kevyo89
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| posted on 1/2/19 at 12:42 PM |
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Front Suspension advice?
Hi guys,
I've made wishbones as per the Haynes book but I am fitting them to a Ron Champion spec chassis, with mounting points repositioned. The guys at
Procomp have been kind enough to give me some advice regarding position of the mounting points. I was advised that with the lower wishbone level, the
supper wishbone should ideally have a 5 degree angle. That positions my brackets/arms something like so:
However, when retaining the original upper shock mounting position, it angles the shock very dramatically and I am wondering if this is ok? Bearing in
mind that the lower wishbone is level, i.e. what it would be when at ride height, the shock would surely compress with full bodyweight and therefore
the shock won't be positioned at such a dramatic angle like this?
Would it be more appropriate to position the shocks like so:
[Edited on 1/2/19 by kevyo89]
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kevyo89
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| posted on 1/2/19 at 03:11 PM |
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Ahhhh - I made a mistake. I've just switched the shocks around as I realised I had the front shocks in the rear LOL! Now I've got the
front sorted and I don't think I will need to reposition the mounts:
Now however, I have a 16" open length rear shock, which will be far too big! More stuff bought incorrectly!!
I do have about 2 inches of space where I could reposition axle shock mount lower down. The Ron Champion book suggests doing this and has pictures for
reference where another builder has done this to accommodate a longer shock. Can you think of any reason why this shouldn't be done?
I could position the new shock mount directly below by 2 inches in the hope that the 16" shock would work fine?
[Edited on 1/2/19 by kevyo89]
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40inches
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| posted on 1/2/19 at 03:32 PM |
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On the front suspension. Place the shock wishbone bracket as near to the ball joint as possible, and bring the top bracket out from the chassis. As in
this photo:
 
Description
Assuming that the shock will not foul the wishbone?
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kevyo89
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| posted on 1/2/19 at 05:40 PM |
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quote:
Originally posted by 40inches
On the front suspension. Place the shock wishbone bracket as near to the ball joint as possible, and bring the top bracket out from the chassis. As in
this photo:
Description
Assuming that the shock will not foul the wishbone?
Thanks mate
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johnemms
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| posted on 1/2/19 at 08:18 PM |
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Your rear shocks are correct..
You need to modify the rail under the axle to allow for adequate droop..
I recon...
Own chassis & Build - First time pass!!
"7's" aren't really "cars", they are 'experiences"
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kevyo89
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| posted on 1/2/19 at 10:03 PM |
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quote:
Originally posted by johnemms
Your rear shocks are correct..
You need to modify the rail under the axle to allow for adequate droop..
I recon...
Modify the rail under the axle in what way?
[Edited on 1/2/19 by kevyo89]
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Angel Acevedo
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| posted on 2/2/19 at 05:29 PM |
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quote:
Originally posted by kevyo89
quote:
Originally posted by johnemms
Your rear shocks are correct..
You need to modify the rail under the axle to allow for adequate droop..
I recon...
Modify the rail under the axle in what way?
[Edited on 1/2/19 by kevyo89]
How about something like this upsde down?
[img]https://www.locostusa.com/forums/download/file.php?id=2481[img]
Beware of what you wish.. for it may come true....
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PumaWestie
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| posted on 3/2/19 at 06:58 PM |
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The front shocks look to be too long for the job. The lesser the angle on the shock the better. Moving the top shock mount outwards will help reduce
the angle. The lesser the angle, the better the motion ratio and therefore a softer spring can be used to get a decent wheel rate
At the rear cut a section out of the chassis member under the rear axle tube and brace with a length of box section underneath it to gain more
clearance
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Oddified
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| posted on 4/2/19 at 09:01 AM |
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As with any suspension, it's a compromise. Shock angle can control roll to a point, reducing roll bar stiffness, decoupling the opposite side
which helps grip on bumps. Down side is as mentioned above with the increasing spring rates/shock control because of the motion ratio. Ideally the
angle shouldn't go past drawing an arc centred on the RC through the shock mounts though.
Ian
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rusty nuts
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| posted on 4/2/19 at 12:19 PM |
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I’m sorry to be so blunt but I can’t help wondering how long it will take for some of those welds to fail ?
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froggy
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| posted on 4/2/19 at 11:34 PM |
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I had to make some major changes to my front end to accommodate the v8 and I started by blocking the chassis up at a sensible ride height allowing for
a 10-15mm drop without running out of shock travel then setting the shock at 70/30 bump to droop and making a dummy strut out of box section . Got my
shock a decent amount under 45deg and built the top mounts to suit which in my case included a bolt in brace across the top to take the load off the
top rail being a fairly hefty motor . Wheels were on as well and I glued a welding rod onto the bolt going through the inner bottom arm pivot to have
a visible line showing the intersection through the steering rack pivot to the upper arm inner pickup to minimise any bump steer
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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PumaWestie
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| posted on 5/2/19 at 08:24 AM |
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There is no getting away from the fact that the shocks are simply too long for the job I'm afraid. You need to set the car on blocks at the
required ride heights to determine this for yourself rather than playing around in mid air. The previous poster gives you a good idea of how to
proceed.
My advice would be to sell the shocks that you have on and buy some of the required correct length once you have determined it
[Edited on 5/2/19 by PumaWestie]
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froggy
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| posted on 5/2/19 at 10:17 AM |
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My front shocks are a similar length and the top mounts extend 4” beyond the frame rail with the brace to tie them together purely to run a decent
angle and not have to run a massive rate spring to hold it up as it’s a heavy car
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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