my guess is some kind of wobbly stub axel...

your right, none of the bravo's, marea's, coupe's etc had torsion beams, Jug your going nuts....

Steve H said:

It doesnt involve heating/bending the rear arms as I dont feel this can be carried out accurately enough

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in a workshop you can get it accurate to 0.1 degrees on most cheap equipment, the expensive stuff is far better. personally i think 0.1 degrees is more than enough. it does the job for the professionals so its good enough for me.

SediciRich said:

Jug none of the bravo's had torsion beam, they have springs, or I'll eat my hat if im wrong.

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bulldog5046 said:

your right, none of the bravo's, marea's, coupe's etc had torsion beams, Jug your going nuts....

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you made me doubt myself for a minute, even though i remember jacking the car up by the beam several times.

then i checked the manual- its hat eating time.

(yes i know they call it a torsion bar instead of a beam, but that is due to the direct translation from italian. in england it called a torsion beam)

what did you guys think the trailing arms were connected to

Ha ha were getting pedantic here, I'm talking torsion beam like the Peugeot 205/306 etc have as the springing medium, but I can see how the function of the cross beam can be to transmit torsional force. I'll eat half my hat you can have the other half LOL!

Surely that's just the subframe? It's not quite the same as a torsion bar suspension spring.

bulldog5046 said:

my guess is some kind of wobbly stub axel...

your right, none of the bravo's, marea's, coupe's etc had torsion beams, Jug your going nuts....

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Again offset bore, but need to machine the end of the arm to reset the caliper mount position so its parallel to the disc. Maybe steve is going to resite the main pivot to an auxiallry section as an intermediate link, with the new pivot point angled for camber - that could be a bolt on job perhaps....

sediciRich said:

I'll eat half my hat you can have the other half LOL!

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seems fair

Hellcat said:

Surely that's just the subframe? It's not quite the same as a torsion bar suspension spring.

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yes you can call it the rear subframe, but technically it is a torsion beam because it resists twisting between the 2 trailing arms.

some cars have a different type of rear subframe that does not do this, and the subframe is only there to mount the bits on to the chassis. i cant remember what you call that type tbh, a cross beam or something like that. some cars have 2 rear subframes, with another name i cant remember (like the french style torsion beam setup you're talking about). some cars dont have seperate arms, its all one, thats called an axle beam (like an escort or most cars with the damper inside the spring). the name of the subframe(s) tells you what the setup is.

most (all?) subframes have a specific name, in the same way a punto is a car but its still called a punto.

Fair play jug, if you can get it to 0.1 degrees, I didnt imagine it was that accurate. What effect the heat has just bugs me a bit though. I've done a bit of research on it, and it seems a legitimate way of doing it.

Steve H said:

What effect the heat has just bugs me a bit though.

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the oldschoolers who showed me used warm engine oil to quench the arm after. they said that was done so it cooled at exactly the right speed to ensure the metal retained its original properties. they were old with lots of facial hair, so i believe them

an that wont burst into flames or nothing like

Steve H said:

Fair play jug, if you can get it to 0.1 degrees, I didnt imagine it was that accurate. What effect the heat has just bugs me a bit though. I've done a bit of research on it, and it seems a legitimate way of doing it.

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I know my friends in the clio cup (the renault sport series i.e. Toca competitors) heat and bend the steering arms to change ackermann angles. My only worry on the fiat arm is the amount of area to heat and the amount to get it to bend. The clio guys (JHR racing) had thick steel plate to bolt the hub to were talking 1/2 inch steel, then heat and bend with a scaffholding tube. That was with a bit of iron about <1inch CSA, look athe arm!!

Jug is right quench in oil -its iron you're heating and different cooling rates will change it into different composition, hopefully it wont break!!

dave said:

an that wont burst into flames or nothing like

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no of course not, oil is a very common quench fluid even in industry.

ain't that normally whale oil?

dave said:

ain't that normally whale oil?

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tbh i have no idea about whale oil, but it would be a good name for a sex lube.
i doubt there are enough whales on earth to satisfy 1 year of industral quenching, so i doubt it is a common thing to use these days.

sediciRich said:

I know my friends in the clio cup (the renault sport series i.e. Toca competitors) heat and bend the steering arms to change ackermann angles. My only worry on the fiat arm is the amount of area to heat and the amount to get it to bend. The clio guys (JHR racing) had thick steel plate to bolt the hub to were talking 1/2 inch steel, then heat and bend with a scaffholding tube. That was with a bit of iron about <1inch CSA, look athe arm!!

Jug is right quench in oil -its iron you're heating and different cooling rates will change it into different composition, hopefully it wont break!!

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What's an ackerman angle?

Surely bending the arm just leaves you with the same issue that the toe in will change with suspension travel.

Hellcat said:

What's an ackerman angle?

Surely bending the arm just leaves you with the same issue that the toe in will change with suspension travel.

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Ackermans angle is a static thing im pretty sure, its what makes the inside wheel turn less than the outside one.

I know how to set it up on recumbent bikes, but not cars, so I hope this makes sense.

Run an imaginary string thru from the kingpin in a straight line thru where the steering rod and arm meet and extend backwards. Do the same to the other side. If the strings cross in the centre of the rear axle, you now have Ackermans angle. If not, a redesign in in order.


I really hope that works for you

Ah yes. Think I need to get the lego out to play with this.

Hellcat said:

Ah yes. Think I need to get the lego out to play with this.

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If I was on my laptop I have a slideshow showing how we achieved this on our HPV's. But im not, and I wont be near the thing for a while, so I think you are going have to be creative. I'd use Technic, much better for this kinda stuff than Duplo

I've made several models using technic. Lifts, planes (didn't fly), and tonnes of mechanical proofs of concept. It's suprisingly useful stuff.

For sure, its brilliant, I got heaps of it as a kid, and when I go home, I think that I will break out the tub and have a play.

My fav kit that I bought was a trailbike, with a fully working two stroke engine.

OMG that sounds awesome.

Best I got in lego was a pneumatic JCB/Combined Harvester or the 'control centre' where you could program routeines.