[Fot] Leaf Springs TR4

[TR4 Tony]

Joe

I run 185 lb 5 leaf springs on BST and still get a good deal of squat if I really push or launch hard, but good stability in corners and limited roll. That's a full steel bodied car with an FIA cage, so probably heavier than yours. 

My experience is if you go much harder than that the tail end gets airborne over bumps, which whilst makes good pictures and certainly is entertaining, isn't very quick. I also run my fuel tank in more or less the standard position, which isn't as hard on the springs as one on the boot floor.

By contrast, on 3VC we have 7 leaf 165lb springs, but that sweet machine is all alloy skinned, only a rear bar, big tank in the standard spot, and is exceptionally well balanced on them. You'll see from the pics taken at the ADAC event I went to with Chris and Kas a few years ago that 3VC hunkers down on hard cornering because its softly sprung, but the car sticks like its glued as a result.

I'd hesitate to go much out of this range knowing what I know, so perhaps try a 165 plus a spare middle leaf (I think they add between 15 and 20 lbs to the rate) and swap it in and out to see what you like. I did this with BST which is why I've settled on a repeatable spec which I can now get via TR Enterprises in the UK.

Lastly, you might care to look at dampers too - both my cars are soft sprung / hard damped,pointy handling and I like it this way but done very differently due to chassis stiffness. 

Regards

Tony 




Sent from my iPhone

On 16 Sep 2013, at 14:54, Joe Alexander <n197tr4 at cs.com> wrote:

> Kas mentioned that we needed a higher spring rate at the rear.
> 
> Reviewing pictures certainly seems to confirm that.
> 
> What's the FOT experience.
> 
> We are looking at going to a spring shop, adding a leaf, and re-arching.
> 
> The car is very neutral with the current suspension. We are supposing that making some changes at the front will be required, too.
> 
> All help and insights will be appreciated.
> 
> Thank you...
> 
> Joe A.
> 
> 
> 
> Sent from my iPad
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