Just a question here ... I am finally getting around to installing the spherical bearing kit in my rear uprights. Earlier in this thread, one post mentions that the bushing is an easy slip fit into the upright, and that the OD of the bushing is 1.495". My bushing is 1.501", and the ID of my rear upright seems to be around 1.498", maybe as low as 1.496" (I measure one side slightly smaller than the other).

Was the design of the bushing changed at some point to be a press fit?

Should I be worried about a possibly .004"-.005" interference fit on a 1.5" OD, steel into cast iron? It seems high to me, what I read on the internets is roughly .001" per inch of diameter...

When I do interface fits on bearings at work I typically run .001-.002. Yours should still work but will be tight. I would definitely use heat to get it together

.005" is not intereference fit on steel, it's "does not fit". I would take the upright to a machinist and have it reamed to size.

Well, I'm hoping Sean chimes in, I'm curious if he intentionally made a design change that would require a press.

I agree, .005 is no press fit. I'm going to try and hone out the bore of the upright a bit more, I would think it'd be more like 1.498" like the other side.

If it comes to machining stuff, I have a lathe in my garage ... I'm no pro, but I'm sure I can turn a couple thou off the bushing if required.

Thanks for the input,

Mike

Speaking straight from my ass, my money is on dimensional variance at the upright. Remember that the OEM is sticking a rubber bushing in there which will easily absorb a 0.005" variance in ID.

You speaking straight from your ass is more reliable than many other sources. :-)

Dimensional variation in the upright is probably some of it. I went back yesterday after zeroing my calipers properly and the upright varies between 1.495" and 1.500" ... it's not round. The bushing is a perfect 1.500".

Earlier in the thread, the bushing was described as being 1.495" ... so I think that changed at some point.

I turned a piece of round stock to 1.492" yesterday and it's a touch too loose. I think 1.495" will be perfect. I'm going to turn a test piece and see before I touch the bushings.

Mike

I got this done this morning out in the garage. Turning them down to 1.495" made them a stiff fit partway through by hand, and easy with the vise. I didn't worry about the finish on the OD, I figured it would help the Locktite grab better.

I'm happy with these results.

Thanks for the advice!



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5 years after buying, I'm considering finally installing mine now that I'm going to install coilovers and hopefully the bronze/poly bushings that 949 is going to be selling. It's a dual duty street/track car.

1. How are you PNW guys finding the weathersealing with the rubber cups? Anyone reached the end of life of any bearing, QA1 or the finest Aurora/NHBB? How many track days and street miles?
2. I want to get the RUCA eccentric setup like AWR/V8R control arms like BBundy and others have done. I've got the standard aluminum spacers Do I just need to lathe up some similar steel spacers with a larger ID to clear the larger eccentric bolt?

Bonus question: The final design link on SADfabs website is down. Anyone willing to share this design so I can hoard these designs for future reference.

I used the Timken seals that were referenced in this thread. My advice would be just to get the Sadfab kit. The bore is machined for the spherical and clips. Very simple install.

I have the Sadfab kit including the seals. I bought it from this very thread in 2016 and have done nothing with it since.

I want to change up the spacers to run an eccentric bolt in that location as a few other people did, and I want to hear long term feedback from the people that have been using them since.

How would the eccentric bolt be useful in the upper location. The spherical already allows for some deflection. The upper knuckle is captured by UCA there - how would the eccentric bolt and cams allow for adjustment - are you also modifying the arms and welding tabs to them ? I just don't see a benefit nor have seen the discussion on this. if you have a link to this topic, please share

The point isn't deflection, the point is adjustment. On a stock Miata, all adjustment for rear toe and camber is done at the eccentrics on the inside of the lower control arms. You can't change toe or camber without changing the other.

By using an eccentric at the outside of the RUCA, you make it adjustable in length just like any other adjustable control arm like Paco motorsports or those janky SPL parts. Use the stock eccentrics on the LCA to set toe, then you can use the eccentric at the RUCA-O to adjust camber. The toe adjustment will still affect camber, but you can easily compensate by using the adjustable upper control arm. V8Roadsters, AWR, and a few other companies sell control arms that are set up to add another stock eccentric bolt to the RUCA-O for camber adjustment.

NA & NB Miata Rear Upper Control Arms - V8 Roadsters
Control Arm - Rear Upper Adjustable Bare - AWR Store (awrracing.com)

I haven't found any detailed discussion on this forum, but if you carefully read the above posts in this thread you will find that several people bought spherical kits with different spacers to fit the eccentric bolts. I'm trying to make aligning my car myself a bit more feasible.


So... any feedback on my other question Stevos? How are yours holding up, and whats the age/mileage/track day count you have on them, and what bearings did you go with? Have you inspected them? The only maintenance related feedback I see is one post from Sean after 1 year of usage, and that was almost 6 years ago. I'd like some more data points.

Ah - I see the slotted arm. Regarding longevity - my sphericals were just put in with new seals. Since it's a dedicated track car, it should not see any snow or water unless on track. Honestly the seals are $30 for the set and jus treat it as a yearly maintenance. I did pack the cavity with PTFE grease and this should help anything from getting the aurora bearing wet.

No offense but I'm looking for feedback from people that have had these on their car for multiple years, not advice from someone with a fresh install. Surely there is someone out there who has put a few thousand miles on these things - long enough to say the bearings are good for years and years of driving, or that they need regular replacement. I'm not worried about the cost of seals (the Mcmaster ones are $5.23 for a pack of 5) I'm more concerned with not having to replace a $120 set of bearings every year if I'm driving 10k miles on the street. That's fine for a trailered car that's entirely track focused, but not what I want for a car I still regularly drive to work and on road trips.

Perhaps the lack of feedback should clue me in that there isn't any bad feedback about longevity, but I figured it was worth asking about. Sean's post after a year of driving is a single data point, and there's no mention of mileage or track day count. More data would be nice.

No offense taken. I just want to let you know Aurora AIB-10T is sold via Pegasus for $25 a piece. It's easy to replace every 2 years. The seals i used in my install are Timken 480889 and seals up the spacer well from elements. Now you got my interest on the slotted arms from AWR. I wish they would sell a DIY kit to weld at home. Seems like 2 plates and slotted.

I was one of the early adopters, ran a set on my racecar with the same sort of camber adjuster. If you are sufficiently serious about your racing you will no doubt be running delrin or poly/bronze bushings and these are the finishing touch. If you are running any other bushing you will not get a lot of value from them./gratuitous advice.

This was a trailered racecar, not in PNW, but on my wet finger in the air I got 4-5 seasons racing before the car was parted out, with no replacement and maybe checking and regreasing every year or so. Replacement is easy if/when required.

Just do it. If it doesn't work out, sell them, there will be a queue when you advertise them.

Wow, that definitely changes the math of how often I'd be willing to replace them! Thanks for the link. At that price I am almost certain I'll install them. I guess I had just been finding them on Auroras site, not Pegasus.

Still interested in long term feedback though! And any input on the eccentric bolt spacers

EDIT:Sorry, hadn't seen Gee Emms post when I wrote this.

I'll be running them with Fox coilovers and I plan to buy the poly/bronze bushings that Supermiata says will be on sale in February. No way I'd install these with rubber bushings. I've been doing 4-5 track days and about 10k miles a year for the past few years.

There was a Sadfab poly for sale in classifieds for $550 if you want to get started sooner. I am interested on the RUCO you plan on purchasing.

If the spacers can me still machined, I can ask Bronson and see if he is willing to turn few.

Not sure what you call 'track days', here that is a (relatively) low key semi-social, club oriented 'sprints' (ie timed laps, not w2w racing - though some clubs do that too). Unless you are seriously chasing pots (which I was, and I have a couple of shelves of them at Club, multi-Club and State level) I think your RUCA-O spherical is overkill.for that level of competition. If you see yourself stepping up, or I have misunderstood the nature of your competition, or you just want to run them, feel free to ignore me.

The poly/bronze are fine on the road, you might need to do a bit more greasing to ensure there is enough to keep the crap out where you are, Mine have been in for a few years now and I just hit them with some grease every year or so - no issues to date. I have poly/bronze in that RUCA-O location, and have found them satisfactory on the road and the track. If the car had delrin, that would be different though, but then it would not be a road car ...

No, you pretty much hit the nail on the head. It is definitely overkill. I wouldn't buy them if I were starting over, but they're sitting there in my parts pile and tempting me.