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Rear Leaf Spring Elimination Kit


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Finally:-

There were unwritten gentleman's agreement on those days (Kevin forced people to keep to it)...common sense really.....

 

1/ I lend you my car, you bend it/break it you pay for it.....

So we all lent each other cars, trailors whatever....Kevin lent me his capri once, I lent him my Vitesse...

So what? Big deal.

Normal behaviour no?

You didn't get someone venting all over the internet "I washed your dirty jeans in my machine".

 

There was NO internet, no E-mail, no mobiles phones, and much better it was too.

 

2/ People had to pay for gear.

You just didn't walk off with/order stuff and come up with some lame excuse.

This worked on the following lines....

(you did this, you did that....you didn't have to fight for stuff, Kevin would come up to you after some giant all night marathon, with a wad of cash...)

"look mate " how much do I owe you"?

Same for Paul.

That is how you make cars that win races.

 

Race cars ALWAYS cost much more than planned.

That is the way they are.

If you don't like this, don't get involved in motor sport.

Go and do gardening or fishing instead.

PERIOD.

 

Don't pretend you like it, if you're no good at making a fast lap, or you have a heart condition.

You've NO business pretending you're any good.

If not, You're just on it for an EGO TRIP, like 100s of others, and MONEY is no substitute for talent.

 

It depended on honesty. SURE, but let's say after 25 years+, that doesn't need to be proven.

 

How come we could do all that, with what we had, instead of people bitching & shouting, trolling I haven't made anything that won any races but then not paying their bills like all the crap we have now?

 

Sure thing, I wouldn't DREAM of giving anyone a hand today, for that very reason....

What's that?

 

EGO TRIP madness, and sure as good 'ole Jim 'l fix it Savile it's gonna find you out, even long after you're dead.

Edited by Nick Jones
Statement like that can bring lawyers and we don't want them. Public forum not the place for private dispute
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You guys have seen this before but here's a pic of my double link rear suspension. Remember we are required to use the original mounting points so we're more limited in the creativity.

 

With this I was able to dial out most of the bumpsteer and get a pretty good camber curve BUT it's way too fiddly should you have a shunt or break something at the track. It's really easy to get the links in a bind if not careful. I had a double action pnuematic cylinder to sit in place of the shocker and I could run the suspension thru it's travel against the spring.

 

If I were to do it again I think I'd keep the single point A-arm and work on strut rods to control travel. It worked for McClaren MK8's after all but they had lot smarter people than me drawing it up....

 

Rearrods003.jpg

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Remember we are required to use the original mounting points so we're more limited in the creativity.

 

Don't know about your limited creativity, Steve!

ESpecially whe it comes to spoofing scrutineers.

Remind me now. Which model Spit had TWO wishbone brackets on the chassis rail?

 

BIG smiley!

John

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Of course, none had two.

 

But the original mounting point is there and in use. Scrutineering is a tightrope where you interpret the rules to the max. There's a thousand things I see in the rules on your side of the pond I'd LOVE to exploit. But the rules define the boundaries. That we push. SCCA was the rule of the land in our racing. To this very day Steve Sargis and Sam Halkias, just to name a few, are still beating the modern competition with their old Triumph iron.

 

My childlike mind has always said that any Triumph racer should be helping any Triumph racer to finish above the challengers. Secondary to that, we race among ourselveles.

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My childlike mind has always said that any Triumph racer should be helping any Triumph racer to finish above the challengers. Secondary to that, we race among ourselveles.

 

And there, in a single sentence, is an innate proof that Steve is a man to be liked, admired, and fed beer. Were it were that I could see you across a grid someday.

 

C.

 

(They got decent go karts in Vegas? Friday the 16th still good? Match race before a couple'o quiet beers?)

 

 

 

 

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A "double action pnuematic cylinder"?

Brief googling reveals this to be a bicycle pump in reverse that works both ways, given a supply of compressed air.

Do you mean that you had compressed air on the car, or that you used a disconnected cylinder instead of a damper as a telescopic strut to test and develop your suspension ideas?

I like that idea, and I'm always keen to steal other peoples'! Do DAPCs come with either a bush-ring or a spherical joint on either end? Where would I look for one, please?

John

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Pnuematic cylinders are common as muck in industry. Do a google for Bimba and find their online catalog. There's lots of others, any industrial supply house, bearing suppliers, should have catalogs. I have the Bimba number somewhere in the files. They are available with any end configuration, studs, eyes whatever...

 

The cylinder replaced the shocker for the experiments and an air regulator from the garage air adjusted it's travel position against the spring. I'll find the number for you but your's will likely be shorter. Note my shocker mounts lower on the vertical link than standard.

 

A "double action pnuematic cylinder"?

Brief googling reveals this to be a bicycle pump in reverse that works both ways, given a supply of compressed air.

Do you mean that you had compressed air on the car, or that you used a disconnected cylinder instead of a damper as a telescopic strut to test and develop your suspension ideas?

I like that idea, and I'm always keen to steal other peoples'! Do DAPCs come with either a bush-ring or a spherical joint on either end? Where would I look for one, please?

John

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Just getting caught up here... Actually the SIII GT6 with the lower wishbone has two chassis pickups on each side-if you count the radius rod attachment on the floor of the body. I am considering a lower A arm with two frame attachments points and a single point on the lower portion of the upright. This should cure bump steer, but I'm not sure how to cure spring twist under heavy loads. This is a situation I fear is occurring when using only the bottom leaf of the standard unit (with coil overs to augment).

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This should cure bump steer, but I'm not sure how to cure spring twist under heavy loads.

 

I simply don't get this.

There's no such thing as "bump steer" at the rear.

What you are getting is just variable TOE angle.

 

You can only get a change in geometry if you have castor, and the rear doesn't have any (to speak of).

The only reason it doesn't get squat is because the wishbones are unequal (reversed) length, so that's good too.

Have you ever seen a GT6 squat?

No, it just doesn't happen, unlike the horrible TR6 trailing arm rubbish.

 

If you look at a properly engineered wishbone rear suspension (Jaguar XJ40), you will see how the single coil over and it's reaction is overcome by introducing rear castor and therefore anti squat, and spacing the bottom wishbone inside anchor points extremely wide to gain rigidity and compactness.

The wishbone is then made extremely rigid with 2 internal anchors and 2 external anchors and these are in fact "braced together" by making one large wishbone.

In fact the outboard lower pivot point has taper rollers internally, & the damper bolts is MASSIVE, which goes to show how important it is.

 

There are downsides to this arrangement particularly under heavy braking,where Jaguar basically destroyed the stability of the entire arrangement by the way it's badly located in the car, but that is not my point.

 

xj40_rear_suspension.jpg

 

The coil over has another major introduction of aggravation here also.

On the E type, they shut the reactions into the rear entire rear subframe, and let the entire subframe move around.

("let" being the Jaguar word for "bodging")

 

On the later system above they drop all the spring reaction into the BODY, (logical in a way) while all the rear suspension does in effect is guide the car.

Under strong torque reactions such as acceleration or braking this unfortunately is not as accurate, so squirming & inaccuracy becomes a major problem, which is why they "let" it have an adjustable toe in system on the X300 (later cars).

 

On the E type, with its balanced system of dual springs and dampers, the damper is easier to upgrade, but has no rear anti squat, but has very weak internal wishbone anchor points. (which DO break).

So it DOES dive, but DOESN'T squirm and doesn't hop under heavy braking, but to do it properly you have to mount the rear subframe solid to the body. (so "let's" have some rear roll bar as well shall we?)

 

So, if you are intent on keeping the anti dive properties of the Mk2 Triumph rear suspension, but do away with the cart spring, you need to fit a REALLY solid dual anchored bottom wishbone, get rid of the radius arm altogether and fit 2 rose jointed tie rods to the centre of the car to the diff area. (making up am anchor plate is dead easy).

You can throw away the rear leaf spring altogether and fit a couple of nonlinear rated springs which can pick up on the body or chassis.

 

If you want to keep the rear spring, then a carbon fibre single leaf would do great as a rigid top wishbone, so you can get the taper/flex point to whatever you like with that idea.

 

That gets rid of the variable toe issues, which once again plague all Triumph cars.

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Here is what I thinking about. Don't know if the the radius arm should be attached to the lower wishbone piece or to the upright (like the factory part) Also, I'm not yet convinced there is actually a problem with using the leaf spring as the upper link (only the lower or longest leaf, that is) The lower wishbone would attach to the upright with the standard long bolt through bushings, with the inboard attachment a rod end. I think the radius rod should have rod ends at both ends and be slightly adjustable up and down at the frame (as shown in the sketch)

 

Comments?

 

Clark

post-1494-0-73073500-1351204142_thumb.jpg

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If you mount the strut rod to the lower control arm lateral acceleration and deceleration forces will be controlled only by the control arm. If the strut rod is connected to the upright.for and aft forces and twisting forces are absorbed by the upper bushing and the strut rod bushing and the lower control bushing. The diff is not solidly mounted to the chassis so any twisting during acceleration or decel. will push and pull the upper rod and the greater the distance from the center of rotation (the drive shaft )the greater the movement. just some thing to think about . I like your approach. On the RoSpit they used two inner chassis mounts so the A reversed. keep updating us on your design. One last thing: the upper rod is sufficient for 90% of cars but if the upper link is adjustable does the lower need to be and that could simplify things.

Edited by motov8id
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I envy your artistic ability Clark .

I finally had a response from KD the other day and he suggests his set up is very close to completion , so may be worth a once over before making any decisions .

Would I be right in thinking that if the diff top mounting plate is widened , making the upper arms shorter , closer matching the lower wishbone length does this not improve castor issues ? The extended length could be supported with triangulated brackets off the sides of the diff top plate .

Perhaps I should comment after spending this weekend studying some basic principles but that would score no ' IMPULSIVE POINTS ' .

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I am not sure I like the threaded bar as the top link. The natural motion of the VL will be to rotate back and foward, only a little, but the threaded section will not control that movement, and may possibly start to work free??

 

Maybe I have missed the point here??

 

However, as my brain is confused with all this stuff, I opted ages ago to stick with (the std) Nick Jones well trodden path. The more I read, the more I am glad I did so.......or maybe I am just lazy :yes:

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In my opinion (and I think I said this earlier in the thread), as drawn, that modified setup will allow MORE unplanned geometry variation than the leaf spring. The problem lies at the inner joint of the new upper link. Whereas the leaf spring is extremely rigid at that point, the bush on the inner pivot will have some flex. The length of the arm from vertical link will mean plenty of leverage on that inner pivot to generate that flex and also mean that a small amount of movement there is a large amount at the outer end.

 

If you must ditch the leaf spring then you need to bring that pivot outboard to reduce the leverage and make the inner pivot as wide as possible - or divide into two as a wishbone.

 

First off I'd try an adjustable lower wishbone and do some experimenting with toe and camber settings as well as tyre pressures before messing with the spring.

 

Nick

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Back from a pleasant 10 mile run, and had some thoughts.

Why are there so many people wanting to ditch the leaf spring? it actually is simple, works well, and the spring acts in the right position, centrally to the upright. Is there any reason a coil-over is superior? and if so, is that superiority enough to justify all the grief in making the top wishbone? that in itself seems to be a nightmare with some huge hurdles to jump over.

 

In fact, Nicks last sentence is what I am trying to say!

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why connect the top link to the diff?i used a length of 1.5"square box with two small plates welded on each end which slip between the body and chassis mount and retained by the body mounting bolt.as said a longer top link will increase roll induced positive camber.

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When designing Silverback, I had been convinced that even the spring could allow some fore-and-aft movement of the top of the upright.

So parallel to and the same length as the original, I fitted a second radius arm that came through the wheel arch and was anchored to a bracket that came up through the floor from the OE bracket. The bracket was braced to the rear roll-over hoop on that side and across to the other. It was, in fact, one of a spare pair of radius arms - I didn't even have to fabricate them. See pic.

 

Have to say, I don't think it made much difference - perhaps the spring is more rigid in that plane than I thought!

 

John

post-690-0-64254900-1351286975_thumb.jpg

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First off I'd try an adjustable lower wishbone and do some experimenting with toe and camber settings as well as tyre pressures before messing with the spring.

 

This may interest you.

I did all of those things years ago.

 

We made the lower wishbone adjustable and could put the pick-up points where we wanted.

Guess what it turned out to be utterly pointless.

The original pick-up position invariably turned out to be the best.

I felt pretty stupid seeing that.

 

secondly I made proper radius arms, with LH/RH threads on, in s/s so they wouldn't rust solid and all nicely done with a machined in HEX to boot rather than some nasty little thing like they have on the factory ones. (very nice work).

It was so well done you could practically adjust the radius rod by hand....

In fact TOE settings WERE quite critical to handling esp with 8" rims.

 

The hic was, I hadn't realised at the time, there was a reason Triumph put rubber bushes in the radius arms....it was to cope with the stupid toe in/toe out variations and the messy geometry.

The moment you anchored it solid it would try to tear itself apart.

 

This is exactly what happened before going over the top with reinforcing the constantly fracturing radius arm mounting.

I had to look at what was going on

 

It was EITHER the bush on the top leaf spring would be forced backwards or forwards in the eye,or even the TWO leafs, bottom and top would be forced to be splayed apart by the geometric variations.

Talk about rigid...it SURE ISN'T once you start putting tonnes of force in there.

 

So in the end this is how it worked!

 

We anchored the radius arm nice and solid, with our amazing reinforced chassis and rose joints, and let the rest of it be jiggled around to cope with it.

As we had a proper reinforced rear end with a semi chassis let in across the body right between the 2 rear wheel arches, and a specially fabricated cover over it, you could view the entire suspension from inside the car moving around as you drove along.

(I won't go into how we made that, it was a ONE OFF)

 

I can assure you when you saw just how much flex and movement there was taking place on the diff mounts and the weird and wonderful excursions of the leaves of the spring, you would have wondered how it worked at all!

 

Most of the clever stuff came from the failed (Kipping) spring, which he had detected as being so unbelievably HARD, that it was unsaleable and indeed UNFITTABLE to any known car. (it used to turn the air BLUE, just forcing it into position, drove me MAD!)

 

As usual,some mental rated production failure turns out to be brilliant for a circuit car....but it wasn't fun to work on.

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Suspicions concerned as to all the movement in that leaf spring set up. I am also aware of the problems associated with rod ended radius rods ripping mounts apart. All this is greatly exacerbated by running on wide racing slicks...

If you could be a little more specific about what you ended up making thing work (and live) I would really appreciate it. Remember, I'm a eff'n yank! Thanks GT for that input.

 

I can't find the Jango ref. on the Club Triumph site. How about a link?

 

Thanks for ALL the comments on this thread.

 

Clark

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