Front Beam Options Technical Topic

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Dipsy
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Front Beam Options Technical Topic

Post by Dipsy » Tue Nov 15, 2005 3:37 pm

Following on from the very useful SA v IRS topic, lets have your thoughts, experiences and ideas on the front end suspension.

What's worked for you? Which adjusters do you prefer? Why narrow a front beam and by how much? Anything that you thinks relevant would be welcome.

Once again, over to you........
Cheers,

Nige
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59 pick up
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if

Post by 59 pick up » Sun Nov 20, 2005 11:00 pm

if you fit a 68 beam in a splitty
-and turn both collars 28mm
around the beam
-when using 145 65 15 tyres
-the steering box will be 40mm from the floor
-and the ball joints won't last
50 miles
-ps if you do, the thud you hear over pot holes are the ball joints trying to escape

-now i reckon, a 16 inch wheel with a 185 50 16
-has the same height as a 185 65 15
-therefore, a turning of 22mm of each collar would do the trick nicely
-any thoughts before i go weld it up?


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Post by sinclair » Tue Nov 22, 2005 10:28 pm

Here's one that might ruffle a few feathers. If you fit dropped spindles, use an adjuster on the lower beam only to releive the torsion spring force trying to seperate your kingpins :wink:
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flat930
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Post by flat930 » Sun Dec 04, 2005 10:56 pm

I wanna know more about this narrowed beam lark, does it affect the handling? My bus runs across to europe reasonably often and is soon to run a 2056 Type IV (IRS'd, Boxwagen discs, etc) so I want something that'll run at good cruising speeds without being twitchy. I do like the look of narrowed beams and if it'll stop my tyres from hitting the arches but still allow it to cruise in a straight line AND go round corners I may make it my next move. Anyone have any input?

Oh and I'm on dropped spindles, gaz shocks, creative springplates, etc, too...

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59 pick up
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.

Post by 59 pick up » Fri Dec 23, 2005 1:43 am

flat930 wrote:I wanna know more about this narrowed beam lark, does it affect the handling? My bus runs across to europe reasonably often and is soon to run a 2056 Type IV (IRS'd, Boxwagen discs, etc) so I want something that'll run at good cruising speeds without being twitchy. I do like the look of narrowed beams and if it'll stop my tyres from hitting the arches but still allow it to cruise in a straight line AND go round corners I may make it my next move. Anyone have any input?

Oh and I'm on dropped spindles, gaz shocks, creative springplates, etc, too...

ACKERMANN ANGLE
Obtaining the correct Ackermann angle is essential for long tyre life as it reduces scrubbing themselves away on corners.
Ignoring such complications as the tyre slip angle, the correct Ackermann angle can be obtained when a line is drawn through both the tie rod ball joints and the lower suspension ball joint and continued until It Intersects the rear axle.
Correct Ackermann is obtained when the two lines intersect at the centre of the rear axle. This is necessary as the wheel on the inside of a corner has to turn at a sharper angle than the outer because the radius of the curve is much less (the width of the vehicle in fact).
Reference to the drawing and photograph of the steering arms will show the very different shapes needed for front and rear rack positioning.
It is not enough just to swap the steering arms side for side if changing the location of the rack as the angle of the arms must also be changed.
Of course the same also applies to wheelbase. The steering arms are angled so as to intersect at the rear axle of the donor vehicle. Lessen the wheelbase and they will intersect behind the axle, lengthen the wheelbase and the Intersection will occur in front of the axle. Depending on how great this change in wheelbase has been, some form of adjustment may be needed. In the case of the Vauxhall range (Viva. Victor etc.) these arms are only bolted on so it might be possible by swapping them to get a more accurate angle.
On some types of spindle/disc combinations the correct Ackermann angle will prove very difficult to obtain as the steering ball joint will hit the disc before the right angle is achieved.
Image

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rubbachicken
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Post by rubbachicken » Sat Jan 07, 2006 9:57 pm

regarding ackermann's angle
i'm planning of fitting an astra power steering rack {well i've started the conversion}
anyhow fitting the power rack the center steering mount has now moved at least 100mm towards the rear of the bus, as the rack is too long to sit in between the torsion bar tubes of the beam, and i have to clear a t25 or 944 servo and mastercylinder so the rack is mounted further ack, wil this interfear with the ackermann angle, i'm not narrowing the beam
Image
i guess the fact that i've put a '68 bay beam on i will a bit, but do you think the rack will
the other thing i have concernes with is bump steer

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59 pick up
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scrub line

Post by 59 pick up » Sun Jan 22, 2006 9:45 pm

scrub line
-the tyre goes flat
-the tyres wall thickness, say 4 inches, -you loose 4 inches
-if the steering box is less than 4 inches from the ground
-that is pants
-bad scrub line

-castor angles whilst the vehicle is diving under braking is a good one too.

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59 pick up
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drilling out the 3 dimples

Post by 59 pick up » Sun Jan 22, 2006 9:47 pm

then having the weight of the van on 1 m14 bolt
-thats good too, as the m14 hollow stock bolt, is there just to centre the leaves

-the dimple recesses in the centre collars - is really quite deep
-the beam then jigged and dimples pressed, id say in a BIG 10 -50 ton press

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OxonPhil
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Post by OxonPhil » Tue Jan 31, 2006 12:42 pm

I realise its not 100% linked, but trying to decide between a narrowed Weedeater beam or just fitting dropped spindles on my stock beam....

Any advantages / disadvantages with either method ??

How much worse is the ride quality when using a lowered beam rather than dropped spindles ??

The only reason I need to drop it, is to match the IRS conversion I'm planning !! (I like being able to look over hedges whilst driving !!!).

:?:

Cheers,

Phil.

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Post by vwJim » Tue Jan 31, 2006 1:10 pm

Ride quality on dropped spindles will be far better than weedeater beam. But just fitting the spindles won't narrow it as much as the CE beam, if that's what you're after.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.

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OxonPhil
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Post by OxonPhil » Tue Jan 31, 2006 1:24 pm

I'm not fussed with the narrow beam (although it does look cool), I just need to level out the height difference of removing the reduction boxes.

I just thought the CE beam would give me the adjustment to get it right.

Are there any advantages is a stiffer ride ?? (I only need to drop it 3.5")

Just want to make the right decision before starting this time......

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Post by vwJim » Tue Jan 31, 2006 3:44 pm

You could always fit some adjusters to your stock beam, then fine tune the height up or down with those, (that's what I've done).

Best of both worlds then.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.


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Post by flat4fanatic » Thu Feb 09, 2006 1:11 pm

ok, this will probably sound a dumb q but whats the idea behind fitting a 68 bay beam to a split?
ta
steve


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Post by Bendito » Tue Mar 07, 2006 9:16 pm

My experience to date:

Brought a lowered bus from the states, it bounced and bounced over bumps. On inspection I had three torsion leaves in so all the suspension was doing was sagging........dangerously!

So when I converted to disks I fitted a creative narrowed weedeater and because I am still waiting for my dropped spindles ( :evil: ) I refitted the standard ones. Now Nick (from M Restorations) who knows everything says that when the dropped spindles are fitted the characteristics of the ride will be returned to a virtually stock feel.

In the meantime I have to wear a gumsheild for driving along! Its really stiff :wink: and there is no travel at all. As the track is now narrowed the steering characteristics feel like they have changed too.

Dont know if this is of any use at all but its my experience? :?
St Bendito says "praise the low'd"!

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Post by jaz » Mon May 01, 2006 1:55 pm

i bought the red 9 design kit from socket on this forum and fitted that, has anyone else used this?

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