Black91n/a

http://sp-tec.com/shop/15_33.html
http://sp-tec.com/shop/15_32.html

Prometheus

iTrader: (2)

Bumping an old thread to see if anybody has any information/ experience with this or similar a product (drop spindles)

It seems like many people in the Miata family go for this accessory. It is on the Miata forums where most information i am able to find is located.

Hoping someone can give me a little info from a FD perspective.

I'm sure some of you "track App" guys have to be using these.

Thanks

~Jesse

Prometheus

iTrader: (2)

Bump?

Black91n/a

I've heard that there's been some failures of these on Miatas (the Miata version obviously), so they might not be as great an idea as it first seems (product specific).

That doesn't mean it's a bad idea, but you might want to look into the strength issue further.

Prometheus

iTrader: (2)

Thanks, this is the only company making a FD specific drop spindle kit.

But I can't find any third party experience or imput on any drop spindle use/ results for a FD application.

I'm wondering if these are being used out there, but are not being discussed (overlooked) compaired to coilovers or other suspension components.

Also wondering; Why only one company manufactures this part) (why isn't there multiple manufacturers?)

ptrhahn

iTrader: (9)

I'm not sure they're necessary on the FD.

gracer7-rx7

iTrader: (16)

Link to Miata thread?


They look very thin compared to the thicker FD spindles. Why are you interested in these?

Prometheus

iTrader: (2)

Google "Mazda Miata drop spindles" and you'll find the forum with the info I have read.

The reason I'm interested is I want to maintain original intended suspension geometry.

Looking to properly build my car, a lot of people have cars that eat themselves.

Extreme camber due to lowering our cars is hard on everything. I assume drop spindles allow you to lower your car dramatically while reducing (eliminating?) severe camber.

+ I just want to learn a little more about this mysterious part for our cars.

I

Black91n/a

The reason behind drop spindles is to allow you to lower the car while maintaining suspension geometry. You can adjust the static camber, caster and toe all you want, but what's more important and what drop spindles do for you is to keep the stock height camber curves, bump steer characteristics and so on while lowered. This is a good thing for almost any suspension.

Prometheus

iTrader: (2)

Is it true that with drop spindles, original suspension travel is maintained?

I see this mated with coilovers, being a fender/tire shredding combo.

Black91n/a

Well it depends on what's limiting the travel. If it's the fenders, body or what not, then no it won't add bump travel, if it's suspension arms, shock travel and that sort of thing, then yes, it can add bump travel.

It should allow you to run a longer shock/spring, so while it might not add to bump travel, it can add to droop travel, which is important too, especially on rough and/or uneven surfaces.

gracer7-rx7

iTrader: (16)

I really don't see this being necessary for an FD at a ride height 25" and over measured to the fenders

The only time I've seen someone need drop spindles was on their FD race car - full caged, stripped, untitled. They were running ride height really low and there wasn't enough shock travel (shock was too long) so they used drop spindles.

ptrhahn

iTrader: (9)

It'd not so much about suspension travel, which will ultimately be limited by the inner fenders either way, especially up front.

Theoretically, what it's about is the arc through which the suspension travels, which becomes more abrupt when the A-arms get further from parallel to the ground.

I still am not sure it's an issue at typical "low" ride heights on the FD.

Sandro

iTrader: (1)

Lowering the car just by using shorter springs (as normally done) causes the roll center to drop more than the drop in center of mass (because of the suspension unequal arms design).

Everything else equal, an increase in the distance between the center of mass and the roll center causes the roll stiffness to decreases, resulting in higher body roll (relatively to the spring/sway bar stiffness used).

With those devices, you can basically lower the car without causing changes to the roll center height.


- Sandro

Prometheus

iTrader: (2)

would you go as far as to say drop spindles mated with other properly selected suspension components would make for a more "neutral" handeling FD?

Black91n/a

You still move the roll center height (you're moving the car) and it does move relative to the CG (since roll center is calculated using the tire's contact patch, which moves relative to the suspensiopn). It'll move less than if you simply lowered the car with shorter springs though. I'd call that more of a side benefit, with the real big benefit being that the camber and toe curves remain intact after lowering.

Sandro

iTrader: (1)

You are right. The roll center still moves and my last statement was poorly formulated. However, it moves up, in the "right" direction.

Let's assume you lower the car only by using drop spindles and keep the same springs. The relative positions/angles of the A arms are unchanged, and so are the instantaneous centers. However, because the car is now lowered, the vertical distance between the instantaneous centers and the ground is reduced. As a result, the the roll center is now higher. The distance between CG and roll center is reduced "twice", because of the reduction in the CG height and the increase in the roll center height.

By the way, I just wanted to highlight an additional "real" benefit, although less intuitive. In no way I meant to diminish the importance of maintaining the correct suspension geometry, travel, camber and toe curves.

- Sandro

Black91n/a

No problem, I just wanted to correct the slight error, it's definitely a good thing. With that smaller roll couple (distance between the CG and roll center) you'll be able to run softer springs and anti-roll bars, which will allow you to retain a given roll stiffness while making the car a bit softer in compression. This will help the car to handle rough surfaces better and should give overall better grip and handling on rough or uneven race tracks. That is a very good thing.

I'd say without a doubt, drop spindles are the way to go for lowering, as long as you increase the stiffness enough to compensate for the lower ride height so that you're not bottoming out and rubbing tires into fenders and so on.

Sandro

iTrader: (1)

After digging into it some more via Internet surfing...

If you are looking for an alternate supplier, you may want to check with Jeff Kiesel (7parts.com)

SM2 champion cars are featured in his websites. Jeff, Erik and Andy, they all use drop spindles. You may also want to check/discuss with them.

Why? "to correct roll center change with lowering" http://7parts.com/erikstrelnieks.html

- Sandro

Prometheus

iTrader: (2)

I PM'd Howard Coleman and he said.

"Hi Jesse,

there is nothing wrong w dropped spindles if done correctly. the key is they are not needed on the FD. the FD can be lowered to a really nice height that works well for track and street. this is due to the proper amount of camber gain built into the suspension.

i do like your concept alot... not messing too much w the tune and getting track time. it will put you in front of most. do keep in mind that the FD, even in stock tune, is cranked up CCP-wise so anything you can do to keep the temps down will pay dividends. if you plan to be ontrack you should run a simple water injection system.

that way you can concentrate on driving and not building motors.

good luck,

howard"

Just thought I'd share.

Thanks Howard!

s1mpsons

iTrader: (5)

Where can I buy these? Any domestic manufacturers or suppliers?

Mahjik

iTrader: (1)

http://www.rhdjapan.com/jdm-low/SP-T...D3S-RX-7-53538

s1mpsons

iTrader: (5)

Holy Crap! $1276.47!!!!! More expensive then I was expecting. If I buy these I am going to make a mold and get them produced and sold here.

Black91n/a

Those appear to be made from plate welded together rather than being a cast component.

ptrhahn

iTrader: (9)

This seems like something there'd be demand for... I'd be interested, but the strength concerns are a big deterent, especially at those prices.

It'd be nice to see an alternative that also addressed the flexing that causes brake pad knockback as well. THEN you'd really have something.