel and how the car gets back to center... this is not your problem

since you done major repair, i'd assume its not a mechanical issue anymore with lower arm, etc...

too neutral alignment means... suka suka drift left...suka suka drift right.... your's is pulling left all the time... so for now don't worry about alignment yet...

so the common problems are...1) tyre related, new tyre or old tyres can both cause the symptom due to conicity. 2) steering related, can be leaky internal o-ring, clogged channel or worn gears, causing imbalance L-R force making car pull left. 3) brake drag.

torque steer can occur at constant speed...its just exaggerated during hard accelerations...
dwRK
post Jan 7 2021, 03:50 PM

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we experienced petrolhead just worked with the alignment guys to set to whatever our fancy... no need rely on machine database

new tyres camber sometimes -1.5 to have some high g fun... old tyres -0.5 to even out wear
dwRK
post Jan 9 2021, 03:22 PM

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QUOTE(zeng @ Jan 9 2021, 01:24 PM)
Thanks .... a good ballpark range of camber angles to work with , I suppose  .
In your experience , is -0.5° camber edge wear easily noticeable by eye sighting or it can only be felt by running hand fingers/palms over tyre surface to 'feel' the wear or no edge wear indication at all ?
A -1.5° camber would give visually noticeable wear indications I guess ...... what about -1° camber wear , can it be seen with naked eyes too ?
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-0.5 is not really a lot, will take quite a bit of time to see uneven inner-outer wear, best is measure thread depth. just remember thread depth can be different for each of the longkang when new, so best keep a record if really serious

for the front, the kingpin angle changes camber angle as you corner, so if -0.5 matches your driving style, you will get even wear. it can wear more on the inside if your mileage is 99% straight line, or more outside if your journey has lots of cornering. there is no one size fits all... but -0.5 is good start and future can adjust from there

running hand around tyre is to check for wave pattern...this indicates absorber problem, nothing to do with alignment

This post has been edited by dwRK: Jan 9 2021, 04:07 PM
dwRK
post Jan 9 2021, 03:35 PM

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this was my front tyre... inner wear from -1.5 camber/toe in, outer wear from hard cornering... overall quite even wear as you can see from center treads

noobs might think this is under inflated tyre so the wear is on the edges... it's not...I pump it 36 psi, lol

this tyre done over 70k km, and rotated twice... my setting now quite neutral about -0.6 to get more center wear whilst waiting for new tyres launch this year...

user posted image

This post has been edited by dwRK: Jan 9 2021, 03:44 PM
dwRK
post Jan 9 2021, 04:25 PM

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your car keep pulling left... what we also don't know is the rear tyre alignment ok or not? yes I know torsion beam nothing to adjust... but if you hit potholes it can lari cause your car to drift also

it won't affect turn left vs turn right steering feel... for that my wild guess is you're on old tyres that have developed strong conicity due to previous suspension problems and lack of rotation
dwRK
post Jan 9 2021, 08:45 PM

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QUOTE(zeng @ Jan 9 2021, 05:26 PM)
Brilliant ........ a picture speaks a thousand words .

You gave me a superbly useful idea here in taking pictures periodically on tyre conditions with attached remarks (as I did with my engine oil blotter spot tests ) ..... as a way of observing and keeping track of developments surrounding alignment angles selection choices and and tyre  wear trending .

The inner edge pattern has a marginally great wear than that of the outer edge . Granted your specific driving pattern and respective proportion of mileages on straight ahead vs cornering/curved roads , I would speculate this inner edge wear is solely attributed to the 'excessive' camber angle of -1.5° , assuming your toe in has never gone into negative toe out during the 70K km usage AND underinflation has never occurred which I suppose is highly likely  . Not sure if you would agree with .

On outer edge wear , I beg to differ from you and wish to argue that it is not contributed by hard cornering as you proposed but 'solely' caused by toe in over huge amount of straight  ahead driving ? I am ignoring quantitative amount or causes of wear within region 5-10 mm from the outer edge sidewall .

dwRK, can you share the amount of toe in as 'installed' then ?

As regards pumped pressure of  36 psi , may I know what is the factory recommended psi for said vehicle ?
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toe is usually very small... around 0.3~1 mm... don't need much & I don't pay too much attention to it, just making sure its +ve or -ve as appropriate

my tyre wear actually suggests my -1.5 camber is not enough, should not be wearing the outside edges too much but I'm reluctant to go higher. fyi hard cornering wear both inner and outer edge...depending on inside/outside wheel... and rwd cars wear slightly different from fwd cars

my car spec is 34... I pump 35-36 for better handling because I have a soft sidewall tyre

This post has been edited by dwRK: Jan 10 2021, 07:28 AM
dwRK
post Jan 21 2021, 03:42 PM

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QUOTE(zeng @ Jan 20 2021, 09:11 PM)
Yeah agree that the 0.3~1 mm toe is very negligible indeed .

This value may translate into 0.05-0.10° depending on tyre size .If it is a -ve toe out (instead of toe in) and in a RWD then it may have no role in your tyre outer edge wear above . In this scenario inadequate -ve camber of -1.5° would likely be the culprit for the outer edge wear .

Btw, is the drive a RWD or FWD ?

Yep agree that both inner and outer edge wear could happen to inside/outside wheels  in a hard cornering indeed .

Hmm... -1.5° camber may be too negative a value for an Avanza that allows up to a 'minimum' of  -0.25° (aka -0°15') . However ,I may consider more negative camber than spec should my tyre wear pattern 'allows' it , who knows .

At 36 psi for a spec'ed 34 psi application, it would likely rule out 'underinflation' issue in assessing your tyre wear pattern, I suppose .
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no need to help analyse my tire wear...no problem here, i just showing as example... 6uest took one look and say same type of wear as his rwd mark x cool2.gif

your average fwd cars don't need so much -ve camber because the kingpin and caster angles are not very high...all these work together and they are designed for city driving, not performance handling... -0.5° should be plenty, then readjust during next rotation...
dwRK
post Jan 21 2021, 03:57 PM

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your videos are a good start...

here watch these for more in-depth understanding

first of a series of 3 videos...


the dynamics of it...


 

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