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Wrapped Springs vs Flex

Posted: Mon Jan 14, 2008 11:05 pm
by Kitika
At the moment i'm setting up some what i think are datsun ute springs. They are about 200mm longer than stock and have three millitary wrapped sections on the spring (2 on the 800mm side 1 on the 500mm side).
These springs are 50mm wide and are a little bit thicker than stock sierra springs. I've made the packs with only 3 leaves but they don't seem to flex very well, as in can't even reach the stock bumpstop.
Given all of the above wuld it be the wrap on the springs not allowing them to flex to there full capability?

Posted: Mon Jan 14, 2008 11:52 pm
by alien
when you talk about spring wrap, most will think you mean instead of the spring being this shape: ( under acceleration, its actually like: S - this is caused by the diff rotating while the center and ends of the leaf are fixed, which generally causes a shudder through the whole vehicle as well as shoterend driveshaft and spring life.

as for the military wrap limiting flex, it shouldnt unless its binding up (get out and check)... you may find the shocks are whats really stopping you. Try disconnecting the shocks and ramping it up to see what it does then.

Posted: Tue Jan 15, 2008 5:03 am
by GRPABT1
I'd be more worried about the thickness and width limiting flex then military wrap (which all good flexy springs have)

Posted: Tue Jan 15, 2008 5:33 pm
by Kitika
I don't have any shocks fitted at the moment i'm trying to get it to flex as much as possible and then worry about measuring it up for shocks. So thats not the problem but the main 2 leaves are made of thicker steel than the stock sierra leaves I wouldnt have thought this extra thickness would matter that much because the spring is longer? I was hoping it could at least reach the original bumpstops.... :?

Posted: Tue Jan 15, 2008 5:51 pm
by 11_evl
have u added any extra weight?

Posted: Tue Jan 15, 2008 6:19 pm
by Kitika
I've got a 32inch spare tyre and a small sized toolbox hanging of my rear bumper but other than that there's not really any extra weight hanging off the back. Do think i need more weight to make these springs work?

Posted: Tue Jan 15, 2008 6:29 pm
by want33s
If you are using ute springs then yes you'll probably need more weight on them to make them flex the way you want..
They are made to carry half a ute plus a 1000kg load and still not touch the bumpstops (unless you hit a big bump) so a Zook with bugger all in it is going to be REALLY stiff even with a leaf or two removed.

Posted: Tue Jan 15, 2008 6:30 pm
by nicbeer
i think i read that you are doing similar to how i was going to do it.

u may/will need less leaves or thinner leaves to make it work i think.

have u got lift from the leaves or more droop? as if lifted u may find they wont arch up enough to reach the bumpstops.

u may even have to do a combo of sierra springs and ute springs under there.

Posted: Tue Jan 15, 2008 7:07 pm
by Kitika
I have got no lift from these springs at all because i dropped the lower load leaf of the bottom of the pack which brought the height back to standard (or close enough). If i do have to swap leaves out and replace with sierra ones i'd have to cut the military wrap of anyways i'm guessing...
The springs are from a datsun 120? There off a small ute not a full sized nissan 720 or hilux so i thought they'd be spring rated fairly close to wat the zooks are?

Posted: Tue Jan 15, 2008 8:44 pm
by 11_evl
if the thickness is noticably thicker than yes it will require more weight to move them. with no extra weight, there will be no movement, ie wont hit bumpstops.

Posted: Tue Jan 15, 2008 10:27 pm
by want33s
Are the datsun springs longer than Zook springs?
If they are, have you moved the rear shackle mounts back? or fitted longer shackles? If you haven't the shackles may not have enough travel to allow adequate flex on the spring.
Datsun 1200 (ute) gcm is 1750kg... thats about 400kg more than a Zook.
Maybe remove another long leaf try it again.. if its TOO soft you can always put one of the shorter leaves back in.

Posted: Tue Jan 15, 2008 11:56 pm
by zookimal
want33s wrote:Are the datsun springs longer than Zook springs?
I thought 1200 ute springs were only around 50mm longer than zook rears, not 200mm. Then again, I've never measured them myself.

Posted: Wed Jan 16, 2008 7:22 pm
by Kitika
I have made up a mount sort of like this to move the spring mount forward because the springs were so much longer than stock.
Image
(sorry for stealing your pic nicbeer can't take a photo of mine as yet)

The shackle angle is very good and i'm using 2 inch extended shackles.
I have to move the axle forward an inch which i'll hopefully get round to this weekend and when i do this i'll see if i can swap any of my old suzuki leaves into the pack to soften it up abit. I have driven it on road without shocks a few times and the ride feels very soft but if its not going to flex up properly something must be wrong somewhere :roll:

Posted: Wed Jan 16, 2008 11:08 pm
by alien
take a photo of the spring pack perhaps??? maybe theres a different combo you can try..