600 Abarth limiting straps

[batman]

My Abarth 600 replica doesnt have straps limiting rear suspension movement/ droop,    are they really necessary for fast road use                  thanks,    Dave

[Paul vander Heyden]

HI Dave,

In my opinion, absolutely YES.  You may never have to use them, but the danger of the rear suspension "jacking" is always present.  It is most likely to happen during a fast series of right-left turns.  Besides, this is a very simply mod.

Regards,
Paul vanderheijden

[batman]

Thanks Paul,   I always wondered what would happen if the inside wheel started to jack just like old Triumph Heralds!        The next question, whats the easiest way to fit some type of strap, steel wire maybe say ,set at about one degree of posive camber.     thanks.   Dave

[Paul vander Heyden]

There are a number of methods and some will be more applicable than other.

1. A strap or cable attached to the chassis and the the swing arm as close to the outer end as possible.
2. A straight rod, attached to the swing arm, going through the chassis in the shock tower area with a rubber shock rubber and a washer and nut.  As the suspension deflects the rod moves up.  When the suspension droops, then it stops when the rod stops at the rubber bump stop.  (This is more for race/rally cars where the rear seat is not used)
3. Fit special coilover shocks that have bee designed with a droop stop, so that the suspension only goes so far.

Good luck,
Paul Vanderheijden
www.scuderiatopolino.com

[Pantdino]

Here is a youtube video that shows how easily a roll-over can happen.  The limiting strap / rod / special shock is absolutely necessary unless you just putt around and never corner fast.

http://www.youtube.com/watch?v=S8Fjvv-r7Fo

This video scares me in particular because once I clearly recall getting up on two wheels in my Fiat 850 Coupe when cornering hard. .

Here's another video of an Abarth on 2 wheels. He's turning right when probably the shape of the road lifts his right side, putting him up on his left wheels. To fix that you would steer to the left, but the guard rail is there. He has no choice but to hit it some:

http://www.youtube.com/watch?v=PwTgl3ugf4U

Jim Oddie

[zippyfiat]

It seems to me that if your car is lowered,  the shocks and springs are stiffer, you have sway (anti-roll) bars, and the wheels/tires are wider than stock, that the chance of the car jacking is greatly reduced?  I'd sure hate to be in an autocross with some quick left/right turns and get flipped over.  Limiting straps are pretty easy to add, and I'm definitely going to install them.

Gil

[Pantdino]

Gil,

I think you are right-- if the rear suspension is lowered by the use of shorter springs the car will not be able to go into positive camber very easily.  My Coppa Mille racer was raced that way without straps, and I suspect many are.  But a road irregularity that tended to fling the car into the air could still get it into positive camber and the wheel could tuck under.  So a strap / rod / special shock is still necessary.

JIm

[batman]

Thanks chaps, but how much static droop/positive camber should I allow.for fast road use.      thanks  Dave.

[Pantdino]

I believe Paul wrote me that you want no more than 3 degrees of positive camber with the suspension hanging.
For a comparison, I measured the hanging camber on my car with its Koni shocks and found 22 degrees. (!!!!!!)

I bought Paul's special coilovers and found about 4 degrees positive camber with the thick urethane bushings it came with, so I used the rubber bushings from the Konis to decrease it some. (Forgot to measure what it is now.).


Jim

[batman]

At the moment all I really want to do,Is to keep the thing fairly standard, except for shorter rear springs and Koni dampers.   thanks