New wheel alignment specs

zoomzoom · Postby **zoomzoom** » Thu Feb 08, 2007 11:19 pm

I took the car in to do another alignment as the springs have been in for a few months now and have settled. When I had a good look at the machine I realised before when I thought it was at -1.5 it was actually at -1* 50'(minutes)so it was only a tad under -2*.

So i checked it out and the minimum I could get on the rear right was-2* 30',(-2.5*) so I set both the rears there with 1mm toe in each side.

Now when it came to the front I remember getting told to always make the front the same if not just a little more so I set it to the same and also with 1mm toe in each side.

Now it seems quite a bit lighter to steer even with +5* castor left and +4.5* right. Also it seems to understeer a bit into corners till it gets the grip to roll the tyre wall over a bit and then it grips like hell on the two outside wheels.

Any opinions or suggestions, I was thinking playing with the adjustable shocks and sways a bit may tune it out? Or should I maybe take a little camber off the fronts? Would taking off the front create understeer at higher speeds?

I still have access to a brand new aligner so I can always take it back and change it some time.

Thanks, Tim

90 na6, kyb agx, whiteline adjustable sways, king low

Charlie Brown · Postby **Charlie Brown** » Fri Feb 09, 2007 3:17 pm

2Â½ degrees negative camber :shock:

is a lot on a NA, especially if you value your tyres.

If you are not using it on the track, but like a bit of spirited driving, back it down to 1Â¼ degrees negative front and rear. You should then be able to crank a bit more castor into the fronts.

One thing you didn't say was how much lower the car is. If you have lowered it 30 - 40mm you can run another Â¼ degree.

Moggy · Postby **Moggy** » Fri Feb 09, 2007 3:58 pm

zoomzoom wrote:So i checked it out and the minimum I could get on the rear right was-2* 30',(-2.5*) so I set both the rears there with 1mm toe in each side.

The impression I got is that you couldn't get any less than 2.5 degrees neg camber. Is that right? Meaning it can't physically be adjusted to less than 2.5.

I have that problem on my car - I can't go any less than -2 rear camber with konis/kings. I'd prefer about -1.2ish but I'm not sure how to go about it.

CT · Postby CT » Fri Feb 09, 2007 5:10 pm

Suggestions: Firstly make sure your front lower control arms are parallel to the ground otherwise you are too low.

Maybe, back the rear toe back to 1/2mm per side - 1mm per side can be a little on the high side. Remove the front toe in - it's a big mistake IMO. Zero toe is preferable or slight toe out to get it to turn in better. Toe in just slows down the front ends response - not really what an MX5 needs. Go zero - will probably fix your turn in issue.

Your bar settings will also affect turn in grip. Go hard on the front and soft on the back and try to tune the back ot the front. Tyre pressures can fine too as well.

zoomzoom · Postby **zoomzoom** » Fri Feb 09, 2007 11:50 pm

thanks guys, I am running king low with kyb agx and I think it sits about 25-30mm lower than std. I really had no idea where to set the front toe, but now I know I might take it in and nock it back to 0mm. As for the rear, if I take the toe out any more it will make for more camber so its kinda a catch 22, which one is worse?

I didnt see exactly how little I can get on the left side as I just did it to mirror the right, but I think it had a much better range of adjustment. The left hand side has copped a knock somewhere along the line before I had the car so I presume it must have shifted the subframe slightly to the right at that time which could be my issue.

Also I have heard a few times before that I should run the same as if not just a touch more camber on the front to the back, thats why I adjusted it up the same. Do you agree?

CT · Postby CT » Sun Feb 11, 2007 8:40 am

The rear of a car with independent suspension (MX5) MUST have at least zero but preferably some toe IN. They must never have toe out as it causes seriously unpredictable handling with the rear end trying to steer the car on compression. Camber on a road car is less important - especially on the rear.

zoomzoom · Postby **zoomzoom** » Mon Feb 12, 2007 10:11 pm

CT, you seem to be pretty clued up, in your opinion should I leave the front the same as the rear on -2.5*? All opinions are welcome. I am going to set the front to 0mm toe. And also would you leave the rear with 1mm toe in each side? I was told this may help with tread wear a little?

Thanks

CT · Postby CT » Wed Feb 14, 2007 1:58 pm

I seriously doubt you will get -2.5 on the front without offset bushes or modified lower arms unless you have the front end in bump steer. For the street, I'd be more inclined to run max of 1.5 neg front and 1 neg rear with zero front toe, 4.5+ castor front and max of 0.5mm per side rear toe in. that said, I used to run -2 neg all round on the road too - it ws sharp but it destroyed the tyres at road speeds. Big camber is not really needed until you are running semi slicks and track speeds. Street tyres just don't have the grip.

zoomzoom · Postby **zoomzoom** » Wed Feb 14, 2007 10:08 pm

What I mean is -2.5 is the lowest I could get on the rear, so should I run less on the front or will this lead to understeer? I have been told in the past to keep the front the same if not more than the back to stop understeer at higher speeds. The car is only really travellig about 3km to a from work once a week and perhaps a weekend drive every couple of weeks as well as the occasional track day. That said I don't really want to tear the inside of my tyres away after 1000km either. Ill have a bit more of a play with it in the next couple of days anyway and see how I go.