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vazbmw
vazbmw Reader
10/21/09 2:22 p.m.

I am trying to improve the handling characteristics of my 1999 GMC Suburban 1500. The undesirable characteristics that I would like to remove are: Wollie at highway speeds, drastic dive under braking, numb steering, overboosted and power steering. As you can see I have not mentioned performance oriented handling, that is because I am not looking to make this handle like a sportscar. I still want a truck, but I want a safer handling truck. I am sure someone will suggest I drive 45-50 mph on the highway, but that is not realistic. Or they will suggest I buy something newer, and that is not realistic. Does anyone know of a company that sells a package to address the above issues? Any companies sell the police package?

I have not found a single source. It would look like I would have to address each one individually, which I would like to avoid.

If not I may start with some great shocks. Any suggestions on truck shocks? I must admit, I don’t know much about trucks.

Has anyone addressed these issues already?

Thanks in advance

andrave
andrave HalfDork
10/21/09 2:29 p.m.

2wd or 4wd?

IIRC there is a cop version of that with stiffer sway bars and a slightly lower suspension. I think bell makes a variety of stiffer lowering suspension parts for it (the rear is easy) and you can probably find some stiffer anti roll bars from bell or suspension technique.

I think summit sells most of the parts you would need.

what size tires do you run? obviously a shorter sidewall will help increase steering feel as well...

Per Schroeder
Per Schroeder Technical Editor/Advertising Director
10/21/09 2:30 p.m.

Hotchkis and others make anti-roll bars, etc for the truckasaurus.

Gearheadotaku
Gearheadotaku Reader
10/21/09 2:32 p.m.

3/4 ton springs, Bilstein shocks, bigger sway bars. Addco has bars.

vazbmw
vazbmw Reader
10/21/09 2:40 p.m.

The question about tires makes me think too. I am running stock 15 inche rim with 235 70's or 75's on them

Those are marshmellows. So I gues I need to do like we do on cars? Start from the rubber up.

I don't want 22" or anything like that, cause I want the truck utility. So I guess 17's or so may be the way to go. What is the common truck size now? 20's

Then move to the shocks and bars

ReverendDexter
ReverendDexter HalfDork
10/21/09 3:18 p.m.
Gearheadotaku wrote: 3/4 ton springs, Bilstein shocks, bigger sway bars. Addco has bars.

This.

But I'm not sure I'd go Bilstein necessarily. Rancho offers a hydraulic shock, which means you get all the dampening, but it doesn't "fight" to sit at any particular ride height. You'll know if you have the right one because when you take it out of the box it won't have the nylon strap holding the piston into the body.

From what I understand, these are much better in off-road situations than gas shocks, as they'll allow the suspension to properly articulate.

GameboyRMH
GameboyRMH SuperDork
10/21/09 3:22 p.m.

Yeah a shorter sidewall should help the numb steering, brake dive and general boateyness, if you don't need the offroad capability.

DeadSkunk
DeadSkunk New Reader
10/21/09 3:58 p.m.

I'd be looking at wider wheels and tires, not necessarily larger diameter wheels. I replaced my 205/70/15 tires on my Astro with 225/70/15s on 8 inch wide wheels. Made a world of difference. It also has some well used Bilsteins. At one point I ran 245/60/15 Yokohamas and it handled nicely.I found the larger tires helped without making the ride quality any harsher.Your Suburban out weighs my Astro by a considerable amount I would think. To me your tires are too narrow.

fiat22turbo
fiat22turbo SuperDork
10/21/09 4:03 p.m.

I'm not sure what a Suburban handle is, but I'm pretty sure you'll see one on Cougar Town. I'm also not sure how to make one better, have you considered plastic surgery?

Seriously, some good suggestions so far. Think of it as an old Muscle car so similar tricks apply.

Here's my solution;

Step one: remove Suburban badge.

Step Two: Place badge on Miata.

Step Three: ??

Step Four: Profit!

Snowdoggie
Snowdoggie HalfDork
10/21/09 4:13 p.m.
Per Schroeder wrote: Hotchkis and others make anti-roll bars, etc for the truckasaurus.

Does Hotchkis make suspension parts for my 1989 Dodge Motorhome? I am already getting the Bilsteins.

For that matter, does anybody still make a front spoiler for my old Dodge Motorhome. It's a Class C with the front end of the old Dodge Van. I know they used to make a lot of stuff for Dodge Vans.

admc58
admc58 New Reader
10/21/09 5:00 p.m.

Suburban autoX with 6 on board... http://www.youtube.com/watch?v=vhsHogEyy-c

The basic 2wd Suburban is a 50/50 weight ballanced truck. I have a ton of track/autoX time in them and they are an absolute blast at the limit. The 3rd row is the best place to ride when doing recon laps at track days..There is nothing quite like the feel of the rear end moving about 4' sideways before it takes a set.

1) Good tires with firm sidewalls. Cheap tires cause all of the problems you are complaining about so start there.

2) Make sure all ball joints & steering Idler arms are in very good condion with minimal flex.

3) Shocks - Koni makes some very good and adjustible shocks that control wallow but still have compliance for bumps/dips...etc.

4) I'd be carefull about adding 3/4 ton springs, it tends to cause ride quality problems and raises the rear putting more weight on the front wheels which causes MORE understeer. Sway bars could help but watch out for end link bind up under load which will cause push or oversteer changes as body roll changes.

Have fun!!!

xci_ed6
xci_ed6 Reader
10/21/09 5:45 p.m.

I'm not sure if it will fit that year, but I recently read that the 454ss steering box is a quicker ratio.

Gonzo_Bmod
Gonzo_Bmod New Reader
10/21/09 5:55 p.m.

I did a wheel and tire upgrade on a 2000 Navigator that was suffering from similar issues and it did help. Went from stock 265/75/17 Continental's to 285/60/18 Pirelli Scorpions on wider wheels and it made a world of difference. Add some tighter springs and bigger bars and it should be pretty good by land yacht standards.

Kendall_Jones
Kendall_Jones Reader
10/21/09 6:31 p.m.

Doesnt the 96+ surburban have speed sensitive steering? Might be an issue with that.

Kendall

Osterkraut
Osterkraut Dork
10/21/09 6:36 p.m.
fiat22turbo wrote: I'm not sure what a Suburban handle is, but I'm pretty sure you'll see one on Cougar Town. I'm also not sure how to make one better, have you considered plastic surgery? Seriously, some good suggestions so far. Think of it as an old Muscle car so similar tricks apply. Here's my solution; Step one: remove Suburban badge. Step Two: Place badge on Miata. Step Three: ?? Step Four: Profit!

No no no. Lose the B and the N in the name. Switch the U and the A. Problem solved!

vazbmw
vazbmw Reader
10/21/09 6:48 p.m.

yes it does have speed sensing steering. How do I know if I am over boosted or not? I would guess I need all the special steering boost measurement tools etc? Dealer?

Overall, looks like wider, lower profile tires are in order I don't need much offroad capability, but I would like it to drive in the mud if I had to. And it must drive in the snow and accept snow chains

Kendall_Jones wrote: Doesnt the 96+ surburban have speed sensitive steering? Might be an issue with that. Kendall
ignorant
ignorant SuperDork
10/21/09 6:53 p.m.

maybe something like this...

RossD
RossD HalfDork
10/21/09 8:44 p.m.
ignorant wrote: maybe something like this...

I hate people....

neon4891
neon4891 SuperDork
10/21/09 8:50 p.m.

I have heard good things about the Edelbrock IAS shocks. That and big sway bars.

alex
alex Dork
10/21/09 9:23 p.m.

This sounds similar to the basic recipe of parts I'll be throwing at my '88 1500 pickup. I'll be watching this thread, thankyouverymuch.

vazbmw
vazbmw Reader
10/21/09 9:24 p.m.

40" I guess the object is to actually drive a Matchbox car in real life Oky Doky

Now we are back to the days of flex tuning the rim. We will have to tune the rims like they used to do the spoked knock-off wheels. Make the suspension solid and let the rim do all the work.

There is nothing like a vehicle hanging from 20" of metal spoke. Wobble wobble

ignorant wrote: maybe something like this...
mad_machine
mad_machine SuperDork
10/21/09 9:59 p.m.

I am betting with your truck being 10 years old.. your bushings and ball joints have to be loose as a goose. I would start with the basics, add good shocks, and go from there

vazbmw
vazbmw Reader
10/21/09 10:07 p.m.

ya, you have said a mouth full, but it has been floppy from the beginning. I think it has loosened up to the point of unacceptable to me now. That, and the fact my BMW is so tight and crisp.

My wife dislikes driving the Suburban because of its lack of handling, which is supposed to be her car. Now she has turned her attention to destroying mine. Maybe I should hotrod the Suburban and too

I guess the 'Burban is due of a few weekends in of garage work. If only it would fit.

mad_machine wrote: I am betting with your truck being 10 years old.. your bushings and ball joints have to be loose as a goose. I would start with the basics, add good shocks, and go from there
andrave
andrave HalfDork
10/22/09 8:36 a.m.

You might wanna check your rubber mounted steering rack too. When the bushings (and occasionally mounting points) fail on those it results in similar symptoms.

are the tie rods and etc all in good shape?

iceracer
iceracer HalfDork
10/22/09 11:09 a.m.

For the age and the mileage I am sure the shocks are shot. New ones will tighten things up.

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