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upgrading the xj
Posted: Mon Apr 05, 2010 1:46 pm
by GRADESCHOOL
As of now i have a rubicon express 4.5" lift with the add a leaf and block in the rear and being my tires are bald and my springs are sagging bad i decided to do some upgrading. Next weekend i am picking up some toyo mt 33x13.5 tires and i still am debating what to do as of lift. I am defiantly going to just put coil spacers in the front but as the rear goes is where i cant make up my mind. I am trying to decide between getting the 4.5" leafs and shackles or to just get the 6.5" leafs. I am going to get rustys springs. What do you guys think? 4.5" springs with a 2" shackle or just get the 6.5" springs?
Posted: Mon Apr 05, 2010 2:16 pm
by White trash
2 1/2" springs and longer shackle for a smoother arc and ride. Then trim a bit to fit the tires.
Posted: Mon Apr 05, 2010 2:21 pm
by GRADESCHOOL
I havent decided yet but im not to sure i want to cut the rear fenders
Posted: Mon Apr 05, 2010 2:24 pm
by White trash
The rear is pretty simple to deal with but it's a bit time consuming...
Posted: Mon Apr 05, 2010 9:15 pm
by commando14
I'd go with the 4.5" or even 2.5" like trashy said... and then slightly longer shackles if needed. 6.5" will have way too much arc, and shouldn't need that much lift to fit 33's. Or get some comanche springs.. longer and less arc.
Posted: Tue Apr 06, 2010 3:40 pm
by GRADESCHOOL
I dont think im liking the idea of 2.5" springs because in the front i have the 4.5" coils and i am adding a coil spacer in the front, i am just looking to have my jeep sit level.
Posted: Tue Apr 06, 2010 5:11 pm
by bobracing
put a bigger tool box in the back.
Posted: Tue Apr 06, 2010 6:18 pm
by tobyw
Leave out the front spacer, you're only running 33's... Trim the front fenders a little bit and put in proper bumpstops. Do NOT lift it any higher.
Go with the 2.5" leaves out back with shackles as necessary. Trim/fold the fenders up to the spot welds, and again bumpstop as necessary.
Bring it over to my place and we'll setup your bumpstops once you have the 33's installed. I'll only charge you a box of (cheap) beer

Posted: Tue Apr 06, 2010 8:57 pm
by White trash
tobyw wrote:Leave out the front spacer, you're only running 33's... Trim the front fenders a little bit and put in proper bumpstops. Do NOT lift it any higher.
Go with the 2.5" leaves out back with shackles as necessary. Trim/fold the fenders up to the spot welds, and again bumpstop as necessary.
Bring it over to my place and we'll setup your bumpstops once you have the 33's installed. I'll only charge you a box of (cheap) beer

You need to get out of here with that logic stuff... Big dumb monster trucks are where it's at...

Posted: Wed Apr 07, 2010 11:44 pm
by GRADESCHOOL
I understand wanting to keep your center of gravity low but toby didnt your xj have about 7.5" of lift? I know i dont need around 6.5" to clear 33's cause it says with my lift i should be able to run them as it is. MY thinking was to clear 33's like i clear my 31's now so in thereoy With a budget boost on top of my lift it should be about the same. im looking to order parts soon im just trying to get a better idea of why stick with smaller springs.
Posted: Thu Apr 08, 2010 5:39 am
by tobyw
Nope, my XJ had ~4.5" of lift, I trimmed the fenders, and ran 31" Boggers with
factory bumpstops. If I wanted 33's, all I would have done was add some bumpstop. In fact, I would have run 35's using the same process...

Posted: Thu Apr 08, 2010 9:56 am
by Cody
I had a 3.5 inch skyjacker lift on my first xj with bushwacker fender flares and ran 31 inch tall tires. i then steped up to a 32 inch tire and bottomed out on the base of hill climbs in the rear and rubbed in the front. I then went with a 1 inch spacer in the front and added some shackels the rear and problem solved...
Posted: Thu Apr 08, 2010 11:18 am
by tobyw
Cody wrote:I then went with a 1 inch spacer in the front and added some shackels the rear and problem solved...
Huh... This tells me a couple things: (1) your rear geometry must have sucked, and (2) your front coils must have been improperly designed.
(1) If you added longer shackles and it stopped you from rubbing the same size tire, this means your suspension was binding and preventing you from reaching the same point of compression travel. The only thing that should limit uptravel is bumpstops, and since you didn't change those...
(2) Similar issue to the rear: your coils must have been completely compressed, which is not a good thing. Again, nothing should limit uptravel other than a bumpstop, and since you didn't change those...
Long story short kids, I don't care how much spring arch you have, how long your shackles are, or how many donuts you decide to stack above your coils, it's all about BUMPSTOPS to prevent tire rub assuming the rest of your suspension is properly designed/setup.
Posted: Thu Apr 08, 2010 11:31 am
by White trash
Stiff springs will limit uptravel as well of course.. And lets face it, skycrapper springs aren't known for their low spring rate.

Posted: Thu Apr 08, 2010 11:38 am
by tobyw
White trash wrote:Stiff springs will limit uptravel as well of course..
tobyw wrote:assuming the rest of your suspension is properly designed
Yep

Posted: Thu Apr 08, 2010 11:52 am
by White trash
99% of the boxed up lift kits are set up too stiff so they hold their lift... So in essence you are correct it wasn't properly designed.

Posted: Thu Apr 08, 2010 7:29 pm
by Wrench
You can save alot of cash if you build your own spring packs. I used leaves from a Chevy in my rear springs. Any 73-87 1/2T rear spring pack will work as a donor.
I am running about 6" of lift on my XJ and 31" tires on 15X8 wheels. Mine rub a little on the inside of the flares under full flex, and my bumpstops are extended about 2".
I think if you are running 33's with stock fenders, you will need to extend your bump stops around 3". If your wheel offset is too shallow, your tires will hit the flares pretty bad. If they are deeper, it will tuck the wheels inside the flares better under full flex.
Posted: Thu Apr 08, 2010 9:57 pm
by GRADESCHOOL
OK so today i ordered 4.5" rear springs to make my xj sit level i also ordered a budget boost but i am not completly sure i am going to install it yet. Toby i am going to have to take you up on that offer for setting up bump stops. I also am getting different tires than i was planning on i am getting some rubicon wheels with some mickey thompson baja claws for doing a small tile job.
Posted: Fri Apr 09, 2010 5:39 am
by tobyw
If those MT's are any wider than a 10.5, you had better order up some wheel spacers... Call back whoever you ordered your junk from, cancel the budget boost, and get some wheel spacers coming instead. The Rubi wheels have way more backspacing than your current black steelies, and you're going to rub on your control arms at minimal steering angle, and likely rub the coil tower during compression travel as well.
Or better yet, cancel all of it, listen to some of the advice that you initially asked for in this thread, and use the money to actually go wheelin?!