Hi guys,

Because of too little groundclearance, I just adjusted the HiLo's on the rear about +10mm this morning.
So far so good.
What I saw earlier on and what my nose was very close to now was the allignment of my rearwheels.
They both have a positive camber and quite a bit of Toe-in.
What should these be and what is the best way to achieve a good allignment on the rear?

I have still boxed, a set of HiLo's, adjustable lower arms and tie-bars and rubbers to put on the front.
Will get to fitting and adjusting these soon with my Trackrite camber gauge.

Hi Harold,
This is what I will use as a starting point.
GTM suspension settings
Ride height front 5” – rear 6”
Camber front & rear 1.5 degree
Castor angle Front 3-5 degree
Castor angle rear 0 degree
Toe in front 3 degree (1/8”)
Rear toe in 2-3 degree
Tyre pressure front 18 – 20 psi rear 22 – 24psi
If you have the original "A" lower arms you will not be able to adjust camber, I had thought when my car is running I will modify my unused A frames to make them adjustable.
Cheers and happy New Year from Africa
John

Hi John,

The suspension at the rear looks the same as the suspension in the front, but without the steering possibillity ofcourse.
There is somekind of adjustable bar instead of the steering arms, to adjust the toe-in I guess.
To get my rear suspension right I should get the same set as the one in the front?
Adjustable lower arms, adjustable tie-bar and new rubbers.

Happy newyear from Holland!

Hi Harold,
So you have standard front (at the rear) bottom arms and tie rods with a steering locking system to adjust toe in, you don't need caster angle on the back, you could cut and lengthen the bottom arms by 1/4" to give approximately 1.5 degree negative camber, or buy adjustable bottom arms and tie rods to do the job properly
I have spent all Christmas and new year holiday in my little workshop, I have just lowered the engine back into the rear sub frame, on the work bench, I will connect the drive shaft universal joints to 'S' output flanges, this afternoon/tomorrow and refit the exhaust system, all freshly painted and glass cloth wrapped.
It has been very cold (for us) normally I'm just wearing my underwear underneath an overall, with the Harmattan winds coming in from the Sahara desert bringing lots of fine sand dust, blocking out the sun a bit like fog, that drops the temperature down to around 10c during the night, so its normal clothes under the romper suit to keep warm.
Happy GTM New Year from Kano
John

Cold over there, hot over here, we had a December without frost at all, never had that since we began measuring temperatures in the early 1900's.

How do you measure Caster on the rear of the car?
You don't need it on the rear, but when I adjust the camber, it probably wont be zero.

A few days ago I raised the rear a bit by adjusting the HiLo's 10mm.
They where at their lowest position, so I raised them both 10mm.
I drove it around for a few miles to let the suspension settle, when I measured the hight it seems that the hight below the sills has raised about 20-25mm.... How is this possible?
This doesn't seem logical to me.

Can I use the hight below the sills (groundclearance below sills) as base to put the left and right side of the car on equal hight?
Even if this means that the HiLo's on left and right Side are not on the same hight?

Greets from Holland
Harold

Hi Harold, When you raise the HiLo 10mm it operates on a lever system, the ball knuckle joint in the HiLo is approximately 42mm from the arm inner pivot and the outer hub ball joint is approximately 171mm giving a ratio of 4 to 1
If you are on a flat level surface you can measure the ride height side to side and front to back, if you have access to corner weight scales that would be a better way of checking side to side, especially for a track car, not so fussy for a road car
John

Hi John.
Ofcourse there is a lever, stupid me, That makes it a lot more logical.
I Also retrieved the hight before the adjustment, it was lower then I thought, so the difference is indeed larger then I thought, about 45mm.

So I will lower it untill both sills at the back are 150mm from the level ground.
I have no acces to cornerweightscales, too bad, but my only track will be public roads, so I Dont think that is necessary.

Thanks for correcting my stupidity...

Cheers

Hi Harold,

Just spotted a small mistake in John's set up post -- I think he means 3mm toe-in not 3 degrees. Also at the back you can't just toe the wheels to each other like at the front as they may not be aligned to the car properly and the car might "crab" -- you need to track each wheel to the center line of the car or some reference point. In the past I've used the sills but you need to check they're parallel. having the rear end set up using laser equipment is probably a simpler alternative.

Steve

Cheers Steve,
Xmas big Oooops, I have always used the string method (actually nylon fishing line) even on race cars, I did bring a not too costly laser tool back with me, but wont be used until the GTM needs its wheels pointing in the right directions, but will cross check with the string until I'm sure the laser is easier/better.
And I should have told Harold that the rear toe in has to be set left and right sides individually. to give the included toe in angle.
John

@John: How does your fishingline-method work?
I have more then enough fishingline in my (too small) garage. I fished a lot before I bought the GTM... now I only go fishing for solutions in my garage.... (and on the GTM forum )

Cheers

http://www.ken555.plus.com/gtm/tracking.html

My method

Good guide, thanks. This does require the sills to be parallel though - I'm guessing they are on the coupe then. Does anyone know if they are on the Libra/Spyder? If not you need to have a longer string and so the axle stands can be further apart (front to back) than the length of the car so you can check they are parallel and square to the car. Ideally you need to roll the car back and forth a couple of m between adjusting and re-measure in case you are creating some tension in the various bushes that then relieves itself when it rolls.

Hi Harold, as per Kens method only I used two steel tubes (or could be broom handle or long pieces if wood) one in front of front wheel and the other behind rear wheel raised on blocks or axle stands (I used beer crates ) to be on the wheel center line, the 2 lengths of fishing line tied at one end to the tube running down the side of the car alongside the sills and around the other tube with a small weight (a large bolt will do) to keep the line tight, you now have two parallel line each side of the car, adjust the fishing line to be equal distance from each front and rear hubs (assuming you don't have wheel spacers on one end you should have the same track front and rear) you can now measure from the front and rear edge of the rim to the fishing line, the front should be toed in 1.5mm each side.
Any questions you can come around when I do mine
John

Thanks guys, that's good information.
One question, how do you know if your front wheels are exactly straight forward ( in the middle position)??
@john: when I'm in the neighbourhood I Will come over and have a look

I'm not sure the libra the sills are a straight line, I've a feeling the track is different front and back?