My thoughts on lifts
10-15-2013, 07:44 PM
#31
JK Jedi
Thread Starter
That works too, to increase room for up travel but will also raise the center of gravity as the body on the JK is very heavy.
Last edited by TheDirtman; 10-16-2013 at 06:45 AM.
10-15-2013, 07:44 PM
#32
Forum Tech Advisor
Steeper control arm angles and the geometry if the mounting points affect the center of gravity of the jeep on steep climbs and descents.
A JK with stock control arm mounting points with the 2" lift will keep better traction on the front tires and have less hop of the rear tires on a steep climb than it would with a 4" lift.
The issue isn't about having a jeep that corners well. It's about the tires keeping traction on steep or off camber climbs.
10-15-2013, 07:46 PM
#33
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10-15-2013, 07:56 PM
#35
JK Enthusiast
The answer to this has to do with how suspension geometry affects anti-squat and brake dive.
Steeper control arm angles and the geometry if the mounting points affect the center of gravity of the jeep on steep climbs and descents.
A JK with stock control arm mounting points with the 2" lift will keep better traction on the front tires and have less hop of the rear tires on a steep climb than it would with a 4" lift.
The issue isn't about having a jeep that corners well. It's about the tires keeping traction on steep or off camber climbs.
Steeper control arm angles and the geometry if the mounting points affect the center of gravity of the jeep on steep climbs and descents.
A JK with stock control arm mounting points with the 2" lift will keep better traction on the front tires and have less hop of the rear tires on a steep climb than it would with a 4" lift.
The issue isn't about having a jeep that corners well. It's about the tires keeping traction on steep or off camber climbs.
10-15-2013, 08:11 PM
#36
Forum Tech Advisor
Dirtman has some really good info here.
I'd contribute an example:
With flat flares and minimal trimming of the rear fender well pinch seam, 35" tires can be run on 4.5" or less backspaced wheels with stock front bumpstops and about 2" rear extended bumpstops. So, you could run shocks that measure up to about 15" collapsed in the front and about 17.5" collapsed in the rear without bottoming them out. To gain more than stock articulation (flex), you'd run as long a shock as your springs would permit, as long as the collapsed length of the shock was at or less than the 15"/17.5".
With the same flat flares and rear pinch seam trimming, 37" tires can be run with 1.25" front and 2.5" rear extended bumpstops.
So, as an example for someone wanting more articulation (flex) with a mild lift of 2.5"-3":
You can run OME 11.5" travel shocks (16" collapsed and 27.5" extended) with 1.25" front extended bumpstops and longer front brakelines--and longer front swaybar links if you run them off road with a Rubi disconnect system.
You can run EVO RockStar (or similar) rear skids/shock relocation brackets that raise the rear lower shock and swaybar link mounting points about 1.5" with 11.5" travel OME shocks (16.5" collapsed and 28" extended), 2.5" rear extended bumpstops, longer brakelines, and longer swaybar links.
With this setup, you would need springs that can handle 11.5" travel without unseating. The rear coils would need lower coil retainers. OME HD springs can handle it. Metalcloak and Rock Krawler 2.5" springs should be able to handle it.
With 11.5" travel at the shock, you will want a flex joint (spherical joint) at atleast one end of at least the lower control arms. The front axle side upper control arm bushings in the axle will last longer if the front upper arms have a joint at the frame side instead of a bushing.
That setup, with appropriate adjustable trackbars, will RTI 1000 on a 2 dr JK with close to stock wheelbase.
The setup significantly increases articulation (flex) over stock because the combination of shock lengths and rear mounting points, extended bumpstops, longer brakelines, longer swaybar links, longer uncompressed spring lengths, etc. allows the full use of 11.5" travel shocks.
I haven't ever measured the actual usable shock travel with the stock setup, but I would be surprised if more than 7"-8" shock travel is useable.
I'd contribute an example:
With flat flares and minimal trimming of the rear fender well pinch seam, 35" tires can be run on 4.5" or less backspaced wheels with stock front bumpstops and about 2" rear extended bumpstops. So, you could run shocks that measure up to about 15" collapsed in the front and about 17.5" collapsed in the rear without bottoming them out. To gain more than stock articulation (flex), you'd run as long a shock as your springs would permit, as long as the collapsed length of the shock was at or less than the 15"/17.5".
With the same flat flares and rear pinch seam trimming, 37" tires can be run with 1.25" front and 2.5" rear extended bumpstops.
So, as an example for someone wanting more articulation (flex) with a mild lift of 2.5"-3":
You can run OME 11.5" travel shocks (16" collapsed and 27.5" extended) with 1.25" front extended bumpstops and longer front brakelines--and longer front swaybar links if you run them off road with a Rubi disconnect system.
You can run EVO RockStar (or similar) rear skids/shock relocation brackets that raise the rear lower shock and swaybar link mounting points about 1.5" with 11.5" travel OME shocks (16.5" collapsed and 28" extended), 2.5" rear extended bumpstops, longer brakelines, and longer swaybar links.
With this setup, you would need springs that can handle 11.5" travel without unseating. The rear coils would need lower coil retainers. OME HD springs can handle it. Metalcloak and Rock Krawler 2.5" springs should be able to handle it.
With 11.5" travel at the shock, you will want a flex joint (spherical joint) at atleast one end of at least the lower control arms. The front axle side upper control arm bushings in the axle will last longer if the front upper arms have a joint at the frame side instead of a bushing.
That setup, with appropriate adjustable trackbars, will RTI 1000 on a 2 dr JK with close to stock wheelbase.
The setup significantly increases articulation (flex) over stock because the combination of shock lengths and rear mounting points, extended bumpstops, longer brakelines, longer swaybar links, longer uncompressed spring lengths, etc. allows the full use of 11.5" travel shocks.
I haven't ever measured the actual usable shock travel with the stock setup, but I would be surprised if more than 7"-8" shock travel is useable.
Last edited by planman; 10-15-2013 at 08:25 PM.
10-16-2013, 05:09 AM
#37
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Dirtman has some really good info here. I'd contribute an example: With flat flares and minimal trimming of the rear fender well pinch seam, 35" tires can be run on 4.5" or less backspaced wheels with stock front bumpstops and about 2" rear extended bumpstops. So, you could run shocks that measure up to about 15" collapsed in the front and about 17.5" collapsed in the rear without bottoming them out. To gain more than stock articulation (flex), you'd run as long a shock as your springs would permit, as long as the collapsed length of the shock was at or less than the 15"/17.5". With the same flat flares and rear pinch seam trimming, 37" tires can be run with 1.25" front and 2.5" rear extended bumpstops. So, as an example for someone wanting more articulation (flex) with a mild lift of 2.5"-3": You can run OME 11.5" travel shocks (16" collapsed and 27.5" extended) with 1.25" front extended bumpstops and longer front brakelines--and longer front swaybar links if you run them off road with a Rubi disconnect system. You can run EVO RockStar (or similar) rear skids/shock relocation brackets that raise the rear lower shock and swaybar link mounting points about 1.5" with 11.5" travel OME shocks (16.5" collapsed and 28" extended), 2.5" rear extended bumpstops, longer brakelines, and longer swaybar links. With this setup, you would need springs that can handle 11.5" travel without unseating. The rear coils would need lower coil retainers. OME HD springs can handle it. Metalcloak and Rock Krawler 2.5" springs should be able to handle it. With 11.5" travel at the shock, you will want a flex joint (spherical joint) at atleast one end of at least the lower control arms. The front axle side upper control arm bushings in the axle will last longer if the front upper arms have a joint at the frame side instead of a bushing. That setup, with appropriate adjustable trackbars, will RTI 1000 on a 2 dr JK with close to stock wheelbase. The setup significantly increases articulation (flex) over stock because the combination of shock lengths and rear mounting points, extended bumpstops, longer brakelines, longer swaybar links, longer uncompressed spring lengths, etc. allows the full use of 11.5" travel shocks. I haven't ever measured the actual usable shock travel with the stock setup, but I would be surprised if more than 7"-8" shock travel is useable.
10-16-2013, 05:13 AM
#38
JK Jedi
Well said by planman also. Imo on travel over 12" you should use coilovers and if for some reason you dont you will need a long coil to keep then seated wich will generally throw lcog out the window... This is of course assuming your not cutting and welding anything. As he said even on 11.5 you will need to retain the rear.
10-16-2013, 06:31 AM
#40
JK Jedi
It's know I've been paying this thread by but i decided to take a look today and WOW this has got to bio the MOST informative thread on here! Great job op
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