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Rendezvous Suspension Upgrades

hawaiianguyhawaiianguy Posts: 86
edited March 11 in Buick
Recently, the rendezvous won the most dangerous vehicle award, i think in part due to probablity of rollovers.

See : http://www.forbes.com/2007/07/26/car...?partner=msnbc

After reading the above article, I wonder if anyone else has successfully done anything to upgrade the supsension on this car to make it more rollover proof.

I would like to consider changing to sport shocks, upgrading sway bars and bushings if possible, as well as perhaps maybe wider tires and stiffer/lower springs.

The problem is, after searching the internet high and low, I don't think anyone makes any suspension upgrades for our cars. I did a search and the best I can find is KYB GR-2 (factory stiffness) struts for the front and KYB Gas-adjust (sport/firm shock) for the rear. I was hoping to find a matching set of sport shocks, but even unable to do that. I am also unable to find any upgrades for sway bars, bushings or springs.

This is very frustrating because after having worked on a project sports car, I found that sporty options such as shocks/struts and swaybars were plentiful for that car. Even for a "volvo" therre is a company called IPD that sells performance suspension components such as beefier sway bars, springs and struts/shocks...

Anyone have any suggestions or ideas where I might be able to find these items?? It seems they are hard, if not impossible to find.
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Comments

  • A really good independent local mechanic should be able to make any modifications you want and not with just out of the box parts. I have such a guy who is honest and capable of ANYTHING mechanical. If the work is better done at a dealer, for any reason, he will tell me. When a Jaguar engine was "eating my lunch" he relpaced it with a Corvette engine which made it the most trouble free and powerful large car I have ever had. Good luck in your search. Les
  • spike99spike99 Posts: 239
    .

    Upgrading this, upgrading that, sure seems like a lot of work and expense - to create a tighter suspension on the RDV factory suspension.

    Is the factory suspension "too soft" (which creates greater risk of roll-overs)? If so, might want to install some air bags. With air bags, you load them up between 5 to 40 lbs - for your wanted ride comfort.

    If Air bags aren't for you... Might want to investigate the Timbren SES product. It's like an air bag without inner air. Some view them as a rubber stopper. If wondering, I have Timbrens on the rear of my 2001 AWD Safari Van (which is also a heavy hauler & Tow Vehicle). Best rear suspension product I've every used. Timbrens is an "install it and leave it" product and removes suspension depth. Great for front mounted Snow Plows or for trailer's with more then 300 lbs of tonque weight. Or, if you load down the rear cargo area of your vehicle (and don't pull a trailer at all). For more info on Timbrens (which are rubber inserts inside the factory coil springs on the RDV factory rear suspension parts), surf: (for FWD RDV models) http://www.timbren.com/timbren-application-guides/application-pdfs/GMRAZT.pdf & (for AWD RDV models) http://www.timbren.com/timbren-application-guides/application-pdfs/GMRREN.pdf

    For suspension improvement on the front, install HD shocks. I hear Monroe makes great HD front shocks. Thus, keeping the front suspension "same depth" but increasing "its time to reach its full depth". Thus, dramatic reduction of the risk of roll-overs (regardless of vehicle model).

    Always remember that roll-overs are from 3 conditions. Suspension depth, time to reach that depth and depth re-bound (on its opposite high side). Timbrens are rubber and have very little "rebound" recovery reaction - unlike steel based HD coil spring replacements. Remove depth on its outer corner side, reduce time to reach full depth on its outer corner and reduce upward rebound on its opposite inner corner side, and the risk of roll-over is dramtically reduced. Same holds true for a fast boat on the water doing a tight sharp corner. Remove depth, remove time to reach full depth and remove opposite side "kick ups". Same holds true for a vehicle performing sharp corners on dry land.

    Hope this helps as well...

    .
  • spike99, thanks for the info! I think when you refer to monroe HD shocks you are referring to the "reflex" shocks that lockout? I didn't know they existed until you mentioned them. My plan was to go with a sportier shock. I'm not sure if they make these for my vehicle.

    Thanks for the info. I will try some kind of bump stop for the rear and see if it helps as well as try to find some lockout shocks for the front.

    I wonder why if it was so simple as using a different type of strut, why the mfg didn't do so in the first place??
  • Just checked their online catalog, Monroe only makes a sensatrac monotube shock, no HD or reflex shock. Looks like I am out of luck for the fronts. Can anyone suggest an alternate mfg that makes HD struts? Unfortunately I don't think I will be able to find any.

    Do I have any other options for the front suspension to help decrease roll over risk?
  • spike99spike99 Posts: 239
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    When the shocks on my Tow Vehicle 2001 AWD Safari Van goes, I'm going to replace with Blistien shocks. These HD shocks are made for towing (for weight support) and they have "reduced" time to full depth valving. I've been told the Blistien shocks are few notches above Monroe's best HD shocks.

    Many Towing / Heavy cargo folks are installing the BILSTEIN brand shocks. For more details, surf: http://www.bilstein.com/tech.php If they make Bilstein shocks for your RDV year and model, might want to investigate this HD shock as well.

    As a side note... The RDV model is made as the "average" cross-over vehicle. A combination of a car and a van. Thus, 4 doors with lots of inner cargo, and FWD for better rain / snow road conditions. To me, the RDV isn't made as a Tow Vehicle or Heavy Hauler Vehicle - on a consistant basis. And it wasn't made to drive like a "zip zip" Sports car either. With this in mind, do drive the RDV for what it was made for. A "put / put" smooth riding family style mini-SUV (cross over vehicle). If you want a zip / zip mini-SUV with lower "roll over" risk ratings, there are other mini-SUVs that are better built. Better built for folks with "zip zip" driving style. If you want to improve the RDV's factory suspension, Timbren add-on and HD shock replacements are a good upgrade. Well worth doing - to make its factory suspension of the RDV even better. But if you want more of a "zip zip" mini-SUV with much tighter suspension (with lower risk of roll over ratings), you might want to investigate other brands of mini-SUVs. Something that can take much more road abuse / aggresive driving style. Something to think about...

    Hope this helps as well...

    .
  • Hey spike99, again, helps a lot. I'm used to driving agressively so I don't see any harm in having an SUV that can handle agressive driving. Besides, even if you drive passively, my concern is that some idiot who is driving along side you on the freeway may try to swerve into you or maybe someone who didn't tie down their load may throw a ladder on the road in front of you when you are going 50mph. The faster you travel in the RDV the more the rollover risk is multiplied! So if you had to suddenly swerve to avoid another vehicle or object on the freeway, you might be setting you up yourself for a rollover. My logic is that even if you don't drive "zip-zip" as you put it, some emergency may necessitate a very controlled manuver, and w/ the soft rdv suspension, that may end up in a rollover in that case. I see a sporty suspension equivalent to more safety in an emergency manuver. So yes, although i do realize it was made like a minivan with 4 doors, I think I would like to add better handling to it to improve it's capability to respond in the event of a high speed emergency manuver. Not that I would want to necessarily drive agressively, but if worse came to worse and I had to to avoid a danger, I wouldn't want to be a rollover casualty because my suspension was too soft...
  • i would like to point out that i think at this point in time no one makes hd shocks for rdz. i have bilstiens on my 84 porsche carrera, and yes they are nice shocks. because of that i already tried to look up a listing for the bilstiens on the rdz, no luck, none made. again, if anyone knows of any other options and/or stiffer, safer replacements for the front struts, please let me know!!
  • spike99spike99 Posts: 239
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    If you are serious about finding a better front shock, I would email the folks at Monroe, Blistien and other well known shocks designers. Ask what they recommend as a HD shock replacement for your RDV. I would even send an email inquire to Timbren Corporation - asking if they have Timbren SES for the front on the RDV as well. Timbrens do remove suspension depth - which also reduces risk of roll-overs.

    Like many companies, these suspension improvement companies don't always list their every product and certainly don't list their "in beta testing" products. Send each of them an email and who knows, they might come back with... "oh ya - we do have something for you... Here's the details.." reply. Or if enough RVD owners send emails to each company, their R&D teams will start working on RDV improvement products.

    Hope this helps as well...

    As a side note... I don't put too much faith in roll-over ratings on some vehicles. Yes, the RDV can flip over. So can a Sunfire and so can my Safari van. Every vehicle has a roll-over rating. Like many, I don't aggressively look for RDV suspension improvements. My limited dollars going into keeping our RDV "on the road" - due to its lack of reliability technical design. Anyway... A few years ago, I do remember the "big fuss" about roll-over ratings on 15 passenger vans. The videos were so powerfull, DOT / DMV were going to remove all 15 passenger extended vans off the road. Some "average guy" installed HD shocks and other low cost "off the shelf" suspension improvements (to remove factory depth, time to full suspension depth on the sharp corners and to remove opposite side "kick back" behavior) and the 15 passenger van suddenly had a better rating then a normal F-150 Pickup. All because a low cost / off the shelf suspension improvements was used. Something that 15 seat passenger van designers missed themselves. So yes. I see your point about looking for low cost "off the shelf" suspension improvement products for the RDV. Something that is also worth doing (on any brand of vehicle)....

    .
  • tidestertidester Posts: 10,110
    the factory suspension "too soft" ... might want to install some air bags

    I thought the point of air bag suspensions was to soften the ride. Can you pressure them up enough to get the stiffness you want?

    tidester, host
    SUVs and Smart Shopper
  • Spike99. I saw the Timbren product. About how much did it cost you for yours? And did you install yours yourself? I can see where this would come in handy, as I did install an aftermarket hitch for a hitch mounted bike rack, and with the 2 bikes on there, the rear suspension will bottom out and hit a speed bump when I go over it with the bikes. Not only will this product help with that, but it might help with the handling as well..

    I wanted to ask how easy is it to install the Timbren product? I've replaced struts and shocks on my other car before, but I have not yet removed the springs on the rdv. I looked at it, looks like if you remove the shock, the lower arm will release down far enough to remove the spring. Is this correct? Obviously I suppose you would have to keep some tension on the arm so it doesnt snap down when you remove the shock then slowly release it. Is this all I need to do to remove the spring? Is it fairly a simple matter of just removing the shock and slowly releasing the arm down till the spring is uncompressed? Is putting it back pretty easy as well??

    As far as rollover, I agree that every car is prone to rollover, yet I can tell a big difference when driving my sports car vs. the rdv, that the rdv with the higher center of gravity and soft suspension is much much more likely to flip. So, I'd like to make it just a tad safer. Minimal cost for a big safety improvement is the goal here. And you can't deny that these cars are terrrible in that situation. What I like about SUV's is the ride height puts you above the bumper imapact zone of a normal sedan (side impact), however because of the higher ride height you are now more prone to rollver. I guess you can't have it all, but I'd like to try...

    host - i think the airbags he's talking about go inside the spring and prevent the car from bottoming out. they dont' look like they would make the suspension softer. see jc whitney online for an example.
  • tidestertidester Posts: 10,110
    i think the airbags he's talking about go inside the spring and prevent the car from bottoming out

    Ah, yes! That would do it. Thanks for the insight.

    tidester, host
    SUVs and Smart Shopper
  • When you are going 50mph on the freeway, just pretend something got thrown on the road in front of you and you had to swerve to avoid it. Gently try to swerve the rdv at that speed and I swear, you'll get the feeling like you are about to rollover. I did this test after reading the article about the rdv being the most dangerous vehicle, and I wasn't happy with the results. Luckily, we don't encounter situations like these every day. But, you never know, someday it might happen. And it is not unfathomable that this situation could occur to anyone, a mom with kids for example, and not just someone who wants to drive it like a sports car.

    I'd just like to add an added margin of safety in such a situation by improving the suspension and handling a bit.
  • spike99, one other question. when you say HD shocks, what does HD stand for? Bilstien is the only one who seems to use the term "HD" and I suppose this means heavy duty? Wouldn't this mean any sport shock? On the other hand, monroe sells the "reflex" brand and they say it is good for vehicles with "high center of gravity like suv's", it can supposedly sense and adjust to acceleration. But monroe does not call this "HD". I'm not sure if the term "HD" is applicable across all brands. I know in general gas and monotube are supposedly more durable than other types of shocks. When you say HD do you mean just "sport" as opposed to comfort shocks? For example, KYB sells the gas-adjust model, which is monotube and stiffer and sportier than their GR-2 which is a "factory replacement" and more comfort than the gas-adjust. It is also twin tube. I would think any "sport" shock is going to be better than a comfort shock, however, the monroe "reflex" does specifically say it is designed to counter handling problems with vehicles that have a high center of gravity like an SUV.

    Thanks in advance.
  • spike99spike99 Posts: 239
    .

    HD means Heavy Duty. Which means "better then stock" shocks. Some folks call their "better then stock" shocks Sports tuned and others call them HD shocks. In general terms, HD means "better then stock" replacement shocks - regardless of the sub name a shock factory calls them.

    .
  • If that is what you meant by "HD shocks" then it's the same thing I meant by "sport shocks". That's why I was looking to replace the shocks with KYB. So really, what you said and suggested was no differnt than my idea to replace all 4 shocks with HD or "sport" shocks. That was the minimum I was going to do. Unfortunately KYB sells sport or HD shocks for the rear on the RDV, but the front is only stock.

    Thank you however for the suggestion about the timbren. If that costs a lot less than the replacement shocks (about $80 each or $190 total), then it sounds like a better option.

    Another question though. On the tibren, what would happen if you are using these and your shocks are worn? You think it would still be better to have the timbren instead of HD shocks for the rear? Or maybe I should install both. I don't think I need new shocks now, so the timbren is probably okay for now. But when the rear shocks do need to be replaced, I am going to also go with an HD shock.
  • on an interesting note a rep from timbren just returned my email asking how much their product was, saying "We do not sell coil inserts for Buick Rendezvous. Our product is a suspension enhancement system for pickups, vans and heavy duty vehicles." this is strange, becausee their application guide shows they do.
  • after checking the cost, the timbren product is actually MORE EXPENSIVE than a pair of kyb gas adjust (sport) shocks for the rear. I think i'd probably rather get the shocks than the timbren. I was quoted about $180 for the timbren, and I know the shocks are maybe $150 a pair or so plus shipping. to be fair, it is probably around the same price with shipping, but sport shocks seem like they would do more for the suspension than timbrens which only limit the travel.... so if i had to choose, i'd say the shocks...
  • spike99spike99 Posts: 239
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    WOW hawaiianguy.

    You sure are "very aggressive" in your research and trying to narrow down the best suspension upgrade for you - for your RDV. And, you might be over analyzing the words of one's feedback. Upgrading a vehicle's stock suspension isn't a perfect science. There's now "first time" right or wrong way of doing it. Always keep this in mind - when doing your raw research.

    To me, shocks reduce the "time to full suspension depth" compression - by the use of valving. Compression and rebound valving is used in either gas or oil based shocks. Every vehicle shock desigh (or selection of simular vehicle design) is based on "average cost" shocks that are made for "average expected" load. Or, in some cases, based on "average exepcted" driving style. A mini-SUV has might softer shocks when compared to a 2 door Ford Mustang.

    If one needs or want to reduce the "time to full suspension compression" depth (which creates a firmer ride comfort), they would replace their facory shocks. Some supsension shops call their shocks "sports tuned" and some call theirs version "heavy load tuned". And at the detailed level, both versons of shocks have different valving. But the main point is, their "specialized" built shock is much better then a factory stock shock.

    Ok - what's the big deal about shocks and how does it apply to reduction in roll-overs? More "firmer" shocks means a more firmer ride. With more firmer shocks and you take a sudden "emergency avoidence" corner, its time to full compression depth is more time (when compared to a stock shock). Thus, a roll over at xx ground speed on the same sudden U-turn won't happen until 120 degrees into the turn - instead of stock shocks at 90 degree. I'm using these numbers as examples but hopefully, you can see its improvement in degrees. If you "jerk away" from a fast hiway road just doing fast speed, the firmer shocks will reduce the risk of roll over. Especially if turning a sudden under 110 degree turn. For unloading driving comfort, the "top end" of the shock is often firmer. Some folks don't like a firmer "unloaded" ride.

    Timbrens (which are like air bags without inner air), you remove its "bottom end" suspension depth. With Timbrens, the ride comfort at near empty vehicle is unchanged. When more load on the vehicle (like a front mounted snow plow) or on the rear (for heavy hauler / Tow Vehicle) or a very tight suddent U-turn, the vehicle's factory "top suspension" goes down, and its Timbrems start working. The Timbrens are soft rubber. The more "pressed down", the more they work. And yes, they work with factory shocks. But the best part is, the Timbrens (and air bags - which you can adjust ride comfort) reduce roll-overs. They reduce roll overs because they reduce the inner corner of the vehicle going down (which keeps its top end gravity lower). The less the corner of the vehicle goes down (like in a right corner skid on dry pavement), the less risk of roll-over.

    If one has limited dollars to spend, which would I buy??? This is a hard quesiton to answer... If you like the upper suspension comfort and want to reduce suspension depth, then go with Timbrens. Or, go with air bags (which are adjustable). If you feel the upper part of your vehicle is too mushy, install air bags (add more air in them) or install better shocks. If you feel your vehicle has too much "little jitter" on its upper end, then install "better then factory" shocks. And if your vehicle's front or rear bounces more then 2 times (Mechanic's manual shock test), then replace its shocks. If you feel your upper riding comfort is ok and you want to reduce suspension depth, then install Timbrens or Air bags (with adjusted amount of air in them).

    When it comes to using 3rd party suspension upgrades, there's no perfect selection. Some like adding stronger HD replacement Coils, some like adding +1 leaf (which my vehicle also has), some like Timbrens (which my vehicle has), some like Air bags and some like HD shocks. Each vehicle and the driver's wants / needs is different.

    If wondering... I've tried many different suspension improvements (re: Timbrens, air shocks, +1 leaf spring, Torsion bar adjustments and HD shocks) on my current Tow Vehicle. For a picture, surf: http://ca.pg.photos.yahoo.com/ph/j_papple/detail?.dir=1815&.dnm=5860re2.jpg&.src- =ph & http://ca.pg.photos.yahoo.com/ph/j_papple/detail?.dir=1815&.dnm=af04.jpg&.src=ph-

    For my 2001 Safari Van Tow Vehicle, I'd install Timbrens in its rear and HD Shocks (like Blistien or Monroe;s best HD Shock) in its front. If my vehicle had too much suspension depth in the front, I'd install Timbrens on its front (and probably keep its factory shocks). Luckly, Timbrens for both front and rear are avaialable for my vehicle.

    I cannot tell you which suspension improvement for your RDV to get. Only you can make that choice. I can tell you my experiences with +1 leaf, Timbrens, Air Bags, Air Shocks (avoid them at all cost) and HD shocks on my Tow Vehicle. And if given a choise to do it again, which upgrade I'd only use (on the same vehicle) in the future.

    Hope this helps as well...

    .
  • spike99, FYI, i understood everything you said and more. I've been tuning my porsche for suspension with sway bars, stiffer springs and sport bilstiens, so yes, I already do know the effect these types of improvements have.

    what I did want to point out was that your original reply said it was a "waste of $" or "expensive" to be replacing things to upgrade suspension.

    all i wanted to point out is that I was quoted $230 for timbrens via email and $180 locally, and that in itself is MORE than replacement sport shocks.

    from what I gathered by your initial comment (my idea to upgrade the suspension parts was expensive, and you spend your dollars to keep it on the road), i thought you were suggesting a much more cost effective solution. When I priced it out I was suprised to find that in fact your solution is even more expensive.

    so, no, i do not think I am over-analyzing. I just took what you said at face value and when I priced out your suggestions they were just as expensive, if not more expensive. Also, I took a look at some airbag kits and they are several hundred dollars if not more. Labor to remove springs to install kits such as these would also be costly. So my point here is I do not see how you claim that your suggestions are more cost effective than was my original solution to upgrade shocks on all 4 corners to stiffer than stock.

    your help is still appreciated though. thanks.
  • spike99spike99 Posts: 239
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    In your original post...

    "I would like to consider changing to sport shocks, upgrading sway bars and bushings if possible, as well as perhaps maybe wider tires and stiffer/lower springs. "

    To me, sure sounds like you originally wanted to install more then shocks. It sounds like you were originally thinking of installing stronger lower springs, wider tires, sway bars and bushings... Sounds like much more expensive upgrade then "replacing stock shocks".

    Have a good one...

    .
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