Bump Steer remediation

stojadin

Low Mileage
Ritmo Gr.2 front supension (1).jpg
Ritmo Gr.2 front supension (2).jpg

Ritmo 75 Gr.2, one of the variations on the theme
 

stojadin

Low Mileage
This is from either very early example of Ritmo Abarth 75 Gr.2 or the car made it to the spec. because the control arm is made from original part.

Abarth have made rinforzato control arms and knuckles with the desired lower control arm attachment point. These two part have found way in the production versions of the Ritmo/Strada Abarth 125&130TC. They can still be found but expensive.
Ritmo 125 - 130 TC Abarth control arm and nuckle.jpg

RITMO GRUPPO 2 ABARTH 1975 -77 KIT AVANTRENO RINFORZATO.jpg

Ritmo Gr.2_09.jpg

Ritmo Gr.2_10.jpg


Ritmo Gr.2_11.jpg


I believe you saw solution with raised inner control arm point (with the same intent)
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/fiat-128-ski/127501/page1/
 

Dr.Jeff

True Classic
This is from either very early example of Ritmo Abarth 75 Gr.2 or the car made it to the spec. because the control arm is made from original part.

Abarth have made rinforzato control arms and knuckles with the desired lower control arm attachment point. These two part have found way in the production versions of the Ritmo/Strada Abarth 125&130TC. They can still be found but expensive.
View attachment 44450
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View attachment 44454

I believe you saw solution with raised inner control arm point (with the same intent)
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/fiat-128-ski/127501/page1/
Thank you, now I see what was done. This is referred to as a ball joint "flip" in other circles, and is a common modification when dramatically lowering a car. They have come up with a neat approach to reverse the taper in the knuckle (upright) and to remount the joint on the other side of the arm, so the stock parts can be modified to do this. It might(?) be possible to do a similar mod to the X's stock components. They also do the same thing with the tie rod when the original design has it located on top of the steering knuckle.
 

fiatfactory

Steve Cecchele
It doesn't actually look like they reversed the taper at all, I think they drilled it out and inserted a bolt which passes thru a spherical joint which has been inserted into the lower control arm... no ball joint boot, and the distance from pivot to mount with a ball joint tapered pin is much greater... picture doesn't show the underside on the ball joint, but my guess would be you'd see the head of a bolt on the underside of the arm.

The trouble with a straight flip, is that the pin normally inserts from the top at an angle, if you flip the ball joint upside down (which on a 128 sedan or a ritmo is possible due to the arms design) you would effectively pull the bottom of the hub inwards (creating positive camber and reducing the SIA)

Thats why the inner point is adjustable for length, to firstly correct for this difference, and secondly it would allow geometry changes to alter things lke the scrub radius when larger wheels / tyres are used.

On a 128 coupe or an X19, flpping the arm isn't possible because of it's design being a left / right specific am. So my lemons racer I've replaced the ball joint pin with a spherical joint and a bolt, repositioned to under the arm, the bits will be here in about a week from the UK and I'll show you how it's done, but this is an artists impression. Pulling the lower pivot point inwards by 10/12 mm which this will do is no issue in my setup as I've increase the SIA considerably by repositioning the upper pivot inwards, so the fact that it pulls some negative camber out is beneficial for me.

20210322_172452.jpg

at the rear a similar change, but I dont think it will fit into 13" wheels as the lower arm / ball joint just clears my 14's

Fiat part numbers that begin with "702" are generally from Abarth works, not available thru Fiat dealers generally....it wont even appear in the dealer price lists from the 1980's.

SteveC

SteveC
 
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