Need Stiffer Rear Coils

icspots

Paramagic
:
2012 Mazda 5
Also I’m halfway through my suspension job. Passenger side is done, but the lower bolt for the driver side shock is not quite seized. I got the driver side spring out, and had the head of the shock bolt about 1/2” out before dinner last night, so I sprayed a bunch of PB blaster on it and called it a night. Hoping to go out and work on it for a bit shortly and really hoping that bolt comes loose today so I can take it for a drive And see if this was all a terrible idea.

The passenger side shock was rusted all to hell at the top of the cylinder, and that side was sitting a half inch lower than the other side. I’m sure the shocks being done was not helping my load handling.... then again my extra weight in the car probably didn’t do the shocks any favors.

The H&R lowering springs are the same 14” as the 5’s springs.
 

Attachments

:
2013 Mazda 5 GS
Also I’m halfway through my suspension job. Passenger side is done, but the lower bolt for the driver side shock is not quite seized. I got the driver side spring out, and had the head of the shock bolt about 1/2” out before dinner last night, so I sprayed a bunch of PB blaster on it and called it a night. Hoping to go out and work on it for a bit shortly and really hoping that bolt comes loose today so I can take it for a drive And see if this was all a terrible idea.

The passenger side shock was rusted all to hell at the top of the cylinder, and that side was sitting a half inch lower than the other side. I’m sure the shocks being done was not helping my load handling.... then again my extra weight in the car probably didn’t do the shocks any favors.

The H&R lowering springs are the same 14” as the 5’s springs.
Nothing like Mazda's characteristic rust making these jobs a treat! Super interesting that the lowering spring for the CX7 and the 5's stock spring are the same. Really interested to hear your feedback!
 
:
2008 Mazda5 GT
Or make friends with a person who has a spring tool which measures the spring rate. Got a funny story from a guy on another forum with a new Mz3. Took his new red aftermarket springs and set them off in the corner while he was doing other stuff, then realized he’d put the red springs in with the red springs for three of his other cars and they all looked identical. He had to put them on his spring tool and check all the spring rates for comparison.
If you (or a friend) have a home gym with a few hundred lbs worth of weight, you can also do some simple measurements. Put the coil spring inside of the weight rack (rod or cable) for safety. Spring rate is measured as lb/in. Keep adding weights in 25, 50, 100 lb intervals, measure compressed spring and document. Good way to observer progressive vs linear springs. Be safe.

Vorshalg use to offer free OEM spring rate measurement. You'd need to mail in any OEM spring, they'll dyno and post the values on their site for reference but will throw away the spring. Their site has been updated so you can try to contact them.
 
:
2008 Mazda5 GT
Also I’m halfway through my suspension job. Passenger side is done, but the lower bolt for the driver side shock is not quite seized. I got the driver side spring out, and had the head of the shock bolt about 1/2” out before dinner last night, so I sprayed a bunch of PB blaster on it and called it a night. Hoping to go out and work on it for a bit shortly and really hoping that bolt comes loose today so I can take it for a drive And see if this was all a terrible idea.

The passenger side shock was rusted all to hell at the top of the cylinder, and that side was sitting a half inch lower than the other side. I’m sure the shocks being done was not helping my load handling.... then again my extra weight in the car probably didn’t do the shocks any favors.

The H&R lowering springs are the same 14” as the 5’s springs.
Looking at the H&R spring, I may have remembered the end coils wrong. That looks like 3" ID??? Can you confirm? Hard to tell by the pic. If so, look at eibach's catalog. They offer 3" ID springs at various rates and length.
 
Oh I know there's a big hit to the MPG, not just with the lift and bigger tires, but with the rack up there too. It's a compromise we're willing to make at this point. But I would've loved to do a before/after comparison. I'll see if I can sort out what sort of MPG it gets this month and compare to others' who are running a stock setup!
I'd be interested to see the numbers you come up with as I'll likely be taking a similar route modifying my 5.
 

icspots

Paramagic
:
2012 Mazda 5
Looking at the H&R spring, I may have remembered the end coils wrong. That looks like 3" ID??? Can you confirm? Hard to tell by the pic. If so, look at eibach's catalog. They offer 3" ID springs at various rates and length.
Noted. I’ll measure them the next time I’m out there. Had a delay on a seized bolt so it’s still up on stands. Both springs are in, though I should be able to get a measuring tape through the lower coils to check them out. Off the old Mark 1 eyeball they look nearly identical in ID diameter to the OEM. The coils looks maybe a little beefier.
 

icspots

Paramagic
:
2012 Mazda 5
Nothing like Mazda's characteristic rust making these jobs a treat! Super interesting that the lowering spring for the CX7 and the 5's stock spring are the same. Really interested to hear your feedback!
The springs are the same overall length, but you can see in the photo that the spacing is larger on the H&R spring on the lower section, so should have improved weight capability.

I remember one memorable brake job on my sister’s 5. Front axle done in 20 minutes. Rear axle one rotor took 45 minutes to get off. Finally gave it a smack with a 16lbs sledge hammer and it fell right off. Walked over to the other rear rotor, hefted the hammer and the rotor literally just fell off based on the threat.

Thus far every other bolt on this job has come off with a little applied leverage.
 
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icspots

Paramagic
:
2012 Mazda 5
If you (or a friend) have a home gym with a few hundred lbs worth of weight, you can also do some simple measurements. Put the coil spring inside of the weight rack (rod or cable) for safety. Spring rate is measured as lb/in. Keep adding weights in 25, 50, 100 lb intervals, measure compressed spring and document. Good way to observer progressive vs linear springs. Be safe.

Vorshalg use to offer free OEM spring rate measurement. You'd need to mail in any OEM spring, they'll dyno and post the values on their site for reference but will throw away the spring. Their site has been updated so you can try to contact them.
No home gym here, but there’s a pretty well stocked gym at my work (once I get off C-19 leave and can go back to work). Springs are already in the car, but I was kind of interested in putting defined weight in the back of the car and seeing how the suspension holds up.
 

icspots

Paramagic
:
2012 Mazda 5
Looking at the H&R spring, I may have remembered the end coils wrong. That looks like 3" ID??? Can you confirm? Hard to tell by the pic. If so, look at eibach's catalog. They offer 3" ID springs at various rates and length.
Okay, just went out to grab something and whipped out the tape measure. OEM 5 rear springs appear to be 3.25” ID. H&R 3.5” ID. Not sure if being partially compressed would make them open up an extra 0.25”, so I’d assume they’re a slightly larger ID.
 

icspots

Paramagic
:
2012 Mazda 5
To make this whole process more fun and potentially fraught with more rusted bolts, Assuming the lowering springs work out for me, my OEM springs may be going into my sister’s ‘08 model since the 2nd gen got better springs than the 1st gen. I think 1st gen may have been using Mz3 springs.
 

icspots

Paramagic
:
2012 Mazda 5
Job is done, wheels are on, and I’ve done my test drive. So far I can say I’m absolutely satisfied. I ended up searching online inventories yesterday and found a Lowe’s 25 miles away with a corded 1/2” 450lbs electric torque wrench in stock (and it came with impact sockets in the sizes I needed to boot!). Sadly I got home with that only to find someone did a bait and switch and returned the “impact wrench” with a cheaper standard drill in it’s place. All told that cost me two hours and 100 miles of driving out and back twice. Impact wrench broke the stuck bolt loose. I actually drove it back in a little bit (not all the way, I had a 1/2“ to play with) then was able to wire brush the end threads, lube it up and worry it in and out for about 10 minutes and got it out by hand. Then replaced the bolt cause I didn’t want to do that again.

I did a quick drive around the block without issues, then loaded in the kids and went for a longer drive which included bumps and twisty roads. Initial impression coming out of the driveway (which I did harder than normal intentionally) was it was rock solid without being uncomfortable. Going around the first 90 degree turn in my neighborhood it was immediately evident that all of the slop I noted in my pre-job test drive was gone. Body roll was significantly reduced, and the understeer feeling was non-existent.

Driving over some moderately large speed humps at speed the rear end compressed, bounced the kids a little in the third row, but it wasn’t uncomfortable or jarring at all. Only noise was from the stuff in the storage tray above the spare tire. Taking it through the twisties did two things. 1) it immediately made evident the struts also need to be replaced.... absolutely mushy by comparison. I don’t blame them, they have 91k miles on them. 2) it gave this car the closest it’s ever had to an ‘on the rails’ type feeling. There was a very minor bit of the oversteer feeling, but I can’t say that wasn’t just the outside front strut compressing too much. It didn’t drive like my old ‘05 3 did, but it wasn’t far off despite being significantly heavier and taller.

So measurements: Measured from lower edge of fender panel across the center of the wheel to the ground.
Before mods: 26.5” Left / 26” Right
On the wheels: 28” Left / 26.5” Right
trip around the block: 27” Left / 26.75” Right
Longer drive: 26.5” Left / 27.25” Right

I assume the initial on the wheels disparity is because the passenger spring had been installed and compressed in place (trailing arm still hanging free) for over a day and a half vs. the driver spring which was just bolted up last night. For the differences as we drove around I assume the shocks will take a little bit to settle fully. There was some general bouncy feeling while just driving around, so either the shocks need to settle more fully, or the OEM ride style KYB Excel G shocks aren’t up to fully dampening the springs. If it persists I may look at swapping in the stiffer KYB gas adjust shocks and see if that evens it out more ( I just reread where AnthonyVerde said he did that and it helped). If that happens then I’ll just move the Excels over to my sister’s 1st gen 5 along with my 2nd gen springs, so no real loss. (EDIT: chatted with some smart people who recommended not doing the gas adjust on progressive springs, only on linear ones)

With the caveat that I only have about 20-30 miles on them on one drive I’d currently recommend this set up to anyone else as an improvement.
 
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Job is done, wheels are on, and I’ve done my test drive. So far I can say I’m absolutely satisfied. I ended up searching online inventories yesterday and found a Lowe’s 25 miles away with a corded 1/2” 450lbs electric torque wrench in stock (and it came with impact sockets in the sizes I needed to boot!). Sadly I got home with that only to find someone did a bait and switch and returned the “impact wrench” with a cheaper standard drill in it’s place. All told that cost me two hours and 100 miles of driving out and back twice. Impact wrench broke the stuck bolt loose. I actually drove it back in a little bit (not all the way, I had a 1/2“ to play with) then was able to wire brush the end threads, lube it up and worry it in and out for about 10 minutes and got it out by hand. Then replaced the bolt cause I didn’t want to do that again.

I did a quick drive around the block without issues, then loaded in the kids and went for a longer drive which included bumps and twisty roads. Initial impression coming out of the driveway (which I did harder than normal intentionally) was it was rock solid without being uncomfortable. Going around the first 90 degree turn in my neighborhood it was immediately evident that all of the slop I noted in my pre-job test drive was gone. Body roll was significantly reduced, and the understeer feeling was non-existent.

Driving over some moderately large speed humps at speed the rear end compressed, bounced the kids a little in the third row, but it wasn’t uncomfortable or jarring at all. Only noise was from the stuff in the storage tray above the spare tire. Taking it through the twisties did two things. 1) it immediately made evident the struts also need to be replaced.... absolutely mushy by comparison. I don’t blame them, they have 91k miles on them. 2) it gave this car the closest it’s ever had to an ‘on the rails’ type feeling. There was a very minor bit of the oversteer feeling, but I can’t say that wasn’t just the outside front strut compressing too much. It didn’t drive like my old ‘05 3 did, but it wasn’t far off despite being significantly heavier and taller.

So measurements: Measured from lower edge of fender panel across the center of the wheel to the ground.
Before mods: 26.5” Left / 26” Right
On the wheels: 28” Left / 26.5” Right
trip around the block: 27” Left / 26.75” Right
Longer drive: 26.5” Left / 27.25” Right

I assume the initial on the wheels disparity is because the passenger spring had been installed and compressed in place (trailing arm still hanging free) for over a day and a half vs. the driver spring which was just bolted up last night. For the differences as we drove around I assume the springs will take a little bit to settle fully. There was some general bouncy feeling while just driving around, so either the springs need to settle more fully, or the OEM ride style KYB Excel G shocks aren’t up to fully dampening the springs. If it persists I may look at swapping in the stiffer KYB gas adjust shocks and see if that evens it out more ( I just reread where AnthonyVerde said he did that and it helped). If that happens then I’ll just move the Excels over to my sister’s 1st gen 5 along with my 2nd gen springs, so no real loss.

With the caveat that I only have about 20-30 miles on them on one drive I’d currently recommend this set up to anyone else as an improvement.
I am looking into doing the same upgrade on my M5. Where did you order your H&R springs? How do you like the set up now that you’ve had it for a little while?
 
And then I run across this. Closeout on H&R Sport Springs with a claimed 1.3” lowering on the CX7. $189. That’s more expensive than the helper air bags, but cheaper than new OE CX7 springs at $100/side, and potentially not as much of a height rise as the OE CX7 springs.

Thoughts?

View attachment 224632
Looks like a good option. Where did you purchase these springs? Thank you.
 

icspots

Paramagic
:
2012 Mazda 5
Looks like a good option. Where did you purchase these springs? Thank you.
I got mine from tire rack on a close out for $189 before shipping. I guess they were clearing old stock becuase they’re now $250 on tire rack. The set I got were the 29050.1 sport springs (for a 2012 CX7) if you want to search around other places.
 

icspots

Paramagic
:
2012 Mazda 5
Great, thank you! Did you put the springs on the front and back?
So far I’ve only done the rear springs and replaced the worn shocks. I haven’t gotten around to the front struts yet, and I’m still mulling over leaving it stock (with replaced struts). Based on the measurements posted in this thread (I think the beginning of page 2) the front CX7 springs may be 1-2“ taller than stock, so I might end up with more front end rise than I got in the back. Also possible the feel would compensate for that. So some things to confirm before I got that route. The biggest issue was the rear end sagging and more frequently hitting bumps, entrances, etc when weighed down with stuff and people.
 

phunky.buddha

Booga Booga?
:
DFW TX
:
No mo MZ5 want MX5
Like 150lbs on the roof itself... or using the mounting points?
I don't think it specified... but I assume that's through the mounting point since all models have them. The roof is kinda flexy, I definitely wouldn't put anything significant on it without the rack.
Or make friends with a person who has a spring tool which measures the spring rate. Got a funny story from a guy on another forum with a new Mz3. Took his new red aftermarket springs and set them off in the corner while he was doing other stuff, then realized he’d put the red springs in with the red springs for three of his other cars and they all looked identical. He had to put them on his spring tool and check all the spring rates for comparison.
Ha nice!
Vorshalg use to offer free OEM spring rate measurement. You'd need to mail in any OEM spring, they'll dyno and post the values on their site for reference but will throw away the spring. Their site has been updated so you can try to contact them.
I took mine to Vorshlag, they're local. Sad part is that I can't find the data for the rear springs, only the fronts- and I'm not sure if they're mixed up with the Nissan Frontier springs I took in at the same time. I'll try and decipher the scribble from that measurement session, but I'm not optimistic.
Okay, just went out to grab something and whipped out the tape measure. OEM 5 rear springs appear to be 3.25” ID. H&R 3.5” ID. Not sure if being partially compressed would make them open up an extra 0.25”, so I’d assume they’re a slightly larger ID.
Depending on the design, springs can be designed to expand as they compress. Not sure if the 5 springs do that, but I don't think so.
So far I’ve only done the rear springs and replaced the worn shocks. I haven’t gotten around to the front struts yet, and I’m still mulling over leaving it stock (with replaced struts). Based on the measurements posted in this thread (I think the beginning of page 2) the front CX7 springs may be 1-2“ taller than stock, so I might end up with more front end rise than I got in the back. Also possible the feel would compensate for that. So some things to confirm before I got that route. The biggest issue was the rear end sagging and more frequently hitting bumps, entrances, etc when weighed down with stuff and people.
I'd honestly keep the fronts factory. Most of your loading will be in the rear anyway, plus increasing front rate will bring that understeer back. Stiffer rear = more turning fun. Also, when you're looking for replacement shocks for the rear, see if you can find something with more compression and rebound damping capability. Since you're running higher rates, you need a higher capability shock to keep the movement under control. That'll bounce your kids around in the third row if your springs overpower your shocks on the rebound, good shocks or not. Stuff meant for the Mazdapseed 3 fits in the same space, so that might be a good place to start. When I was looking, a few of the bigger mainline shock companies distinguished between MS3 and MZ3 shock applications, but most do not- of course MS3/MZ5 applications would be designed for higher loads and spring rates.
 

icspots

Paramagic
:
2012 Mazda 5
Like I said, I’m mulling it over. I still haven’t ordered the new struts yet. To be clear I’ve never really had interest in making handling improvements to the car.... of course at the time I still had my 3 to go play around in. The spring replacement just started as a way to get better support in the rear for weight. Doesn’t mean I don’t appreciate it having less body roll. I realize the sway bar would be the way to go if that was the intention of the mods, but what I got is side effect.

The understeer comment was a mis-type. It was actually giving a little oversteer, however I think that was due to the struts being toast and overcompressing on the outside corner. It was less with the rear shocks replaced because the rear end was floating around as much, but there’s still a bit there.
 

icspots

Paramagic
:
2012 Mazda 5
Small update. New KYB struts and mounts arrived yesterday and today. Out of curiosity and was dry fitting the H&R springs on the strut. Looked good to go. Then dry fit the mount on the spring..... problems. The OE springs (as pictured in page 2 of this thread) Have a tighter 4.5” diameter on the top coil. The H&R springs are a continuous diameter all the way through. The result is the entire strut mount (minus the top plate) sits inside the spring, and there’s nothing for the spring to push against. There are H&R springs for the 5 which would mate with the strut mount, but they’d be lowering springs.

If anyone has a friend with a license for ordering random springs from a manufacturer we could see if there’s a progressive H&R spring which would fit the car but keep the same ride height designed for another vehicle. They won’t sell individual springs direct to consumer, so you’d need a retailer, or someone with a license for it (Track mechanic, auto cross, etc.). Does make me wonder if it would be worth finding that information out for anyone wanting to buy just the rear springs..... I mean what the heck am I going to do with these two front springs?

But what that means is I’ll be sticking with the OE springs on the front struts. My spring compressors should be arriving in the next couple of days, then I just need to have work time to get them done.
 
:
2008 Mazda5 GT
Small update. New KYB struts and mounts arrived yesterday and today. Out of curiosity and was dry fitting the H&R springs on the strut. Looked good to go. Then dry fit the mount on the spring..... problems. The OE springs (as pictured in page 2 of this thread) Have a tighter 4.5” diameter on the top coil. The H&R springs are a continuous diameter all the way through. The result is the entire strut mount (minus the top plate) sits inside the spring, and there’s nothing for the spring to push against. There are H&R springs for the 5 which would mate with the strut mount, but they’d be lowering springs.

If anyone has a friend with a license for ordering random springs from a manufacturer we could see if there’s a progressive H&R spring which would fit the car but keep the same ride height designed for another vehicle. They won’t sell individual springs direct to consumer, so you’d need a retailer, or someone with a license for it (Track mechanic, auto cross, etc.). Does make me wonder if it would be worth finding that information out for anyone wanting to buy just the rear springs..... I mean what the heck am I going to do with these two front springs?

But what that means is I’ll be sticking with the OE springs on the front struts. My spring compressors should be arriving in the next couple of days, then I just need to have work time to get them done.
The spring barrel (Y, S, straight) has not bearing on fitment. This typically affects the progressive/linear behavior of the spring. Btw, you are only measuring I.D. on the top and bottom most coils only, correct?

That said, if the top coil is too wide to fit the Mazda 5 top mount, I'd think the solution could be as simple as getting matching CX7 top mounts. Look at some parts diagram to get a quick visual confirmation. The top mount consists of bearings+isolator fitted inside of a hard mount housings. This part 'should' be interchangeable b/c the top mount only uses the shock piston nut to secure the spring; the top housing mounts the whole assembly to the chassis. What needs to be confirmed is if the Cx7 top mounts aligns with the 3 holes on the Mazda 5 chassis, which I'm betting it will.
 
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