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#1
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Setting up Suspension
I know this has been covered numerous times on loads of forums but what and how is the best way to setup the car.
The reason I ask is my suspension is different to the book. My front top wishbones are adjustable with inboard rose joints for caster and the threaded adjuster is slightly further back than book spec also. The front lower wishbones are also modified to clear the steering rack extension for the Mx5 version with the outer pickup point lower on the bottom ball joint bracket. I've read that you have your lower wishbones level as a reference point for setting up but on mine they will need to be angled down slightly, is this correct. I guess what I'm really looking for is advice on the following questions for an Mx5 based Haynes. 1, Ride height front and rear. 2, Camber front and rear. 3, Caster front. 4, Toe in/out front and rear. 5, How to eliminate bump steer. 6, Where and what order to start first. I know it probably seems lazy on my part but as there are more Mx5 builders joining the forum I thought this would be useful for a lot of new members also.
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Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction. Albert Einstein http://s1199.photobucket.com/albums/aa472/JohnoSS1/ Johno |
#2
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Hi Johno, try Rich at Great British Sportscars, he is really helpful, and he will give you the dimensions of the mx5 gbs zero. That should give you a really good basis to start with, then just fine tune to suit. That's what I am doing, because the mx5 roadster build spec is so vague, I don't think that anybody has even gone into this.
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#3
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From what I've read here, spud69 designed the SSC MX-5 suspension with the aim of having the geometry, roll centres, etc. as close as possible to the Sierra-based roadster. So I would think the initial set-up should be almost the same.
Front: 5.5° caster, -2° camber, ~1° toe in. 110-120 cm ride height. Rear: 0 caster, -0.5° camber, 0 toe, 120-130 mm ride.
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Albert Haynes Roadster FAQ | Haynes Builder Locations Gallery, build thread in Lithuanian / via Google Translate. |
#4
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Like Albert says except that you may need to go with a bit of toe out to get it to self centre enough for IVA.
It's a matter of trying it out really, with the sort of accuracy the average home builder can get it's always going to vary slightly from build to build so be prepared to take your time and adjust it until it feels right, or rather until it gives you the feel that you want. Your driving style and personal preferences will have as much influence as the design itself. |
#5
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Front and rear toe can be got pretty dam close by making yourself a string computer
Get 2 lengths of wood the width of an inch or 2 wider than the car clamp them together and drill a hole in either end then take 2 equal lengths of string about 6 inch longer than the car and feed them into the holes and tie Now using tone stands the same hight as the wheel centres to support the wood so the string is either side of the car measure from the string to the wheel centre making sure its square on all corners (this may take a while) then you can set the toe by measureing the front of each wheel Its a bit long winded but its basically what they do in garages only the do it with lasers these days |
#6
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I measured rear toe by clamping a spirit level to the spindle and measuring distance from the chassis.
Front toe is also pretty easy to measure with a long straight edge touching the front of the wheels and a set square, or by clamping two pieces of suqare section tube to the front wheels. I tried the string method too, but found it more difficult.
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Albert Haynes Roadster FAQ | Haynes Builder Locations Gallery, build thread in Lithuanian / via Google Translate. |
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