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Discussion Starter #1
I'm ordering the RK 3.5"X-Factor lift for a 2015 JKU. I'll be running 35's and Rancho 9000's. Trying to get everything ordered, but can't get a definitive answer on bump stops. The shop placing the order is telling me 2.5", but I've read that with this kit I may need 3". Just trying to order it all right the first time. Thanks
 

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You can always order them after you get the lift installed, just get your jeep to flex to the limit you want and measure the distance between the bumps already on there. I was also told 3'' but I have yet to stuff it to confirm, make sure you buy the RK stops, they are at a slant to keep the sway bar discos from contacting them with the axle moved back.
 

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Discussion Starter #5
A good rule of thumb is to match the coil Height. 3" front / 2" rear is a good start. It ultimately comes down to the shocks compress lengths. On RK's site, under your lift choice. You'll see the part numbers for shocks and required bump stops to go with them. You want the 31/32 9000 shocks btw.
Can I put this together without the bump stops? Then go ahead and flex it to get measurements, order the bump stops, install bump stops without needing another alignment. I'll be installing the lift, and then taking the Jeep for an alignment if needed. Then taking it to the shop where they're going to remove my wheel sensors, and installing on the new MT Classic III's with MT baja radial MTZ's.
 

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Can I put this together without the bump stops? Then go ahead and flex it to get measurements, order the bump stops, install bump stops without needing another alignment. I'll be installing the lift, and then taking the Jeep for an alignment if needed. Then taking it to the shop where they're going to remove my wheel sensors, and installing on the new MT Classic III's with MT baja radial MTZ's.
By flexing it out without bumpstops you'll be putting all the compression force on your shocks (depending on what length you're running) which is not recommended.
You're better to look up your shock lengths via the part numbers and determine the best bumpstop that way.
Alignment won't be effected by bumpstop lengths, alignment is done at ride height
 

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Discussion Starter #7
You can always order them after you get the lift installed, just get your jeep to flex to the limit you want and measure the distance between the bumps already on there. I was also told 3'' but I have yet to stuff it to confirm, make sure you buy the RK stops, they are at a slant to keep the sway bar discos from contacting them with the axle moved back.
Are these RK stops necessary with the x factor kit as it comes with an adjustable rear track bar? It sounded to me like you only need those particular stops if you're keeping the oem trackbar. Not sure if the RK rear trackbar addresses the axle being moved back. I would think so though.
 

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Are these RK stops necessary with the x factor kit as it comes with an adjustable rear track bar? It sounded to me like you only need those particular stops if you're keeping the oem trackbar. Not sure if the RK rear trackbar addresses the axle being moved back. I would think so though.
Yes, they have nothing to do with the track bar. The sway bar links are moved back 1 inch but still ride up close to the stops.
 

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Are these RK stops necessary with the x factor kit as it comes with an adjustable rear track bar? It sounded to me like you only need those particular stops if you're keeping the oem trackbar. Not sure if the RK rear trackbar addresses the axle being moved back. I would think so though.

Every jeep is going to be different, but depending on how far you move the axle and sway bar back, you can contact the bump stop with the sway bar end links. I wish I had a picture, The instructions say to move the sway bar back 1'' which would compensate for the axle moving back 1'' and keep the end links straight....in theory, I moved mine back the inch but moved the axle farther to center it in the wheel well, which put the top mounting point for the sway bar over the axle while the bottom mounting point is behind the axle. Can you kind of picture that angle? again every jeep is different and every setup different, but I did see a thread where RK commented to use their bumpstops for this reason, that may be more directed to 2-doors also idk. I have a 4-door and I will need those angled bump stops to clear the links when the rear is compressed.

Marslim is right with not wanting to put the compressed load of the jeep on the shocks, I didn't clarify to well. compressed shock length measurement and a little math is the safest way no doubt.
 

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Normally we recommend 3" of bump stop for the 35's. I run those on my Jeep since I have the 2.5 flex with 35's. The RK stood are great because you can stack them if you need more bump stop. Like Ken said try to match the springs and you'll be at a good starting point, then flex test it to see if you need more.

Jeremy
 

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By flexing it out without bumpstops you'll be putting all the compression force on your shocks (depending on what length you're running) which is not recommended. You're better to look up your shock lengths via the part numbers and determine the best bumpstop that way. Alignment won't be effected by bumpstop lengths, alignment is done at ride height
One issue. Its not 1/1 because the axles move in a arc.

The best way to do it is by compressing the axles and measuring. Going by shock specs is just the start.
 

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Discussion Starter #12
Ok, it's paid for. Order getting placed today for 3.5 X Factor, and 35's. Now I have to let him know whether I want the FlashCal or ProCal. I started a different thread. Just wondering if they do the same thing. Flashcal is 10 bucks cheaper. Don't know if I need something that will change shift points.
 

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Ok, it's paid for. Order getting placed today for 3.5 X Factor, and 35's. Now I have to let him know whether I want the FlashCal or ProCal. I started a different thread. Just wondering if they do the same thing. Flashcal is 10 bucks cheaper. Don't know if I need something that will change shift points.
Id say AEV because its tried and true
 

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I have the flashcal and it is upgradeable to a flashpaq also. I have a 6 speed though so no shift points other then what I choose. The flashcal will read engine codes also so that was a big plus in my book. There is another thread about the 2 and there differences and I believe a lot of autos had issues with flashcal. idk if they still do but there were a few that had to do quite a few updates and patches to get it working right. Manuals never seemed to have this issue.
 

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Discussion Starter #15
I just read that AEV was kind of a pain in that it used dip switches, and each thing you program had to be entered individually. I don't know it to be correct, but I thought you program all functions into the Flashcal and then plug it in.
 
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