front lower wishbone (TCA)

[bobbrown]

Interesting thought, going to Alloy;

The originals had a cross-brace to the triangulation link, obviously making them handed;

During acceleration and braking, I would think the triangulation link plays a big part in keeping the geometry true?

How does the ommision of the cross-brace effect 'things'?

Gordon

The triangulation link has not been left off, there are two additional holes towards the inboard end that allow the connection of the link.
I was trying not to make the main part handed so the link is bolted to it and then bolted to the existing half of the link

[markv]

One other question: should these be fitted in pairs (i.e., both left and right side, to keep it all symmetrical) or is it OK just to put one side on?

[bobbrown]

One other question: should these be fitted in pairs (i.e., both left and right side, to keep it all symmetrical) or is it OK just to put one side on?

As they are dimensionally the same then there should be no reason to suppose you could not fit just one but I would think you would want to change both if the old ones have crumbled to a heap of iron oxide.

[Gordon]

Interesting thought, going to Alloy;

The originals had a cross-brace to the triangulation link, obviously making them handed;

During acceleration and braking, I would think the triangulation link plays a big part in keeping the geometry true?

How does the ommision of the cross-brace effect 'things'?

Gordon

The triangulation link has not been left off, there are two additional holes towards the inboard end that allow the connection of the link.
I was trying not to make the main part handed so the link is bolted to it and then bolted to the existing half of the link

So I see - good idea!

[ashm]

I do not expect this item to be much lighter than the original but also no heavier as aluminium is 1/3 the weight of steel but I have made it thicker than it probably needs to be.

I do not percieve the differing coefficients of expansion to be that much of an issue, as the differance of the two materials over say a 30 degree temperature rise is about .005" if my calculations are correct.

Probably wise on the dimensions... just thought I saw an opportunity to shave some unsprung mass!

Yep, I get 4.3 thou per foot over 30 degrees, not a lot at all. I suppose I should do the maths before I ask silly questions!
I've had bad times with part steel, part ally rifle triggers on hot days. The errors must have been tiny fractions of a thou, since the whole mechanisms were only about an inch across! Crazy.

Adam

[Candles]

Well I think this is a fantastic idea and would be dead keen on ally. The only slight misgiving I have is that although these aircraft spec alloys are very strong, they are quite susceptible to high-cycle fatigue. Will we have to X-ray the TCAs every 5000 miles?
Back to being serious, I presume at the thicknesses you mention the metal will not be deflecting at all, so I'm guessing the fatigue isn't a problem.

Are you planning on supplying matching triangulation links? It would look silly with the old ones bolted to the machined ally

[bobbrown]

Are you planning on supplying matching triangulation links? It would look silly with the old ones bolted to the machined ally

That's a thought and the other half is not subject to the same loads as the main link as it is only controlling fore and aft movement.

[Alan_C]

Count me in too please, aluminium, black anodised with ball joints and bushes.

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)
22. Alan C (cutlea01) inc ball joints & bushes

[RichardK]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K(inc ball joint and bushes pls)
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)
22. Alan C (cutlea01) inc ball joints & bushes, black

[mvf906]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K(inc ball joint and bushes pls)
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)
22. Alan C (cutlea01) inc ball joints & bushes, black

23. mvf906 ( £ dependant )

[nicowalker1]

Bob you are a very clever guy!!!
ill watch this post closley as im having to watch the £'s i may join the list later but cant commit at the moment

[ab2cv]

Bob you are a very clever guy!!!
ill watch this post closley as im having to watch the £'s i may join the list later but cant commit at the moment

Ditto.

I'll be taking a closer look at mine whilst fitting the new HI-SPEC calipers and making a decision from there.....

Alan

[bobbrown]

I have had a closer look at this and have now ruled stainless steel out as an option due to strength issues

for example yeild strengths
Stainless steel 304 2100 Kg/cm2
Mild steel 3840 Kg/cm2
Aluminium 7075 4640 Kg/cm2

there are two areas that the tensile strength is important and that is where the bushes and ball joint fit the weakest area is the inboard one but in 7075 aluminium should be capable of taking in excess of 23 tonnes, in mild steel 17.5 tonnes and the one I have a concern over stainless steel 9.5 tonnes.
Thats assuming my calculations are correct and there are some factors I have not taken into account but they will only increase the figures not decrease them.

Bob

[saska]

for example yeild strengths
Stainless steel 304 2100 Kg/cm2
Mild steel 3840 Kg/cm2
Aluminium 7075 4640 Kg/cm2

Bob, firstly thanks for all the work you're doing on this one. The front TCAs are what I would regard as crucial to the safety of the car so have 2 questions:
1. Do you think galvanic corrosion would be an issue where steel meets the aluminium? It is usual to ensure that the 2 metals do not physically touch so as produce the anode/diode pair.
2. Steel will bend, AL7075 may be stronger but, when its limit is reached, it breaks. Recently friends in a Mitsubishi Carisma hit a rock that had fallen out of a dry stone wall. Rock was approx 1ft high X 2ft wide by 1.5ft deep and they hit it at about 50 mph. The wheel & tyre were both gonzo, the TCA was bent but everything was still attached, albeit the NSF wheel was pointed somewhere west of Greenland. They stopped the car safely and pulled it safely off the carriage way about a quarter mile past the rock. How do you think an aluminium component would fare in such a scenario?
Your figures above would account for why Lotus went for galvanised steel on the rear wishbones of the S2 rather than stainless to fix the NA/SE rear wishbone corrosion issue.

[bobbrown]

Galvanic corrosion should not be a big problem as carbon steel and aluminium are in fact quite close to one another.
The voltage differance between the two is quite small around 0.05 V IF it was stainless steel and aluminium then this figure is more like 0.5V.
So if you fit steel bolts through aluminium there will only be slight galvanic corrosion, use stainless steel ones and the reaction will be much greater.
This does assume that there are no protective coatings and as the parts are going to be anodised and it may well be a good idea to paint them as the anodising does give a good surface for paints to bond to.
If this was a major issue then brake parts would also suffer and they seem not to do too badly, take a look at the rear caliper bracket and that is after over 15 years,

hub corrosion.jpg

however if you look at the A pillar then there can be a bad reaction between the seal carrier (stainless steel) and the aluminium section of the A pillar that the screen attaches to, I think this suffers badly due not only t the materials but also there is a nice electrolyte layer of foam rubber.

Hit a large object at 50mph and you are asking for trouble if the wheel is smashed what difference does the fact that the TCA was just bent make?
I have seen a Honda S2000 that had an accident it his an island in the centre of the road at a junction and that smashed the wheel and the front lower wishbone and that was probably less that 40 mph, I think the trick is not to hit things, particularly large things like big trees as the tree always wins.
.

[bobbrown]

I know there are some concerns about using 7075 aluminium but is is stronger than people think, heres a link to a video of aircraft landing gear which is made from 7075 aluminium, OK they are allowing the aluminlum to flex but it show it will flex with out breaking Link

[ashm]

Neat video!

[BFG in the BRG]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K(inc ball joint and bushes pls)
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)
22. Alan C (cutlea01) inc ball joints & bushes, black
23. mvf906 ( £ dependant )
24. BFG in the BRG inc ball joints & bushes

If I am not too late- only stumbled across this one whilst looking up CV Boots Every cloud......

[Candles]

Bump!

I have the car jacked up for the winter now and was about to start stripping (the car's suspension, not my Elan maintenance overalls!). Are we going ahead with this or shall I keep my spanners in the toolbox for now?

Candles.

[Nige]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K(inc ball joint and bushes pls)
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)
22. Alan C (cutlea01) inc ball joints & bushes, black
23. mvf906 ( £ dependant )
24. BFG in the BRG inc ball joints & bushes
25. Nige (possibly 2 sets, depending on price) Ball Joints and bushes as well please.

Bob, I'm in for this provided my car is repaired (looks like it's going ahead) I'm not in any hurry as the car will see little use given that it's in for repair and I have a number of other things to do first.