Rock Krawler 3.5" X Factor vs Flex
JK Junkie
Joined: Jun 2013
Posts: 3,697
Likes: 2
From: Grosse Pointe, MI
There is someone on here that is running the RK 1.5" lift with flat fenders and 37s. It's not about lift height it's about proper bumpstops, proper length shocks, and enough clearance for the tires. Yes a 3.5" lift will allow him to run 37s but without the proper components mentioned already he will still have rubbing or other issues.
I had 14" of travel with 37s and 2.5" of lift. Required very minor trimming in the rear.
JK Newbie
Joined: Dec 2014
Posts: 83
Likes: 0
From: Germany
Yes and he has no up travel only down. The point of a lift is to give up travel which is important. Plus I don't want to hit my bumps tops every pot hole. Your travel does stay the same total distance but it switches from down travel o up travel which is better for higher speed running. Plus if you run longer shocks to get that down travel without the the proper lift you can do damage. Unless you bump stop the hell out of it in which case it's a rough ride on you and your jeep and will look retarded without large tires. Finally up travel can help prevent you from rolling over as easily in some situations
JK Junkie
Joined: Jun 2013
Posts: 3,697
Likes: 2
From: Grosse Pointe, MI
Yes and he has no up travel only down. The point of a lift is to give up travel which is important. Plus I don't want to hit my bumps tops every pot hole. Your travel does stay the same total distance but it switches from down travel o up travel which is better for higher speed running. Plus if you run longer shocks to get that down travel without the the proper lift you can do damage. Unless you bump stop the hell out of it in which case it's a rough ride on you and your jeep and will look retarded without large tires. Finally up travel can help prevent you from rolling over as easily in some situations
Up and down doesn't really matter much when you have 7" of travel.
Thread Starter
JK Newbie
Joined: Apr 2015
Posts: 76
Likes: 0
From: Houston, Texas
Thanks for the good info on here!
Last question, because the lift height won't be as much will upper control arms be necessary to run 37s? In some cases I know you have to trim the pinch seam with the larger tires and I am trying to avoid that.
Last question, because the lift height won't be as much will upper control arms be necessary to run 37s? In some cases I know you have to trim the pinch seam with the larger tires and I am trying to avoid that.
JK Junkie
Joined: Jun 2013
Posts: 3,697
Likes: 2
From: Grosse Pointe, MI
Front lowers should do it. Trim the pinch seam if needed. No reason not to. They actually come from the factory now with it trimmed. Won't hurt value or anything. Very easy to cut and then fill with JB Weld. You can get a little tune of the factory paint as well.
JK Enthusiast
Joined: Jul 2014
Posts: 441
Likes: 0
From: Virginia Beach
Ok, this is exactly my point. Explain to me how adding an inch of lift will help tire rub?
The shocks are the same. The axle can only droop to the point the shock is fully extended and compress to the point the shock is fully compressed. That is the linear line of travel (y axis). Where you sit on that line is determined by coils.
Let's say you have 10" of total travel. With a 2.5" coil you have 4" of up travel and 6" down. Then you get 3.5" coils. Now you have 5" up and 5" down. However, your tire still follows the same line of travel. If you rub now, you'll rub with more lift. To fix the rub you need to limit uptravel and that is done with bump stops. More lift does nothing.
The shocks are the same. The axle can only droop to the point the shock is fully extended and compress to the point the shock is fully compressed. That is the linear line of travel (y axis). Where you sit on that line is determined by coils.
Let's say you have 10" of total travel. With a 2.5" coil you have 4" of up travel and 6" down. Then you get 3.5" coils. Now you have 5" up and 5" down. However, your tire still follows the same line of travel. If you rub now, you'll rub with more lift. To fix the rub you need to limit uptravel and that is done with bump stops. More lift does nothing.
I may be looking at this incorrectly but if you add 1" more lift via taller springs and 1" more bumpstop you would negate the extra 1" you were trying to gain in uptravel correct? And longer shocks would just mean a longer shock body which would mean they would bottom out sooner at full compression again negating the extra 1". All you would gain is a little extra droop which I think is where you open up concerns for other components, ie. driveshaft, etc.
JK Junkie
Joined: Nov 2011
Posts: 3,863
Likes: 1
From: Bossier City, LA
I was referring more to the pinch seam in front for the wheel well, might not be an actual pinch seam. The rears come trimmed already on bottom with the newer years. As invest mentioned you can just trim it if not. It's not hard and had no negative effect
Last edited by DunnyBunny; May 1, 2015 at 07:14 AM.
Thread Starter
JK Newbie
Joined: Apr 2015
Posts: 76
Likes: 0
From: Houston, Texas
Thanks for all your help!
JK Freak
Joined: Oct 2014
Posts: 768
Likes: 1
agree 100%. Just explaining their rationale better than they can and how i was convinced to get a 3.5. Yes I run a 3.5 and regret it with every unnecessary purchase due to issues I don't need to deal with. I'll repeat there is NO WAY I would go over 2.5" if I could do it over. But I'm already in too deep in my wallet to go back.