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Suspension design Question (Shock Lengths)

Posted: Wed May 10, 2006 11:35 am
by bruiser
I'll start by saying I have a 4 inch suspension lift in my 80 series cruiser with custom drop boxes. This setup works pretty dam well but are we not all looking for that extra bit of flex.

Question

The limiting factor for flex is the shock. Why not install the longest shock I can find that will still allow for a little upward travel from resting position but shitloads of drop.

Will there be any negitive impact and how large a shock could I go.

I was thinking one that was only 2 or 3 inches from fully compressed in resting state. I also have spring retainers installed so there should be no problem with poping out coils

Feed back appreciated.
Burnsy

Re: Suspension design Question (Shock Lengths)

Posted: Wed May 10, 2006 1:19 pm
by Heathx4
bruiser wrote:I was thinking one that was only 2 or 3 inches from fully compressed in resting state.
My pushy has more uptravel than that :?

I think you're asking for a really harsh ride - speed bumps, kurbs, humps, etc. are either going to top out your suspension, or work it really hard. That translates to some pretty severe jolts inside the cab. Not that it's unheard of - check some of the sporty road cars, I think they probably only have a few inches uptravel.

The other thing to consider is that you're not going to get a shock that travels down any further than its own height compressed, simply because the piston can be no longer (and in fact, a bit shorter) than the shock outer.

Not that designing for more droop than compression is a bad idea. In fact, done right, the concept suggests a low CoG, less cutting and controlled travel.

Posted: Wed May 10, 2006 2:13 pm
by bruiser
As far as the harsh ride. I don't load my car so I would not expect to get much more than 3 inches of upward travel on road in normal conditions.

As for shock lengths and travel, the idea is to buy a larger shock therefore more travel, it's just that most of the travel available will be down with a small amount up. But the overall travel from full compression to full extension will be greater.

Burnsy

Posted: Wed May 10, 2006 2:15 pm
by Tiny
as long as you extend the bump sotps so the shocks are not the acting as bump stop then in theory it would be fine

Posted: Wed May 10, 2006 2:31 pm
by +dj_hansen+
How about getting custom shock towers so you can run the larger shocks and still retain uptravel?

Posted: Wed May 10, 2006 2:33 pm
by JOHNZ
Tiny wrote:as long as you extend the bump sotps so the shocks are not the acting as bump stop then in theory it would be fine
I agree with tiny.the risk is bottoming out the shocks in compression which will cause the shocks to fail. I you were to bottom the slowly it would be ok, as most shocks have internal bumpstops. fast bottoming such as speed bumps or jumps would destroy the shocks.
cheers JOHNZ

Re: Suspension design Question (Shock Lengths)

Posted: Wed May 10, 2006 3:10 pm
by jeep97tj
bruiser wrote:I'll start by saying I have a 4 inch suspension lift in my 80 series cruiser with custom drop boxes. This setup works pretty dam well but are we not all looking for that extra bit of flex.

Burnsy
What are theses???

Posted: Wed May 10, 2006 3:16 pm
by bruiser
+dj_hansen+ wrote:How about getting custom shock towers so you can run the larger shocks and still retain uptravel?
This would be the best way to go. I don't no if you can do this with an 80, unless I cut holes in the floor. :twisted:

Posted: Wed May 10, 2006 8:19 pm
by ludacris
Pull your shocks out then flex the beast and measure how long a shock you need and also supply the length of when the beast is sitting stable so you dont end up with a too bigger shock.

Ludacris

Posted: Wed May 10, 2006 9:13 pm
by ats4x4dotcom
Ridepro have a comp shock which is nice and long, and with a mod to the rear top mount, and a bump stop spacer, you could fit these 12" stroke shocks to the back.

The fronts they have a longer shock for a GQ/GU but the 80 one is still a little while away, though you could use the 12" rears on the front with a new top mount also.

I was running them on my truck, before i fitted triple bypass Fox shox.

shocks

Posted: Mon May 15, 2006 5:43 pm
by vanbox
no to hijack the thread, but i have a similar query in which i am fitting a 6in lift to my GQ swb and the shocks wil be bought after i put the lift in.

i want to use tuff dogs 45mm adj all round and have snake racing custom rear lower shock mounts.

my question is do the shocks come in a standard (eg: 6in longer than standard)....or can i flex it up and like mentioned measure and order?

thanks
PAUL

Posted: Mon May 15, 2006 6:01 pm
by Dee
hey bruiser.

what spring retainers do you have and where did you get them. More info?

I ask as i have exactly what you are requsting.

My GU has 3 inch raised heavy duty springs. The slightly stiffer springs give a firmer (which i prefer in the gu) ride. My rear shocks are approx 1" too long (when flexing up a wheel, the dropped side has about a 1" gap between spring and spring seat).

When jacking the the car up at the chassis, at full droop i can remove springs.

The problem with this is the sprigs pop out at the bottom (but go back in upon returning travel) All the paint has ripped off the bottom of the springs because of all the movement and are now starting get a bit rusty.

In saying this, the shocks never bottom out on uptravel and i get pretty good flex in the rear for a 3" lift. (shocks are longer)

Im about to stick in a rear drawer system, and if the added weight saggs the rear at all i can always stick in a coil spacer without losing down travel.

The sound of the springs going in out does get annoying tho (doesnt happen on road)

I read in another thread that depending on the spring, you should get the same amount of compression in the opposite direction of travel with the same amount of force.
My question is, If i was to put spring retainers in, would i lose any down travel or would the axle be heavy enough to stretch the spring longer and keep the flex, or would the spring be too stiff? Anyone?

Re: shocks

Posted: Mon May 15, 2006 6:58 pm
by +dj_hansen+
vanbox wrote:no to hijack the thread, but i have a similar query in which i am fitting a 6in lift to my GQ swb and the shocks wil be bought after i put the lift in.

i want to use tuff dogs 45mm adj all round and have snake racing custom rear lower shock mounts.

my question is do the shocks come in a standard (eg: 6in longer than standard)....or can i flex it up and like mentioned measure and order?

thanks
PAUL
I wouldnt go 6" in a SWB dude... your shaft angles will be way up the creek, and it will be really really tippy sideways and long ways... At most, 3" spring lift and 2" body, and with choppin and front arm spacers you should easily fit 36's.

In answer to your question however... yes flex it up with no shocks in, take measurements of full compression, extension and level and take them to a shop and search their catalogues for something that will fit :D

Posted: Mon May 15, 2006 7:33 pm
by waxhead..
won't the compression (or lack of) on one side be a limiting factor to the droop at the other end of the axle. As in, if left hand rear is compressed to the bumpstop, how is the right hand rear going to continue to droop? I know there will be marginal pivoting of the diff-housing on the bump stop, but it will only be marginal. [/b]

Posted: Tue May 16, 2006 8:42 am
by Dee
waxhead.. wrote:won't the compression (or lack of) on one side be a limiting factor to the droop at the other end of the axle. As in, if left hand rear is compressed to the bumpstop, how is the right hand rear going to continue to droop? I know there will be marginal pivoting of the diff-housing on the bump stop, but it will only be marginal. [/b]
yes thats what i thought aswell. Once you stop uptravel on one side you limit down travel on the opposite.

Posted: Tue May 16, 2006 6:13 pm
by vanbox
yes flex it up with no shocks in, take measurements of full compression, extension and level and take them to a shop and search their catalogues for something that will fit
thanks but does the same company make various length shocks? i want to use tough dog only as i have ridden in a 6in lifted shorty that rides betta than my current 2in lift (shocks worn out).

if i gave tough dog the measurements will they have a shock to suit...or will they only come in a 6in lifted (standard ratio for compressed v extended).

also i am putting raised lower rear shock mounts on to raise clearance. i know these need to be welded on after the lift to clear springs etc. can i weld the mounts on the diff as is? or do i need to remove certain things (diff oil etc).

is it also benificial to raise my front shock towers to allow a longer shock?

thanks everyone
PAUL

Posted: Tue May 16, 2006 6:44 pm
by redzook
DEEV8 wrote:
waxhead.. wrote:won't the compression (or lack of) on one side be a limiting factor to the droop at the other end of the axle. As in, if left hand rear is compressed to the bumpstop, how is the right hand rear going to continue to droop? I know there will be marginal pivoting of the diff-housing on the bump stop, but it will only be marginal. [/b]
yes thats what i thought aswell. Once you stop uptravel on one side you limit down travel on the opposite.
no it will actually help the thing flex as it has somthing to pivot off, forcing the other side down