Upgrading My Current RK Kit
06-02-2015, 05:19 PM
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Upgrading My Current RK Kit
So on my 2010 2dr JK I have what I assume is a Rock Krawler 2.5" Max Travel kit. The kit was on the Jeep when I bought it almost two years ago now and I looked up the part number on the springs which told me they are RK 2.5" springs. Then I noticed that it seems like I have RK's lower control arms front and rear which after looking at their website, the max travel kit is the only one they offer that comes with four control arms. Now if all of those assumptions and research are correct, then on to the question.
Once my current tires get closer to the wear bar, I intend on putting 37's on it but I still want to have plenty of room to flex and tuck them. That being said, I would like to just buy RK's 3.5" springs and swap them in. While i'm in there, I figured I might as well get RK's upper control arms for the rear (for right now, fronts also a little later probably) and swap them at the same time so that I can center the rear axle in the wheel well as I lift her higher.
So there's my plan, my question more so is, will it really be that easy? Just swap the springs out and rear upper control arms? That just seems too easy and if it's too easy, I feel like I overlooked something important which is why I'm inquiring from you more experienced Jeep folks out there who may have been there, done that. Thanks in advance guys (and gals).
Once my current tires get closer to the wear bar, I intend on putting 37's on it but I still want to have plenty of room to flex and tuck them. That being said, I would like to just buy RK's 3.5" springs and swap them in. While i'm in there, I figured I might as well get RK's upper control arms for the rear (for right now, fronts also a little later probably) and swap them at the same time so that I can center the rear axle in the wheel well as I lift her higher.
So there's my plan, my question more so is, will it really be that easy? Just swap the springs out and rear upper control arms? That just seems too easy and if it's too easy, I feel like I overlooked something important which is why I'm inquiring from you more experienced Jeep folks out there who may have been there, done that. Thanks in advance guys (and gals).
06-02-2015, 06:05 PM
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You are on top of the caster/pinion adjustment.
Both axles will shift to one side a bit. Do you have adj trackbars? (probably not enough to worry about if you don't)
The lift height will be in the range for a draglink flip, so you might want to read a few threads on that.
The shocks may be a bit short for the new lift height. Find the specs for them and see what you think.
The swaybars will be angled down a bit. Do you have adjustable links?
Depending on tire size and flare clearance, the bumpstops might need a little tweaking, or they may not.
The brakelines will be stretched a bit more. Verify if you still have the stock ones on, or longer aftermarket lines.
Saw that you have aftermarket driveshafts, good to go there...
Both axles will shift to one side a bit. Do you have adj trackbars? (probably not enough to worry about if you don't)
The lift height will be in the range for a draglink flip, so you might want to read a few threads on that.
The shocks may be a bit short for the new lift height. Find the specs for them and see what you think.
The swaybars will be angled down a bit. Do you have adjustable links?
Depending on tire size and flare clearance, the bumpstops might need a little tweaking, or they may not.
The brakelines will be stretched a bit more. Verify if you still have the stock ones on, or longer aftermarket lines.
Saw that you have aftermarket driveshafts, good to go there...
Last edited by nthinuf; 06-02-2015 at 06:09 PM.
06-03-2015, 12:03 AM
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My concern was just the typical 'stock driveshaft with taller lift'. Ya know, the steeper angle pinching through the boot, and the joint spitting out all the grease and then seizing.
06-03-2015, 05:36 AM
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You are on top of the caster/pinion adjustment.
Both axles will shift to one side a bit. Do you have adj trackbars? (probably not enough to worry about if you don't)
The lift height will be in the range for a draglink flip, so you might want to read a few threads on that.
The shocks may be a bit short for the new lift height. Find the specs for them and see what you think.
The swaybars will be angled down a bit. Do you have adjustable links?
Depending on tire size and flare clearance, the bumpstops might need a little tweaking, or they may not.
The brakelines will be stretched a bit more. Verify if you still have the stock ones on, or longer aftermarket lines.
Saw that you have aftermarket driveshafts, good to go there...
Both axles will shift to one side a bit. Do you have adj trackbars? (probably not enough to worry about if you don't)
The lift height will be in the range for a draglink flip, so you might want to read a few threads on that.
The shocks may be a bit short for the new lift height. Find the specs for them and see what you think.
The swaybars will be angled down a bit. Do you have adjustable links?
Depending on tire size and flare clearance, the bumpstops might need a little tweaking, or they may not.
The brakelines will be stretched a bit more. Verify if you still have the stock ones on, or longer aftermarket lines.
Saw that you have aftermarket driveshafts, good to go there...
He has a 2010. My understanding is that it is only the 2012+ jk's that need that spacer.
My concern was just the typical 'stock driveshaft with taller lift'. Ya know, the steeper angle pinching through the boot, and the joint spitting out all the grease and then seizing.
My concern was just the typical 'stock driveshaft with taller lift'. Ya know, the steeper angle pinching through the boot, and the joint spitting out all the grease and then seizing.
06-03-2015, 05:46 AM
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He has a 2010. My understanding is that it is only the 2012+ jk's that need that spacer.
My concern was just the typical 'stock driveshaft with taller lift'. Ya know, the steeper angle pinching through the boot, and the joint spitting out all the grease and then seizing.
My concern was just the typical 'stock driveshaft with taller lift'. Ya know, the steeper angle pinching through the boot, and the joint spitting out all the grease and then seizing.
this is interesting....I didn't realize the 2.5 and 3.5 used the same arms in the right kits.
06-03-2015, 05:49 AM
#7
JK Junkie
A common misunderstanding about running larger tires is that more lift will help you clear them. That is not the case. Here is how it works.
- Right now the travel of your tire is determined by two things: 1. your shock when fully extended, which is max droop so to speak; and 2. your bump stops, which is what stops the axle from traveling further upward.
- Assume the shocks and bump stops stay the same, what happens when you go from a 2.5" to a 3.5" coil? All it does is change where you are on the line of travel. Let's say right now you have 10" of travel and it is 5" up and 5" down. Then you get 3.5" coils. Now your travel is 6" up and 4" down. The max droop and max compression points have not changed.
- What have you gained with 3.5" coils? Potential driveline and steering issues, a high center of gravity, and that's about it.
- How will you clear larger tires? Either add more bump stop or remove the things that are in the way (e.g. flat fenders, cutting metal, etc.).
Point is, more lift does nothing in terms of flex or stuffing the tires. If you have to add more bump stop, all you are doing is removing suspension travel. I say this often, but most people with large tires have the same or less travel than a stock JK. It is funny how everyone is looking for the super flexy system when they are running 8" of travel.
- Right now the travel of your tire is determined by two things: 1. your shock when fully extended, which is max droop so to speak; and 2. your bump stops, which is what stops the axle from traveling further upward.
- Assume the shocks and bump stops stay the same, what happens when you go from a 2.5" to a 3.5" coil? All it does is change where you are on the line of travel. Let's say right now you have 10" of travel and it is 5" up and 5" down. Then you get 3.5" coils. Now your travel is 6" up and 4" down. The max droop and max compression points have not changed.
- What have you gained with 3.5" coils? Potential driveline and steering issues, a high center of gravity, and that's about it.
- How will you clear larger tires? Either add more bump stop or remove the things that are in the way (e.g. flat fenders, cutting metal, etc.).
Point is, more lift does nothing in terms of flex or stuffing the tires. If you have to add more bump stop, all you are doing is removing suspension travel. I say this often, but most people with large tires have the same or less travel than a stock JK. It is funny how everyone is looking for the super flexy system when they are running 8" of travel.
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06-03-2015, 06:02 AM
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You have the shorter RK rear lower arms. Option 1/ buy the uppers and longer lowers.
Option 2/ call RK and request a shorter set of rear uppers.
The 1st option will move the axle back 1" or so. The swaybar will have to be moved back. Coil wedges, either move the TB frame mount back or run their double adjustable track bar. Much easier and less work to do option #2 which i did.
Front CA's. You are fine with just the lowers. You might have to dial down caster running a aftermarket driveshaft.
As mentioned adjust sway bars, longer shocks depending on what you have and bump stop.
A highsteer kit is personal choice.
Option 2/ call RK and request a shorter set of rear uppers.
The 1st option will move the axle back 1" or so. The swaybar will have to be moved back. Coil wedges, either move the TB frame mount back or run their double adjustable track bar. Much easier and less work to do option #2 which i did.
Front CA's. You are fine with just the lowers. You might have to dial down caster running a aftermarket driveshaft.
As mentioned adjust sway bars, longer shocks depending on what you have and bump stop.
A highsteer kit is personal choice.
Last edited by kjeeper10; 06-03-2015 at 06:41 AM.
06-07-2015, 10:45 AM
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A common misunderstanding about running larger tires is that more lift will help you clear them. That is not the case. Here is how it works.
- Right now the travel of your tire is determined by two things: 1. your shock when fully extended, which is max droop so to speak; and 2. your bump stops, which is what stops the axle from traveling further upward.
- Assume the shocks and bump stops stay the same, what happens when you go from a 2.5" to a 3.5" coil? All it does is change where you are on the line of travel. Let's say right now you have 10" of travel and it is 5" up and 5" down. Then you get 3.5" coils. Now your travel is 6" up and 4" down. The max droop and max compression points have not changed.
- What have you gained with 3.5" coils? Potential driveline and steering issues, a high center of gravity, and that's about it.
- How will you clear larger tires? Either add more bump stop or remove the things that are in the way (e.g. flat fenders, cutting metal, etc.).
Point is, more lift does nothing in terms of flex or stuffing the tires. If you have to add more bump stop, all you are doing is removing suspension travel. I say this often, but most people with large tires have the same or less travel than a stock JK. It is funny how everyone is looking for the super flexy system when they are running 8" of travel.
- Right now the travel of your tire is determined by two things: 1. your shock when fully extended, which is max droop so to speak; and 2. your bump stops, which is what stops the axle from traveling further upward.
- Assume the shocks and bump stops stay the same, what happens when you go from a 2.5" to a 3.5" coil? All it does is change where you are on the line of travel. Let's say right now you have 10" of travel and it is 5" up and 5" down. Then you get 3.5" coils. Now your travel is 6" up and 4" down. The max droop and max compression points have not changed.
- What have you gained with 3.5" coils? Potential driveline and steering issues, a high center of gravity, and that's about it.
- How will you clear larger tires? Either add more bump stop or remove the things that are in the way (e.g. flat fenders, cutting metal, etc.).
Point is, more lift does nothing in terms of flex or stuffing the tires. If you have to add more bump stop, all you are doing is removing suspension travel. I say this often, but most people with large tires have the same or less travel than a stock JK. It is funny how everyone is looking for the super flexy system when they are running 8" of travel.
I'm assuming bumpstops are very straightforward in the fact that you just measure the length of the bumpstop from top to bottom but someone correct me if i'm wrong. If I am correct in this, my front bumpstops are about 1 3/4" and the rear appear to be about 2" bumpstops. I'll tack on a few pictures at the end of this reply for some clarification (and besides, who doesn't like pictures). As far as removing things that are in the way, I have flat flares already and the front seems to be pretty free from things that could rub but the rear is in dire need of being recentered because it is currently too close to the pinch seem/rubi rail to be able to flex much. If I could push the rear axle back in the wheel well, I think that would solve that issue.
So it seems like in addition to 3.5" coils and rear control arms, I also might need to get shocks with a longer travel in order to have more overall flex. And then just play with bumpstops to keep the tires from stuffing too much and rubbing on the inside of the fenders.
You have the shorter RK rear lower arms. Option 1/ buy the uppers and longer lowers.
Option 2/ call RK and request a shorter set of rear uppers.
The 1st option will move the axle back 1" or so. The swaybar will have to be moved back. Coil wedges, either move the TB frame mount back or run their double adjustable track bar. Much easier and less work to do option #2 which i did.
Front CA's. You are fine with just the lowers. You might have to dial down caster running a aftermarket driveshaft.
As mentioned adjust sway bars, longer shocks depending on what you have and bump stop.
A highsteer kit is personal choice.
Option 2/ call RK and request a shorter set of rear uppers.
The 1st option will move the axle back 1" or so. The swaybar will have to be moved back. Coil wedges, either move the TB frame mount back or run their double adjustable track bar. Much easier and less work to do option #2 which i did.
Front CA's. You are fine with just the lowers. You might have to dial down caster running a aftermarket driveshaft.
As mentioned adjust sway bars, longer shocks depending on what you have and bump stop.
A highsteer kit is personal choice.
As promised, here are the pictures I took:
Front bumpstop
Rear bumpstop
06-07-2015, 12:53 PM
#10
JK Junkie
The pictures show your stock bump stops. The white foam stop will fully compress at full flex. Look at the receiving end of those on your axle and there should be aftermarket bump stops.
It's not as simple as getting longer shocks. You're pretty much at these for standard shocks. If you go longer, you'll have to add bump stop to prevent over compressing and damaging the shock. You essentially gain mostly down travel. At that point you need to determine if you will be running angles that your drive line can't operate at. If so, you'll need limit straps. In addition, it is very likely that you'd over extend the coils. So, you'll need retainers, at which point you may lose most of what you gained. It can be done, but you will need to start looking at modifying the shock mounts.
It's not as simple as getting longer shocks. You're pretty much at these for standard shocks. If you go longer, you'll have to add bump stop to prevent over compressing and damaging the shock. You essentially gain mostly down travel. At that point you need to determine if you will be running angles that your drive line can't operate at. If so, you'll need limit straps. In addition, it is very likely that you'd over extend the coils. So, you'll need retainers, at which point you may lose most of what you gained. It can be done, but you will need to start looking at modifying the shock mounts.