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Experiment: replacing lower control arm bushings with spherical bearings

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33K views 30 replies 12 participants last post by  eq1  
#1 · (Edited)
I hired a machine shop called Kingpin Machine to replace the rubber bushings in a set of G1 Insight lower control arms with spherical bearings. There are some photos of the work in progress here:

https://www.facebook.com/KingpinMachine/photos_stream

The compliance bushings (big donut of rubber that allows the lower control arm to pivot) are tearing on my car and I was curious how much improvement in steering accuracy/feel could be gained vs. the expense of additional vibration and harshness.

So I ordered a set of spares from a wrecking yard, had them shipped to Kingpin (in September 2013) and hope to have them back soon. Only downside is he wasn't able to replace the ball joints so hopefully they're good enough.

It'll probably be a while until these are mounted on my car but thought I'd share a progress update nonetheless.

Joel
 
#2 ·
Sounds interesting. Not sure what all those arms are though in the pictures - they don't look like the insight control arm...

In general I'm kind of interested in 'tightening up' the suspension too, like doing something with the front control arms and maybe even a rear sway bar. But everything seems to take too much time and money... Bearings in the front control arms seems like they'd be pretty harsh... Keep us posted...
 
#3 ·
Make sure the spherical bearings are easy to replace. I have a couple on the front of my integra DC2, I run 'traction bars' from the lower control arms where the shocks mount that attach to a new crossmember at the front between the chassis rails. This is to prevent the controll arms pulling forward under acceleration and back when braking. The bearings last about 18 months before the start to knock. This is what I'm taking about, and the EP civic 'traction balls' is pretty much what you are doing:

Traction Bars - Full-Race.com
 
#4 ·
Thanks for doing this. I am also interested in doing this. I was going to measure it and see if any of the newer civic or even the dc5/ep3 kits they have would fit. I'm assuming that Kingpin is taking that long because it is custom? I have a feeling that it would help keep my car "planted" better when I accelerate. My car is all over the road when I punch it.
 
#5 ·
eq1: the pictures show the bearings before installation into the Insight control arms.

Puggie: I'll be sure to ask about the replacement procedure. This will be my very first foray into owning a car with spherical bearings in the suspension.

dkim48: Yes, the job was totally custom and required fitting the work in between other jobs that were more worth his time. The bright side, the way I look at it at least, is that for a completely custom one-off, my total cost is less than $600. We haven't discussed what the cost would be for additional parts but I'm sure he'd love to earn back some of the R&D he isn't charging me for.
 
#6 ·
I tried posting photos of the finished arms from my phone but it kept overwriting the files. Maybe because they have the same name? Regardless, the Facebook link shows the final product. When I get on my computer, I'll upload pics directly as well.

Joel
 

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#7 ·
Very interesting experiment.

Good luck.

They look nice and those are the bushes that normally produce the classic low speed squeaking sound and require lubricating in most Insights.

I expect noise will be transmitted to the chassis and it will be interesting to see how long they last.

Thanks for being a guinea pig.

I wish a few others would do the same with the ideas they have.
 
#8 ·
Puggie: I heard back about the replacement procedure: "To be honest, the bearings are a pain in the *** to replace. The reason why is I use Loctite 609 to retain the bearings in the sleeves and so they have to be heated and pressed to compromise the Loctite. But I believe that trusting just interference/c-clip to retain the bearings is unsafe. Essentially everyone out there uses cheap bearings and does a poor job of sizing the bearings to the sleeves. I don't think your bearings will wear out that quickly unless you put an *** load of miles on the car. But sphericals are not a great idea on a street car as I told you from the beginning! :) But still, I will be very surprised if they are worn out in 18 months."
 
#11 ·
UPDATE: I got the control arms installed today. I've only driven a couple of miles but initial feedback is that yes, you hear and feel more road vibrations. But, in the couple of miles of driving, it didn't feel too bad and I think I'll get into being able to feel the road more. For those keeping score, yes, this makes the Insight more Lotus-like :)

A tip for those of you, like me, who didn't know this trick to remove ball joints without a special tool:

On the Insight, I wedged a 3/8" Craftsman ratchet handle, the wide way, between the control arm and the knuckle, dropped the wheel w/the jack suddenly and the trick worked two out of three tries total for both sides. It is quite an impressive trick to see & hear--POP goes the ball joint. :)

The quality of workmanship on the spherical bearings conversion is excellent and everything fit perfectly. I think this is impressive considering the machine shop didn't have access to the car to take any measurements or check anything--they just took a pair of wrecking yard-sourced lower control arms and converted them for me.

If interested in a set for yourself: Kingpin Machine | Designer, manufacturer and retailer of uncompromising components for road race cars.

I'll provide an update after logging a few more miles.
 

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#13 ·
Marvellous. I will shortly have a spare set of arms. Once I've sorted the PU bush conversion I may look at doing a spherical bushed set out of curiosity.

Am I right in thinking your bushed are a press fit into sleeves that are pressed into the arms? No circlios used?

Have you considered using the spherical bearing boots you an get?



Sent from AutoGuide.com Free App
 
#14 ·
It's brilliant and left field idea to try but I can't believe the noise/vibration will be tolerable.

Our roads are pretty bad over here, good luck. Keep us posted.

Perhaps for a track car :?
 
#15 ·
On my commute to work today I observed some interesting things. Under most circumstances, including little bumps, seams, imperfections, etc. you feel...the road, which I really like. However, on certain surfaces with what I'm guessing is a regular pattern of little undulations caused by certain paving processes,there's a pretty annoying "drone" that's very directly and somewhat unpleasantly transmitted through the steering and can be heard. It's enough to be a real turn off I'm sure for some (not sure yet if that includes me).

From the sounds of it, the mod to eliminate the power steering & related drive gearing plus new OEM lower control arms might give a better increase in road feel while keeping NVH at stock levels. Dunno, I plan on doing that mod soon as well.

I have a lot of respect for the NVH engineers who strike the balance between feel, handling & comfort.
 
#16 ·
I put spherical bearings on my Omni with great results. When driving over railroad tracks the car would be pointing in a different direction, after the bearings it was night and day, true tracking and the car has a smoother ride, just the opposite of what you would expect. The Insight arms are significantly different but I would still pursue the mod. Pics are of the Omni.

Image
Image
 
#17 ·
@Fishcleaner: Those arms look nice!

Another Update: I've figured out one pattern related to the additional NVH from the spherical bearings--often when you accelerate, you get a persistent vibration. Once you reduce throttle, coast or decelerate, the vibration goes away. Considering that minor annoyance, I think the additional road feel and more precise sense of control offered by the spherical bearings are a net plus. I've found it isn't at all harsh under a pretty wide variety of surface imperfections and I'm enjoying the driving experience more than I did before the install. Combined w/the rear sway bar, I actually look forward to carving corners, roundabouts, on-ramps, etc. these days. For still rockin' the RE92's, I think that's saying something. :)
 
#18 ·
I am surprised this is coming out as positive.

I installed poly bushings in my corvette Z06 a few years ago, and the improvement was not worth the maintenance over O&M bushings (for the average joe).

Going to spherical bearings in a car that already is limited in noise mitigation... you are my hero man..

I wanted to do sphericals in the Vette, but it was pricey..

In hindsight, Sphericals in the Vette would have been much less maintenance (and pain in the butt) than those poly bushings.
Note to self: ALWAYS put in grease zerks regardless of what the poly bushing vendor says about graphite impregnated and not needing grease zerks...

It is a major job swapping out bushings.. so great effort dude!
 
#20 ·
UPDATE: It's been about 2 weeks w/the arms on the car. I've got a pretty good feel now for when/how the vibration happens. It seems to start at 2000-2200 RPM and smooths out about 2700 RPM when you're on the throttle. Unfortunately, this is the sweet spot in the RPM range for cruising around so I'd definitely caution anyone thinking about doing the mod if the buzzing vibration would bother you (it bothers me somewhat). When it's not buzzing within this RPM range, the mod has benefits that I really, really like. The accuracy of the steering inputs, the increased precision of how the car tracks on the road, the feedback from the road that lets you feel what's going on, etc. are all great.

Now that I understand the vibration is engine RPM dependent, it's got me thinking that the rubber in the OEM mounts serves a dual purpose--to isolate road vibrations from the chassis AND to isolate engine vibrations from the chassis. I'm assuming that the engine vibration is transmitted along the drive shaft to the hub/knuckle, through the balljoint (which is OEM in my case), along the lower controls arms and into the chassis via the new spherical bearings. I *never* considered the control arms as part of the engine vibration isolation system. I do know that most/all attempts to stiffen the OEM engine/transmission mounts have led to rather alarming increases in vibration due to the inherently un-smooth 3-cyl engine. I guess the Insight is particularly sensitive in this regard and it makes me wonder if other 3-cyl cars like the Geo Metro are as well?
 
#23 · (Edited)
UPDATE: It's been about 2 weeks w/the arms on the car. I've got a pretty good feel now for when/how the vibration happens. It seems to start at 2000-2200 RPM and smooths out about 2700 RPM when you're on the throttle....
I wonder if this might help: buy an inexpensive Civic bump stop - a durable 'multi-cellular urethane' foam rubber material - slice it into several washer-sized pieces (maybe ~1/4" thick), and then insert those washers at the metal to metal junctures on the control arms, I'm thinking mainly on the rear mount location... Maybe try an "SB108" bump stop, I think you get 2 for like $12 at Amazon. The hole in the middle of the bump stop is the size of the shock rod, so like 12mm, or maybe 14mm, probably just about right to fit the control arm bolts through it... The SB108 would probably be better than the Civic because it's more or less a perfect cylinder shape, whereas the Civic stop tapers. You could make more washers from the Sb108s, all about the same size. I'm guessing you'll need about 4 per side...

Here's a link: [ame]http://www.amazon.com/KYB-SB108-Strut-Boot/dp/B000COBXBE/ref=sr_1_1?ie=UTF8&qid=1397889839&sr=8-1&keywords=sb+108+bump+stop[/ame]

$14 for 2.
 
#22 ·
Nice theory. To your question, yes it's the rpm regardless of the gear.
 
#24 ·
I feel it's time for an update on this experiment. Crazy as it may sound, I feel like the vibration has gotten better and/or I've gotten used to it. The particularly curious thing is I think I felt a big drop in vibration after cleaning my EGR plate. I'm not sure of the exact behavior of the EGR valve but in general I believe they close under a certain amount of load/vacuum drop but I suspect at part throttle cruise in the 2000-2700 rpm range the plugged EGR system was causing mild bucking/vibration that was much more noticeable w/the spherical bearing arms. Now with a clear EGR, the engine runs smoother and I often forget there ever was a pesky amount of vibration.

So, call me satisfied with the vibration level and very happy with the crisp, directness offered by the spherical bearings. That said, I think new OEM arms would still be the best option for most folks.

Joel
 
#25 ·
Pretty sure I wouldn't mind this. How much would they charge to duplicate? :D
 
#26 ·
$220 for the inner pivots and $260 for the compliance bearings. (I'm assuming per-pair)

Eli, my plan is to wait until my GAZ struts are installed, see if I'm happy with the overall handling of my Insight and if so, buy a nice fresh battery from you. :) If not, the plan is to bail on the Insight and drive something I enjoy more that's still economical. Based on the success of the rear sway bar prototype & other suspension mods, I'm pretty confident I'll be calling you within a couple of months.

Joel
 
#27 ·
Spherical noise

My Lotus 7 replica has a 4 link rear axle setup with a panhard rod. The rear links are all Rose spherical bearings. The sheet metal at the back of the car drums/vibrates at about 3000 rpm very badly. The engine is solid mounted to the chassis and is probably running at a resonance point of the rear sheet metal but I'm pretty sure the spherical rose joints are getting into the act because nothing vibrates anywhere else on the car.

Luckily the engine doesn't have much torque at that low an rpm so I just consider it lugging the engine and start downshifting.

And yes you hear all the noises the rear axle makes when you let off or give the car some throttle. The car is very harsh riding and you feel every pebble on the road. But that's what you get for driving a 1000 lb race car on the street.
 
#28 ·
@olrowdy01--that sounds pretty extreme, and very fun! My Insight is much, much more tame it sounds like in terms of vibration. In my case, it's more of a nuisance in contrast to OEM NVH levels and only within a narrow RPM band in proportion to engine load (yes, you can scale the "volume" of the vibration with your right foot.). The rest of the time, the car just feels more crisp and less affected by road imperfections that I guess cause the OEM rubber bushings to deflect and allow for non-idea alignment conditions and thus more squirming around mid-corner, especially if you hit a bump.

I'm pretty curious how wiggly my rear axle beam mounts are @160k miles? Lower on my todo list is to convert to VW bushings as I've seen described by our friend in Russia on this board (name escapes me).