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-   -   Drop spindle discussion (https://www.miataturbo.net/race-prep-75/drop-spindle-discussion-70469/)

Midtenn 02-05-2013 12:41 PM

Are they bending in a similar location and is it a simple matter of just adding a little gusseting. I also wonder if its a bad batch (material is wrong or out of spec) or its a design problem.

emilio700 02-05-2013 01:31 PM


Originally Posted by albumleaf (Post 975491)
Just another data point, a LS2 autocross/weekend toy NB bent one of those V8Roadsters arms running 225/45/15 RS3s at an autox earlier last year. No contact with curbs, etc. V8R replaced it for free, but it's not very confidence inspiring.

V8R has revised their tubular arms no less than 5 times that I know of.

It sounds like the several comments of "autocrossers bend stuff that road racers can't" are based solely on problems with early V8R arms. The spherical bearing tubular Cr-Mo type arms used on Jesse Prathers EP car would probably be just fine on a national level SSM or CSP car.

Soo..
Back to the context of the thread, yes any drop spindles designed for the Miata should be strong and stiff enough for any conceivable usage they might see, including autocross.

bbundy 02-06-2013 11:35 PM


Originally Posted by emilio700 (Post 975521)
V8R has revised their tubular arms no less than 5 times that I know of.

It sounds like the several comments of "autocrossers bend stuff that road racers can't" are based solely on problems with early V8R arms. The spherical bearing tubular Cr-Mo type arms used on Jesse Prathers EP car would probably be just fine on a national level SSM or CSP car.

Soo..
Back to the context of the thread, yes any drop spindles designed for the Miata should be strong and stiff enough for any conceivable usage they might see, including autocross.

I know an SSM Miata that completely folded both sides at once a set of EP Miata front upper arms during straight line braking on a smooth asphalt surface during the first event on them. They claimed they had never had a failure before.

It is interesting that EP Miata’s design for their rear upper arm has zero for aft stiffness only attaching to one of the chassis side spots. Must just twist the hell out of the lower arm with for/aft and braking loads.

The V8R arms look better but they did go through some design iterations that looked pretty sketchy to me on the front lowers.

http://www.destinationssm.com/wp-con...5/H42C0815.jpg
http://www.destinationssm.com/wp-con...5/H42C0819.jpg

Leafy 02-06-2013 11:42 PM


Originally Posted by bbundy (Post 976117)
I know an SSM Miata that completely folded both sides at once a set of EP Miata front upper arms during straight line braking on a smooth asphalt surface during the first event on them. They claimed they had never had a failure before.

It is interesting that EP Miata’s design for their rear upper arm has zero for aft stiffness only attaching to one of the chassis side spots. Must just twist the hell out of the lower arm with for/aft and braking loads.

The V8R arms look better but they did go through some design iterations that looked pretty sketchy to me on the front lowers.

We'll have to see what I end up concocting when I get around to having time to design a full set for my car. I fully intend to manufacture a jig for welding them so I could potentially bring these to market as I wont be limited by my agreement with the shop at school that doesnt allow me to make a profit. Mmm no compromise arms designed specifically for SSM or higher cars, with actual FEA backing them up. Hopefully I'll get around to this before I nuke a set of stock arms. :giggle:

z31maniac 02-07-2013 08:49 AM


Originally Posted by Leafy (Post 976118)
We'll have to see what I end up concocting when I get around to having time to design a full set for my car. I fully intend to manufacture a jig for welding them so I could potentially bring these to market as I wont be limited by my agreement with the shop at school that doesnt allow me to make a profit. Mmm no compromise arms designed specifically for SSM or higher cars, with actual FEA backing them up. Hopefully I'll get around to this before I nuke a set of stock arms. :giggle:

I'm interested. I have a set of V8R front uppers on my track car now. 15 20minute sessions so far with no issues. I bought these ~July of last year.

As long as you add some extra adjustability for camber.

flier129 02-18-2013 12:45 PM

Andrew Keisler(a guy from Knoxville,TN) is getting serious about a prototype drop spindle.

Drop Spindles 101

I told him to send a prototype to you, Emilio. I also asked him about the loss of droop travel. I'm going to guess some spacers would be a lot easier than having a whole new shock made, initially at least.

Edit: Not 100%, but last I heard he's shooting for a ~$800 or less price-point.

emilio700 02-18-2013 03:22 PM


Originally Posted by flier129 (Post 980193)
Andrew Keisler(a guy from Knoxville,TN) is getting serious about a prototype drop spindle.

Drop Spindles 101

I told him to send a prototype to you, Emilio. I also asked him about the loss of droop travel. I'm going to guess some spacers would be a lot easier than having a whole new shock made, initially at least.

Edit: Not 100%, but last I heard he's shooting for a ~$800 or less price-point.

If and when we get spindles from one of three different potential sources, we will just add spacers to the upper mounts to mock it up. When we're sure they work and are in production, we'll build special Xidas with a longer body/shaft and more droop travel for them.

flier129 02-18-2013 06:06 PM


Originally Posted by emilio700 (Post 980265)
If and when we get spindles from one of three different potential sources, we will just add spacers to the upper mounts to mock it up. When we're sure they work and are in production, we'll build special Xidas with a longer body/shaft and more droop travel for them.

Heh, the ultimate "how to make your miata go fast on 15x10s, slicks, and aero" package.

Are the ASTs shock body shorter than OEM shocks?

Dr Pooface 06-27-2013 01:57 PM

Weekend Racer has these up now, drop spindles with bolt on sealed front bearings...

Miata Front Chromoly 1.5 Drop Spindles with Race Hub - $799.00 : Weekend-Racer - Auto Racing Safety Equipment, Auto Racing Gear, Auto Racing Helmets, Auto Racing Suits, We're amateur racers just like you.

Leafy 06-27-2013 02:12 PM

The bushing set they sell looks exactly like the muraha one, except the muraha ones are mad tyte jdm yo and cost less. I wonder what they cost without the jdm tax...

guttedmiata 06-28-2013 12:18 AM

I just installed Keisler Automation's drop spindles up front.

What I have are prototypes - first set other than what Andrew has tested on his own car.

All aluminum. Super light. 2" drop. Priced better than you can imagine.

He's tweaking the design slightly right now and is also working on a design with a bolt on hub.

Dot3 06-28-2013 12:20 AM

How many different shops are making these?

Hese are making me excited.

j_man 06-28-2013 10:42 AM


Originally Posted by guttedmiata (Post 1026177)
He's tweaking the design slightly right now and is also working on a design with a bolt on hub.

I saw the pictures of the bolt-on hub design, but seems there is no provision for the ABS in those? Or is a different ABS sensor used which is part of the bolt-on hub - i.e. like the NC Miata?




Leafy 06-28-2013 10:44 AM


Originally Posted by j_man (Post 1026276)
I saw the pictures of the bolt-on hub design, but seems there is no provision for the ABS in those? Or is a different ABS sensor used which is part of the bolt-on hub?



Looks like the bolt on hub has built in ABS. No idea if its would work with the stock abs without a translator board.

JasonC SBB 06-28-2013 11:39 AM

Running a smaller o.d. tire (very short sidewalls) will have the same geometry effect as drop spindles.

e.g. 225/30/15 would drop the car by 1 inch. It would have 4% smaller rolling diameter though.

Would such a tire not be a good solution?

Leafy 06-28-2013 11:45 AM


Originally Posted by JasonC SBB (Post 1026292)
Running a smaller o.d. tire (very short sidewalls) will have the same geometry effect as drop spindles.

e.g. 225/30/15 would drop the car by 1 inch. It would have 4% smaller rolling diameter though.

Would such a tire not be a good solution?

One trouble becomes tire temps. I would be seriously concerned with even an auto-x turbo miata overheating the 255 13 hoosiers in the A6 compound in the middle of a run. And the other trouble is the 275 is faster than the 255. I dont know what the road racer options are. But I know some of those guys are already running the super short 13" options.

NiklasFalk 06-28-2013 12:01 PM


Originally Posted by JasonC SBB (Post 1026292)
Running a smaller o.d. tire (very short sidewalls) will have the same geometry effect as drop spindles.

e.g. 225/30/15 would drop the car by 1 inch. It would have 4% smaller rolling diameter though.

Would such a tire not be a good solution?

Shorter contact patch in theory.

But as we all know, tires are not available on custom order (any size, any construction, any compound, any thread, ...) but rather as discrete options and you have to adjust to what's available.

I'd love to have 1" drop in the spindles and gain angles, bump range (with less than optimal dampers), etc.

If there are several designs on the way now, it will probably be something nice and decently priced to aim for in 2018 or so when I get around to it... :)

j_man 06-28-2013 12:31 PM


Originally Posted by Leafy (Post 1026277)
Looks like the bolt on hub has built in ABS. No idea if its would work with the stock abs without a translator board.

Most cars nowadays run Bosch ABS units and many of those use 44 teeth per rev wheels. I guess if that hub is like that (doen't come from some exotic application) it should work. Is there info on what kind of car is it from?

Asking since the main use of such spindles would be Miata prepped for racing. And if the class allows ABS, a Miata with a decent ABS would be faster than non ABS one every time (assuming everything else on the two cars is the same of course) ...




Leafy 06-28-2013 12:38 PM

The guy who was peddling them before said they were from a toyota. So MR2 front or Celica rear are the most likely I would think.

Vilko 06-29-2013 11:59 AM

I recently installed the rear driftworks knuckles in my s13. I had to go from 16 to 17" rims to stop the LCA scrubbing the inside of the wheel under hard compression, had to change shocks to stop them from fouling on the drive shafts (I have larger skyline gtr diff and shafts). There was a few other small things like rearranging brake lines, but nothing major. These are obviously very specific to the car and the more extreme 40mm drop, but still some things to be aware of for these types of products.


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