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Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sun May 26, 2013 11:41 pm
by Rmc
Notice dude in the first pic still has a tiny bit of shaft showing( safety margin) also keep in mind limit straps stretch on average 1 inch in length per 12 inches of strap length. Back to that safety margin keep it in mind for the droop position also. Doubled straps may be necissary,( less stretch). Straps also gain a stretch memory over time( they stay stretched out) so u can start with a 10 inch strap and it can turn into an 11 in a year.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Mon May 27, 2013 9:03 am
by D1cker1
Shocks mounted on top of leaf spring plates are about 2 inches, give or take higher that they lower oem shock mount location..
In that Scenario a 18 could be utilized
- ImageUploadedByTapatalk1369670499.820127.jpg (98.78 KiB) Viewed 2485 times
..
This pictures shows a 18" 2.5 fox shocks mounted on the spring plate on a stock leaf spring.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Mon May 27, 2013 5:18 pm
by cs_drums
1. Take all but your main leaf out make a spacer to take the place of the other springs and bolt up your rear end.
2. bolt your shock onto the lower mount, compress your shocks with .5" left of shaft, cycle rear to full bump.
3. put a piece of card board where you are going to build your upper mount, swing the shock forward and backward with a pen through the hiem, making a arch on the card board.
4. Cycle the rear to full droop, extend your shock minus .5"
5. Again on the card board, swing the shock forward and backward with a pen through the hiem, making a arch on the card board.
Where the to arches intersect will be your ideal mounting point, utilizing all of the shocks travel. If you need to, error on the side of leaning it farther forward.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Tue May 28, 2013 10:53 am
by ChaseTruck754
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Tue May 28, 2013 11:47 am
by Travisfab
I used a chunk of wood on mine as well, no need to over engineer a temp spacer
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Jun 14, 2013 6:27 pm
by 95_Bronco
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 12:04 am
by Cactus Cooler
So I was at the HDRA Reno race earlier this year and came across an Silver F-150 Prerunner w/ leafs. I spotted something I haven't seen before on leaf spring hangers, not sure what the purpose was for. 1st thought some kind of integrated sway bar? But it had one already. 2nd was, some kind of internal helper spring?? Was hoping someone could share what they know/think this is??, forgot I had the pics and just came across recently.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 7:29 am
by MOSS2
Cactus Cooler wrote:So I was at the HDRA Reno race earlier this year and came across an Silver F-150 Prerunner w/ leafs. I spotted something I haven't seen before on leaf spring hangers, not sure what the purpose was for. 1st thought some kind of integrated sway bar? But it had one already. 2nd was, some kind of internal helper spring?? Was hoping someone could share what they know/think this is??, forgot I had the pics and just came across recently.
I had an idea I have wanted to try to use a spindle and bearings for shackle pivots. Perhaps that is what this is. I was going to use a small car unitized hub to make it easier than that though.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 7:44 am
by philofab
The shackle is just on a different type of pivot. When your shackles get too long they allow a lot of lateral deflection which creates high speed instability. If the shackle is mounted to a unit bearing or spindle there is no side to side movement. This is why you see panhard bars on front axles with a lot of spring arch or long shackles.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 8:06 am
by cs_drums
philofab wrote:The shackle is just on a different type of pivot. When your shackles get too long they allow a lot of lateral deflection which creates high speed instability. If the shackle is mounted to a unit bearing or spindle there is no side to side movement. This is why you see panhard bars on front axles with a lot of spring arch or long shackles.
On my 64 kit the shackle hit the hanger quite a bit I was gonna do delrin bushings to tighten it up but this seams like another option.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 8:18 am
by Kel Fab Creations
I switched to Derlin on my shackles as the upper bolt head was rubbing on the mount. Problem fixed.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 10:17 am
by cs_drums
Oh the idea is now eating my mind. I have found all the part I need now I just need to spend $$ and get to work.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 11:45 am
by Kel Fab Creations
cs_drums wrote:Oh the idea is now eating my mind. I have found all the part I need now I just need to spend $$ and get to work.
To switch to Derlin? Just switch the bushings out.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Fri Oct 04, 2013 4:07 pm
by cs_drums
Kel Fab Creations wrote:
To switch to Derlin? Just switch the bushings out.
Nope spindle mounted shackle
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sat Oct 05, 2013 8:44 am
by Kel Fab Creations
I see.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sat Oct 05, 2013 12:53 pm
by Rmc
This may have been covered before, but question:
Pitfalls of spring under vs spring over? Is axel wrap the same in both configs?
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sat Oct 05, 2013 12:56 pm
by Kel Fab Creations
I've heard spring under will produce less axle wrap. Kinda hard to tell but I didn't notice any when I took that footage of my rear suspension.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sat Oct 05, 2013 12:59 pm
by Rmc
A guy I know told me there's more under and I'm having a hard time wrapping my head around as to why.
Re: Start Your Go-Fast Build-Rear Suspension
Posted: Sat Oct 05, 2013 6:32 pm
by philofab
Spring under:
1. Gravity helps stop axle wrap.
2. Allows lower ride height with more spring arch.
3. Different geometry due to front pivot being higher. (changes anti squat & affecting roll understeer/oversteer) (usually worse)
Allows a longer spring (due to more arch)
4. U-bolts hold vehicle weight in tension.
5. Less chance for negative arch in compression.
Spring over:
1. More ground clearance.
2. U bolts do not hold vehicle weight.
3. Different geometry due to front pivot being higher. (changes anti squat & affecting roll understeer/oversteer) (usually better)