Hello RX7 Community!

I have reached out to HPPFab to design and produce a full spherical bearing set for the FD3S and thought you all might be interested in a group buy of this well thought out unique product.

I come from a BMW race car background and have tracked and raced various E46 and E36 BMWs for the past 8 years. The BMW market has an abundance of excellent bushing and bearing choices, very much unlike the RX-7. For a long time, I have been looking for a full spherical bearing set for my RX-7 but have always found the few options to be lacking in an area or two. Most kits come from Japan, carry a high price tag, and utilize a bearing that is not readily available. The cheaper kits tend to have an unknown bearing, so the quality is also then unknown and replacement is not an option when they fail. HPPFab's design has solved these issues.

Here are some standout features of the kit:

The kit uses a commonly available teflon lined, high quality Aurora bearing. This is critical for longevity of the bearing and also, when you do need to replace a bearing, you can actually find it off the shelf and do not need to purchase another full kit. I simply keep a few extra bearings in the garage.

The kit is complete and replaces all rubber bushings in the suspension. This kit does not include the rear pillow ball bearings as they are not an issue if in good working condition and or can be replaced with spherical pillow ball upgrade kits readily available. Nor does it include the rear toe links as there are also many excellent options out there.

Included in the kit are:
- Front Lower Control Arm Bushing replacement spherical bearings x4
- Rear Upper Control Arm Inboard Bushing replacement spherical bearings x4
- Rear Upper Control Arm Outboard Bushing replacement spherical bearings x2
- Rear Lower Control Arm Inner Bushing replacement spherical bearings x2


Example: One bushing replacement includes machined anodized aluminum housing, spherical bearing with two stainless steel spacers and snap rings.

Available options on request:

- 4130 chromoly rear trailing arms with Aurora rod end two Stainless Steel offset spacers and a ARP 12 point SS bolt for rear attachment to lower control arm.
- 4130 chromoly upper control arms designed to achieve maximum negative camber with spherical bearings and replaceable ball joint stud for the outer connection to the spindle.
- 4130 chromoly race rear toe links with Aurora rod ends, jamb nuts and stainless steel spacers.


The kit is race proven. This design was created and run by Carter Thompson who is a multiple time SCCA National SSM Champion Autox Champion. Precision and responsiveness are king in Autox.

Common Questions on Spherical bearings:

What is the benefit of switching to spherical bearings?

Precision, directness and stability on the limit is how I would describe it. Because there is no compliance in the bushing, every input is direct and not deflected. Steering is more sensitive and immediate. Because the alignment does not change as much because of the flex of the bushing, when the car has slip angle, it feels more progressive and direct as well.

How would you compare these to a hardened polyurethane bushing? Will noise, vibration and harshness increase?

Yes. NVH will increase. NVH will also increase with harder aftermarket poly bushings. Sometimes these poly bushings will also squeak which can be annoying. That said, I daily drove a BMW for years with fully spherical bushings. It did not bother me, but it may bother you. For me, I found poly bushings to be just as annoying as spherical, but your perception may be different.

Don't bearings have a short life span?

All bushings and bearings require maintenance. Poly bushings need to be replaced every so often as they slowly become more and more pliable and lose their precision just as rubber bushings do. Spherical bushings also need to be replaced as they will slowly lose their tolerance. You will be replacing bearings more frequently than poly bushings but the replacement process is easier in my opinion. I had to replace a bearing every 1.5 years or so in the bearings that were most exposed to the elements on my daily driver E46 M3 in the PNW where it rains a lot. Your results may vary. Other bearings that were less exposed lasted many more miles. More precision comes with some more maintenance. That maintenance is popping in a new bearing when needed rather than having to press in a new poly bushing. Is it worth it to you? It very much was to me.

As this is a group buy, Carter has extended a generous group buy discount as follows:

1-4 sets: $2900
5-9 sets $2100
10+ sets $1700

I personally am very excited to increase the true driver's car nature of the RX-7 through this bearing kit and hope you all are too. If you track, autox or enjoy driving your RX-7 the way it was intended, this kit may be a good option for you.


Please indicate your interest below and thank you for your interest!

 

Count me in for a set!

Great opportunity for sure!

 

HPPFab has awesome products and the best base for development (competitive racing).

If there is no defect with the existing much less expensive Hard Race sperical bearing press in sets I would advise HPPFab focuses on the pieces Hard Race does not offer.

Note Hard Race offers 2 year warranty on their sperical bearings.

Hard Race does not offer-
Rear upper arm shock mount (hard race has a bushing)
Rear lower arm inner
Rear lower arm outer
Rear trailingbarm front (spherical here causes cracking, so would have to be rubber isolated- most people just re0lace trailing arm).

Please advise if there are known defects with the Hard Race spherical bearing sets.

 

I have a couple of pictures of the spherical bearing kit that I am using in my race car to let everyone can get a good idea of what they will look like. Also, It would be a great discussion on comparing other manufacturers options and known defects.

Below is a representation of the "kit" close to in car positions.


Below is an exploded view of the assembly. All positions have the same type of parts but of course different dimensions.






I do have some replacement trialing arms; I will post up actual pictures of the arms once I can get some good pictures. These arms a a little different than the current aftermarket arms. I use 4130 chromoly not aluminum with ARP rear hardware and offset bushings to help with larger tire size inner clearance.

 

Is item 7 above an ARP piece in place of Mazda NLA YA02-1006?

 

With your kit is it possible to replace the spherical bearings without pressing out the entire *bushing* replacement part?

I ask because that looks like a possibility with the snap ring construction and it sure would make maintenance (replacement) easier.

 

Absolutely they can be replaced with our removing the housing from the control arm. As you know snap rings can be tricky but much better the pressing out bushings for sure.

CT

 

Being able to "just" use snap ring pliers and an arbor press to replace the spherical bearings coupled with the use of off the shelf Aurora bearings makes this kit very desireable since this is seasonal maintenance.

Im definitely thinking twice about buying the cheaper Hard Race China spherical bearing kit...

 

This is an excellent discussion to open. Lets look at the cost to compare the Hard Race set of bushings vs the HPP ones.

I will try to compare apples to apples, If you purchase a set of front lower control arm bushings from hard race they are 425 a set of 4. Yes this is a good price. The 4 lower bushings out of the complete package in this group buy and I am assuming the 10+ group buy pricing. The set of 4 for the front comes out to be $582. Yes, these are $157 more expensive. Lets say you just buy the Auroa 3070-12 3/4" spherical bearing at 55.05 ea ( no shipping) is $220.20 for four to complete the front lower control arm set. As you can see the bearings are a considerable cost. If you then take the bearing cost out and replace them with inexpensive COM12 bearings let say 16.90 ea at rod end supply then that brings the price of a set to $429.60 with comparable bearings. So these are $5 more in this example.

I will sit down and put a spread sheet together with HR vs HPP if needed. I am not trying to bring any others down just to compare to make the desicion process easier for the end user.

Also to note the Auroa bearings are 700 and some change for the complete kit. The cost of the bearings are not discounted as much as the machined parts for volumes. Hope this makes since and helps explain the price tag a little better.

 

Just for the sake of argument, at the current exchange rate, a full set from Auto Staff costs less than $1300. https://www.auto-staff.net/sp/sp/sp_...t1-MPB-FD.html
And you can get them with extra camber/caster.

 

Never mind, I am dumb. That was just the front axle. Haha.

 

The current set of spherical arms I have is JDM and the spherical carriers were only mild interference fit into the stock arms and spot welded to the arms to keep them in place.

This is actually a really quick way to put these in/change them out if you have a TIG welder and keep buying the same brand.

I dont have a TIG and I dont know the brand, so...

Just illustrating for people that companies that produce these have varying implementation .

 

If you are interested in selling them in piecemeal kits per set of suspension arms like Hard Race that would give us a direct comparison in price.

If you list part # and price of replacement bearings customers will readily be able to see the value of your product once they realize these are seasonal maintenance items when racing.

 

Might be interested in 2 kits at 10+ group pricing.

Will this kit require any machining to control arms to fit the bushings?

Also, what does the pricing look like for the upper control arms, trailing arms, and toe links?

Out of curiosity does anyone have direct experience with SuperNow’s spherical bushings and how they compare to this kit?

 

I would also be interested at 10+ group pricing.

As to the Super Now spherical bushings, a friend has them on his street third gen (it came like that and we just left them on) and to tell you the truth, in terms of ride quality I couldn't tell a difference. Steering inputs did feel more direct, though. No idea what bushing replacement might look like on them.

 

Let's get the list going!

1. Flyweight

 

Hey Chon,

No machining or modification are required to install the bearing housings to your OEM control arms. They are a slight press into the OEM arms which will hold them in place like and the snap rings are for extra insurance and to mostly locate them in the center.

I will get a list together to separate everything out as sugested I will add the upper control arms, Trailing and tow links to that list.

 

Have you been able to source upper and lower ball joints? I know the old ones need to be cut.

 

[QUOTE=BLUE TII;12621323]If you are interested in selling them in piecemeal kits per set of suspension arms like Hard Race that would give us a direct comparison in price.

OK, here is what I came up with. I did some rounding to make it easier for me.

*pricing with Auroa PNB-10T, PNB-12T sherical bearings:

$580- Front Lower Control Arm Set of 4.
$540- Rear Upper Control Arm (inner) set of 4.
$290- Rear Upper Control Arm Shock Mount set of 2.
$290- Rear Lower Control Arm (Inner) set of 2.

Total for all is $1700.

Extra parts no minimum for GB with sherical bearing purchase.

*below parts have Aurora AURAM-10T rod ends:

Chromoly rear trailing arm GB price $350 set of 2, normal price $400
Chromoly rear tow links GB price $375 set of 2, normal price $425

TBD on FUCA ( Blue TII gave me a good idea, he just doesn't know it yet)

Chromoly Front Upper Control Arms GB price TBD

 

I reached out to Hardrace to ask what bearings they use and what their cost was for the bearings and Jim Forsyth, their Retail Sales Manager said:

"Hardrace HQ don't specify the bearing pack specifically but they will sell them separately if/when they do need replacing."

This kit by HPP uses the highest quality, available off the shelf, not just from HPP, Aurora bearing. You are buying a service item, and in my humble opinion, you should understand its cost, and were to get it, not to mention its quality. The HPP kit is for me. It utilizes a high quality (read lower service interval), readily available, reasonably priced bearing.

Not to mention, no more squishing in poorer performing plastic bushings when they wear out. Slide out the old bearing and slide in the new. Lots of time and energy saved.

 

^^
Quick search of part # looks like maintenance cost to replace an Aurora spherical bearing in HPP kit would be ~$150.

Sounds like a very good value.

 

Im hoping its an eccentric front lower control arm front bushing for camber and a spherical bearing kit for stock front upper control arm.

I like the eccentric spherical in lower arm for toe because it-
1) increases track width instead of decreasing track width.
2) increases wheel clearance to shock body (same distance hub face to shock lower mount, but more shock angle from increased distance to shock upper mount) instead of decreasing wheel clearance to shock like a shortened upper arm.
a) more wheel clearance to shock allows for higher offset wheel which decreases scrub radius.

But, if there are better reasons to gain static camber by shortening upper arm- please inform me.

 

I haven't installed / driven on them yet for comparison Chon (see Simon's response on some experience above), but for visual comparison I just unpackaged the last of my SuperNow kit this past Friday

I ordered them too early to consider what's looking like an awesome comparable kit from Carter, but considered Mazdaspeed Comp, Powerflex, Superpro, and J-Auto and Sake Bomb Garage partial kits




















Carter - what do you use for a lubricating anti-seize? Any experience with Red Grease Bearing Lubricant?



@Flyweight @HppRX7
What size ARP 12 point SS bolt are you using for the Trailing Arm, item #7 below?

​​​​​​​

 

Carter - what do you use for a lubricating anti-seize? Any experience with Red Grease Bearing Lubricant?



@Flyweight @HppRX7
What size ARP 12 point SS bolt are you using for the Trailing Arm, item #7 below?


Hey ZumspeedRX-7

Those bushings look great. Those are two peice with the bearing in the middle correct? It woudl be interesting on the press fit into the arms Thanks for posting those up. that is a great comparision too.

About the lube for the bearings. I never put any lube in mine as they have PTFE liners that self lubricate. I am not sure about those bearings if they are PTFE lined or not. Sorry I do not have any input on that.

As of the ARP 12 point bolt, I use part number 715-2500 it is not a metric bolt as it is a 3/8-24. I just use a 3/8-24 tube end on the trialing are to accomodate for that.

CT

 

All compliments to Imaizumi-san of Super Now Enginerring - he has done some cool things over the years


Yes, the SuperNow's are two piece with the bearing in the middle

For comparison, the SuperNow kit is comprised from NMB Minebea pieces:
- MBWT14 bearings throughout
- HRT16E NMB NOE200 rod ends - two trailing arm, two toe link
- HRT16E NMB NOE200 rod ends - two toe link

All of the NMB pieces above are PTFE lined



Is the trailing arm ARP 715-2500 bolt the same thread length / grip length / 3/8 thread as Mazda 9YA0-21-006(NLA)?


Do you know Kevin Doe? Have you guys traded some calculations?