Right!

I've read dozens of threads, tried a few threads myself to which I have had some really helpful answers, but I really need to nail this 'cos it's driving me insane!!

The plan is:

1. To cater for the fact I am building a +442, I need to lengthen the wishbones.

2. I want to try and keep the ratio of length:width the same as the originals to preserve the bending load figures.

3. I am running a 52" axle and 10mm spacers to give me a reasonable clearance for the rear wheels (not massive but hopefully enough)

The trouble is, this means exrtending the distance from lower bone balljoint to centre of bushes from 340mm to 410mm. To maintain the ratio this means that the distance between mount outer edges increases from 343mm to 404mm!!

The same for the top bone makes the new spacing 288mm!!

My question is, do I reduce the width between bushes slightly and try and use the existing LA/LB and FU1/FU2 or do I move FU1 and FU2?

I am just worried about loads and weak spots!

Sorry for the essay so early in the morning but this is doing my head in and I can't really move on until I get this sorted.

Thanks all.

i would just keep the mounts in the same place myself, and change the angle of the legs. If you are concerned about affecting strength, you could up the tube gauge, but i myself wouldnt be worried about that.

The front track doesn't have to be the same as the rear, so you may not need to increase the width by so much, if at all.

Some pictures or diagrams of the parts in question would help a lot

John

whats wrong with having the front narrower than the back? makes no odds really and there's plenty of good handling cars like that like that, Testerosa, Countach to name a couple. If the fronts working then I'd say sod it and leave it the way it is

quote:

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Originally posted by Mr Whippy
whats wrong with having the front narrower than the back? makes no odds really and there's plenty of good handling cars like that like that, Testerosa, Countach to name a couple. If the fronts working then I'd say sod it and leave it the way it is

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quote:

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Originally posted by mr henderson
The front track doesn't have to be the same as the rear, so you may not need to increase the width by so much, if at all.

Some pictures or diagrams of the parts in question would help a lot

John

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quote:

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Originally posted by Daddylonglegs

quote:

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Originally posted by mr henderson
The front track doesn't have to be the same as the rear, so you may not need to increase the width by so much, if at all.

Some pictures or diagrams of the parts in question would help a lot

John

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John, I'm working on the premise that the book design (for all it's other faults) was probably OK in the handling department so as the axle was 100mm wider and I also had 20mm extra in the form of spacers, that I should increase the front wishbones by the same amount to keep the realtionship between the two.

John

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quote:

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Originally posted by Daddylonglegs

quote:

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Originally posted by Mr Whippy
whats wrong with having the front narrower than the back? makes no odds really and there's plenty of good handling cars like that like that, Testerosa, Countach to name a couple. If the fronts working then I'd say sod it and leave it the way it is

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I'm just going on what I was told by one of the chaps at the Stafford show (on a chassis tuning stand). He reckoned that the slightly wider front gave a little more understeer to reduce the risk of a 'pendulum' effect if being a little heavy on the right foot coming out of corners

I'm no expert so couldn't really say one way or the other but what he said seemed to make sense?

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I've been digging in my memory pit, and have come up with the fact that the 442 is designed to provide the extra width body but using a standard nosecone.

If you feel that you must have the front track the same as the rear, you could just increase the width of the chassis rather than the length of the wishbones.

quote:

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Originally posted by Mr Whippy

quote:

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Originally posted by Daddylonglegs

quote:

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Originally posted by Mr Whippy
whats wrong with having the front narrower than the back? makes no odds really and there's plenty of good handling cars like that like that, Testerosa, Countach to name a couple. If the fronts working then I'd say sod it and leave it the way it is

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I'm just going on what I was told by one of the chaps at the Stafford show (on a chassis tuning stand). He reckoned that the slightly wider front gave a little more understeer to reduce the risk of a 'pendulum' effect if being a little heavy on the right foot coming out of corners

I'm no expert so couldn't really say one way or the other but what he said seemed to make sense?

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hmm I bet you could find 101 different opinions on such things...

considering then number of cars produced with the front wider than the rear I'd say that one goes on the 'less believable' shelf

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thats my point, there isn't any that produce a car with the front wider that the back, unless its a 3 wheeler

Honestly there's much better ways of dealing with oversteer, which is hardly an issue on a 7 anyway. If you want an example of bad cars for pendulum effect and oversteer look at a beetle or porsche, none have ever had the front wider than the back to sort it or ever even heard that being recommended.

All reminds me of my mad b$st$rd mkI Capri what a car for fish tailing who ever thought 3ltrs could be so much fun



[Edited on 7/1/09 by Mr Whippy]

Interesting discussion HERE from a couple of years back

quote:

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Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back

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quote:

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Originally posted by Mr Whippy
thats my point, there isn't any that produce a car with the front wider that the back, unless its a 3 wheeler

Honestly there's much better ways of dealing with oversteer, which is hardly an issue on a 7 anyway. If you want an example of bad cars for pendulum effect and oversteer look at a beetle or porsche, none have ever had the front wider than the back to sort it or ever even heard that being recommended.

All reminds me of my mad b$st$rd mkI Capri what a car for fish tailing who ever thought 3ltrs could be so much fun



[Edited on 7/1/09 by Mr Whippy]

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quote:

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Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back

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quote:

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Originally posted by Mr Whippy

quote:

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Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back

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gods reminds me of star trek forums when their 'discussing' who was the best captain...

which is Kirk btw, just don’t even start to disagree!!!

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no comment

IMHO, if you lengthen a wishbone then you should also increase the tube diameter or wall thickness, or both.

It's not so much an issue for me as I have built a +4, (4" added to the centre of the car, front to back) so my
bones are book length. (caster dim changed to aid self centering)

It does make the front track slightly narrower than the back, but as I understand it that's how a book car is.


Paul G

quote:

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Originally posted by Mr Whippy
thats my point, there isn't any that produce a car with the front wider that the back, unless its a 3 wheeler

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I think the 205 gti is the same, wider front track.

And I think evo's and scoobies are the same.

My volvo 240 donor also had wider front track, and if memory serves me right it got wider in later models and back stayed the same!!

I was also told it improves turn in..

quote:

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Originally posted by MikeRJ

quote:

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Originally posted by Mr Whippy
thats my point, there isn't any that produce a car with the front wider that the back, unless its a 3 wheeler

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The Citroen Visa GTi had a wider front track than rear, and that handled pretty well.

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If you make it to the end of the thread I posted earlier, you will see that it's not just the Citroen Visa GTi. There's also the Noble m15 (89mm wider at front), Ferrari F430 (53mm wider at the front) and the Lamb Gallardo (30mm wider at the front)

quote:

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Originally posted by Richard Quinn
If you make it to the end of the thread I posted earlier, you will see that it's not just the Citroen Visa GTi. There's also the Noble m15 (89mm wider at front), Ferrari F430 (53mm wider at the front) and the Lamb Gallardo (30mm wider at the front)

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Most old renaults are wider on the front than the rear.

I remember someone telling me that the Renault's 5 rear wheels had uneven lenght if you measured them from the front ones.

If you intend to compete with the car, when you are just brushing the Armco with your front wheel if the track is wider at the front at least you will know that the rear wheels aren't going to thump the metal!

quote:

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Originally posted by Phil.J
If you intend to compete with the car, when you are just brushing the Armco with your front wheel if the track is wider at the front at least you will know that the rear wheels aren't going to thump the metal!

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It seems that there are various solutions available for this problem, if indeed it is a problem.

Quite often a pointer to the answer can be found in defining the question. Before that can be done a number of decisions need to be made, and those will depend on such things as
the intended purpose of the car
the funds available
the time available
the facilities available
how soon the project needs to be completed
etc
etc
etc

John

quote:

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Originally posted by mr henderson
It seems that there are various solutions available for this problem, if indeed it is a problem.

Quite often a pointer to the answer can be found in defining the question. Before that can be done a number of decisions need to be made, and those will depend on such things as
the intended purpose of the car
the funds available
the time available
the facilities available
how soon the project needs to be completed
etc
etc
etc

John

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I was building a +442 and I wanted to keep the original mx5 track which meant custom wishbones. I also moved the fu tubes
FYI The tube was bigger at 3/4"x1/8" wall CDS tubing.



[Edited on 7/1/09 by liam.mccaffrey]

quote:

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Originally posted by liam.mccaffrey
I was building a +442 and I wanted to keep the original mx5 track which meant custom wishbones. I also moved the fu tubes
FYI The tube was bigger at 3/4"x1/8" wall CDS tubing.

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actually I built it arse about face, I built the front angled assembly(LA and LB) then built the wishbones between an adjustable position jig holding the hub/upright and the suspension brackets on LA and LB.

It was only then I made and fitted the FU tubes to the free suspension bracket attached to the free end of the top and bottom bones. Does that make sense??

so to asnwer your question I changed their position before the chassis was finished

Check out my build diary below for some pics

[Edited on 7/1/09 by liam.mccaffrey]

[Edited on 7/1/09 by liam.mccaffrey]

quote:

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Originally posted by liam.mccaffrey
actually I built it arse about face, I built the front angled assembly(LA and LB) then built the wishbones between an adjustable position jig holding the hub/upright and the suspension brackets on LA and LB.

It was only then I made and fitted the FU tubes to the free suspension bracket attached to the free end of the top and bottom bones. Does that make sense??

so to asnwer your question I changed their position before the chassis was finished

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quote:

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Originally posted by Daddylonglegs


Yep, makes total sense. Trouble for me though is that I have already welded in FU1 and FU2 so it would mean cutting/grinding them out and making new ones. I am not sure what impact that would have on strength around that area?

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Thanks for that.

Nope, not had to do that yet, not due to error anyhow, just to alter the side rails to my liking.

So far been really lucky with warping etc, but there is still time

Think I'll sleep on it and make a call tommorrow.

John

to be honest i think you could just build your custom bones to the site where your FUs are now and not worry about the ratio's.
if you are worried about strength throw in an extra gusset or strut like i have with my top bones

if you are worried though its really no big deal to chop out the FU's and follow the kind of custom bone route i did, it was really easy.


I wont lie its was time consuming I spent a week of days doing little else. I was really please with them though

[Edited on 7/1/09 by liam.mccaffrey]