Alignment before getting new tires

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Doesn't matter......... it's a wheel alignment and not a tire alignment.
But the tires could affect the wheel alignment just like a bent tie rod would. I could see if the old tires are worn unevenly they would sit differently on the alignment rack's turntables then new tires. Align with the old tires and then install the new ones and it then may wander or pull to one side or the steering wheel may not be centered again.
 

Jimmy_Russells

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FWIW here are the original tires that came on the car at 10k miles. I had the alignment checked at that time and it checked out alright, toe was close to zero on each side but the spec is quite narrow on this car. A lot of people on the RS3 forum had the same issue with theirs so I just chalked it up to something wonky with the OE tire. But now 14k miles later my Contis are doing something similar, but they are not down to cords yet. So it may just be normal.

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But the tires could affect the wheel alignment just like a bent tie rod would. I could see if the old tires are worn unevenly they would sit differently on the alignment rack's turntables then new tires. Align with the old tires and then install the new ones and it then may wander or pull to one side or the steering wheel may not be centered again.

measurements are taken on the rims, not the turntables.
 
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FWIW here are the original tires that came on the car at 10k miles. I had the alignment checked at that time and it checked out alright, toe was close to zero on each side but the spec is quite narrow on this car. A lot of people on the RS3 forum had the same issue with theirs so I just chalked it up to something wonky with the OE tire. But now 14k miles later my Contis are doing something similar, but they are not down to cords yet. So it may just be normal.

View attachment 87061

get rid of all toe, toe + negative camber can do this. both toe-out or -in. What happens when the suspension and drive train get loaded up?
 

Jimmy_Russells

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get rid of all toe, toe + negative camber can do this. both toe-out or -in. What happens when the suspension and drive train get loaded up?

Yeah I was under the impression before that only toe out would do this, but I don't think that is the case.

The S3 has a spec of something like 0.05 - 0.4 degrees per side, whereas the RS3 is 0.0 - 0.1, so they clearly want to keep it close to zero. Maybe mine is more positive now, I will get it checked out when I put the summer wheels and tires back on, probably in March. At least these lasted 40-50% longer than the originals.
 
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Why would it be better? Staggered set-up also, rotating impossible.
.
Assuming no excess suspension part wear or crash damage, my belief is that getting an alignment with new tires at recommended PSI and 1/2 a tank of gas will give you as good of a shot as possible at the "ideal" settings versus a tire that may be worn irregularly from previous misalignments and/or part issues.

It's more of a "feel good" and "in for a penny, in for a pound" thing when new tires are also on the table because I do recognize that alignments are measured from the wheel.
 

Jimmy_Russells

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It's more of a "feel good" and "in for a penny, in for a pound" thing when new tires are also on the table because I do recognize that alignments are measured from the wheel.

I did a bit more reading last night and it seems that the only difference between a new and old tire is a slight change in geometry because of tread depth difference changing ride height slightly. Of course because tires wear you're never going to have an ideal setup to align, like you said something like 1/2 tread and 1/2 tank would probably be the best scenario. I know the Audi dealer actually puts a weight on the driver's seat too (or at least it's part of the formal procedure).
 
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I did a bit more reading last night and it seems that the only difference between a new and old tire is a slight change in geometry because of tread depth difference changing ride height slightly. Of course because tires wear you're never going to have an ideal setup to align, like you said something like 1/2 tread and 1/2 tank would probably be the best scenario. I know the Audi dealer actually puts a weight on the driver's seat too (or at least it's part of the formal procedure).
Yeah I think every little bit counts, especially for trying to squeeze the most out of a more expensive set of tires.

I always give my local shop my weight (225 lbs+) on the night drop slip when I get an alignment in case it helps.
 
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Of course because tires wear you're never going to have an ideal setup to align, like you said something like 1/2 tread and 1/2 tank would probably be the best scenario.

Again dudes, no. Half tread isn't 'ideal' because it doesn't even matter.
Developing suspension kinematics (and elasto-kinematics) is my profession
for >25 years. Do yourself a favour and believe me when it comes to this.
User error and even rig tolerances are MUCH bigger than anything caused by
tread depth or uneven tread wear could ever be. It simply has no relevance.

Please don't get me wrong, but I don't get why people who don't know anything
about suspension geometry use to provide 'recommendations' based on feelings
alone. How could this be helpful? It's just misleading at best.
.
 

Jimmy_Russells

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Again dudes, no. Half tread isn't 'ideal' because it doesn't even matter.
Developing suspension kinematics (and elasto-kinematics) is my profession
for >25 years. Do yourself a favour and believe me when it comes to this.
User error and even rig tolerances are MUCH bigger than anything caused by
tread depth or uneven tread wear could ever be. It simply has no relevance.

Please don't get me wrong, but I don't get why people who don't know anything
about suspension geometry use to provide 'recommendations' based on feelings
alone. How could this be helpful? It's just misleading at best.
.
I already said I am not sure, which is why I posted the thread. Even in the post you quoted above, I said "probably." Half tread and half tank seemed to makes sense to the layman (me) because it is a middle ground. If they don't matter, that is fine too, it's actually better.
 
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.
Yep, it's actually better. My intention was to say not to overcomplicate things.
Concentrate on what actually matters. A proper and complete (including caster)
alignment done by a professional. Sadly the majority of alignments is mediocre
at best. Is you suspension stock? Any lowering would increase front camber and
thus explain increased inner shoulder tire wear.
.
 

Jimmy_Russells

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.
Yep, it's actually better. My intention was to say not to overcomplicate things.
Concentrate on what actually matters. A proper and complete (including caster)
alignment done by a professional. Sadly the majority of alignments is mediocre
at best. Is you suspension stock? Any lowering would increase front camber and
thus explain increased inner shoulder tire wear.
.

It is stock, but the RS3 is significantly lower than an A3

If this is the way it is, that is fine, the front tires still lasted 15k so it is not terrible, and I drive it pretty hard sometimes. But obviously if the alignment is out and I can get more tire mileage + maybe better reponse and handling that would be a win/win. If not, so be it. I do like the way the car drives now so I don't want to do anything drastic.
 
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Would you guys take your little love fest somewhere else? Please look up what staggered fitment means.

Also the alignment is done with the wheel, not the tire. Theoretically it shouldn't really matter but common sense says probably better to do it after, it's just not as convenient for me and I was hoping to extend treadlife on the old ones by a few thousand miles. Truthfully I don't even know the alignment is the problem it may just be the way the car is set up.
The alignment itself won’t change before or after new tires, but, if the current front tires have uneven tread depths (between left and right tires) that can affect the steering wheel being straight. We always roadtest after the alignment, and the steering wheel may not be perfectly straight, due to uneven tread depth of the front tires. So we make a small adjustment to straighten it. If new tires are installed after that, then the steering wheel will be off center the other direction afterwards. Only takes a 1mm difference in tread between the left and right front tires to makes a noticeable difference.
 

Jimmy_Russells

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The alignment itself won’t change before or after new tires, but, if the current front tires have uneven tread depths (between left and right tires) that can affect the steering wheel being straight. We always roadtest after the alignment, and the steering wheel may not be perfectly straight, due to uneven tread depth of the front tires. So we make a small adjustment to straighten it. If new tires are installed after that, then the steering wheel will be off center the other direction afterwards. Only takes a 1mm difference in tread between the left and right front tires to makes a noticeable difference.

I don't know how stupid this is but I've actually adjusted the tie rods to straighten the wheel quite a few times on various vehicles because I am kind of OCD about it. My understanding is that as long as you mark the rods and turn them the same amount (lengthen one and shorten the other), the alignment wouldn't really change. Sometimes I will turn them as little as like 1/32 of a turn and it makes a noticeable difference. I don't know how much you need to turn a tie rod to make a substantial change like say 0.2°.
 
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I don't know how stupid this is but I've actually adjusted the tie rods to straighten the wheel quite a few times on various vehicles because I am kind of OCD about it. My understanding is that as long as you mark the rods and turn them the same amount, the alignment wouldn't really change. Sometimes I will turn them as little as like 1/32 of a turn and it makes a noticeable difference. I don't know how much you need to turn a tie rod to make a substantial change like say 0.2°.
I normally go by wrench flats. There are 6 wrench flats on the tie rod adjustments. Normally when I am adjusting for steering wheel off due to tires, the steering wheel is off by about 5-10 degrees. Turning both tie rods 1 wrench flat (which equals about 4 minutes per side) is enough to straighten it.

I will also sometimes do two wrench flats on only one wheel (8 minutes), to make a variation in total toe, if I don’t like the “feel” of it during the road test.
 

hrv

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I don't know how stupid this is but I've actually adjusted the tie rods to straighten the wheel quite a few times on various vehicles because I am kind of OCD about it. My understanding is that as long as you mark the rods and turn them the same amount (lengthen one and shorten the other), the alignment wouldn't really change. Sometimes I will turn them as little as like 1/32 of a turn and it makes a noticeable difference. I don't know how much you need to turn a tie rod to make a substantial change like say 0.2°.
I do this too and you are right as long as you turn each one the same amount you are OK......
 

Jimmy_Russells

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I normally go by wrench flats. There are 6 wrench flats on the tie rod adjustments. Normally when I am adjusting for steering wheel off due to tires, the steering wheel is off by about 5-10 degrees. Turning both tie rods 1 wrench flat (which equals about 4 minutes per side) is enough to straighten it.

I will also sometimes do two wrench flats on only one wheel (8 minutes), to make a variation in total toe, if I don’t like the “feel” of it during the road test.

According to Google, one minute is .0167 degrees so you'd really have to move the rods a fair bit to affect the actual alignment a significant amount. That is good to know.
 
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