Stronger Springs and Struts for rear suspension

Handling, suspension, and brake tuning discussions
Post Reply
blue_can
Posts: 209
Joined: Fri Jul 13, 2007 4:21 am
Location: San Diego

Stronger Springs and Struts for rear suspension

Post by blue_can »

I have done a fair bit of heavy hauling over the years in the vibe. For exmaple while remodeling my backyard I probably transported about 20,000 - 30,000lbs of material mostly loaded to capacity - a few times a bit over (not deliberately but rather due to miscalculation). For example I bought a batch of travertine tiles for my shower remodel a few days ago. The sales person miscalculated the weight and as a result I brought the while load in one batch and it was weighing around 900lbs.

Anyway the net result of all this is that the rear is sagging and somewhat lower than when the vehicle was new. I don't particuarly want the expense of owning a pickup truck so are there any options to beef up the rear suspension to better handle heavy loads.
'07 Vibe
xcmtb83
Posts: 14
Joined: Mon Jul 30, 2012 3:49 pm

Re: Stronger Springs and Struts for rear suspension

Post by xcmtb83 »

I am wondering the same thing. I started a thread asking if the all wheel drive rear coils would work on the rear of a base front wheel drive but no one chimmed in. I am ASSUMING the awd coils are longer but do not know for sure. I am basing this off of the fact awd models sit 2-3" taller. All I know is it does not take much to make the rear squat with a hitch, bike rack and 2 mountain bikes on the back...Oh, and 2 Mastiffs bumming in the back. 8-)
blue_can
Posts: 209
Joined: Fri Jul 13, 2007 4:21 am
Location: San Diego

Re: Stronger Springs and Struts for rear suspension

Post by blue_can »

Yes I just saw your other post. I guess there are no replies because not many people are interested in this - a lot of threads seem to be about lowering.

Looked online and saw they do sell helper springs exactly for this purpose but not found anything that would fit the Vibe. Some of the universal ones may work but again I've not seen any explicit info to say it would. I will post back if I find something that would work.
'07 Vibe
beemerphile1
Posts: 505
Joined: Tue Jul 14, 2009 12:12 am
Location: NE Ohio

Re: Stronger Springs and Struts for rear suspension

Post by beemerphile1 »

This is a subject that I am interested in but unfortunately can't offer any help. Since I tow a trailer I would love to have helper springs. I really don't want stronger springs because it rides harsh enough now when not towing.

I have checked on airbags and helper springs and found nothing compatible.
NE Ohio - home to the most successful Pontiac drag racing team in history - Bill Knafel's "Tin Indian" and also home to Summit Auto Racing.
2009 Vibe base 1.8L auto towing 2009 Aliner Sport hardsided pop-up
dragon64
Posts: 131
Joined: Mon Oct 27, 2008 1:42 am

Re: Stronger Springs and Struts for rear suspension

Post by dragon64 »

xcmtb83 wrote:I am ASSUMING the awd coils are longer but do not know for sure. I am basing this off of the fact awd models sit 2-3" taller. 8-)
Stiffer springs don't necessarily mean that they have to be longer. There are 3 parameters to determine the spring rate. The diameter of the wire, the number of active coils and the diameter of the coil less the wire dia. For my own '09 I had custom made 70 duro urethane spring coil dampers to insert between coils to reduce the number of active coils of the rear springs. Each urethane donut increases the spring rate by about 10-12 % using two donuts in each spring increase the spring rate more that 30% in the first 1" of compression. I did this modification with a single donut to improve handling without changing the ride height or ride comfort rather than cargo carrying capacity. At one point I had considered building a single convoluted load leveling airbag system and when as far as to make CAD productions drawings but plans at work to tow a trailer more than just in and out of a warehouse was cancelled.

Also if you are carrying additional weight over the OE specs you will also have to consider the load rating index of the tires. The index of the stock Goodyear RS-A is 89. Some manufactures load index can be as low as 87 or as high as 94 if it is an extended load (XL) tire at max air pressure. If you are carrying or towing a lot of extra weight remember that you also have inflate your tires accordingly to accomodate the additional load.
2009 Vibe 1.8L Manual - DBW controller, Hydraulic engine damper, S/S brakeline retrokit,22mm solid Rear ARB, urethane rear coil dampers, Front strut bar with brake cylinder brace, PIAA 410 driving lights, PRM Intake Wilwood front brakes, Lexus hood lifts
cythraul
Posts: 117
Joined: Sun May 15, 2011 7:38 am
Location: Montreal, QC, Canada

Re: Stronger Springs and Struts for rear suspension

Post by cythraul »

dragon64 wrote:For my own '09 I had custom made 70 duro urethane spring coil dampers to insert between coils
This sounds very interesting but my lack of mechanical knowledge led me to be looked at as an alien by my local mechanic when trying to explain this.

From what Google helped me, looks like "70 duro" is a measure of hardness of the rubber (in this case bonded with urethane.)

Can you give a bit more info on the necessary parts to acquire and how to modifying them?

Thanks! :)
2007 Vibe 1.8L Automatic 185K, B&M 70264 Transmission Cooler, Custom 2" hitch receiver.
dragon64
Posts: 131
Joined: Mon Oct 27, 2008 1:42 am

Re: Stronger Springs and Struts for rear suspension

Post by dragon64 »

Duro= Durometer is a unit of hardness for any polymers and rubbers. The material I used is solid uerthane not a bonded rubber/ urethane composite. I work on contract for automotive aftermarket manufactures. Having friends in the industry that manufacture OE/aftermarket parts I can have gets parts made for me that may not be readily be available. The reason for custom making urethane is because rubber becomes softer over time were urethane does not.

Installing the donuts is not that hard. It is just a matter of jacking up and supporting the car, removing that rear wheel then slipping the donut in between two or more coils. The donut is tie wrapped to the coil so it dosen't fall out.

As for were to buy them Longacre make a donut that may fit the stock springs but not available at regular speed shops. You might be able to order through Summit or Jegs or a race shop. Another but expensive option I've been looking at for someone else is Super Spring - Sumo spring.

If you are towing/ carring heavy payloads The stock specs tires are the biggest limiting factor. The Goodyear RS-A load index pretty much maxed out at the manufactures payload rating. I would go to a 94XL load index giving you an extra 200lbs (at 40psi)over the axles. On my car I just put on a set of 225/50-16 tires with a load index of 96XL giving me almost 300bs (at 40psi) more over the axles. I would also recommend installing a stffer anit roll bar if you are towing. this will help to keep the car and trailer under control in a cross-wind.
2009 Vibe 1.8L Manual - DBW controller, Hydraulic engine damper, S/S brakeline retrokit,22mm solid Rear ARB, urethane rear coil dampers, Front strut bar with brake cylinder brace, PIAA 410 driving lights, PRM Intake Wilwood front brakes, Lexus hood lifts
cythraul
Posts: 117
Joined: Sun May 15, 2011 7:38 am
Location: Montreal, QC, Canada

Re: Stronger Springs and Struts for rear suspension

Post by cythraul »

dragon64 wrote:Duro= Durometer is a unit of hardness for any polymers and rubbers. The material I used is solid uerthane not a bonded rubber/ urethane composite. I work on contract for automotive aftermarket manufactures. Having friends in the industry that manufacture OE/aftermarket parts I can have gets parts made for me that may not be readily be available. The reason for custom making urethane is because rubber becomes softer over time were urethane does not.

Installing the donuts is not that hard. It is just a matter of jacking up and supporting the car, removing that rear wheel then slipping the donut in between two or more coils. The donut is tie wrapped to the coil so it dosen't fall out.

As for were to buy them Longacre make a donut that may fit the stock springs but not available at regular speed shops. You might be able to order through Summit or Jegs or a race shop. Another but expensive option I've been looking at for someone else is Super Spring - Sumo spring.
Thanks for the precision on urethane versus rubber. That make total sense.

Unfortunately, being in Canada limits a lot my options in obtaining these donuts. And I have no contact in the industry. Ask me about a computer part and I can help however. ;) The Coil SumoSprings looks a lot like what you are describing. I'll check how hard they can be to obtain. Can't find any suspension related products on Longacre site.
dragon64 wrote:If you are towing/ carring heavy payloads The stock specs tires are the biggest limiting factor. The Goodyear RS-A load index pretty much maxed out at the manufactures payload rating. I would go to a 94XL load index giving you an extra 200lbs (at 40psi)over the axles. On my car I just put on a set of 225/50-16 tires with a load index of 96XL giving me almost 300bs (at 40psi) more over the axles. I would also recommend installing a stiffer anti roll bar if you are towing. this will help to keep the car and trailer under control in a cross-wind.
What I currently have is Michelin Defenders 205/55R16 which are fairly new (last spring.) They have a load index of 91 which is 77 lbs over the 89 OEM (I assume) load index. What's the model of your 96XL? I can only find 94 for my tire size:

http://www.tirerack.com/tires/TireSearc ... iameter=16" onclick="window.open(this.href);return false;

and for 205/50R16, the only one that is 96XL is the Hankook Ventus V12 evo K110. There are other 96 but mostly winter tires. I never looked up Hankook tires. Can't believe that I can get good rubber for 64$/tire. I always had good results with Michelins for summer and Nokians for winter (I live north to the 49th parallel. :)

http://www.tirerack.com/tires/TireSearc ... iameter=16" onclick="window.open(this.href);return false;

Anyway, I wonder how if a set of 205/50R16 would fit on my current wheels.

You puzzle me with the 40 psi comment.. why 40? The car calls for 32 psi. This forums mentions a lot of people jumping the pressure to 35-37. Very few over that. Is it written somewhere that a tire of, say, load index 91 will be able to support 1356 lbs at X psi where X is not equal to car recommended pressure?

Which brings me to something that is not clear in my mind: according to my door sticker, the read axle GAWR is 840 kg (1851 lbs.) How does this translate to the tire load index? I mean, if it was 1:1, we'd need tires with a load index of 102 to achieve the GAWR.. which is (probably) impossible to find for our cars. How can the stock load index rating of 1279 lbs be enough? Is the tire capacity divided by two or is this totally unrelated?

Good point on the anti-roll. I'm already thinking about it. Still no idea what to get at this point tho. ;)
2007 Vibe 1.8L Automatic 185K, B&M 70264 Transmission Cooler, Custom 2" hitch receiver.
dragon64
Posts: 131
Joined: Mon Oct 27, 2008 1:42 am

Re: Stronger Springs and Struts for rear suspension

Post by dragon64 »

Unfortunately, being in Canada limits a lot my options in obtaining these donuts. And I have no contact in the industry. Ask me about a computer part and I can help however. ;) The Coil SumoSprings looks a lot like what you are describing. I'll check how hard they can be to obtain. Can't find any suspension related products on Longacre site.
Super Spring is distributed in Canada by Keystone so can be order by any retail shop that uses them as a vendor. For Longacre look here http://www.longacreracing.com/products. ... ng+Rubbers" onclick="window.open(this.href);return false;
What I currently have is Michelin Defenders 205/55R16 which are fairly new (last spring.) They have a load index of 91 which is 77 lbs over the 89 OEM (I assume) load index. What's the model of your 96XL? I can only find 94 for my tire size:
I bought one of the last sets of Falken Ziex ZE-912. In the size 225/50-16"I bought there are to P/N# one had a 91index and when normally stocked and the other had a 96XL which was not a normally stocked P/N# just after christmas Falken was blowing out the 912 at under $40 cost to make way for the new ZE950

and for 205/50R16, the only one that is 96XL is the Hankook Ventus V12 evo K110. There are other 96 but mostly winter tires. I never looked up Hankook tires. Can't believe that I can get good rubber for 64$/tire. I always had good results with Michelins for summer and Nokians for winter (I live north to the 49th parallel. :)
Hankook are good tire but have really bad customer service if you get a tire with a manufactures defect. BTW I run Toyo GSi-5 on my car in the winter
Anyway, I wonder how if a set of 205/50R16 would fit on my current wheels.

You puzzle me with the 40 psi comment.. why 40? The car calls for 32 psi. This forums mentions a lot of people jumping the pressure to 35-37. Very few over that. Is it written somewhere that a tire of, say, load index 91 will be able to support 1356 lbs at X psi where X is not equal to car recommended pressure?
A 205/50-16" would be under diameter for the Vibe correct size should be 205/55-16 or 225/50-16. A tire being under sized will cause the speedo to be out and increase the the numbers of revs per mile/ km which can increase the tire temp.

The air pressure recommended on the car is for comfort with an average load with the OE tires. If increase the load, Air pressure needs to be increase to compensate. If you look at the side of the tires you will see that the max.load is at an air pressure higher that 32psi. If you are have 94XL load index for normal driving you would have to lower your the air pressure to around 26-28 psi instead of the stock 32psi because of the stornger sidewall and to max tread life. When unloaded I usually run the rear tires 2psi less that the front.
Which brings me to something that is not clear in my mind: according to my door sticker, the read axle GAWR is 840 kg (1851 lbs.) How does this translate to the tire load index? I mean, if it was 1:1, we'd need tires with a load index of 102 to achieve the GAWR.. which is (probably) impossible to find for our cars. How can the stock load index rating of 1279 lbs be enough? Is the tire capacity divided by two or is this totally unrelated?
This is a good question, I believe that rating is per each wheel. Let me contact a few friends in the industry next week.
2009 Vibe 1.8L Manual - DBW controller, Hydraulic engine damper, S/S brakeline retrokit,22mm solid Rear ARB, urethane rear coil dampers, Front strut bar with brake cylinder brace, PIAA 410 driving lights, PRM Intake Wilwood front brakes, Lexus hood lifts
cythraul
Posts: 117
Joined: Sun May 15, 2011 7:38 am
Location: Montreal, QC, Canada

Re: Stronger Springs and Struts for rear suspension

Post by cythraul »

dragon64 wrote:Super Spring is distributed in Canada by Keystone so can be order by any retail shop that uses them as a vendor. For Longacre look here http://www.longacreracing.com/products. ... ng+Rubbers" onclick="window.open(this.href);return false;
Oh! I see them. But these are rubber. Looks like you can choose the hardness for these donuts while the SuperSpring don't even list that specification. They don't specify either if their urethane is bonded or not with rubber.

I'll probably get the Longacre.. way cheaper then the SS. After all, the car is a 2007 at 185K. I *hope* to drive it 3-4 years (touching wood -- just did my first repair on the car last month: water pump.) I assume the rubber of the Longacre will last that long. Otherwise, I can still get two another pairs and I'm still under the SuperSpring price for a single pair.
dragon64 wrote:I bought one of the last sets of Falken Ziex ZE-912. In the size 225/50-16"I bought there are to P/N# one had a 91index and when normally stocked and the other had a 96XL which was not a normally stocked P/N# just after christmas Falken was blowing out the 912 at under $40 cost to make way for the new ZE950
Next time you see that deal, let us know. If you don't have the chance, buy their stock and sell them back to us. You'll certainly make a few bucks and we'll still have a deal! ;)
dragon64 wrote:Hankook are good tire but have really bad customer service if you get a tire with a manufactures defect. BTW I run Toyo GSi-5 on my car in the winter
Well, life is busy enough without that risk. I bought the Michelin at Canadian Tires because of three factors. One, they are Michelin and I never heard of issues with them. Second, CT offers a no-hassle repair/replacement policy. Third, mail-in rebate that they actually honours.

I'll check out the Falken tho. The 912 225/50R16XL (P/N: 28922672) seems still available at a few places.. but not at the price you paid. :( And the 950 does not have any XL. Btw, Michelin Defenders are rated quite good on threadwear, which was another part of my decision to get them. How are the Falken in this respect? Reviews are mixed.. Looks like people having issues with threadwear are heavy footed.

I saw some Achilles. Looks like their customer support is even worse then Hankook. :)

Oh yeah, Toyos.. I used to have a set of Toyo Observe G-02 on my Altima 2000 before my Vibe. They were awesome. Also had Open Country H/T (M/S) on my 4WD 98 MPV. Could not locate a good deal when I was looking for some winter tires last autumn so I went back to the Nokians that I've been using since I started driving. I was able to get a very good deal on a set of Hakkapeliitta 7 195/65R15XL. Interestingly, I just realised that they are a set of 95XL! :)
dragon64 wrote:A 205/50-16" would be under diameter for the Vibe correct size should be 205/55-16 or 225/50-16. A tire being under sized will cause the speedo to be out and increase the the numbers of revs per mile/ km which can increase the tire temp.
Sorry, I meant 225/50R16, I know about tire sizing. :)

I wish that in tire rack or similar sites, you could enter your target size and it would display all "compatible" sizes. I've made a few tests and for 16 tires, looks like it's either the stock 205/55 or your 225/50. Anything else throws the speedo off and I hate that.

BTW, your 225/50R16XL are 9-10% larger. Any issue with that? I understand why they need to be that large to get to 96XL and why we can't find 94+ for 205/55R16.
dragon64 wrote:The air pressure recommended on the car is for comfort with an average load with the OE tires. If increase the load, Air pressure needs to be increase to compensate. If you look at the side of the tires you will see that the max.load is at an air pressure higher that 32psi. If you are have 94XL load index for normal driving you would have to lower your the air pressure to around 26-28 psi instead of the stock 32psi because of the stornger sidewall and to max tread life. When unloaded I usually run the rear tires 2psi less that the front.
Adjusting pressure relative to the load makes sense indeed. But, wow.. how can a laymen like me be expected to be able to know the right tire pressure given the tire specs and the load? I'm so cartesian.. :)

For example.. I've got these 91T that I'd run (unloaded) at 34-35 PSI. Looks like it's not a good idea since it's a bit stronger then the stock 89. So I'd assume you'd probably run then (unloaded) at 32 front and 30 on the rear. Or does this apply only to XL tires?
dragon64 wrote:This is a good question, I believe that rating is per each wheel. Let me contact a few friends in the industry next week.
Thanks! I've found this since:
According to Federal Motor Vehicle Safety Standard (FMVSS 571.120):
The sum of the maximum load ratings of the tires fitted to an axle shall not be less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle’s certification label (tire information placard).
So if I interpret this correctly, the bare minimum load capacity of a tire would be GAWR divided by the number of wheels on the axle (two in most case.) Consequently, to support a GAWR of 1852 lbs, we'd need a tire with a load index of... 78 (937 lbs!) Following that standard, the stock 89 would be adequate, my 91 quite enough and your 96XL, overkill. Confusion ensues. :)

That being said, I loaded my rig on a scale the other day and I was surprised to see that the front axle had 810kg, the read 890kg (!) and the pop-up trailer 620kg (1786, 1962, 1499 kbs respectively.) That's with a 20lbs propane tank that's probably not quite full. So I'm definitely over the specs on the read axel. I'll move the battery which weights around 55 lbs (AGM) from the front to the compartment behind the trailer axle where the charger is located. I wish the axle of that trailer would be a wee bit more in the front.

The odd part is, that I had a custom 2 hitch receiver installed to be able to get a WD system. Unfortunately, I neglected to consider the weight of the.. weight distribution system (~60lbs.) Prior to this, my last trip to that scale showed 840, 840 and 620 (1852, 1852 and 1367lbs.) I was better off but the rear sagged too much and the bottom of the hitch was scraping a bit when passing over the camping speed bumps.

With the WD in place, I have 3 inches difference between the front and rear fenders and the trailer is almost level.

Image

Image
2007 Vibe 1.8L Automatic 185K, B&M 70264 Transmission Cooler, Custom 2" hitch receiver.
dragon64
Posts: 131
Joined: Mon Oct 27, 2008 1:42 am

Re: Stronger Springs and Struts for rear suspension

Post by dragon64 »

The Falken are a semi performance tire so tire wear is going to be high but does have great wet traction and generally have tread wear as long as you remember that it is a prefomance tire and not a touring tire. The ZE-950 225/50-16 is a 96XL My 225/50-16" are the same diameter as a 205/55-16" listed diameter for both are 24.9"

A good inexpensive tire with a high load rating is the Nankang NS-20. Their 205/55-16 is a 94XL and their 225/50-16 is a 96XL. These are a perfomance tire so tread wear rating is going to be lower than a touring tire.

One thing I should mention that if you do go to a 225 with tire you should mount them on at least a 7" wide rim not a stock 6.5" rim. That 1/2" sucks the sidewall in enough that it can affect handling with increased sidewall flex. On the Vibe with traction control this can really freak out the sensors and constantly engage the traction control especially on Toyota manufacture car with a sports package. When I was working in the tech dept of a aftermarket wheel mfgr. we had to work directly with Toyota's techs on a Rav-4 with the Sports package because the customer downsize the wheels for winter with a taller sidewall tire and the car brakes were constantly engaging. Toyota told us that the traction/ staibility control was seeing more vehicle lateral movement outside the factory parameters that the system was freaking out and engaging the brake to keep the car straight

At the aftermarket wheel mfgr we had charts supplied by tire manufactures for inflation compensation. For tire with a 91load index where the original tire is a 89 @ 32psi, I would say the new inflation value would be around 29-30psi front and possible 2psi less in the rear depending on how you load your car.

Being an industrry insider I know that tire inflation needs to be adjusted and wouldn't expect the average consumer to be aware of this fact athough we had discussed was of educating the consumers. The bigger problem is most tire shop don't know or don't care that you need to adjust tire inflation based on load index either. Of course for a tire shop it is better for them if a tire is over inflated because the tires wear faster. In the winter this creates a safety hazzard because there is less rubber contacting the road if you are running a 94XL @32psi because there is only a narrow band of rubber in the middle of the tire contacting the road. On the other hand in the winter you have to monitor the air pressure more closely because air pressure will drop around 2-3psi for every -10C temp change

I like that you have a weight distribution system and that you are adjusting the weight with in your trailer. This does a lot to take weight of the rear axle of the car and putting more of it over the trailer axle. I've seen cars towing a trailer flip due to to much weight over the tongue and the landing gear dig into the pavement when the car suspension bottoms out going over a large bump.
2009 Vibe 1.8L Manual - DBW controller, Hydraulic engine damper, S/S brakeline retrokit,22mm solid Rear ARB, urethane rear coil dampers, Front strut bar with brake cylinder brace, PIAA 410 driving lights, PRM Intake Wilwood front brakes, Lexus hood lifts
beemerphile1
Posts: 505
Joined: Tue Jul 14, 2009 12:12 am
Location: NE Ohio

Re: Stronger Springs and Struts for rear suspension

Post by beemerphile1 »

dragon64 wrote: ...Being an industrry insider I know that tire inflation needs to be adjusted and wouldn't expect the average consumer to be aware of this fact....
Since it states on the sidewall of tires; "xxx load capacity at xxx PSI" it has always been clear to me that less PSI means less load capacity. No need to be an industry insider to understand such a simple concept. Many of the larger tire manufacturers have charts on the web giving more information on tire load and the correct PSI for different percentages of max load.
dragon64 wrote: ...I've seen cars towing a trailer flip due to to much weight over the tongue and the landing gear dig into the pavement when the car suspension bottoms out going over a large bump.
I highly doubt that, a tongue jack or stabilizers will yield a long time before a car will flip. I can't visualize how that could possibly happen.
NE Ohio - home to the most successful Pontiac drag racing team in history - Bill Knafel's "Tin Indian" and also home to Summit Auto Racing.
2009 Vibe base 1.8L auto towing 2009 Aliner Sport hardsided pop-up
Post Reply