Gemini springs rates..thoughts

[phil]

I have found out that Arthur Jackson use to run a 380lb front spring and a 235lb rear spring in his gemini and recommends this in his setup manual. This is also what Stewart Wilkins recommends (they do work together now).

To me this sounds more like track spring rates. They are also very long. 380mm from centre of rim to bottom of wheel arch on the rear, when fitted. Should be ok for rock climbing, a little high for a dirt road I would think.
Any thoughts, advice appreciated.

[Spac]

Remember that the Gemini front end has a motion ratio of roughly 2:1, unlike most strut front ends which are around 1:1 - so that 380lb/in spring is more like 190 at the wheel.

[phil]

Yeah.. forgot all about that, good old wishbone front end.
190 sounds more like it. Still not a fan of the super height I'll have.

For the other gemini guys out there,
King springs: front std 295lb. low 310lb
rear std 135-220lb. low 140-225lb

Was thinking of getting the lowered kings and using the gemini/commodore rubber spring seats as packing for height.
Phil.

[Kaptainballistik]

After driving Keith Ross' Gemini, They seem to handle quite well at that height! ( Ill swap him some HP anyday!)

Also, The setup stated works with off the shelf Billies, And Mr Jacson would know more than most mortals about handling...

[Mozza]

also for the Gemini fans out there,
there is 2 (maybe more!) different depths in the front lower arm on the Gemini's, where the spring seats this can change your ride hieght!

Also when packing the springs you cant use Commodore (rear) packers/spacers they are too big in Diameter,
Use EA Falcon front, or any other thing of the same diameter.

Also for those on a tight budget you can also use LJ Torana 6 cylinder front springs, they are the same Diamater, and work well on both surfaces

Thats 10c worth from me!!!

[rms]

Originally Posted by Spac

Remember that the Gemini front end has a motion ratio of roughly 2:1, unlike most strut front ends which are around 1:1 - so that 380lb/in spring is more like 190 at the wheel.

Wheel rate is spring rate X (motion ratio ^2)

Wheel rate is 95 lb/in.

[phil]

Thanks guys for the input.
Mozza, I've found the the non RTS lower arms are the ones that require a diffrent height spring TX & TC gems. Waiting to be corrected.
Kaptainballistik, Arthur is the man, not doubting him or Stewart Wilkins, just didn't look right to me. As many gemini rally photo's i have are of lowish cars, with the odd exception. Bilsteins are on the way. Hoping for a few more ponies with a very mild cam and twin webers.

So with that some what sorted, the brake bias issue....

[rowdytoot]

The non RTS control arms give you more ride height- that's what I run in my car, and it's still too low with kings lows ( I assume they are lows- smee???? ) in it....another 30 mm of ride height would be handy...

my car is up on stands at the moment, but I'll check my current ride heights on the weekend- I'd be guessing that there is about 20-30 mm between the top of the tyre and the guard at the rear, and a probably ~ 60 mm at the front...

you definately don't want the ride height at what mine is in the rear though... the floor on my car has taken a pounding over the years, sure it handles well, but rough sections make you cringe like nothing else..

[Haggers]

Originally Posted by phil

I have found out that Arthur Jackson use to run a 380lb front spring and a 235lb rear spring in his gemini and recommends this in his setup manual. This is also what Stewart Wilkins recommends (they do work together now).

To me this sounds more like track spring rates. They are also very long. 380mm from centre of rim to bottom of wheel arch on the rear, when fitted. Should be ok for rock climbing, a little high for a dirt road I would think.
Any thoughts, advice appreciated.

I quote from Arthur Jackson's bible of Gemini Prep (1994 update)

Front: "Use 390 ln/in springs. Remember that RTS lower wishbones require a different length spring to the non RTS type"

Rear: "Use 230 ib/in springs (or possibly 300 lb/in). THe 300 il/in springs give more oversteer, but definitely require rally rate shocks to prevent axle tramping"


Haggers

[Shabby]

I cant remember what springs we ran in the front, TG Gem but we ran standard in the rear and all was good especially with the gun Monroe GT shocks. It was fast enough.


Shab

[wbell]

I will be using King Springs on the frront raised 3/4 inch and standard rate / height on the rear.
I like the car to have a tail down attitude as this gives better weight transfer (Grip) when cornering.

If you find this setup a little too understeery on turn in then raise the rear spring rate with King Spring Standard height.

It is very important to have the low speed valving set corectly on the front shocks. If it is too hard then the car wont break well, you need to get the front to dive alittle (squat) under brakes.

What diff ratio are you guys using.

Cheers
Wayne Bell

[scooter]

Originally Posted by Haggers

I quote from Arthur Jackson's bible of Gemini Prep (1994 update)

Front: "Use 390 ln/in springs. Remember that RTS lower wishbones require a different length spring to the non RTS type"

Rear: "Use 230 ib/in springs (or possibly 300 lb/in). THe 300 il/in springs give more oversteer, but definitely require rally rate shocks to prevent axle tramping"

Haggers,

Your Gemini, when you acquired it, had King, std height heavy duty front springs, and std RTS rear spring with half a coil chopped off the top and bottom. With the Works spec Bilstiens, they seemed to work quite well.

[Haggers]

Originally Posted by scooter

Haggers,

Your Gemini, when you acquired it, had King, std height heavy duty front springs, and std RTS rear spring with half a coil chopped off the top and bottom. With the Works spec Bilstiens, they seemed to work quite well.

Yes it worked fine. You had the asymmetrical upper control arm mounting bolts too. Fully Gemini hectik mate. Can't remember what we did with them when the car went to Gemini heaven.

Haggers

[Spac]

Originally Posted by rms

Wheel rate is spring rate X (motion ratio ^2)

Wheel rate is 95 lb/in.

Quoted for truth (and because I'm not too proud to admit that I forked up).

Given that the motion ratio is more like 1.7:1, then the wheel rate is sounding better and better all the time.

[Corty]

Gents,

The Top arms were sent back to Mr scooter Esquire a while back for one of his projects and the shocks ended up in ur new gemini and the spring did as well if memory serves me correct