When I look in the parts catalog or technical data for the fulvia I find only one type of rear axle. I do have different ones myself though:
- a S1 type with cast iron ends having positive camber (v-shape) from an early 1.2
- a S1 type with alloy ends with positive camber from a 1.3 rallye
- a ? type with alloy ends and negative camber (like a tent).
Does anybody know more about that latter type. I have fitted one like that to my S1 and the camber is negative enough to see it without measuring it. I fitted it because the weight difference is about 4 kg and only noted later that it was somewhat different. Thinking that it was a special one, I was surprised to find one again on a car that I bought last week.
When trying to measure it, I came to about 1 degree of negative camber.
Anybody any thoughts?
Negative camber at the rear??
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Paul de Raymond Leclercq
Re: Negative camber at the rear??
I have never seen a negative-camber rear axle specified so it's possible that someone has modified yours.
The aluminium-alloy ends were used on most of the Fulvias up to 1970/71; later cars had iron ends as fitted to the 2000 cars.
Paul
The aluminium-alloy ends were used on most of the Fulvias up to 1970/71; later cars had iron ends as fitted to the 2000 cars.
Paul
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Peter
Re: Negative camber at the rear??
Hey Paul,
That is really interesting. I now have two of those myself, and two of my friends have one. One has a 540 tag to it. I'll try and measure the angle of all of them and compare. The positive one I measured was about 1 degree. This is large enough to see with the eye.
That is really interesting. I now have two of those myself, and two of my friends have one. One has a 540 tag to it. I'll try and measure the angle of all of them and compare. The positive one I measured was about 1 degree. This is large enough to see with the eye.
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Paul de Raymond Leclercq
Re: Negative camber at the rear??
Peter,
My understanding is that the axles were always camber-neutral.
What does give the impression of positive camber at some angles is the rear toe-in which is specified from memory at 1-3mm. I believe that the 818-540 cars were specified differently - I cannot find my technical data book - and I seem to recall that the works may have reduced the rear toe on some cars to reduce understeer - or more properly attempt to induce oversteer.
Interestingly - and a bit off-topic - I have been told by a Fulvia expert that I know, that some works rally cars ran without rear anti-roll bars. This I believe was for "loose" conditions where oversteer was not in short supply!
Paul
My understanding is that the axles were always camber-neutral.
What does give the impression of positive camber at some angles is the rear toe-in which is specified from memory at 1-3mm. I believe that the 818-540 cars were specified differently - I cannot find my technical data book - and I seem to recall that the works may have reduced the rear toe on some cars to reduce understeer - or more properly attempt to induce oversteer.
Interestingly - and a bit off-topic - I have been told by a Fulvia expert that I know, that some works rally cars ran without rear anti-roll bars. This I believe was for "loose" conditions where oversteer was not in short supply!
Paul
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Peter
Re: Negative camber at the rear??
Paul,
1) The way I measured the camber:
car on a perfectly flat floor, large 90degree hook on the ground, next to the middle of the rear rim. Measuring the difference between the bottom distance and top distance from hook to rim. Very well repeatable and the right outcome everytime: '66s1 with alloy ends: positive. 4 others: negative. I am in the garage this afternoon. Will do the same for my s2 1600. I assume it has iron ends.
2) Something really off-topic: I used to do the same with Alfetta's I raced on the track. If you make your suspension springs stiffer the effect of the rear sway bar being a little too stiff can cause extreme oversteer. Removing it cured it (as most 75 drivers do). The real solution in my view is to fit a stiffer front sway bar. That is what I am doing with my Fulvia this winter.
2.5) Have you ever seen that the works guys turned their long spring leave on the rear up side down to lower the rear?? I found a guy who drives fulvia's on endurance races. He managed to have only 3 leaves at the front and 3 in the back. of these 3 only one is effectively working, the rest is 'fill up'. The working one is off course thicker than standard (twice?). This saved him 15kg on the car. Will experiment with this this winter. I guess you have a special setup yourself.
Peter
1) The way I measured the camber:
car on a perfectly flat floor, large 90degree hook on the ground, next to the middle of the rear rim. Measuring the difference between the bottom distance and top distance from hook to rim. Very well repeatable and the right outcome everytime: '66s1 with alloy ends: positive. 4 others: negative. I am in the garage this afternoon. Will do the same for my s2 1600. I assume it has iron ends.
2) Something really off-topic: I used to do the same with Alfetta's I raced on the track. If you make your suspension springs stiffer the effect of the rear sway bar being a little too stiff can cause extreme oversteer. Removing it cured it (as most 75 drivers do). The real solution in my view is to fit a stiffer front sway bar. That is what I am doing with my Fulvia this winter.
2.5) Have you ever seen that the works guys turned their long spring leave on the rear up side down to lower the rear?? I found a guy who drives fulvia's on endurance races. He managed to have only 3 leaves at the front and 3 in the back. of these 3 only one is effectively working, the rest is 'fill up'. The working one is off course thicker than standard (twice?). This saved him 15kg on the car. Will experiment with this this winter. I guess you have a special setup yourself.
Peter
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Paul de Raymond Leclercq
Re: Negative camber at the rear??
Well Peter, we live and learn! I shall be interested to hear the outcome.
Yes the trick is to fit a 2000 front anti-roll bar (18mm instead of 16mm) this is 60% stiffer.
I found that I had too much roll at the rear - even with 7-leaf (one inverted) at theback. I now have a 16mm rear bar which has been very successful. I believe that modern tyres, having improved grip induce additional roll hence the need for stiffer bars.
Currently I have six-leaf springs at the back; I have removed the bottom short leaf and added an extra second leaf at the top. This was described in Carlo Stella's book.
Paul
Yes the trick is to fit a 2000 front anti-roll bar (18mm instead of 16mm) this is 60% stiffer.
I found that I had too much roll at the rear - even with 7-leaf (one inverted) at theback. I now have a 16mm rear bar which has been very successful. I believe that modern tyres, having improved grip induce additional roll hence the need for stiffer bars.
Currently I have six-leaf springs at the back; I have removed the bottom short leaf and added an extra second leaf at the top. This was described in Carlo Stella's book.
Paul
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Peter
Neutral at the rear for S2, positve for 1.3S
Paul, measured my s2 1600's rear camber:
Neutral (between -0.2 - +0.2 degree) indeed.
The 1.3S had about 1degree positive.
As said, will make an effort to measure the FOUR negative camber rear axles that I know of and update it here.
Related to this, what is your idea about toe in at the front? What are the effects of changing it?
Neutral (between -0.2 - +0.2 degree) indeed.
The 1.3S had about 1degree positive.
As said, will make an effort to measure the FOUR negative camber rear axles that I know of and update it here.
Related to this, what is your idea about toe in at the front? What are the effects of changing it?
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HF1.6
Re: Neutral at the rear for S2, positve for 1.3S
Hi,
additional toe-in at the front will reduce your turn-in responsiveness, but you will get a return in the form of better straight line stability (not a big issue anyway with the Fulvia) and some reduced understeer.
Of course the opposite is true if you dial in more toe-out (or less toe-in).
Mike
additional toe-in at the front will reduce your turn-in responsiveness, but you will get a return in the form of better straight line stability (not a big issue anyway with the Fulvia) and some reduced understeer.
Of course the opposite is true if you dial in more toe-out (or less toe-in).
Mike
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Paul de Raymond Leclercq
Re: Neutral at the rear for S2, positve for 1.3S
Since the Fulvia was specified to have 1-3mm toe-out, I take Mike's side and run my car more or less parallel. I think that front toe-in on a Fulvia would make it a little twitchy.
Paul
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Paul
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Paul de Raymond Leclercq
Re: Neutral at the rear for S2, positve for 1.3S
Peter it is possible that there could be a slight bend in the axle to give positive camber.
As I say I do not think that positive or negative camber was specified for the Fulvia.
Paul
As I say I do not think that positive or negative camber was specified for the Fulvia.
Paul