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Discussion Starter · #1 ·
Sooo I live in New Mexico and drive over brutal roads for a living. My poor Aero doesn't like the conditions. I was thinking of getting a Grand Cherokee but then it dawned on me to pick up a 900 and maybe do a lil' off road suspension set up on it - Bilsteins, etc. Anyone gone that route before? Don't really need to lift it up I think, just maybe some stiff shocks and A/T tires.

Crazy?
 

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not crazy...saab have some rally car lineage. The 900 should work just fine, what are you looking at for clearance?
 

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Discussion Starter · #3 ·
not crazy...saab have some rally car lineage. The 900 should work just fine, what are you looking at for clearance?
Well more than my Aero. :D

I was thinking of simply trying to fit taller tires and some stiff shocks. Can you raise the suspension at all (ie. springs/shocks)? The air damn in the front may need to be modified as they become snow plows over certain roads.
 

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What I would do would be to remove the springs and use trolley jacks to simulate suspension travel over rough terrain. In other words, jack the car up at the rear right corner to simulate suspension compression at the front left corner. With the spring removed the suspension will be able to fully compress up to the bump stop. Getting the height, mounting and construction of the bump-stops right would be the key to preparing the car for off-road use. You need to leave the tyre on the car while you test suspension travel. You need to be able to rotate the tyre and turn the steering from full left to full right. This will tell you how much clearance you have for increased tire height. Prop the lower ball joint on the lower control arm so the tyre is off the ground by 1/2 an inch so you can rotate it with the suspension compressed.

Normal 900i springs and probably turbo shocks would be a good combination.

When the car comes down to the ground when both front springs fully compress the bump stops need to be long enough and stiff enough to prevent the car grounding out at the front. That's how you gotta play it. Same goes for the rear, but not as difficult.

I have thought about doing this to help driving on London streets. They don't maintain the roads properly here and they delibrately install speed humps down so many roads in order to try and keep you going slowly. All it does is pi55es me off and makes me want to build a car that can cross them at speed. You know... all about building the car to suit the use and in the case of London the ideal car is an automatic 9000 aero. Just a shame they blow up their gearboxes so easily.
 

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Where I live now most of the roads are dirt. Only the main roads are blacktop.

I've driven my 89 900i around on dirt a lot since moving here and it's fun, but the biggest problem is keeping dust out. The boot space of the car gets choked with it, mostly because of seals that don't seal quite right any more around the hatch, and the vent hidden down behind the back bumper allows dust laden air a direct route straight to the under-floor space.

Since the car is a hatchback, with the heavy doors, the seals on the doors have to cope with a lot more movement from vibration, etc. and that lets dust creep into the cabin area.

The engine bay gets full of dust too. I've got one of the 5 mm rally-style skid plates on the car which would save the engine and trans a lot of headache from stones, etc. Dust in the engine bay eventually leads to dust getting in through the cabin air intake. My car even though it has no A/C still has the evaporator in place (that's going to change soon) so there is no dust filtering.

I think the best car for off roading would be a 2 door sedan config which would have the tightest body in terms of rigidity, and lots of room, if desired, so install better seating and even a roll cage to do it properly.

Getting the suspension right is certainly a big part of off-road driving. But it all depends how someone is going to drive. If someone intends to drive a C900 off road like it's a rally car, then yes it needs a lot of careful attention to avoid nasty consequences of things breaking with little or no indication of impending doom.

For normal spirited dirt roading, just good TLC is all that's needed.

Craig.
 

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There are some spacers available for raising both the front and rear suspension. In my opinion, the standard turbo suspension without swaybars, front or rear, is about as much as you need really. 60mph on washboarded gravel roads still feels very good. The only place where you would need more is off-road in some severe conditions. I've driven through fields off road in mine with no problems. If you get to the point where clearance is an issue, then traction will probably also be a problem without modifications such as an LSD.

FWIW, I travel to places in rural Montana, Wyoming and Alberta frequently without issue. Many times, this is in mountainous conditions on poorly maintained dirt roads (you really couldn't even call them gravel).
 

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Everything I've said is in relation to pot holes or severe uneven surfaces causing maximum suspension compression if crossed at any sort of speed. If the conditions are just plain flat gravel or flat dirt then just use the car standard and don't bother changing any of the suspension.
 

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I dont think its crazy at all. In fact, thats sort of what Im trying to accomplish on my 900. Ive been looking into some spring spacers for a bit of lift. From my research, a one (1) inch lift is about all you can do. The swedish dynamic rear spacers can be bought for cheap and the only front lift Ive ever found is the MSS setup. I plan on doing a custom setup and get some spacers turned on the lathe where I work. Im doing this in hopes of getting a set of truck tires put on. Yah, I know....truck tires, ;oops: but its impossible to find a passenger car tire that is aggressive enough to handle proper off-road without going to a crazy expensive rally tire setup. The size scares me a little bit, but I wont know until I try. ;)
 

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I think people aren't listening here! :lol:

The springs don't matter. It's all about the bump-stops. That's what stops your car from hitting the ground and it's also what stops the tyres from hitting the inside of the wheel arches. If you setup your bump-stops properly then the car will be able to travel over any surface and when it comes down from a height the spring platforms will hit the bump-stops and prevent the tyre from contacting the wheel arch and the bottom of the car from contacting the ground. Without modified bump-stops the car will hit the floor and the wheels will hit the inside of the arches. Makes no difference which springs you have as they can always be completely compressed. A stiffer spring will take more load to compress completely but then that means you can do the same piece of road 2mph faster than before so you are only postponing the inevitable.

Some ordinary springs will be fine but I wouldn't recommend turbo springs or lowered springs. Much better off with longer 900i springs for crossing rough surfaces.

Offroad tyres aren't expensive. Here are some new ones for £50.00 each: http://www.demon-tweeks.co.uk/Motor...petition_Tyres/Maxsport_Alaska_Tyre/1790/2236
 

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I think people aren't listening here! :lol:
I hope youre not talking to me. :confused: I know what bumpstops are and do. The reason Im adding a spring spacer is to add body lift. Added body lift usually (dependent on the arch size) allows for a larger diameter tire which equals more actual ground clearance without sacrificing suspension travel. Thats what Im after. Ive worked on offroad suspension setups on my buddies trucks before, so this stuff isnt new to me. whats the point of making an offroad rig without more clearance?

I also should have been a bit more clear on my tire choice..... I need something that is on road / off road capable. A rally tire that aint.
 

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The tyre I linked to is good on smooth grass or polished tracks as well as offroad.

Ground clearance is only half the issue and not the most important half.

Like I say, simply fiddling with the springs to increase the ride height isn't going to allow larger tyres. The larger tyres will get caught on the wheel-arches when the springs compress.
 

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Speaking of listening..... :lol:

Like I said in my other post, I know what bumpstops are and Im not simply "fiddling" with springs. Ive worked on this kind of stuff before. I know that you dont know me, but dont assume Im stupid. :nono;
 

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Oh boy, this thread took a turn for the worse. :p I respect your input, but please dont be condescending. We are adults.....right? If you think springs dont matter in an offroad setup, hop over to an offroad forum and ask those guys. Thats like saying springs dont matter in a road race setup. And of course its not JUST about the spring or JUST about bumpstops or even any ONE thing in the suspension. All things need to work together to have a good setup.
 

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If you are modifying to get more ground clearance then a different spring will help. But with healthy 900i springs you are already fairly high off the ground anyway. With the 900 setup, if you install some really long springs and leave it at that, you won't have improved the cars off road ability unless you are simply talking about how well it will climb over a very large mound at 2mph. So no, springs aren't very significiant in this case although I agree, for your buddies with their off-road trucks, that's a different story. Furthermore, the 900 suspension setup is not designed to be used with very long springs. The suspension is designed for the springs it normally uses. The driveshafts hit the bottom of the openings at the front and all the brake hoses will stretch if the axles drop too far. So once again, it is not all about the springs.

The 900's biggest problem, whether you are using sports springs and sports shocks or comfortable springs and comfortable shocks will be the pitching and diving. As you cross lumps and dips the nose will keep digging into the ground and you need to stop that happening if you want to cross uneven terrain at speed.
 

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Raising height will improve ground clearance and I think even a 1" lift will help, combined with taller tires which will offer more progressive slide when they begin to loose traction.

I don't think a 1" lift will affect the drive shaft in the drive shaft tunnels. I'm about to jack up my 900 to get the engine out tonight so I'll have a look.

The rear suspension utilizes a pan-hard rod which will shift the rear axle (and wheels, obviously) to the left if raised. This can be accommodated for with an adjustable pan-hard rod. Luke at SaabRally sells these for a reasonable $95. Nice kit with captive eye spherical bearings rather than bushes at the ends.

Go over to that forum and see what the c900 rally types have to say. I think they may be more agreeable. I am pretty sure Luke has raised his rally 99 (which has identical suspension). He has also fitted coil-overs front and rear. A lot of effort but you get out what you put in.
 

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yes, of course a 1-inch increase in ride height will give you more clearance. That's obvious. But how much faster would you be able to travel before the compression of the springs catches up with you once more? 1, 2 or 3 mph faster? This is the point. It is not the ground clearance which will stop you. It's what happens when the car dives into the ground after crossing a large hump at 40 or 50mph. That is more important than springs or spring spacers.

The rest of what is being said is valid. But I maintain springs and spring spacers are not the answer to everything, and not by a long way!
 

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I totally agree with that and if you re-read my earlier post, I mention that a one inch lift is about all that is tolerable on the 900. Of course its not designed for a BIG lift or very long springs, (one inch isnt either of those) but it can tolerate small lifts just as it tolerates small drops. Why does MSS and SAS offer a lift if it shouldnt be done? Brake lines can be lengthened easily if they are shown to bind or stretch and the biggest factor, as you said, is the bottom of the frame which is certainly being taken into consideration with this lift as Im sure it did for MSS and SAS and their kits. Im not sure what convinced you that I think its all about the spring, but Ill be the first to admit that its not and never said it was. ;)

And just to note, its not my intent to make a rally car that races over this stuff. Colorado offroad is a completely different game than rally. (which btw, Rally America has a stage in Steamboat where I live and its on a well groomed gravel road) Im talking about 2 foot snowfalls, large rocks, deep ruts, steep inclines to certain doom etc. Clearance is a big deal around here and Ive bottomed out on the gravel road right by my house because of the ruts and plowed the snow on our road with this car. Any bit more clearance I can gain is welcome. Slow and steady is how its done on this type of offroading..... And anyways, I drive an N/A 900, I dont have much of a choice. :p
 

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It is not the ground clearance which will stop you. It's what happens when the car dives into the ground after crossing a large hump at 40 or 50mph. That is more important than springs or spring spacers.

But I maintain springs and spring spacers are not the answer to everything, and not by a long way!
Agreed. We haven't even begun to discuss shocks yet :D I think it is a real shame SAAB pulled out of rally before the 900 had a chance to cut it's teeth. Off road is where my N/A 900 performs best!
 

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In my neck of the woods (said as ******* as possible) Offroad ≠ Rally. No high speeds whatsoever. Maybe it is considered the same in other parts of the world and thats where some confusion is stemming from. Not to say that the points arent valid at all (because the still are), but the suspension setup for this

(typical colorado offroad) is going to be different than a high speed rally setup. When I bottom out its not because the suspension is fully compressed, but because the road rises to meet the underside of my car. Dont get me wrong, I still need to consider what happens at full compression, but much less than if I were doing 50mph.


Genty: Saabrally forum is where Ive been getting a lot of my information. Great site with heaps of info. Lukes build is incredible.
 
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