I'm doing front end work and rear end work.
I'm installing eibach sportline springs and Bistein struts on my 89 IROC-Z. Not to mention Steering componets from Lower ball joint to lower ball joint with Napa's NCP series componets. ES poly bushings.

I havn't pulled it apart yet but was wondering if anyone has fab'd thier own Strut mounts. . They don't look that difficult. But, I think 350 bux for simple shape metal is a little much.

I've read for 6 hours on searches. It is hard to follow these threads. People start off good and go on to other things in the middle of the topic. So I started off thinking about the idea only to relize the conversation when totaly out the door.

My questions are......
1) What type of bearing do I get...?? I'm thinking dual cone to withstand both directions of force.
2) What force will be applied that the bearing will need to withstand...?? Strut motion and spring pressure...??
3) Inner diam is easy......Measure strut...!!! But outer diam...???
Should it be as big as I can get. Thus spreading forces more...??
4) Is it really cost effective...?? I think bearing will be most of cost. Metal is cheap.

Or maybe i'm just thinking to much about it........
If i've missed a link please shoot it at me please....!!!!

 

Where did you get that figure?

Spohn sells stock style replacements for less than half of that.

Ground control sells one that goes in a modified stock housing for a little over $200.

Check with a local parts store for price of stock replacement.

Are you looking for stock or better than stock?

 

[QUOTE]Originally posted by Lo-tec
[B]Where did you get that figure?

Spohn sells stock style replacements for less than half of that.

Ground control sells one that goes in a modified stock housing for a little over $200.

Here is what I looked at
http://www.hawksthirdgenparts.com/in...?v=1&pid=11391

I have spent all my extra play money and it will take some time to get $200 for a good set of mounts. I want a better than stock. As you see the springs and struts i'm installing.

Depending on the bearing price I can make my own I'm thinking for less than 20 in metal.

 

https://www.thirdgen.org/techbb2/sho...hreadid=274414

I would try and copy these from ground control...reuse stock mount housing and make the alum. housing for bearing. I believe it is 2 bearings in one, a spherical bearing in the center surrounded by roller bearing on the outside. I would check ground control's website for their description.

 

I read thru your other thread...
It looks like you have to do a lot of mod'n to get those to fit. Including cutting the Strut tower. This doesn't sound like a good idea to me.
Why would they offset like that...?? The OEM mounts are centered. Wouldn't that toss the alignment way of of whack... And looking at the plate installed your at your limits and it hangs over the edge. I think its a good idea what they have but, perhaps centering is the key. I will post whatever idea I come up with.

 

The reason for the offset is to increase the range of camber and caster for alignment. On earlier cars like mine, max caster is around 3 degrees and max camber is a little over 1 degree. I'm trying to get around 5 to 6 degrees of caster. I think the roadrace guys use these to crank up the camber. The only way to accomplish this is either slot the tower (and relocate lip because of strut interference), remove and relocate strut tower, or an offset mount. All three require grinding and welding. I haven't done an FEA yet, but am hoping to this week and will post increase in alignment when done.

 

So this would help your driving/touring but, eat the crap out of your tires....??
Mine is going to be a daily driver.
I'm a noob when it comes to suspension work. I havn't done much but shocks in the past. But, I read aaaaaaalot and learn fast. I'm just going for something I can corner desent on and feel safe when over the 130mph mark. The local parts store sells OEM replacements for $85 bux eachz(Gabriel). I don't know the quality of these. I will do a search on here later when I get some study time. I'm sure I can find something on them.

Mainly what i'm looking for is information on the pressure that this new suspension will inflict on these strut mounts. Then I can design something around that number. May be cheaper and less headache to just buy some. I don't think these companies that make aftermarked strut mounts are going to give me any information that would be a loss of sell to them. Eibach will not give any info on there springs. I havn't tried bilstien yet.

 

Heh, I wish I had pics of what I did with my 83… I moved the top of the tower and when checked on an alignment machine I could get a little more then 7.5* caster and 2.5* camber on both sides, the thing looked stock, and everything cleared, no hassles with the dust boot…

If I was to do it again, it would actually be easier to just cut the center section out of the top of the strut tower, trim some off of the back and inside of the cutout and reweld it with spacers. Grind it flat, add a little paint and again, every one will think it was built that way. If you’re at all decent with a welder it will cost you nothing to do and would only take an hour or 2.

I guess you don’t end up with the trick looking strut bearing mounts… boo hoo…

 

Okay I did some research at the local autozone.......
The Gabriel Strut mounts that they sell OEM style for $85 bux.
They have a NACHI bearing.....they have a nice website thou...
The bearing Specs are as follows....
-Cylindrical Roller Bearings
-17mm ID
-40mm OD
-12mm Bore
It has a static load of 7950N which is about 1800 lbs of force
It has a Dynamic Load of 12600N = 2800lbs of force....

This to me sounds like poopie....!!!!!

I would like to know what kind of bearings Sophn and Ground Control use in there mounts...??

What does everybody else think of these numbers....???

 

The numbers look fine to me… I don’t know what this incredible amount of force is that everyone seems to think that these things are under, but I’d bet that 90% of the time it doesn’t exceed a few hundred lbs.

Based on those dimensions, if I was building my own I’d probably just use a good size uniball with a 5/8” shaft opening. You could probably just build it out of 2 plates, a bottom plate cut in the pattern for the stock mount, and a smaller top plate that sandwitches the uinball in place. I’d bet that 3/8” aluminum (maybe ½” to be safe) and 3/8” bolts to hold the 2 plates together would be plenty, it wouldn’t even require any fancy machining, just 3 slots and 5 holes….

 

Not if the alignment is right. I've been running 1 deg neg camber for the last 10 or 12 years without tearing up the tires. An increase in caster is all I'm after and that will not cause any extra wear. A little more camber probably would, but not caster. The increase in handling and steering feel from a good FEA to similar specs as mine as compared to stock will make a big difference. When I first had it done I couldn't believe how much better the car turned as well as high speed stability.

As far as the load goes, I don't think it is too high either. I just pulled out the original mounts from my car (178K miles) and still intact. The rubber biscuit that holds the bearing in them is what causes them to flex under load. The only loads imparted on them are up/down over bumps and sideways when turning...they don't hold up the car but merely locate the strut for alignment.

 

That's what I was thinking... our springs are taking the most force, the strut is just dampening everything.

I can compress a strut by hand, but I can't compress a front spring by hand!

 

When you had your FEA done you had them -1 deg on camber. What differences did you notice. Or was it just the FEA all togeather...?? What advantages are there from caster adjustmnets...??

So there is a rubber biscuit that holds the bearing in on the OEM Mount. I have 150k on mine and I havn't taken it apart yet. I don't like her being out of commission very long so i'm trying to do homework before I put her down. I guess you can't buy just the rubber if its worn..??

I guess I can pull the cap off the mount and move car up/down to see if there is any play. I would jus t hate to spend that much money and time on something and find out a "bad rubber" will give her the shakes... no punn....

U guys are right too.... The strut should not put that much force on the bearing anyway... I was way overthinking it..

Thanks for tolerating a front end noob.....

 

The FEA as a whole made a big difference. I don't even know what the stock specs are, and you won't know how bad yours is until you get it on an alignment rack. The extra camber is kind of a bandaid due to the strut design of the front end with only a single lower control arm. The extra caster helps it turn better. I am in no way a suspension expert and if you search a little I'm sure you'll find different people running different settings.

However, when I had mine done I was shocked at how much better my car handled.

I would check the strut mounts by removing the cap and bouncing the car..I just now put the ground control ones on. I've been running the stock ones for the last 12 years.

 

A majority of that force is take by the mount in rebound, in compression, yes the spring takes it. The rebound foces are where all the force is at.

Try to pull up on a compressed strut VERY fast. there is enough dampening to control the rebound of a 800#/in spring that is compressed a couple of inches, that is a significant amout of force.

 

Just to expand on the whole "spring force vs strut force" thing... The point of the spring is to absorb the energy as the wheel hits a bump, while the point of the strut (shock) is to control the motion (response) of the wheel. If you've got 800 lb springs up front, hit a dip, and compress 3", you've now got an extra 2400 lbs force stored in the springs. The strut resists this force on rebound (but not 2400 lbs at once, since it's over the rebound time). It also resists the instant wheel movement when you hit a sharp bump like a pavement crack, a curb on the racetrack, etc, which has much higher forces for such a small change. Since we're not riding in a caddy highway cruiser couch, those sharp little bumps happen so fast, that the shock will not absorb it all, and transfers that right to the car (through the strut mount), at thousands of lbs force.

Below is a shock dyno curve, w/ force plotted (from one of the corner carver folks at: http://corner-carvers.com/forums/sho...ock+dyno+graph



I've got the Ground Control strut mounts, and it's a single spherical bearing captured between the two billet alum plates.

 

Andre,

Thanks for the link. I had seen that on c-c before.

I was just making a point, that there is quite a significat amount of force there, I was just trying to point even with the design of our suspension, the strut mounts do take a beating.

 

Somewhere between -.7 and -1.4 usually results in the best tire wear (depending on how hard you drive your car). Something in the -1 and greater range will eliminate much of the understeer built into these things from the factory, and should still be flat enough not to hurt braking.

Hey andris, do you have a pic of your GC ones? Sounds a lot like what I was trying to describe….

 

Well I was wrong........ I called NACHI and he faxed me the specs on the bearing...
Dynamic Load of 9550N
Static Load of 4800N
Even worse that what I thought first time........

The strut mounts do take a beating.... So this is important if I wan't my car to last a while.
So what if I drill out the ribbets on the oem houseing and replace the bushing and bearing myself....???
Is it possible..... I can get a bearing but, can we get the bushing...??

I'm just trying to get the best for a buck....

Thanks again guys for all your input...!!!!

 

The bearing is molded in to the rubber bushing. You would have to find it as an assembly. It will come out, but I don't know if you can just replace that. You would have to weld it all back together when done. That seems like a lot of work if all you're looking at when done is ending up with a stock replacement that you could purchase outright.

 

Any this is why I tell people I will never us aluminum bearing mounts with coil overs.

 

I'm not sayin I don't believe ya... But, look at these pictures I took and tell me what kind of bushing is molded in there. I don't see any room.

If the width of the bearing is 40mm and the thickness of the metal is 2mm then It leaves about .5mm of space for a bushing....

If you have taken yours apart please toss up some pics so I pick up what your throwing down please..

I think I can grind the pins and drive them out. Those pins are a dime a dozenl. I would have to re-tack weld them in there.

I just find it hard to believe that a stock replacement is $85 bux each. You can buy the bearings for $10 bux each( and better than what comes in a stock replacement). This seems like a no brainer unless your mount is all rusted out.

 

another pic of bearing width

 

The whole thing in your picture is the bushing, not just the center. The rubber biscuit the bearing is riveted into would be what is really worn out, not the bearing. When you drill apart the outer case, what is in the middle comes out as an assembly. Second pic in this post shows the inside after being drilled apart.

https://www.thirdgen.org/techbb2/sho...hreadid=274414

The stock bushing/bearing assembly pretty much fills the entire hole.