Suburban Suspension and Tire Options: Need Some Advice

[ngoluba]

Hello everyone, I'm new to CK5. Have an '87 GMC 2500 4x4 350TBI/TH400/NP208/4.10s, 150k, bone stock. It's time for some new tires and wheels which leads to a whole litany of choices and options. /forums/images/graemlins/thinking.gif

I live in western Colorado and am surrounded by fantastic 4 wheeling opportunities. I've been impressed with the comfort and capability of the stock vehicle off road. The break-over and departure angles are a bit of a problem. I'm looking to improve this with sliders, larger tires and maybe a suspension lift.

Tires: Considering 33's or 35's and perhaps a softer 4" all spring lift that will help make room for the new rubber while soaking up the bumps. I'm not completely averse to cutting the wheel wells if it can be done cleanly to reduce the required lift and enable full suspension articulation.

I would like to use an aggressive tread radial tire that is not too noisy on the highway, has a decent tread life, can air down on the trail to soften the ride, but with sidewalls that can stand up to the jagged rocks and the weight of this full size. BFG Mud Terrains and Goodyear MT/Rs seem like the safe bets, but I am also considering the Interco TSL SSRs and the Mickey Thompson Radial Baja Claw. Decent performance on wet roads and ice is important to me as well and I'm guessing difficult to find with this style of tire. What are your thoughts?

I've got a 60/14ff pair sitting around with 4.56s I planned to use on another project, but they could be drafted if the stock axles (10/14sf) and gears (4.10) aren't up to the task. I would prefer to use the existing axles/gears if possible.

Springs: I'm shooting for good ride both on and off road with improved off-road capability. Does anyone know the OEM spring rates front and rear (56") for the 3/4 ton? What are your thoughts on spring rates, price, and performance for the offerings from BDS, Tuffy, Skyjacker, Superlift, Rancho, Rough Country, others? Who would you recommend as a good vendor to deal with? I'm heading over to Denver this weekend to check out 4WheelParts Truck Fest. I'm inclined to install everything myself, but I could be tempted to let a competent vendor install it if the price was right.

Airbags: I'm thinking about Firestone Ride-Rite airbags in back so I can level it up when fully loaded and/or pulling a trailer. They list spacers for lifted vehicles if I go that route. I'm hoping this can balance the desire for supple springs without losing the load carrying capacity for hauling and towing. I've been told the bags will limit articulation. Anyone have experience with these?

Shocks: Any thoughts? Nitrogen charged? Bilstein 5150s? $100/shock seems a little pricey are they worth it? How about the 5100s? Other recommendations?

Overall, I'm looking to tap the wisdom of fellow Suburban owners to find a complete package of components that work well together on a Sub. What have you done? How did you like it? If you were starting fresh and had it all to do over again, what would you do (springs, shocks, wheels, tires, other)? Any and all thoughts and advice welcome and appreciated.

 

[sled_dog]

First things first, this has to be the BEST first post I've ever seen on this board /forums/images/graemlins/smile.gif. No stupid, can I fit this with this, open minded, intelligent questions, right on man. Alright now down to it.

I'd say 4" of lift and 35s is a great direction to go in. WIll require a little trimming especially with good flex but not as much as a lot of people on here with say 38s on 4" of lift of course.

For a tire, all the ones you listed are good tires, I'd look at the MT/Rs or the SSRs personally. The Baja Claws would have the worst road manners I would say(not from experience though). The MT/Rs, SSRs, and BFG MTs are all good on/off road vehicle tires.

Now as for your axles, well thats a point of debate. Lockers in the front and rear will REALLY help your offroad ability, but hurt your axles. 35s is what I would say is the limit of the axles under the rig now. If you decide to keep the present axles, I seriouslly hunt for another 14 bolt ff for the rear with 4.10 gears. The SF axles are junk in my opinion. I have an 89 Burb with the SF and the first mod I'm doing to it is a FF. If you are not going to do that other project I'd say put the 1 tons in and have piece of mind. A front locker with 35s will be pushing the 10 bolt, basically thats its limit, and it can be pushed over the limit in harsh situations. Not to mention the 4.56 gears can only help when it comes to crawl ratio. THe bigger tires will offset the gear ratio remember.

For springs, the best ones out of the list you gave I'd say are BDS and Tuffy. Thats based on flex. Tuffy will probably ride a little nicer. I have BDS on my K5 and I got them cause they were CHEAP. www.jds-offroad.com $180 for both springs without bushings. I didn't want bushings anyway cause I got a fully greasable suspension setup from ORD, www.offroaddesign.com they also sell Tuffy springs. As for the rear springs, a shackle flip would be my recommendation. ORD sells a kit, you will find it on their site and a review here on CK5. It flips over the rear leaf hanger and keeps the stock springs. That gives you the ride of stock, lift, and a better articulation to boot.

Airbags, sorry can't help there, sounds like a good idea but how to make it work with everything else I just don't know.

Shocks, I'd say Bilstein 5150s all the way. They are more expensive but you are paying for quality flat out. I know everyone I've EVER heard of personally using them, says they will never go back to a cheap Rancho or even something like an expensive Rancho 9000. Now to make full use you will need longer shock mounts up front and relocated rear mounts. Check the tech section of CK5 for an article about Ford front shock towers, that will give you the room needed for a good set of Bilsteins.

I have not yet built my Suburban but I likely will be VERY soon, and if you want the list of what I'm gonna do, I'm gonna keep the 10 bolt up front, put in a full float 14 bolt, add some 4" BDS front springs, add some shackle flips in the back, 35" MTs most likely, and Bilstein 5150 shocks. Notice though I have not yet built it so I can't tell you how I like the setup.

 

[Jonny-K5]

i agree with everything that sled dog said. although you might consider going with a good A/T instead of one of those you mentioned. my personal favorite is the BFG A/T KO.
they provide great on road manners and decent grip in all offroad situations except mud. reason i suggest those is you say wet/icy handling is just as important as offroad traction.

the BFGs are severe weather rated so they are perform exceptionally well in wet/icy situations.much better than any M/T will do.my TSL's are pretty scary in icy conditions.

ive got a set of KO's on my truck for the street/trails and a set of tsl's for mud bogging. i've tried the tsl's on trails in the local mountains and i think the A/Ts work just as well 99% of the time. they even worked better in deep snow. tsl's would tend to dig and bury the truck when the BFG's would just float over the top.

good luck with your truck, it sounds like your well on your way to building a very capable rig.

 

[darkshadow]

welcome, first off get us some pics!!!!!!
you sound like you got a good plan, my .02 cents: forget air bags unless your hauling rocks with a trailer full of rocks your ok (and even then) i have put tons of weight in my sub and hardly even compress the springs /forums/images/graemlins/waytogo.gif

if you want a real good all around tire, i have hurd very good things about pro comp x terains, great tire clears good and isent loud on the road.

oh and lets see some pics!

 

[mtn. burb]

Welcome! This is indeed a terrific first post. /forums/images/graemlins/waytogo.gif

I also have an 87' Suburban. I think going with 35's and a 4" set of springs would be very productive for you.

As for tires, I like the Interco products. Ask about SSR's or the TSL radials. I am not familiar with tires other than Interco's.

As for springs, I went with Skyjacker, and I like them. They flex really well, and it rides quite well on the road. However, what I hear most often from my friends here is that Tuff Country 4" springs up front and an Off Road design shackle flip in the rear is the hot set up.

Be open to fender trimming, it really pays off and when done with a hand held cutting wheel it can look very presentable.

As for axles, I did some difficult trails with the stock 10b/14bff set, and was lucky not to blow them up. I was careful, etc. I did replace them with what you have on standby, a D60/14FF w/ 4.56 gears. It depends how aggresivly you desire to wheel the Suburban. Or how much you want to build a another rig with the 1-ton stuff.

Airbags. Hmmmmm, nah. Although the guy with the Suburban in TTC 2004 had a set. But he ran 44" Boggers.

Shocks. I can hardly wait to dump my Skyjacker shocks for Bilsteins.

I have to go to work....hope this helps.

/forums/images/graemlins/thumb.gif

 

[muddysub]

ahhh a new sub culture member... welcome, my name is scott one of the sub guys here i guess im the prez of the ck5 sub culture (all sub club) since no one else calls them selves that. lol

yeah ive got a 1989 3/4 ton suburban and i started with 4" springs, i dont recommend starting any smaller since you'll only wish you have gone bigger, 35s are a good size with 4" springs and will require some fender trimming, not a lot though.

MT/Rs are an awesome tire for a dual purpose street/trail truck, a lot of guys run and really like them.

ill tell you right now there are 2 things i did wrong on my suburban.... 4" blocks on the rear and a 2" body lift. once you've experienced the downsides to lift blocks you will hate them. and ive had more problems since i installed the body lift on my sub, not to mention it creeks and pops more and GM only put bolts through 10 of the 14 body mounts on suburbans, the other 4 arnt even drilled so as soon as you flex it up the pucks fall out never to be seen again. you could drill the floor and install bolts but im just going to get rid of it.

springs... tuff country EZ rides are the softent out there ive heard, i have pro-comps and HATE them. superlift soft ride springs arent bad either.

shocks... bilstiens are better then ranchos, if you're getting ranchos get 9000s theyre better than 5000s, but more expensive.

check out my webshots in my sig for pics of my fender cutting to make 36" swampers fit under 4" of lift.

 

[Diesel Dan]

You'll soon find out subs are way cool off road!

Fender trimming with 35s is a must, my 6" springs still tag the fenders with no trimming. $100/shock isn't that expensive for a good shock. Remote resevoir fox shocks for my Dodge/Ram are $500/ea. Bilstiens are $250/ea, guys on the TDR hate the Rancho RS9000s compared too the bilstiens. If you can afford it, get a good shock considering the weight of a suburban.

Tires, I'm running General 35x12.50R-16.5 General Grabber M/Ts. Can't commment on ice/snow since I store it for the winter months. They are fairly quite on the road and decent in the sand. I have a detroit in the back and am not as concerned about the rear axle. Going with a detroit instead of a Gov-loc takes alot of the shock load off of the axle shafts.

Starting all over?
If I don't sell the sub this fall I may do just that.
12V Cummins, 47RE auto, D60 front and D70 rear /forums/images/graemlins/grind.gif.

 

[Jonny-K5]

[ QUOTE ]
Decent performance on wet roads and ice is important to me as well and I'm guessing difficult to find with this style of tire. What are your thoughts?


[/ QUOTE ]

i still say the BFG A/T KO's cant be beat for wet/icy road conditions. they are much better offroad than most people give them credit for.sucks in mud, but good trade off for a Daily driver/trail rig.

 

[sponsoredbydad]

I'D HAVE TO AGREE WITH JOHNNY BFG'S RULE HERE IN SO CAL WITH SO MANY DIFF TERRAIN OPTIONS.ALTHO I RUN 315'S I HAVE NO RUB AND NO TRIMMING WITH STOCK SPRINGS /forums/images/graemlins/burb.gif87 GOOD LUCK WITH WHAT EVER YOU DO

 

[6.2puller]

WOW, how do you get away with that on stock springs?

I have 35s on my 86 3/4 ton with 2" lift and liberall trimming and can still rub pretty hard if I am not carefull. I don't wheel mine hard, I have a jeep for the hard stuff. Mine is for taking the family out to the remote camping areas and touring some logging roads etc.
For my usage the 10bolt and SF14bolt have held up fine. I don't know what people are breaking on the SFrs but the shafts are pretty good size for 35s. The only thing axle wise I have modified is the lockouts that I changed to manuals. The autos were to quirky for me.

As far as gearing I think you will be very happy with the 4.10s and 35s on the highway. It brings your highway RPM way down and the fuel mileage goes up on the higheay. I gained 3-4MPG going from 32s to 35s on the highway. Lost about the same on back road stop and go but for my towing needs when heading camping the 4.10s work well with 35s and the 3 speed. If you had O/D like my pickup then you would be able to go deeper in the gear dept without loosing much in the hiway dept.
I run BFG ATs and love them for my application. They work well in most situations. Mud they are not good at and crossing over downed rotting trees is generally my other hang up. They do have sidewalls of silk though. I have punctured a good many sidewalls so get the road hazzard plan /forums/images/graemlins/thumb.gif

 

[6.2puller]

One more thing, SSRs weigh a lot more than most tires of the same size. Take that into account when looking at your axle size and strength. I know my 10bolt has been fine with 35" ATs but the extra weight plus grip of a SSR might be different.