Wheel Alignment Perfect; car still does not go straight

Wheels, Suspension, Brakes & Tyres questions and answers

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Sasso

Re:

Postby Sasso » Mon Apr 21, 2008 7:30 pm

eastla wrote:
Sasso wrote:
eastla wrote:
Sasso wrote:If it tracks differently on power to off power sounds like a shocks problem. Are your superstreets set with the same settings both left and right? Is the spring sitting properly? Is your swaybar binding?


I am pretty sure that the SS's are installed properly as are the Sways.
Got them done by Centreline that are known to be good.



Never assume. Doesn't hurt to check.


You are probably right about that :)
Problem is that I am in SE suburbs and Centreline is approximately 1.5 hours drive from my home.
I have already travelled back there 4 or 5 times for little niggling problems with the suspension over the last month or so.
Dont really want to go back at this point.
Also, I am pretty clueless with these things myself and would not know how to check it myself.

If anyone can suggest someone local that could check things out for me that would be fantastic?


You turn a knob on top of the shock and count the clicks. Didn't you get instructions?

eastla
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Re:

Postby eastla » Mon Apr 21, 2008 7:55 pm

Sasso wrote:
eastla wrote:
Sasso wrote:
eastla wrote:
Sasso wrote:If it tracks differently on power to off power sounds like a shocks problem. Are your superstreets set with the same settings both left and right? Is the spring sitting properly? Is your swaybar binding?


I am pretty sure that the SS's are installed properly as are the Sways.
Got them done by Centreline that are known to be good.



Never assume. Doesn't hurt to check.


You are probably right about that :)
Problem is that I am in SE suburbs and Centreline is approximately 1.5 hours drive from my home.
I have already travelled back there 4 or 5 times for little niggling problems with the suspension over the last month or so.
Dont really want to go back at this point.
Also, I am pretty clueless with these things myself and would not know how to check it myself.

If anyone can suggest someone local that could check things out for me that would be fantastic?


You turn a knob on top of the shock and count the clicks. Didn't you get instructions?


No, unfortunately I did not get English instructions; only Japanese.
Even though I was told by Centreline that I have Aus spec Super Streets.
2007 MX5 LE

Fatty
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Postby Fatty » Mon Apr 21, 2008 8:03 pm

thats odd , my aus spec teins purchased and installed at centreline came with englich instructions :?

i guess they haven't got around to writing the NC instructions in enlglish yet :roll:

anyway, what sasso is getting at, is that it;d be worth checking that the shocks are set to the same amount of \"clicks\" at each wheel. this is easy to check with the little allen ket tool they would have supplied you.

eastla
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Re:

Postby eastla » Mon Apr 21, 2008 8:18 pm

Fatty wrote:anyway, what sasso is getting at, is that it;d be worth checking that the shocks are set to the same amount of "clicks" at each wheel. this is easy to check with the little allen ket tool they would have supplied you.


I do have the tools that came with the coilovers.
Could someone please point me to some instructions on how to do it.
I have been searching for the last half hour with no luck as yet.
Also, can this all be done by jacking up the car; or do I need to pull the trim out to do this?
I have no idea how to remove the trim.
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JBT
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Postby JBT » Mon Apr 21, 2008 9:02 pm

I still think the problem is being caused by zero front toe. There may also be a setback condition exacerbating it.
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eastla
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Re:

Postby eastla » Mon Apr 21, 2008 9:11 pm

JBT wrote:I still think the problem is being caused by zero front toe. There may also be a setback condition exacerbating it.


Um excuse my ignorance; but what does setback mean?
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JBT
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Postby JBT » Mon Apr 21, 2008 9:13 pm

Image

eastla
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Re:

Postby eastla » Mon Apr 21, 2008 9:15 pm

JBT wrote:Alignment terms.


Thanks ;)
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Lukus

Re: Wheel Alignment Perfect; car still does not go straight

Postby Lukus » Mon Apr 21, 2008 9:19 pm

eastla wrote:Had my NC wheel alignment done as car was pulling left; still does the same thing after alignment.

I am finding that it tracks slightly left particularly as I come off power.
Under full accerleration it goes pretty straight, same when just coasting.
The main problem is as I come off minimal power.
Over all though it seems to always pull very slightly to the left.
I read in another thread that it may have something to do with large amounts of camber and zero toe combination.

I have Tein Super Streets on and also Whiteline adjustable sway bars.

Any advice or guidance would be much appreciated.


Alignment Settings:

Front:
toe 0mm both sides
Camber L-2.26 r-2.25
Caster L 7.46 r 7.56


Rear
toe L 1.1mm r 1.2mm
Camber L -2.04 r -2.02


Looking at those specs, 0.1mm on the rear toe and that small difference in caster would do it.

I would throw it back on the same machine and see what it says. I have had similar problems. Due to the crowning on our roads (at least, here i Sydney on alot of them) the cars i align generally get similar caster specs but reversed so that it will naturally go against the slight crown. Keeps the wheel straight. Essentially, those specs (especially the rear) are steering it left. At the moment, the rear is steering the car.

Just reading over what has been said, and MxJadeMonkey has already mentioned it, but i guess that confirms it.

eastla
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Re: Wheel Alignment Perfect; car still does not go straight

Postby eastla » Mon Apr 21, 2008 9:27 pm

Lukus wrote:
eastla wrote:Had my NC wheel alignment done as car was pulling left; still does the same thing after alignment.

I am finding that it tracks slightly left particularly as I come off power.
Under full accerleration it goes pretty straight, same when just coasting.
The main problem is as I come off minimal power.
Over all though it seems to always pull very slightly to the left.
I read in another thread that it may have something to do with large amounts of camber and zero toe combination.

I have Tein Super Streets on and also Whiteline adjustable sway bars.

Any advice or guidance would be much appreciated.


Alignment Settings:

Front:
toe 0mm both sides
Camber L-2.26 r-2.25
Caster L 7.46 r 7.56


Rear
toe L 1.1mm r 1.2mm
Camber L -2.04 r -2.02


Looking at those specs, 0.1mm on the rear toe and that small difference in caster would do it.

I would throw it back on the same machine and see what it says. I have had similar problems. Due to the crowning on our roads (at least, here i Sydney on alot of them) the cars i align generally get similar caster specs but reversed so that it will naturally go against the slight crown. Keeps the wheel straight. Essentially, those specs (especially the rear) are steering it left. At the moment, the rear is steering the car.

Just reading over what has been said, and MxJadeMonkey has already mentioned it, but i guess that confirms it.


So just to clarify.

I currently have the following caster settings:
Caster L 7.46 R 7.56

You suggest I go to the aligner and ask them for the following caster setting?
Caster L 7.56 R 7.46

And I should leave all camber and toe settings as they currently are?
2007 MX5 LE

Lukus

Postby Lukus » Mon Apr 21, 2008 10:17 pm

As for the caster, that is correct. I would run the left hand side with more caster.

Camber front and rear is ok. You'll get some camber thrust (where it will pull a little bit over bumps if the bump is on one side and not the other) but that's it. It's the price you pay for more camber.

I would get them to re-do the rear toe though. They should be the same. If they can get it that close, they can get them exactly the same. Anything else is being lazy. Trust me, i should know because i do wheel alignments :lol: When i'm feeling lazy or it needs to be gone 20 minutes ago, 0.1mm difference would be fine. If i was paying for it to be done, i'd expect it to be the same.

eastla
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Re:

Postby eastla » Mon Apr 21, 2008 10:40 pm

Lukus wrote:As for the caster, that is correct. I would run the left hand side with more caster.

Camber front and rear is ok. You'll get some camber thrust (where it will pull a little bit over bumps if the bump is on one side and not the other) but that's it. It's the price you pay for more camber.

I would get them to re-do the rear toe though. They should be the same. If they can get it that close, they can get them exactly the same. Anything else is being lazy. Trust me, i should know because i do wheel alignments :lol: When i'm feeling lazy or it needs to be gone 20 minutes ago, 0.1mm difference would be fine. If i was paying for it to be done, i'd expect it to be the same.


Thank you VERY much for the advice.

Im gonna get this done, hopefully this week and Ill let you know how it goes.

Cheers
2007 MX5 LE

Lukus

Postby Lukus » Mon Apr 21, 2008 11:06 pm

You are most welcome.

Update us when it is finished. And don't pay for it to be sorted if possible. I should have been done the first time!

Sasso

Postby Sasso » Mon Apr 21, 2008 11:57 pm

By the sounds of it you have two completely different problems. One is the tracking the road camber, the other is inconsistent tracking from off to on power.
Road camber tracking is not so bad, just an alignment thing, too little toe in front or rear will cause straight line instability. As will fat low profile tyres. Caster helps it stay straight but makes the steering wheel feel crap.
Perhaps you should try 2 or 3mm rear toe in instead of 1mm.
I really don't know why they use mm rather than degrees, because wouldn't the actual angle change with different wheel sizes. I mean I use 2-3mm toe in on the rear and 0toe on the front, I did it myself with some fishing wire and a ruler (and camber gauge and helper that can subtract quickly), and the car tracks pretty straight. But my 3mm on a 14\" wheel is more than 3mm on a 17\" wheel so perhaps you aren't running enough toe in on the rear. Zero toe on front give a nice turn in.

Your other and more concerning problem is that it tracks differently when you accelerate and brake. As I said, to me this sounds like something is broken or not even in the suspension somewhere. It could also be wrong wheel alignment values or not enough of something, like toe. But I remember back when I raced RC cars and I used to get different tracking when I accelerate and it would make going down the straight a pain, I didn't fix it until I got a proper alignment tool and learnt how to build the shock absorbers properly (yes they have oil in them and are adjustable).

I don't own Teins, yet, but im pretty sure you just count the clicks in any one direction until you hit a stop, then count back and make them all even (and see if they're different). You just need to open the hood and find the tops of the shocks. In the boot you might have to take some of it apart to get to the top of the shock.
Sway bar you should disconnect from the endlinks and make sure it can rotate fairly easily. And make sure the endlinks are the same length and not binding either.

The other thing is your brakes could be gripping differently left to right side if its pulling under brakes. One brake disk could be contaminated, just drench it in brake cleaner (try to avoid getting where the pads slide unless you want to regrease it).

Although I think its just a rear toe problem, more toe in should fix your instability. If that doesn't work, something is wrong, it shouldn't be that hard to get it to go straight.

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Re:

Postby JBT » Tue Apr 22, 2008 6:53 am

Sasso wrote:By the sounds of it you have two completely different problems. One is the tracking the road camber, the other is inconsistent tracking from off to on power.
........... too little toe in front or rear will cause straight line instability....

That's my thoughts. Static zero toe at the front will be toe out when the car is moving and can cause the instability problems.

The normal measurement for toe is shown in mm. About 2mm total toe in (i.e. 1mm per side) both ends will work fine. 0.1mm difference in toe from side to side will be undetectable.
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