Live axle, and tyre wear Vs pressures.

[Zephyr Speedshop]

Hopefully some of the more knowledgeable guys can school me on this.

So Im relatively new to RWD on track with my fisher fury that has a English live axle.

Last year at Goodwood (particularly extreme example) I was absolutely nukeing the outside should of my rear tyres. And ended up running a few psi more that than I would normally to try and stop the tyre rolling over so much.

This was on A0008s with a square 185 section all-round.

I've now moved to 185 front and 205 rears and using A052s.

Have you guys got any stragies for my so Im not leaning on the outside shoulder quite so hard?

More negative camber would be a massive help but obviously not an option.

Is there something I can do with my driving style and maybe pressures so I'm not immediately killing them.

Car weights 590kg. Not that powerful at 130bhp
I usually target 18psi hot however I'm not sure where I need to be with the a052s yet.

I'm at brands on Monday so I can report back my findings




Hairpin at Bedford so pretty low speed.

[Bertrum]

You need to get the live axel setup properly, they can be bent to achieve what you need, toe and camber.

No idea who still does it though but would assume someone who preps rally escorts could help

[Zephyr Speedshop]

Bertrum said:

You need to get the live axel setup properly, they can be bent to achieve what you need, toe and camber.

No idea who still does it though but would assume someone who preps rally escorts could help

How does that work with the half shafts? Certainly in the English axles there is zero provision for any angle changes?

[Florida_Man]

I track a Mustang GT with a solid rear axle and there’s not much I can do ($10k cambered rear axle aside) for outside tire wear in the rear. I just rotate the tires more often. Bending axles is a bit of a bodge and you would only get 0.5 of camber before you run into
Issues with bearing imo

[braddo]

The rear tyre might be folding over because the tyre pressure is too low. I would try 25psi hot and see how it goes. Then I would look at softening the rear roll relative to the front (i.e. softer rear ARB if you have one, or firmer front ARB).

Is it possible for these axles to gain positive camber under cornering stress?

I had a Caterham for a couple of years with a de dion axle, soft suspension and sticky tyres and I didn't get outer tyre wear problems on track days.

[Zephyr Speedshop]

So yesterday I had my first day with the a052s an it was significantly better. For tyre wear/feeling.

I don't have a rear roll bar as such although the 4 link in a fury is setup to use the axle as as and arb by inducing twist.

I don't have a font ARB.

I was expecting the outside shoulder temps to be way higher than the inside. But all pretty even with a laser. (I know I should really use a pyrometer but I don't have one)

For reference the front inner shoulders were about 5c hotter than the outside. It's about -1.5 camber on the front.

I've annoyed myself by being very timid with changes yesterday. But I was still getting used to some braking system changes and the new tyres/staggered setup. Think on the next one I'll be abit more comfortable to try stuff.

I did stiffen the dampers all round in the afternoon and it was way more planted/stable. But not really any quicker (lots of traffic tho)

Here's a quick onboard, if you're interested

[Jim Spencer]

Hi

Sylva Striker Mk3 owner here, (so live axle, outboard front suspension) which I think is pretty much what's under yours, certainly the chassis is basically the same.

Ran it for many years at speed events, went quite well.

The single biggest difference we made to the handling of the car was to fit a front ARB, prior to that we'd ended up with very hard front springs to get the roll out of it, and consequently the car ended up stiff to get a balance into it. The front ARB allowed us to go back to a much more compliant setup, car was nicer to drive (especially if somewhere bumpy or needing to use the kerbs) and much quicker overall.

I think somebody produces a kit of bits to fit one to a fury, but if not the components are available to construct one.

[Zephyr Speedshop]

Jim Spencer said:

Hi

Sylva Striker Mk3 owner here, (so live axle, outboard front suspension) which I think is pretty much what's under yours, certainly the chassis is basically the same.

Ran it for many years at speed events, went quite well.

The single biggest difference we made to the handling of the car was to fit a front ARB, prior to that we'd ended up with very hard front springs to get the roll out of it, and consequently the car ended up stiff to get a balance into it. The front ARB allowed us to go back to a much more compliant setup, car was nicer to drive (especially if somewhere bumpy or needing to use the kerbs) and much quicker overall.

I think somebody produces a kit of bits to fit one to a fury, but if not the components are available to construct one.

interesting, that sort of tally's with yesterday. stiffening the damping made the car more stable/planted. however came at no gain in lap time, which suggests to me (in my admittedly limited understanding) I was sacrificing overall grip for some more stability.

maybe I should try softening the rear damping and stiffening front to confirm.

the fury has inboard suspension but there's defiantly some with a front ARB, more investigation needed

[Jim Spencer]

Zephyr Speedshop said:

interesting, that sort of tally's with yesterday. stiffening the damping made the car more stable/planted. however came at no gain in lap time, which suggests to me (in my admittedly limited understanding) I was sacrificing overall grip for some more stability.

maybe I should try softening the rear damping and stiffening front to confirm.

the fury has inboard suspension but there's defiantly some with a front ARB, more investigation needed

Hi, ahh ok, so like a Mk2 Striker (too many different versions of these things!) in which case yes there's certainly been front ARB's fitted by various people.

I'd suggest the effect you've experienced with the stiffer shocks will have been to reduce the rate of roll, hence it feeling more stable. What we experienced, by continuing down that route (steadily stiffer springs and shocks) was ending up with something that responded but went through 'stable' to 'twitchy' and hence one lacked confidence in it, you lost the 'feel'. ARB on the front, back to softer springs and shocks valved to suit (& the cars weight) transformed it, loads of feel, you could properly lean on it and when either end did let go it did so without biting you.. we (brother and I shared it) went from borderline competitive to right on the pace.

[Jim Spencer]

While I'm thinking about it (been a few years..) the other thing I'd suggest looking at is the diff.. Quaife ATB will make a properly noticeable difference if you're running an open one, it'll make the car more predictable at the limits.
IMHO, and this can be a good pub debate, in a car this light they're preferable to a plated LSD.

[Zephyr Speedshop]

Jim Spencer said:

While I'm thinking about it (been a few years..) the other thing I'd suggest looking at is the diff.. Quaife ATB will make a properly noticeable difference if you're running an open one, it'll make the car more predictable at the limits.
IMHO, and this can be a good pub debate, in a car this light they're preferable to a plated LSD.

its got a blackline torsen in. i find the car is very controllable at or just over the limit. hard to explain and maybe its also to-do with me being used to heavier cars. but i feel like it could use more grip all-round, its well balanced. just feel like it could go faster. perhaps im at my limits with it rather than the cars.

i big factor in this is my confidence in the brakes as previously they were like an on off swich. yesterday they were a lot more progressive, with a lot more feel. but theres still abit of a mental block from really leaning on them, that will come.

yesterday was defiantly progress the car was alot more stable than ever before.

[braddo]

Jim Spencer said:

Hi
...
The single biggest difference we made to the handling of the car was to fit a front ARB, prior to that we'd ended up with very hard front springs to get the roll out of it, and consequently the car ended up stiff to get a balance into it. The front ARB allowed us to go back to a much more compliant setup, car was nicer to drive .. and much quicker overall...

This was exactly the experience by tuners of the old 105 Giulia Alfas. In the US people were using crazy front spring rates to manage roll but in UK/Europe it was found to be more effective to use a bigger front ARB and relatively softer spring rates.

And to remove the rear ARB. And to manage ride heights to keep roll centres in the right range.

[Zephyr Speedshop]

This picture speaks volumes about a front ARB, ill start looking at options and ideas on what can be fitted.

[Jim Spencer]

Yeah, you can almost see the front of that fighting the rear... Lol keep us posted how you get on!

[Panamax]

Jim Spencer said:

Quaife ATB will make a properly noticeable difference if you're running an open one, it'll make the car more predictable at the limits.

Hello understeer. (The flip-side of less oversteer.)

[Zephyr Speedshop]

Panamax said:

Jim Spencer said:

Quaife ATB will make a properly noticeable difference if you're running an open one, it'll make the car more predictable at the limits.

Hello understeer. (The flip-side of less oversteer.)

Certainly not been an issue yet. Even with a 130 bhp it's quite happy to drive on the throttle.

[Panamax]

Zephyr Speedshop said:

Even with a 130 bhp it's quite happy to drive on the throttle.

I guess that's a fair point in such a light car.

[CKY]

Zephyr Speedshop said:

Have you guys got any stragies for my so Im not leaning on the outside shoulder quite so hard?

More negative camber would be a massive help but obviously not an option.

I ran 1.25 degrees of negative camber on a live/solid rear axle RWD racing car for 5 seasons or so before I sold it, it is an option but you just need someone who knows what they're doing - unfortunately contemporary racing cars haven't had live axles for some years, so it's a bit of a 'dying art' (especially getting it done so accurately in terms of camber and toe). I presumed (as a previous poster mentioned) the additional angle for the half shafts would lead to increased bearing wear, however both times the rear axle was stripped during the Winter there was nothing obvious.

[braddo]

Back in the day with big spring rates instead of an appropriate front ARB

[Zephyr Speedshop]

braddo said:

Back in the day with big spring rates instead of an appropriate front ARB

I definitely don't have the articulation to achieve that