ArAKern
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| posted on 14/12/17 at 03:48 PM |
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Droop stops a thing? (opposite to bumpstop)
Ok so from the advise i have been given on my suspension setup I ideally need longer shocks all round.
between the mount points for the dampers the i measure a range of 275 - 350mm so if i fit a 14" shock with open length of
356mm when on full droop in theory the suspension will hit a hard point before max travel is this ok? or should i go for a shorter damper
and have the damper as the limit to travel?
Thanks
ArA
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Bluemoon
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| posted on 14/12/17 at 04:24 PM |
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quote:
Originally posted by ArAKern
Ok so from the advise i have been given on my suspension setup I ideally need longer shocks all round.
between the mount points for the dampers the i measure a range of 275 - 350mm so if i fit a 14" shock with open length of
356mm when on full droop in theory the suspension will hit a hard point before max travel is this ok? or should i go for a shorter damper
and have the damper as the limit to travel?
Thanks
ArA
On 7 this is I think normally done by the damper, can't you move the mounting points up by 6mm?
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james h
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| posted on 14/12/17 at 05:23 PM |
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I know that on OEM suspension, you can have what is called a 'rebound buffer'. I don't know if this is common in the aftermarket
though.
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loggyboy
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| posted on 14/12/17 at 05:27 PM |
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Shouldnt really matter as no force is ever put in to droop, unlike compression. However shock lengths should be set to match intended swing, and
governed by the manufacturers guidance.
Mistral Motorsport
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james h
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| posted on 14/12/17 at 05:35 PM |
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In rebound the unsprung mass is accelerated by the compressed (and now extending spring). Unless this is reacted by the tyre on the road, the force
will be taken up by the damper piston/tenon and therefore also the suspension upper bush/clevis.
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loggyboy
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| posted on 14/12/17 at 05:43 PM |
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quote:
Originally posted by james h
In rebound the unsprung mass is accelerated by the compressed (and now extending spring). Unless this is reacted by the tyre on the road, the force
will be taken up by the damper piston/tenon and therefore also the suspension upper bush/clevis.
Yes but only if you in a rally car going from one extent to the other over a jump - unlikey to happen in track/road car. So unless your crashing, in
which case is probably the last of your worries!
Its also damped, reducing the acceleration, so Even if you get to full lift on track due to high cornering forces or kerb hopping, the load will not
be travelling far to gain momentum.
Only track exception for jumping I can think of is cadwell park, but even then the road drops away slowly giving suspension a chance to extend with
reduced force.
Mistral Motorsport
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snapper
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| posted on 14/12/17 at 06:45 PM |
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In the dim and distant past I had a Marstro 2.0L efi, faster than an Escort XR3l which I had stolen.
The Meastro has this really weard and troubling problem of the front shocks bottoming out on full droop, now I’ve got air in a number of cars but the
thunk of shocks reaching the end of travel is unnerving, I just don’t like it.
There is nowhere on a shock to put a negative bump stop, I have heard of straps that stop the shock reaching full droop because a strap is cheaper
than a new shock, but you’ll still feel an unearthing thid
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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jps
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| posted on 14/12/17 at 07:10 PM |
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quote:
Originally posted by snapper
An Escort XR3l which I had stolen
Despite the passing of time it's always best not to openly confess ;-)
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mark chandler
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| posted on 14/12/17 at 07:25 PM |
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On full droop the front springs are loose on my car, it looks unsettling on the trolley Jack as the retainers could move although in practice its not
been a problem or I would replace with shorter shocks or longer springs.
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roadrunner
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| posted on 14/12/17 at 10:31 PM |
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quote:
Originally posted by jps
quote:
Originally posted by snapper
An Escort XR3l which I had stolen
Despite the passing of time it's always best not to openly confess ;-)
If it's time to confess.
I had my Orion injection Ghia stollen.
Looking back, it was a good thing to happen really. ;-)
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coyoteboy
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| posted on 15/12/17 at 12:41 AM |
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quote:
Originally posted by loggyboy
quote:
Originally posted by james h
In rebound the unsprung mass is accelerated by the compressed (and now extending spring). Unless this is reacted by the tyre on the road, the force
will be taken up by the damper piston/tenon and therefore also the suspension upper bush/clevis.
Yes but only if you in a rally car going from one extent to the other over a jump - unlikey to happen in track/road car. So unless your crashing, in
which case is probably the last of your worries!
Its also damped, reducing the acceleration, so Even if you get to full lift on track due to high cornering forces or kerb hopping, the load will not
be travelling far to gain momentum.
Only track exception for jumping I can think of is cadwell park, but even then the road drops away slowly giving suspension a chance to extend with
reduced force.
I have a peugeot 306 with really poor aftermarket front shocks. Just driving off a kerb is met by an almighty "top out" bang that sounds
like the wheel is coming off. It does it on some potholes too. The problem is the rebound damping is too weak near the top of the travel and the
spring rams the shock open with a bang. Feels and sounds awful.
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Angel Acevedo
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| posted on 15/12/17 at 01:59 AM |
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quote:
Originally posted by ArAKern
Ok so from the advise i have been given on my suspension setup I ideally need longer shocks all round.
between the mount points for the dampers the i measure a range of 275 - 350mm so if i fit a 14" shock with open length of
356mm when on full droop in theory the suspension will hit a hard point before max travel is this ok? or should i go for a shorter damper
and have the damper as the limit to travel?
Thanks
ArA
You may modify wishbones to have appendages to touch against chassis. Or chassis to have appendages to touch wishbone.
Hou sturdy they need to be and how big the force acting upon them is te ral question.
Provided you won´t be reaching full droop very often, you may get away with some ingenuity a welder and some pieces of steel.
Beware of what you wish.. for it may come true....
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Camber Dave
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| posted on 15/12/17 at 08:53 AM |
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Insufficient travel in droop is never good on the rear. You will get frequent knocks as the dampers ‘top out’ which can eventually cause premature
failure.
It can also give a loss of traction as the unloaded wheel is lifted from the road in roll, exiting a corner. Protech do extended top eyes that fix
this quickly.
However, for track use, front dampers with restricted droop can be a trick to restrict roll. As mentioned by James H, the inner spring extending
assists in pushing the sprung mass outwards and upwards. If the droop is limited, the roll moment adds more load onto the outer spring and further
motion lowers the front of the car not raising it as normally happens.
Protech can add an internal buffer to dampers used as droop stops. Its purpose is to prevent internal damage.
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Dingz
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| posted on 15/12/17 at 12:06 PM |
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quote:
I had my Orion injection Ghia stollen.
Was that a German cake shaped like an Orion?
Sorry.
Phoned the local ramblers club today, but the bloke who answered just
went on and on.
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Mr Whippy
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| posted on 15/12/17 at 12:27 PM |
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very common in the 4x4 world, called suspension limiting straps
All series landrovers had these as standard on the back, although using much beefier fabric than just seatbelt stuff that's the norm these
days
As demonstrated in this pic it's not the damper that is at risk but joints and driveshaft CV's. Although for road cars going full droop is
going to be very rare
[Edited on 15/12/17 by Mr Whippy]
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SJ
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| posted on 15/12/17 at 02:57 PM |
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quote:
quote:
I had my Orion injection Ghia stollen.
Was that a German cake shaped like an Orion?
Sorry.
Just what I was thinking!
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ArAKern
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| posted on 16/12/17 at 12:30 PM |
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Ah the venerable Austin Maestro that takes me back, first car I had access to (my parents) which I wrote off  did it properly mind rolled it every
panel and every piece of class smashed 
So thanks to the responses so in conclusion (i will not be fitting straps) Should I option:-
1, select a shock open length longer than the physical suspension travel.
or
2, select a shock open length shorter than the physical suspension travel.
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daviep
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| posted on 16/12/17 at 04:05 PM |
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2
“A truly great library contains something in it to offend everyone.”
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motorcycle_mayhem
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| posted on 18/12/17 at 09:23 AM |
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My ex-military 1967 SII LR has straps running around the axle from mounting points on the chassis above. The spring hangers are all lower on these
military variants, giving a considerable ride height and articulation (even with the horse cart spring architecture).
However - I wouldn't do this on my 7 or race car. On the race car, I shortened the shock pushrod (eye end) - which is what you might be able to
do in this case?
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snapper
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| posted on 18/12/17 at 09:52 AM |
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Desmond Tweeks do spring assistors, just light poundageflat coils that take up the skack
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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Oddified
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| posted on 19/12/17 at 12:00 PM |
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In model car racing, droop stop adjustment is as critical/important setting as is spring rates/damping/camber/castor etc etc. Adjusted to within 0.1mm
lhd/rhd if your racing at a reasonable level (national, euro's or world championships).
Ian
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