Daddylonglegs
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| posted on 7/1/09 at 09:29 AM |
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wishbone Design
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.
It looks like the Midget is winning at the moment......
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JoelP
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| posted on 7/1/09 at 09:38 AM |
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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.
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mr henderson
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| posted on 7/1/09 at 09:38 AM |
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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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Mr Whippy
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| posted on 7/1/09 at 09:38 AM |
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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
Fame is when your old car is plastered all over the internet
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Daddylonglegs
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| posted on 7/1/09 at 09:45 AM |
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quote:
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
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?
It looks like the Midget is winning at the moment......
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Daddylonglegs
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| posted on 7/1/09 at 09:48 AM |
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quote:
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
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
It looks like the Midget is winning at the moment......
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mr henderson
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| posted on 7/1/09 at 09:59 AM |
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quote:
Originally posted by Daddylonglegs
quote:
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
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
I knew that was why you wanted to do it, I was just saying that it isn't strictly necessary. Car design involves a lot of compromise, and
changing one thing to improve some aspect may have a less desirable effect elsewhere.
I've not studied that 442 design in detail, but, faced with the situation you are describing, I would not be at all surprised if I decided to
keep the front as is.
John
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Mr Whippy
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| posted on 7/1/09 at 10:03 AM |
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quote:
Originally posted by Daddylonglegs
quote:
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
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?
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
Fame is when your old car is plastered all over the internet
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mr henderson
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| posted on 7/1/09 at 10:11 AM |
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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.
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Daddylonglegs
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| posted on 7/1/09 at 10:12 AM |
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quote:
Originally posted by Mr Whippy
quote:
Originally posted by Daddylonglegs
quote:
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
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?
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
I think you are probably right there
Please tell me though that you mean front 'narrower' than the back on production cars otherwise I'm even more confused 
It looks like the Midget is winning at the moment......
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Mr Whippy
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| posted on 7/1/09 at 10:28 AM |
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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]
Fame is when your old car is plastered all over the internet
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Richard Quinn
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| posted on 7/1/09 at 10:40 AM |
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Interesting discussion HERE from a couple of years back
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Mr Whippy
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| posted on 7/1/09 at 11:00 AM |
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quote:
Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back
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!!! 
Fame is when your old car is plastered all over the internet
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Daddylonglegs
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| posted on 7/1/09 at 11:04 AM |
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quote:
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]
DOH!
Sorry m8, being a complete numpty again!
I guess my head is so full of suspension issues I am not with it (that's my excuse anyhow )
Must admit, I borrowed a Capri 3Litre S some years back and it was 'Fun'
It looks like the Midget is winning at the moment......
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Daddylonglegs
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| posted on 7/1/09 at 11:08 AM |
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quote:
Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back
Blimey! am I glad I didn't read that before I started to even think about the track widths 
It looks like the Midget is winning at the moment......
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Richard Quinn
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| posted on 7/1/09 at 11:31 AM |
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quote:
Originally posted by Mr Whippy
quote:
Originally posted by Richard Quinn
Interesting discussion HERE from a couple of years back
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!!!
gods indeed! It's no use referring to them as them. You were obviously
there too. I rest my case M'Lud!
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Mr Whippy
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| posted on 7/1/09 at 12:05 PM |
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no comment
Fame is when your old car is plastered all over the internet
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907
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| posted on 7/1/09 at 12:08 PM |
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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
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MikeRJ
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| posted on 7/1/09 at 12:39 PM |
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quote:
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
The Citroen Visa GTi had a wider front track than rear, and that handled pretty well.
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johnston
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| posted on 7/1/09 at 01:04 PM |
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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..
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t.j.
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| posted on 7/1/09 at 01:04 PM |
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quote:
Originally posted by MikeRJ
quote:
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
The Citroen Visa GTi had a wider front track than rear, and that handled pretty well.
A Visa   handling well, I just can't be... next your saying you like the 2CV
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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Richard Quinn
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| posted on 7/1/09 at 01:13 PM |
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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)
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Daddylonglegs
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| posted on 7/1/09 at 01:25 PM |
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quote:
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)
Unfortunately I did make it to the end and now I am really confused
Soooo....I am going to go with the widest seperation I can for the pick-off points without modding the chassis, and I will make the bones as long as I
need to to maintain the ratio I was banging on about earlier in this thread. If the front is narrower than the back then SOD IT! I'll just have
to be more careful on the old right foot
BTW 907, yes I am using different steel. I will be using 25mm x 2mm CDS tube for the bottom and 20mm x 2mm for the top.
JB
It looks like the Midget is winning at the moment......
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l0rd
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| posted on 7/1/09 at 02:11 PM |
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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.
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Phil.J
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| posted on 7/1/09 at 02:21 PM |
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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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