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Zeds in the Wet


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#21 620Z

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Posted 14 July 2010 - 08:43 AM

Lurch nailed your problem in one. It's your rear wheel alignment IMO. Get that fixed and you will be OK.

#22 260DET

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Posted 14 July 2010 - 10:21 AM

I have since purchased a kit so I can adjust the rear alignment without welding. But I would still like to know what is the ideal settings for the rear (castor I think). My understanding is that 0mm is not ideal. If I had to guess I would think 4mm sounds reasonable???


For rear caster just get both sides even near zero I would think, can't recall it being discussed ever but while its important in front, because its relevant to steering movement, at the rear it would tend to make the car more straight ahead stable which could result in front turn in problems, understeer, etc. So avoid any significant rear caster unless there is a rear end stability problem that toe in will not fix.

Rear camber is a relevant adjustment of course  but thats usually measured in degrees.



#23 620Z

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Posted 14 July 2010 - 12:58 PM

Ahhh Galderdi a 4mm toe in would make your Zed handle like crap. You would be sliding all over the place like he is now.
Per 260DET comment when you get the adjustment ready to go on the rear close to zero toe is best. Fronts are a differnet kettle of fish depending on your application. But even then I see people always over doing it on their road cars which results in worn out tyres losing 50% or more of their life.

#24 .

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Posted 14 July 2010 - 01:54 PM

Thanks guys I will aim for 0mm Toe.

Hey Galderdi,  What was the kit you purchased, where from and how much?  :)


Here is the kit I have. I know it is listed as a camber kit. But I figure for the minor amout of adjustment I require I am hopeful I can dial out the front mount more than the back mount to correct the allignment problem. If I can get a small amount of camber in the process all the better.

http://www.thezstore.../PSDC07/23-4171

#25 620Z

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Posted 14 July 2010 - 03:54 PM

Yep there the ones.

#26 Riceburner

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Posted 14 July 2010 - 04:01 PM

Ok Thanks, already have a set in the front, Does anyone sell the rears in Aus?

#27 260DET

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Posted 15 July 2010 - 08:35 AM

Just to be clear, I was talking about rear caster, not toe. Typically a race car like ours would run a couple of mm front toe out, to help turn in, and, a few mm toe in at the rear to keep the rear stable under acceleration, braking etc. Check out what Dat2kman said about his race 280Z, 10mm rear toe in?

#28 Scando

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Posted 15 July 2010 - 01:16 PM

Check out what Dat2kman said about his race 280Z, 10mm rear toe in?


Correct, everybody trys to 'fix' the rear tow in on their Z's but don't always assume you're smarter than the manufacturer.  On the exit of a corner all the weight is on the outside rear tyre.  If this is toeing in slightly then it can counteract the slide.  Also, as dat2kman said, you get natural rear toe out under acceleration.

I've read something about rear caster in the posts above.  Do you mean rear camber?  You can't get rear castor on a Z and all it would do would be to change the wheelbase by a few mm when the suspension went up or down.

#29 .

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Posted 15 July 2010 - 01:33 PM

OK so I seem to be back where I started...... Ignore castor, I am not interested in that for the purpose of this question.

Camber too is a side effect not the primary objective.

It is Toe that I am trying to work out. I have 10mm of toe in on one side and 4mm of toe in on the other. From what I am hearing I am better off adjusting the 4mm side to be 10mm?

#30 Roberto

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Posted 15 July 2010 - 01:47 PM

Exactly the same situation I have found myself in.  :(

At my last wheel alignment after rebuilding my suspension, my rear right toe was +10.3mm and left was +1.4mm.

I tried to ignore this since I wouldn't have known otherwise, but couldn't get it out of my head.....

I bought the TTT adjustable control arms on ebay US and am fitting these to fix.  I will be going with 2mm toe-in.

I hate this stuff because I am mistrusting of most wheel alignment places to do the job properly.....

#31 Roberto

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Posted 15 July 2010 - 01:53 PM

Just out of curiosity, which side had the 10mm toe?  I hope this is not a purposely introduced factory setting.  ::)





#32 .

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Posted 15 July 2010 - 01:55 PM

I will need to double check the report.....If it is to compensate for the weight of the driver, maybe I need to increase it to 35mm :D

#33 Zeddophile

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Posted 15 July 2010 - 08:32 PM

OK so I seem to be back where I started...... Ignore castor, I am not interested in that for the purpose of this question.

Camber too is a side effect not the primary objective.

It is Toe that I am trying to work out. I have 10mm of toe in on one side and 4mm of toe in on the other. From what I am hearing I am better off adjusting the 4mm side to be 10mm?


That would destroy tyres pretty fast, besides making the car push the nose.  4mm toe in OVERALL would be the limit FOR ROAD USE in my opinion, i'd be shooting for that.  And would personally prefer between 0 and 1.5mm per side. (1-3mm overall).  As has been said already by a few different people, with various embellishments.

For what its worth, Haynes manual says "The rear wheels have no toe-in, and a camber angle of 0.5 degrees with the car unladen."  In the interests of gaining a touch more rear end stability, I feel a couple of mm toe-in is an acceptable change.

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Posted 16 July 2010 - 08:29 AM

Thanks for the info. I can see why I couldn't find anything on it before. Its like a debate on politics or something :)

My car is a road registered track car so its sounding like 4mm might be in order.

#35 260DET

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Posted 16 July 2010 - 08:55 AM

A really good wheel alignment bloke, like Ken at Accurate Suspension, Underwood, will check how much dynamic change in toe occurs by working the suspension forward and back while on the aligner. If you have the OE type rubber suspension bushes then there will be a significant amount of change, more than 4mm is not unusual at all. So its not the amount of static toe which is relevant, its the amount of toe the car will have while in motion.

Its these sorts of things which if all done properly can add up to a great car, I know with mine its the handling and braking which make it such a nice car to drive on the track. Power meh, I do faster laps with the boost turned right back.



#36 Scando

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Posted 16 July 2010 - 04:51 PM

It is Toe that I am trying to work out. I have 10mm of toe in on one side and 4mm of toe in on the other. From what I am hearing I am better off adjusting the 4mm side to be 10mm?


I think Dat2kman meant 10mm overall?  I'd be leaning more towards fixing the 10mm side to match the 4mm side.  I think 10mm per side would be overkill.

#37 260DET

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Posted 16 July 2010 - 05:03 PM

Toe for discussion purposes should always stated in total, that is L+R=total, unless otherwise stated. It makes it hard to discuss technical matters if people are not familiar or specific with the terms used.

#38 .

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Posted 17 July 2010 - 07:58 AM

Thanks guys. Its making a lot more sense now. I am looking at the report again. I have 14.5mm of total toe in. The left is 10.5 and the right is 4.0......ouch

As a matter of interest I would expect the toe to increase under acceleration. Is that correct?

#39 Roberto

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Posted 17 July 2010 - 10:22 AM

I believe it is the opposite.  Under hard acceleration, the toe (or toe-in) decreases.  That is why it doesn't hurt to start off with a bit of extra toe. 

From my readings, only a couple of mm is suggested.  +10mm is excessive and will hurt tyre life. 

I am sure for certain racing situations 10mm might be good but not for the street. 




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