Front strut bar for 2016 CX9

Has anyone installed a front strut bar on this suv? Thinking about getting the Autoexe one but not sure how much of an improvement will it provide. I really hope it can make the handling tighter since I feel that the steering is a bit loose on the freeway.

I don't feel any looseness at 80.

A strut tower brace stiffens the chassis. Do you think the chassis is flexing causing the looseness you feel?

Do you have a load in the car? Where is the load located? Evenly distributed or heavy in the back?

Tire inflation pressures all good, 34 F&R cold?

PTguy said:

I don't feel any looseness at 80.

A strut tower brace stiffens the chassis. Do you think the chassis is flexing causing the looseness you feel?

Do you have a load in the car? Where is the load located? Evenly distributed or heavy in the back?

Tire inflation pressures all good, 34 F&R cold?

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Well, I guess I just wanted the car to feel tighter as I read that front strut bar is the most effective way to help a car increase its rigidity by allowing both strut towers to react to compression and tensile forces.

deluxman said:

Well, I guess I just wanted the car to feel tighter as I read that front strut bar is the most effective way to help a car increase its rigidity by allowing both strut towers to react to compression and tensile forces.

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strut bars are a complete and utter gimick, it fancies up your engine bay and does nothing else.

get some sway bars instead

GJ-Molestor said:

strut bars are a complete and utter gimick, it fancies up your engine bay and does nothing else.

get some sway bars instead

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I disagree completely. I have used strut tower bars in previous vehicles (2001 PT Cruiser) which stiffened and flattened cornering in an amazing way. I have one on my 2010 Mazdaspeed3, and it is one of many mods done around the same time, but I still notice considerable stiffening of the chassis at speed while cornering.

I do have doubts about the effect on the CX-9, though, so I am agreeing with you. I don’t know that there is chassis flex in this car, but truth be told, I haven’t tried it so I can’t evaluate it. I find my 2 previous and current 2015 CX-9s to be incredible cornering vehicles, especially given the type of vehicle they are, as a crossover. All of the tests of this class together name the Mazda as the best handler of all of them.

Padre Dave01 said:

I disagree completely. I have used strut tower bars in previous vehicles (2001 PT Cruiser) which stiffened and flattened cornering in an amazing way. I have one on my 2010 Mazdaspeed3, and it is one of many mods done around the same time, but I still notice considerable stiffening of the chassis at speed while cornering.

I do have doubts about the effect on the CX-9, though, so I am agreeing with you. I dont know that there is chassis flex in this car, but truth be told, I havent tried it so I cant evaluate it. I find my 2 previous and current 2015 CX-9s to be incredible cornering vehicles, especially given the type of vehicle they are, as a crossover. All of the tests of this class together name the Mazda as the best handler of all of them.

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Well thats the thing. When you spend some time in the Mazda and go over some bumpy roads, you notice that it is genuinely a very well put together car with absolutely zero chassis flex. I think that a strut brace would be one of the most useless mods for this particular vehicle. Now a PT cruiser? Thats a whole other story, because its level of engineering quality doesnt come anywhere near close to that of Mazda.

Now with the MS3 you had, you didnt install each part seperately so you dont actually know exactly how much the strut brace helped, which is why Im skeptical.

Having spent a fair amount of time with the Mazda and putting it through its paces, this is my conclusion in terms of handling and aftermarket parts:

The chassis itself is extremely well tuned and I like how the suspension is set up, but its a little bit too soft and allows for too much body roll during aggressive cornering. The stock open differential is no good for spirited driving either - I would replace it with a LSD that has a shorter final drive ratio. This will improve traction and handling greatly (this mod is for FWD owners only)
the 6 speed automatic transmission in this vehicle is very well geared, but I think that the final drive should be slightly shorter for a more peppy, racier feel which will yield on better spacing between the gears. I think the RPM is a little too low for highway driving in sixth gear unless you are going quite fast, so you will kill two birds with one stone by installing a new differential.

If you are to spend any sort of money on suspension upgrades, the first place I would look without a doubt is sway bars. They help keep body roll in check and improve steering/chassis feedback without any penalty in ride quality.

Coilovers. The stock suspension sits a little too high for my liking, (Im talking purely about my experience with the Mazda 6 sedan here, although much of this applies to CX-5 owners) but its well tuned for everyday driving and feels sharp as long as you dont push the car too hard. Id recommend taking a look at BC racing coilovers, arguably the best aftermarket suspension you can buy for any car period. Since coilovers are out of question for many of us especially the CX-5 owners, I think sway bars are the most cost effective upgrade that will make a huge difference with how the car drives and no sacrifice in ride quality.

GJ-Molestor said:

Well thats the thing. When you spend some time in the Mazda and go over some bumpy roads, you notice that it is genuinely a very well put together car with absolutely zero chassis flex. I think that a strut brace would be one of the most useless mods for this particular vehicle. Now a PT cruiser? Thats a whole other story, because its level of engineering quality doesnt come anywhere near close to that of Mazda.

Now with the MS3 you had, you didnt install each part seperately so you dont actually know exactly how much the strut brace helped, which is why Im skeptical.

Having spent a fair amount of time with the Mazda and putting it through its paces, this is my conclusion in terms of handling and aftermarket parts:

The chassis itself is extremely well tuned and I like how the suspension is set up, but its a little bit too soft and allows for too much body roll during aggressive cornering. The stock open differential is no good for spirited driving either - I would replace it with a LSD that has a shorter final drive ratio. This will improve traction and handling greatly (this mod is for FWD owners only)
the 6 speed automatic transmission in this vehicle is very well geared, but I think that the final drive should be slightly shorter for a more peppy, racier feel which will yield on better spacing between the gears. I think the RPM is a little too low for highway driving in sixth gear unless you are going quite fast, so you will kill two birds with one stone by installing a new differential.

If you are to spend any sort of money on suspension upgrades, the first place I would look without a doubt is sway bars. They help keep body roll in check and improve steering/chassis feedback without any penalty in ride quality.

Coilovers. The stock suspension sits a little too high for my liking, (Im talking purely about my experience with the Mazda 6 sedan here, although much of this applies to CX-5 owners) but its well tuned for everyday driving and feels sharp as long as you dont push the car too hard. Id recommend taking a look at BC racing coilovers, arguably the best aftermarket suspension you can buy for any car period. Since coilovers are out of question for many of us especially the CX-5 owners, I think sway bars are the most cost effective upgrade that will make a huge difference with how the car drives and no sacrifice in ride quality.

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Do you recommend both front and rear sway bar and any particular brand?

deluxman said:

Do you recommend both front and rear sway bar and any particular brand?

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Yes, get both front and rear. I recommend Megan racing.

IF you like to corner aggressively, have an alignment shop pop the strut pins in your front suspension for an extra -0.5 degree of negative camber. Or you can get camber plates.

deluxman said:

Has anyone installed a front strut bar on this suv? Thinking about getting the Autoexe one but not sure how much of an improvement will it provide. I really hope it can make the handling tighter since I feel that the steering is a bit loose on the freeway.

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Before you spend the money and times on mods, you may want to get a good alignment done to verify the steering looseness is not just a setup issue. Your car is so new I don't think tie rod ends could be loose, but that's also worth a quick check. Tire pressure and brand can also make a difference.

I do my own alignments and can tell you even tiny toe-in/out adjustments can make big differences in steering feel.

Thaumaturge said:

Before you spend the money and times on mods, you may want to get a good alignment done to verify the steering looseness is not just a setup issue. Your car is so new I don't think tie rod ends could be loose, but that's also worth a quick check. Tire pressure and brand can also make a difference.

I do my own alignments and can tell you even tiny toe-in/out adjustments can make big differences in steering feel.

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If you are close to me, I would definitely have you check it out, coz a lot of tire shop did not do a good alligment job plus you end up getting a few nick or scrapes on your wheels.

deluxman said:

If you are close to me, I would definitely have you check it out, coz a lot of tire shop did not do a good alligment job plus you end up getting a few nick or scrapes on your wheels.

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Well if you don't think you got a good alignment, then that's a good place to start. I got so sick of crooked steering wheels and pulling after alignments that I taught myself how to do it.

To check it out yourself without even popping a tire use the time-honored string method. That is what I use for my car. IMHO, A tight string properly adjusted is better than a fancy alignment machine in the hands of an idiot.

Check out this great video for the basics:
https://www.youtube.com/watch?v=Dl0pCDpZYwQ

or here's a great article from Hot Rod Magazine on the same topic:

http://www.hotrod.com/articles/hrdp-0411-wheel-alignment-guide/

I have a dedicated set of cardboard tubes (use conduit, wood, whatever) that are about 12" wider than my CX-9 and have identical holes in them for the fishing line (line stays rolled up when not used). I can have things setup, calibrated and ready for measuring in minutes. I calibrate the parallel lines using the center of the hubs and measure toe from both the tires and rims (just to double check).

Here are the specs for CX-9 toe-in. You are unlikely to need caster or camber adjustments.

Total toe-in [Tolerance 4 { 0.16}] (mm {in}) 2 {0.08}
(degree) 018' 032'

a lot of tire shop did not do a good alignment job

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What adjustments are available on our cars? Certainly front toe-in. Maybe rear toe? Anything for caster or camber, or are aftermarket camber adjusters available?

The car maker sets alignment specs. Often the range of these specs are too broad. Unless you have a specific setting you want, tell the shop, and the tech if possible, that you want the alignment set at the middle of the spec. Not just anywhere within the spec. The customer is always right, (well, almost always), and they can do what you want if they take a couple of extra minutes. Do not accept "in spec." Demand the center of the spec. I had a Tundra with front toe, caster, and camber adjustable. The truck was great if they set the toe & camber at the middle of the spec and the caster at the max allowable. Max allowable was at the end of the spec, but still within the spec range, so the shop had no added liability. CX9s don't have all those adjustments, but get them set the best possible.

All structures flex. All auto bodies flex. Our CX9s flex very little. A strut tower brace will stiffen it, but how much? Will it be noticeable? If noticeable, will it harm the ride quality? (I found that on my old Volvo.) The body flex is part of the manufacturer's total suspension compliance calculation. Or is the body already so stiff that the bar will be a waste of money?

deluxman said:

Has anyone installed a front strut bar on this suv? Thinking about getting the Autoexe one but not sure how much of an improvement will it provide. I really hope it can make the handling tighter since I feel that the steering is a bit loose on the freeway.

Click to expand...

deluxman said:

Well, I guess I just wanted the car to feel tighter as I read that front strut bar is the most effective way to help a car increase its rigidity by allowing both strut towers to react to compression and tensile forces.

Click to expand...

I will say this about the AutoExe Tower Bar - it is a gorgeous looking unit that's for sure and very tempting to boot. Curious - are you considering this in addition to their Front Anti-Sway Bar, or just the Tower Bar (Strut Bar) by itself?

A few things you probably already know or are about to learn:

My only concern with employing anti-sway is if the bar's degree of torsional resistance is too aggressive causing too much loading on the opposite side, which in turn could upset or offset the independence of the suspension causing it to not be able to do its job optimally. So, the question I would have is - how much testing have these guys done on the CX-9 to dial in the effective torsion rigidity of the bar itself to make sure that under/over steer remain in check? SUVs tend to have more under steer. So, at first glance it might seem like an ideal set-up to dial some of that out - the question is how much is too much for that particular vehicle.

The other thing to remember here too is that typically, you would stiffen the rear to dial out unwanted under steer. In this case, you are stiffening the front only (front what I can gather) which could actually have the net effect (assuming you did nothing to the rear) of increasing body roll - probably not the goal you were going after. You might also want to pay some attention to the tires as well. Obtaining less body roll and more rigidity will push the tire harder into the corners - so a higher performance road handing tire might be required to enjoy the full benefits - you'll have to study that.

The other net negative, especially for the CX-9, will be increased road harshness as vibrations will be constantly traveling along the bar itself in varying frequencies and it is unlikely that they will be harmonic or cancel each other out very often to be noticeable. So, expect some loss of what the CX-9 already does fairly well, dampening of road vibrations.

Overall, given all the potential pros and cons, I'd be interested in knowing how this turned out for you, really. The CX-9 has MacPherson struts up front as opposed to a Double Wishbone arrangement and therefore, the Strut Bar should be better able to dampen out more of the force moments caused by the ground level friction going into turns. A Strut Bar will help both systems, but it should help the MP better. Just make sure they use high strength materials as the weak link in any torsion based system will always be materials.

Good hunting and please do remember to update this thread with your results, should you decide to do the install. Or, please PM me once you have some results, please. Thank you.

GJ-Molestor said:

strut bars are a complete and utter gimick, it fancies up your engine bay and does nothing else.

get some sway bars instead

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I'm going to have to politely disagree totally and completely.

In my experience with performance vehicles it all depends on the vehicle - literally. The suspension type and geometry, overall weight distribution, tires, wheels, chassis type - heck in some cases (depending) even aerodynamics all play a role in the resultant steering output you get from a variety of steering inputs and road conditions. But, let's settle down on just the CX-9 - an SUV of all things - let's not forget that.

He could go the Anti-Sway route exclusively. He could opt instead for Adjustable Shocks and Performance Springs. He could combine the two. Or, he could do exactly what he's proposing, which in my humble opinion is taking the middle ground. In fact, this is why I'm so interested in the outcome of his project - I want to know how it works out for him because this is the most 'middle passage' he could possible take for something like the CX-9, just to see how it responds.

The Strut Bar is going to prevent more body roll than is normal for the CX-9, but its secondary role in a MacPherson arrangement will be to distribute the ground level friction forces that end up reaching the suspension components above the tire itself. If the CX-9 were Double Wishbone instead, a Strut Bar would help less but still offer some additional resistance to roll overall. If he went Shocks/Springs, then that would impact ride comfort on a daily basis to a greater degree - it would also improve cornering better than the Strut Bar route, but at what cost in comfort?

I'm not sure what the OP's objective are in total, but it would seem to me that starting with the top side is probably the safest, best and most cost effective way to dial-in and dial-up cornering to his liking. And, yes it does look hot. I have a White Pearl Signature and that beaming hot red would indeed look cool just "sitting under the hood" all by itself doing nothing. Maybe that's enough for him - I don't know. However, I think a Strut Bar (if well designed and manufactured) and some kind of Michelin Pilot Sports could offer enough enhancement to satisfy the appetite of a CX-9 driver - while not turning the felt ride experience into that of a giant GoKart.

Just my two cents - FWIW.

Padre Dave01 said:

... I don’t know that there is chassis flex in this car, but truth be told, I haven’t tried it so I can’t evaluate it....

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It begins to flex the more you push it. They did a good job of tire selection right off the bat, though that could be improved. I get what I consider noticeably more body roll to commence with tire break (squeal) at nearly the same point along the the X-axis of Time after the initial load hits the the corner of the vehicle in a constant turn. I feel some (a bit) can be taken out with better tires. But, I feel that probably (and that's why I find the thread so interesting) an amount that was significantly more noticeable could be removed with a top side bar.

I don't know that I'd want to go the adjustable strut with sport springs route as that would definitely take away my daily driver happiness (comfort) out where I drive all the time. However, I do want to be able to push it slight harder into AND out of the turns up in the hills where I live. So, I was going to look into some methods for increasing rigidity, reducing body roll and flattening the turn sequence just a bit AND without forcing too much harshness in ride comfort.

A delicate balancing act for this particular vehicle - but I suspect it will be fun finding out how to do it properly.

This gets back to my thread on would you buy a GT1 or GT2 version of the CX-9. Mazda, did make it responsive and agile for what it is (an SUV), no doubt. I just want a little bit more of that dynamic, if you know what I mean.

GJ-Molestor said:

Well that’s the thing. When you spend some time in the Mazda and go over some bumpy roads, you notice that it is genuinely a very well put together car with absolutely zero chassis flex. I think that a strut brace would be one of the most useless mods for this particular vehicle. Now a PT cruiser? That’s a whole other story, because it’s level of engineering quality doesn’t come anywhere near close to that of Mazda.

Click to expand...

GJ-Molestor said:

Having spent a fair amount of time with the Mazda and putting it through its paces, this is my conclusion in terms of handling and aftermarket parts:

The chassis itself is extremely well tuned and I like how the suspension is set up, but it’s a little bit too soft and allows for too much body roll during aggressive cornering.

Click to expand...

I think the OP is like me. He's not referring so much to stability in the vertical as opposed to the horizontal. So, and I cannot speak for the OP but for myself, I'd like to dial-in less under steer as naturally as possible without messing with the wheel alignment and burning through tires every few months and without generating too much harshness in the vertical as a net/net result of swapping for racing shocks and springs.

I think if the bar is designed and built correctly with the right materials, it could make a difference with some Pilot Sports or something on that level.

GJ-Molestor said:

If you are to spend any sort of money on suspension upgrades, the first place I would look without a doubt is sway bars. They help keep body roll in check and improve steering/chassis feedback without any penalty in ride quality.

Click to expand...

Now, that's interesting because I've never met the modal effective Sway Bar that did not charge a penalty at the front door of ride quality and those were all sports cars. It would be interesting to see an effective Sway Bar doing its job as an effective Sway Bar, while not charging a door fee on ride quality on front on an SUV chassis like the CX-9. In fact, if such a Sway Bar exists for the CX-9 - then I would appreciate someone telling me where I could find it, seriously. It would be the easiest aftermarket tuning purchase I could probably ever make.

GJ-Molestor said:

Coilovers. The stock suspension sits a little too high for my liking, (I’m talking purely about my experience with the Mazda 6 sedan here, although much of this applies to CX-5 owners) but it’s well tuned for everyday driving and feels sharp as long as you don’t push the car too hard. I’d recommend taking a look at BC racing coilovers, arguably the best aftermarket suspension you can buy for any car period. Since coilovers are out of question for many of us especially the CX-5 owners, I think sway bars are the most cost effective upgrade that will make a huge difference with how the car drives and no sacrifice in ride quality.

Click to expand...

I'm all for the Sway Bar upgrade - but the price paid in ride quality relative to what you get from a stock CX-9, must be significant and undeniable. I offer that I could be very wrong, here. However, like I said, I've never met the Sway Bar that did not charge at the front door for ride comfort reduction in the vertical, while offering credits for horizontal stability in the turns. He's got to find the set-up that works for him, of course. And, starting with just the Strut Bar might be a good way to get his feet wet and get the CX-9 talking to him. If it needs more, I'm sure the CX-9 will tell him that.

My gut tells me that a top side bar and some Sports might do the trick.

Cessna CJ4 said:

I think the OP is like me. He's not referring so much to stability in the vertical as opposed to the horizontal. So, and I cannot speak for the OP but for myself, I'd like to dial-in less under steer as naturally as possible without messing with the wheel alignment and burning through tires every few months and without generating too much harshness in the vertical as a net/net result of swapping for racing shocks and springs.

I think if the bar is designed and built correctly with the right materials, it could make a difference with some Pilot Sports or something on that level.





Now, that's interesting because I've never met the modal effective Sway Bar that did not charge a penalty at the front door of ride quality and those were all sports cars. It would be interesting to see an effective Sway Bar doing its job as an effective Sway Bar, while not charging a door fee on ride quality on front on an SUV chassis like the CX-9. In fact, if such a Sway Bar exists for the CX-9 - then I would appreciate someone telling me where I could find it, seriously. It would be the easiest aftermarket tuning purchase I could probably ever make.




I'm all for the Sway Bar upgrade - but the price paid in ride quality relative to what you get from a stock CX-9, must be significant and undeniable. I offer that I could be very wrong, here. However, like I said, I've never met the Sway Bar that did not charge at the front door for ride comfort reduction in the vertical, while offering credits for horizontal stability in the turns. He's got to find the set-up that works for him, of course. And, starting with just the Strut Bar might be a good way to get his feet wet and get the CX-9 talking to him. If it needs more, I'm sure the CX-9 will tell him that.

My gut tells me that a top side bar and some Sports might do the trick.

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1. A strut bar will make no difference on your car because the chassis is already structurally rigid and does not allow for any suspension components to flex

2. Good sway bars yield no reduction in ride quality. You will just get much more precise handling and less body roll with zero sacrifice in ride comfort. Its the best choice for your needs.

3. If you find that the car understeers too much for your liking, your first and most crucial modification should be adjusting your front camber to something more aggressive (have a good shop tune this to your handling requirements so you do not get uneven tire wear) and TIRES. Get some high performance Yokohama tires.

GJ-Molestor said:

1. A strut bar will make no difference on your car because the chassis is already structurally rigid and does not allow for any suspension components to flex

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Just for the sake of clarity and precision - the Mazda CX-9 employs a unibody construction which means the body and chassis are one. So, yes - in general terms unibody (as opposed to body on frame) construction does provide more rigidity with less weight and thus better handing in the corners. However, I think "better handling" might be the operative phrase here, as the CX-9 is indeed and SUV and does not come with the expectation for handing that a sports car comes with at the point of sale. So, a slight improvement through the use of a strut bar, as opposed to a radical drawing change in handing and ride performance through the use of a sway bar - might be what the doctor ordered for CX-9 owners/drivers having an SUV expectation of performance, while still wanting to be able to push slight harder into the turns.

GJ-Molestor said:

2. Good sway bars yield no reduction in ride quality. You will just get much more precise handling and less body roll with zero sacrifice in ride comfort. It’s the best choice for your needs.

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Again, I have not met one that does one without effecting the other. One of the first mods I did to my old 200 C5 Corvette back when I bought it brand new and had it ordered out of Kentucky, was a http://www.westcoastcorvette.com/ front and rear sway kit. It came with adjustable length metal end links and I had it installed and road tested around the neighborhood in under two hours. Did it allow me to push harder into the turns? Yes, indeed it did. However, it also provided for slightly more resonance and road vibration translation up through the suspension and throughout the front end - and it was more noticeable in normal driving around town while taking turns on bumpy streets.

So, the normal around town driving was sacrificed a bit. However, when I headed south to the back roads and into the canyons with smooth sweeping turns and subtle elevation changes for miles, I never cared about the around town harshness because the overall handling performance was that much better than stock. However, again, on the streets, if I pushed too hard - the front end would plow and start to make the car feel cheaply tuned - which was not a very good feeling. That had more to do with the smaller wheel diameter up front than in the back and the lack luster performance of the stock good year run flats.

GJ-Molestor said:

3. If you find that the car understeers too much for your liking, your first and most crucial modification should be adjusting your front camber to something more aggressive (have a good shop tune this to your handling requirements so you do not get uneven tire wear) and TIRES. Get some high performance Yokohama tires.

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I would agree that this could be part of a fix to understeer. However, I think the OP's approach would be a good first step without altering geometry and without running the risk of a bad camber job. Though it has a unibody construction is also has a MacPherson Strut system and that in inherently means more vibration, more overall movement and flex leading into the strut towers themselves. Too bad that the same company does not offer a Triangulated Front Strut Brace, which would tie in the firewall and provide even more stability both horizontally and longitudinally.

I'm not saying an under bar (sway bar) won't or can't provide more stiffness. I'm saying, does the CX-9 require that much stiffness? I don't know at this point, but I certainly have plans to experiment with handling improvements on my Signature without inviting too much road harshness as described in my C5, which of course came with a completely different handling expectation than my Signature.

Good sway bars yield no reduction in ride quality. You will just get much more precise handling and less body roll with zero sacrifice in ride comfort.

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That can't be. A sway bar is a spring steel torsion bar. It limits one wheel from going up while the other wheel goes down. It limits it by the twist in the spring steel bar. Body roll is exactly one wheel going up (in relation to the body) while the other goes down (in relation to the body). So, if you drive over one bump that evenly raises or lowers both wheels, no problem. If you go over a bump that raises only one wheel, the sway bar will resist that and cause the body to move around.

PTguy said:

That can't be. A sway bar is a spring steel torsion bar. It limits one wheel from going up while the other wheel goes down. It limits it by the twist in the spring steel bar. Body roll is exactly one wheel going up (in relation to the body) while the other goes down (in relation to the body). So, if you drive over one bump that evenly raises or lowers both wheels, no problem. If you go over a bump that raises only one wheel, the sway bar will resist that and cause the body to move around.

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I can definitely feel this when I attack a speed bump at an angle (i.e. leaving after parked in the curb). The suspension would just resist and shakes you violently (headbang)(headbang)(headbang)