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Offset bushing and wheel fitment discussions
Originally Posted by hornetball
(Post 1208589)
My car could certainly use more camber (maxxed out with ~2.5 up front).
Mazda offset bushings The prices listed are the racer discount prices. |
Yeah, I heard that rule was changing. These look like the ISC pieces. I know they work with 15x7, not sure about 15x9. I've got a Mazdaspeed account now courtesy of NASA TT.
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Originally Posted by hornetball
(Post 1209518)
Yeah, I heard that rule was changing. These look like the ISC pieces. I know they work with 15x7, not sure about 15x9. I've got a Mazdaspeed account now courtesy of NASA TT.
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Well . . . dang it . . . hurry up! LOL.
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Originally Posted by emilio700
(Post 1209625)
We tried a set of the ISC's a long time ago with 9's. They do not play well together. So we made our own acetal lower offsets. This (complete acetal kit) is one of the many projects on my list.
Could you elaborate on the clearance issues you ran into with ISCs and 9s? would spacers help? I was about to embark down this path based on another thread on M.net, but it sounds like you have better intel. |
Originally Posted by OneTwo
(Post 1209664)
Emilio,
Could you elaborate on the clearance issues you ran into with ISCs and 9s? would spacers help? I was about to embark down this path based on another thread on M.net, but it sounds like you have better intel. Spacers help tire clearance but create their own problems with wheel rate, instant centers, ackerman. I try to stay away from spacers whenever possible. |
Gotcha.
I'm building up an NB sub frame off the car so I couldn't really mock it up to look. I'm already running your 11.75" fronts with the spacer you provide so I thought I would ask. Thanks! |
If you have an NB subframe, you may not have this problem in the first place. NA subframes are usually the ones that give camber limitations.
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NB's also
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John what do you mean?
I just bought a set of ISC's through a group buy, but I'll be running 9's. Shall I sell them to someone running 8's? |
I meant that NB subframes are limited also. ALL of this depends on ride height also. I had 3.5* neg up front with no offset bushings at 3.75" pinch weld height and you could not have ran offset bshgs in the uppers with 9's as the 9's were rubbing a little without offset bshgs. I have sense raised the ride height 1" [12" frt, 12.25" rr don't know the pinch weld measurement] for this season with the new shocks. I am running these bshgs in the front lower arms fore and aft and am running 10" wheels and 245 tires with no issues. I would not want the offset bushings in the upper arms as having them in the lowers still tilt the upper tire closer to the tower but not as much as upper offset well. Its the first 2 listings as the 3rd is uppers. SuperPro control arm bushings - MiataRoadster - High-performance customer service...and parts for Roadsters
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NB on an NB subframe here. I had/still have camber issues. Initially I had something bent as my camber & caster were very low on one side (<2* camber and <4* max caster at 4.75"-5" ride height).
I swapped stuff, including the subframe from another NB, that fixed both. now i can get gobs of caster (6.5* or 7*?, been a while) and about 2.8* camber on one side and 3.2* on the other (~4.3" ride height). |
Originally Posted by jmann
(Post 1209724)
Its the first 2 listings as the 3rd is uppers. SuperPro control arm bushings - MiataRoadster - High-performance customer service...and parts for Roadsters
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Originally Posted by hornetball
(Post 1209747)
Details on your install? How are you keeping the inner sleeve from rotating? Did you pin it somehow?
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They are installed with the offset to the inside [3 o'clock position] and have had no issues at all with them trying to move as the strain on them is straight on. I can see if they were installed with the offset in any other position they might be wanting to turn. They have been on for numerous track days and rode hard.
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Hornetball I reread your question and the inner sleeve is meant to turn inside the bushing, that is why there is teeth on the ends. These aren't meant to work like a stock bshg. You grease the inner sleeve with supplied lube. How long it stays lubed is another question?, but as my car is not driven on the street think it should be a non issue for quite awhile.
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I might also add that the rear bshg isn't really needed unless you are tinkering with caster. As for camber it only gains you about .2* to .3* .
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Originally Posted by turbofan
(Post 1209709)
John what do you mean?
I just bought a set of ISC's through a group buy, but I'll be running 9's. Shall I sell them to someone running 8's? |
Yup. I was peer pressured, Didn't even want them.
Oh well. Edit: then I realize that you mean I should sell them to you. Sure thing if you want them. |
Eh, maybe at some point. get your car up and running and see if you need em, then talk to me.
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Yeah, get a job and then talk to me.
:giggle: |
Ed Talk to Eddie at AR there in Portland and get some of the ones I linked. He can explain it better maybe then I did. The idea behind the urethane or delrin bushings are not only to harden up the suspension but to remove the increased spring rate that stock bushings cause. The rubber on stock bushings is molded to the inner and outer sleeves and the inner bushing has teeth on their ends that the big washers clamp onto and when the inner sleeve is moved with up and down motion in the arm they twist the rubber which increases spring rates.
Some want the spring rate to be more true to the rate of the springs and the suspension arms to be free moving. With the urathane and delrin setups the inner sleeve is lubed so it rotates inside the bshg.Unfortunately either system works only as long as the lube is kept in working order. Some have tried zerk fittings and other means with iffy success. The best setup is heim joints and there are some people working on making arms that way. But as for getting more neg. camber the bshgs from MR well work just fine. Call Eddie. |
The group buy was set up by Greddygalant, an employee at AR, and who talks to Eddie about all that stuff. The sperical bushing thread that was around lately has a lot of good info in it too.
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I know Martin very well.
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Indeed you do :) I don't know the setup I'll finalize on. But I'm going to go ahead and begin installing poly bushings in the rest of the car over the next few weeks while my car is at the body shop, then full subframe swap.
ANYWAY... RC1's, anyone? |
Originally Posted by jmann
(Post 1209828)
Ed Talk to Eddie at ADR there in Portland and get some of the ones I linked. He can explain it better maybe then I did. The idea behind the urethane or delrin bushings are not only to harden up the suspension but to remove the increased spring rate that stock bushings cause. The rubber on stock bushings is molded to the inner and outer sleeves and the inner bushing has teeth on their ends that the big washers clamp onto and when the inner sleeve is moved with up and down motion in the arm they twist the rubber which increases spring rates.
Some want the spring rate to be more true to the rate of the springs and the suspension arms to be free moving. With the urathane and delrin setups the inner sleeve is lubed so it rotates inside the bshg.Unfortunately either system works only as long as the lube is kept in working order. Some have tried zerk fittings and other means with iffy success. The best setup is heim joints and there are some people working on making arms that way. But as for getting more neg. camber the bshgs from MR well work just fine. Call Eddie. Either you are missing words or you are wrong on a lot of this stuff. I think you mean to say is poly bushing's "spring rate" is higher than a rubber bushing's. If that is the case, then please make sure you clarify, because right now, you are implying that rubber bushings increase the "spring rate" of the car over a solid bushing. This is just not true, a solid bushing has a "spring rate" also, its just extremely high in comparison. This means the deflection in the bushing is reduced, allowing those forces it to go through your shock+spring, vs. being absorbed in the rubber bushing. I think maybe what you meant to say is rubber bushings have increased displacement, when compared to urethane/solid bushings. |
Sorry Joe, John is right.
The rubber bushings bind and make it so the control arms take effort to move. Take your shocks off and try to move your control arms with the stock bushing. You'll notice that they take a lot of effort still to move them up and down and they spring back into place when you let go. With a lubricated poly bushing, the bushing does not affect the movement of the control arms, allowing more precise control of spring rates. This is what john is saying. |
Yet it has been proven and discussed that the lubrication necessary for poly bushings to stay like that is not an easy thing to accomplish. Bundy talked about the grease never lasting, or burning up. Delrin supposedly doesn't need grease, but it also wears really fast.
This thread talks about all this stuff in depth: https://www.miataturbo.net/race-prep...ushings-81552/ and https://www.miataturbo.net/race-prep...cussion-82072/ |
Couple good quotes from there:
Originally Posted by bbundy
(Post 1177213)
I can't decide if the binding issues you might have with delrin are worse than the fact that poly is nearly the worst material in the world if you want your suspension to pivot freely without huge amounts of friction. the radial deflection is not nearly an issue as the amount of force it takes to move your a-arms after poly bushings have been on the car for a few months and all the grease becomes non functional.
Originally Posted by bbundy
(Post 1177361)
did that still dosnt work. As a mater of fact Ive found much more consistant and lower friction with the surface between tha ARM and the bushing being the sliding surface instead of between the bushing and the pin. even with the slots and carfull handleing of how the zerks are installed thats where the grease ends up if using zerks anyway on 10 out of 14 of the bushings. And the greas might stay in place for a single autocross at best then it goes back to taking 40+ lbs of force just to get the A-arms to pivot. Ive measured up to 90 lbs if compleatly left alone for a season. That amount os stiction is a huge detrament to suspension performance. With the V8-roadster arms it seems to be better than stock arms but still sucks.
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Thanks Ed
Lubrication is an issue on poly or delrin bushings as I stated. Bob drives his car on the road alot in weather. We have talked about this. The statement was made above that there was no offset bushings for the lower arm and I was just saying that there is and they have worked fine for me to gain neg. camber up front. I have stock bushings everywhere else so if they bind up a little with time I don't care, they well be just like the stock rubber ones. Until someone comes out with the heim joint ones which well truely work freely I don't want to spend the time nor the money for something that in time isn't much better then stock. |
^yup.
Poly obviously has drawbacks, but you'll notice that in the end of that thread Bob has found a lubrication solution that allows the bushings to be lubed once per autoX season. That sounds pretty fantastic and totally acceptable to me. So copper permatex it is. |
Originally Posted by turbofan
(Post 1209850)
Sorry Joe, John is right.
The rubber bushings bind and make it so the control arms take effort to move. Take your shocks off and try to move your control arms with the stock bushing. You'll notice that they take a lot of effort still to move them up and down and they spring back into place when you let go. With a lubricated poly bushing, the bushing does not affect the movement of the control arms, allowing more precise control of spring rates. This is what john is saying. Am I wrong there? If not, that means the overall stiffness of your suspension system is higher with solid bushings vs. rubber. Sorry if that's not what john was referring to in the beginning, I probably misunderstood. anyways, sorry about the thread jack. |
Originally Posted by Seefo
(Post 1209897)
Am I wrong there?
Poly/delrin/heim joints aren't "solid." They're designed to pivot, and the less friction they have the better. When they do have friction, the effect isn't to return to a "center" position like a spring, rather they just resist movement like a shock -- a really bad shock with inconsistent and unpredictable resistance. OEM rubber bushings pivot rather awkwardly due to being soft and want to return to the position they were in when the suspension bolts were tightened. Anyone who has ever made the mistake of tightening the bolts on an unloaded suspension with OEM rubber bushings knows this. The effect of rubber bushings is often described as "adding spring rate" although the effect is too inconsistent to be useful. |
lets try this again. Unlike the oem bshg that the inner tube is molded into the rubber bshg and it has teeth on the ends that the washers on each end tightens against as you tighten the bshg bolt, so as the arms move up or down it twist the bushing which in turn twist the rubber as it is molded together. The poly has the same inner sleeve with teeth on each end that the same washers tighten up against, but the inner sleeve is not molded to the bushing. Instead it is lubricated on the outside of the sleeve where it rides in the poly bushing and when the arms move the inner sleeve rotates inside the poly bushing if kept lubed properly.
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Joe I see what you're saying -- that's not at all what we are talking about. yes there's going to be much less deflection with Poly bushings, and even less deflection in delrin bushings. But deflection has nothing to do with spring rates, it's simply how firmly the control arms are being held in place during braking (and, in the rear, acceleration) events. It will be affected by spring rates, but it won't really affect the spring rates.
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Durometer != tendency to inhibit rotation
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One more time. The after market bshgs are different in two different ways. The polys are harder so there is less cushioning as far as absorbing bump which in turn makes for a harsher ride, this has absolutely nothing to do with what the other purpose of the poly bshg is and that is freeness of the arms to move up and down as the inner tube is lubed and floating free inside the bshg. The bshg bolt and the washers tighten down on the teeth on the ends of the inner sleeve not the rubber or poly bshg as many seem to think is the case, so with the inner sleeve on the poly being free to rotate as it is not molded to the bshg like the rubber one is it is free to rotate as long as it is lubed.
Two different things here. Kinda like a harder bump stop on a shock verses a softer one has nothing to do with the rate of shock travel, that is controlled by the dampner setting. |
Split to a OEM rubber explanation thread..?
For a poorly maintained setup bonded rubber is hard to beat, the bushings give some torsion spring rate, but close to no binding/stiction. I.e. predictable movement for applied force. A poorly lubes poly bushing can require some force to get moving, something you don't want, since the force/movement isn't linear (or smooth curve). I've been shot down before for suggesting bronze bushing sleeves between the Poly/delrin and the center sleeve. But it would remove the binding issue and reduce the wear of the bushing material. |
Originally Posted by jmann
(Post 1209978)
The bshg bolt and the washers tighten down on the teeth on the ends of the inner sleeve not the rubber or poly bshg as many seem to think is the case
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Curly doin work.
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Yeah, that was a pretty bad threadjack, but the subject was worthy. Well done Curly!
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1 Attachment(s)
I made sleeves for urethane bushings that actually pivot. I replaced all the 7/8” OD sleeves with 4340 ¾” OD Sleeves surrounded by ¾” ID 7/8” OD SAE oil/Teflon impregnated bronze bushings. Rear upper is a spherical.
Don’t have any time on them yet but they feel great I think they will work well. Now requires very little force to move the suspension up and down now. Removed like 40 lbs of static friction in the rear. Performs very close to an all Spherical setup and probably less likely to develop slop as the surface area transfering load of the bushings is much greater than that for a sperical. https://www.miataturbo.net/attachmen...ine=1424977730 |
Where do I place my order.... :)
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Originally Posted by NiklasFalk
(Post 1209994)
I've been shot down before for suggesting bronze bushing sleeves between the Poly/delrin and the center sleeve. But it would remove the binding issue and reduce the wear of the bushing material.
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Dang, Bob, that's awesome. Were they OTS parts from an industrial supply house or did you have to machine yourself?
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Originally Posted by hornetball
(Post 1210154)
Dang, Bob, that's awesome. Were they OTS parts from an industrial supply house or did you have to machine yourself?
For the cam bolt locations I have 4mm thick 7/8" OD washers made so as to better handle high clamp loads without squishing the subframe which was a conscern. |
Would you be willing to share dimensions, I may take this on as my next lathe project.
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That's awesome Bob. Aidan I will donate fundage to the effort, I want a set.
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Also just to make sure I understood it right, the sleeves have uerethane bushing inside them, which stop the binding issues, but create friction issues. By putting the sleeves inside brass bushings you are left with a bushing that doesn't bind laterally yet still can rotate freely?
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I have wanted these for as long as I saw them in Sean's rear knuckle sperical bearing thread.
Just keep in mind, I believe Bundy made this to work with his V8R control arms. You would have to make custom urethane bushings that are 7/8" ID and standard miata OD for these to work. Is this correct Bundy? |
Originally Posted by aidandj
(Post 1210163)
Also just to make sure I understood it right, the sleeves have uerethane bushing inside them, which stop the binding issues, but create friction issues. By putting the sleeves inside brass bushings you are left with a bushing that doesn't bind laterally yet still can rotate freely?
The bronze bushed inner sleeves in the urethane seems to cure the friction problem while retaining the advantages Urethane has over both bonded rubber and delrin solutions. |
Ok that makes sense. For some reason I thought the sleeves you made went around the urethane bushings. So these go inside the urethane and the copper bushing is what slides inside the bushing.
So the sleeve just needs to have the same ID as the normal sleeves in the urethane bushing kit, and then the OD needs to match the ID of the bronze bushings. What size bronze bushings are you using? Got any installed pictures? If the bronze bushing is the part sliding on the urethane bushing then why did you go for the $$$$ steel bar stock. Seems like any standard steel would work. |
i almost bought the isc offset uppers, then after researching, emilios past posts steered me away. i ended up taking his advice and make the front lower offset and couldn't be happier. with delrin in the front and rubber in the rear, binding isnt an issue
https://www.miataturbo.net/build-thr...9/#post1193050 i was going to make a thread a few weeks ago with all the dimensions of various bushings as i make them throughout the car, starting with the LCA front, but i couldnt find my napkin cad drawing in the garage. |
Originally Posted by aidandj
(Post 1210166)
If the bronze bushing is the part sliding on the urethane bushing then why did you go for the $$$$ steel bar stock. Seems like any standard steel would work. https://www.miataturbo.net/race-prep...cussion-82072/ |
I'll re-read all of that. It started to go over my head and I got bored at one point.
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Originally Posted by aidandj
(Post 1210171)
I'll re-read all of that. It started to go over my head and I got bored at one point.
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Originally Posted by hi_im_sean
(Post 1210172)
its very dry
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Bob, with the bronze bushings will lubing still be required? How long do you think these will last? Will the bronze wear at some point?
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Originally Posted by aidandj
(Post 1210166)
Ok that makes sense. For some reason I thought the sleeves you made went around the urethane bushings. So these go inside the urethane and the copper bushing is what slides inside the bushing.
So the sleeve just needs to have the same ID as the normal sleeves in the urethane bushing kit, and then the OD needs to match the ID of the bronze bushings. What size bronze bushings are you using? Got any installed pictures? If the bronze bushing is the part sliding on the urethane bushing then why did you go for the $$$$ steel bar stock. Seems like any standard steel would work. |
Ok so the sliding surface is the steel sleeve and bronze bushing, that makes more sense.
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